I've exhausted my knowledge and I need your help
#1
I've exhausted my knowledge and I need your help
To give you guys an update, I've been at this latest problem for well over a month and I just cannot seem to figure it out. All important back story before I post video.
Over the past few months, my tuner has struggled to get my idle under control. Sometimes it would be perfect, idling right at 1000 rpm. Turn the car on the next day, I'd have to keep the car alive for the first couple minutes from a cold start because it wanted to idle somewhere in the 600/700 range and it would die (engine is street ported). After a few minutes, idle would stick to 1000 rpm....until we start driving. During stops (stop signs, stop lights, etc), it would dip to roughly 800 and jump to 1000..back and forth, back and forth. So I'm reading through the forum and come across numerous threads about adjusting the throttle body. Hell yea, I'm gna fix this. Then...it left me stranded on the side of the road. I was driving along per usual...maybe 35 mph, nothing crazy. Radio goes out first, dash lights next, then the engine, and it will not start. Friend gives me a jump and we head back home. So I'm thinking alternator.
Couple of weeks go by and I get my refurbished alternator back from IR Performance. Everything looks good, sounds good, and runs good. Send tuner the logs from a drive and everything looks stable from his perspective. The very next day I get ready to go for a drive, the car won't idle correctly again. As it warms up, the idle stays around 900-1000 rpm. So I hop in and go for a drive.
-At first, maybe 2 miles down the road, the idle starts to pulsate. Its significantly worse than before...1000-3000-1000-3000...so on and so forth.
- I get on the highway another mile or 2 down the road to come around town and head back home. Take it thru the rev range. Its driving excellent, pulling harder than a mule under WOT...but I get a red light. I downshift to 3rd and I thought I accidentally rev matched. Problem is, I typically don't rev match in traffic. Shift the car from 3rd to neutral....idle is 3000 rpm. Put it in 2nd, car begins to engine break like it normally would. Back to neutral...3000 rpm. Great.
-Heres the icing on the cake. I get off the highway and I'm getting closer to my house. Speed limit is 35. Coming to a stop again with car in neutral...3000 rpm. However this time, I put it in 2nd AND THE CAR IS ACCELERATING TO 3000 rpm!! I nearly smash into the back of a minivan because it caught me off guard. So now no matter what gear I'm in, car wants to be at or above 3000 rpm...even in neutral.
I get the car back to my garage (thank God I didn't hit anything or drive thru the wall) and the car still wants to idle at 3000 rpm. Cut it off and start looking for anything on the throttle body that looks out of the ordinary. Cable isn't sticking, throttle cable mechanism is in working order, gas pedal is working as normal. I'm baffled. Plug up my computer and this is what I see. Keep in mind, car is not running...key is just in the on position
https://www.youtube.com/watch?v=rX_v...ature=youtu.be
I've added grounds, I've cleaned grounds, got a new TPS and I cannot figure this out to save my life. The worst (and probably most important) part about it is even while looking at the screen of the video above, I would unplug a connection and nothing would change. What could possible cause that?
Your help will be MUCH appreciated. If I'm missing any important details, please let me know. Thanks.
Over the past few months, my tuner has struggled to get my idle under control. Sometimes it would be perfect, idling right at 1000 rpm. Turn the car on the next day, I'd have to keep the car alive for the first couple minutes from a cold start because it wanted to idle somewhere in the 600/700 range and it would die (engine is street ported). After a few minutes, idle would stick to 1000 rpm....until we start driving. During stops (stop signs, stop lights, etc), it would dip to roughly 800 and jump to 1000..back and forth, back and forth. So I'm reading through the forum and come across numerous threads about adjusting the throttle body. Hell yea, I'm gna fix this. Then...it left me stranded on the side of the road. I was driving along per usual...maybe 35 mph, nothing crazy. Radio goes out first, dash lights next, then the engine, and it will not start. Friend gives me a jump and we head back home. So I'm thinking alternator.
Couple of weeks go by and I get my refurbished alternator back from IR Performance. Everything looks good, sounds good, and runs good. Send tuner the logs from a drive and everything looks stable from his perspective. The very next day I get ready to go for a drive, the car won't idle correctly again. As it warms up, the idle stays around 900-1000 rpm. So I hop in and go for a drive.
-At first, maybe 2 miles down the road, the idle starts to pulsate. Its significantly worse than before...1000-3000-1000-3000...so on and so forth.
- I get on the highway another mile or 2 down the road to come around town and head back home. Take it thru the rev range. Its driving excellent, pulling harder than a mule under WOT...but I get a red light. I downshift to 3rd and I thought I accidentally rev matched. Problem is, I typically don't rev match in traffic. Shift the car from 3rd to neutral....idle is 3000 rpm. Put it in 2nd, car begins to engine break like it normally would. Back to neutral...3000 rpm. Great.
-Heres the icing on the cake. I get off the highway and I'm getting closer to my house. Speed limit is 35. Coming to a stop again with car in neutral...3000 rpm. However this time, I put it in 2nd AND THE CAR IS ACCELERATING TO 3000 rpm!! I nearly smash into the back of a minivan because it caught me off guard. So now no matter what gear I'm in, car wants to be at or above 3000 rpm...even in neutral.
I get the car back to my garage (thank God I didn't hit anything or drive thru the wall) and the car still wants to idle at 3000 rpm. Cut it off and start looking for anything on the throttle body that looks out of the ordinary. Cable isn't sticking, throttle cable mechanism is in working order, gas pedal is working as normal. I'm baffled. Plug up my computer and this is what I see. Keep in mind, car is not running...key is just in the on position
https://www.youtube.com/watch?v=rX_v...ature=youtu.be
I've added grounds, I've cleaned grounds, got a new TPS and I cannot figure this out to save my life. The worst (and probably most important) part about it is even while looking at the screen of the video above, I would unplug a connection and nothing would change. What could possible cause that?
Your help will be MUCH appreciated. If I'm missing any important details, please let me know. Thanks.
#3
Rotorhead for life
iTrader: (4)
It was hard to see the specifics in the video, but I gather you're running an aftermarket ECU with a DBW throttle, correct? What kind on both counts, and what are you using for the accelerator position sensor (APS) and how is that mounted?
I'm running a Link G4+ ECU with a GM DBW throttle body, and RX8 accel pedal, and with that setup if anything goes out of whack electrically (e.g. the 2x TPS sensors don't track close enough, your DBW PID tuning is jacked up, etc.) the Link's safety fail safe logic will put the DBW into a limp home mode - it won't rev beyond ~1500RPM and it will buck like crazy when you try to give it gas. I'd assume whatever ECU you're running has similar safety fail safes, so my best guess is there's a mechanical issue with the APS - perhaps it came loose and is hanging up mechanically instead of returning to an idle/zero throttle position?
I'm running a Link G4+ ECU with a GM DBW throttle body, and RX8 accel pedal, and with that setup if anything goes out of whack electrically (e.g. the 2x TPS sensors don't track close enough, your DBW PID tuning is jacked up, etc.) the Link's safety fail safe logic will put the DBW into a limp home mode - it won't rev beyond ~1500RPM and it will buck like crazy when you try to give it gas. I'd assume whatever ECU you're running has similar safety fail safes, so my best guess is there's a mechanical issue with the APS - perhaps it came loose and is hanging up mechanically instead of returning to an idle/zero throttle position?
#4
rotorhead
iTrader: (3)
He said it's a mechanical throttle. What ECU is this? The only way it can idle at 3000rpm on a mechanical throttle is the throttle valve sticking open (dashpot or fast idle cam for example), idle air control valve duty too high, or throttle cable/cruise control issue. That's assuming no vacuum leaks. You should be able to take logs and look at TPS voltage and idle air control duty cycle to see what's going on. Spark timing can affect it too of course.
#7
RX-7 Bad Ass
iTrader: (55)
Read this -
https://www.rx7club.com/3rd-generati...ncing-1147118/
If you have a high idle, especially 3000 RPM, there's air getting into the engine that shouldn't be. Period. Either the throttle is stuck open or there's a hole of some kind letting in air between the throttle plates and engine. It's not a ground, it's not an electrical thing, it's air. Idle is set by the air you give the engine.
Start with that and track that down. That could also have been something that was going out for a while (like a block off plate coming loose) and that was causing the idle weirdness.
Dale
https://www.rx7club.com/3rd-generati...ncing-1147118/
If you have a high idle, especially 3000 RPM, there's air getting into the engine that shouldn't be. Period. Either the throttle is stuck open or there's a hole of some kind letting in air between the throttle plates and engine. It's not a ground, it's not an electrical thing, it's air. Idle is set by the air you give the engine.
Start with that and track that down. That could also have been something that was going out for a while (like a block off plate coming loose) and that was causing the idle weirdness.
Dale
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gracer7-rx7 (03-02-21)
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#8
Racecar - Formula 2000
I had a minor issue with the secondary throttle plates sticking causing a hesitation during light-throttle acceleration. It was caused partially by carbon buildup in the throttle bores. So it occurs to me that since your issue is intermittent, you may be having a similar, but more serious version of the same problem. Intake manifold temperature changes and thermal expansion, etc., could either relieve or exacerbate the issue.
So I would check to make sure it isn't sticking slightly open - it wouldn't take much to cause a 3K-RPM idle, and might not be immediately apparent on inspection. The 1st thing I'd look at while it's doing it is whether the secondary throttle stop is in firm contact with the lever that is attached to the secondary throttle plates.
So I would check to make sure it isn't sticking slightly open - it wouldn't take much to cause a 3K-RPM idle, and might not be immediately apparent on inspection. The 1st thing I'd look at while it's doing it is whether the secondary throttle stop is in firm contact with the lever that is attached to the secondary throttle plates.
Last edited by DaveW; 02-26-21 at 10:57 AM.
#9
RX-7 Bad Ass
iTrader: (55)
One solid test on the TB is to remove it from the car and shine a light behind it. If you see light around the throttle plates, they aren't totally closed.
The fast idle cam will hold the throttle plates open, you do have to manually kick that down to close them. Also I have seen cases where someone removed that cam and the linkage was still there and jammed up/got stuck and kept the TB open.
Dale
The fast idle cam will hold the throttle plates open, you do have to manually kick that down to close them. Also I have seen cases where someone removed that cam and the linkage was still there and jammed up/got stuck and kept the TB open.
Dale
#10
rotorhead
iTrader: (3)
With key on, engine off, record a datalog. Look at TPS raw voltage if you can. while taking data, go under the hood and move the throttle plates as well as the fast idle cam (it can be rotated away with your finger). if you see that the TPS voltage is decreasing when you physically try to close the throttle plates more, then it's possible you are sticking under normal circumstances. I've seen the physical dashpot on the throttlebody stick and not close smoothly.
#11
Thanks for everyone who responded. Today I made sure to update my Haltech ESP to the latest version, update the Haltech 1500 firmware to the latest version, and in doing so I wanted to disconnect everything from the UIM and TB to show you all what issue I'm having. Note: car is not running, key is in the on position. Video posted below, then I'll start individually responding to your replys. Thanks again.
#12
If you have a high idle, especially 3000 RPM, there's air getting into the engine that shouldn't be. Period. Either the throttle is stuck open or there's a hole of some kind letting in air between the throttle plates and engine. It's not a ground, it's not an electrical thing, it's air. Idle is set by the air you give the engine.
Dale
Dale
What ECU is this? The only way it can idle at 3000rpm on a mechanical throttle is the throttle valve sticking open (dashpot or fast idle cam for example), idle air control valve duty too high, or throttle cable/cruise control issue. That's assuming no vacuum leaks. You should be able to take logs and look at TPS voltage and idle air control duty cycle to see what's going on.
With key on, engine off, record a datalog. Look at TPS raw voltage if you can. while taking data, go under the hood and move the throttle plates as well as the fast idle cam (it can be rotated away with your finger). if you see that the TPS voltage is decreasing when you physically try to close the throttle plates more, then it's possible you are sticking under normal circumstances. I've seen the physical dashpot on the throttlebody stick and not close smoothly.
#13
I've had similar issues with setting up my 1500. If you disconnect the IAC valve while your idle is up there does it drop? If so there's your culprit. Take it out, give it a clean and see if that helps. I'm suspect of mine sticking open or closed. The other thing to play around with is the frequency setting on the haltech for the IAC.
As for the voltages moving around, could be a noisy earth signal to the ECU?
As for the voltages moving around, could be a noisy earth signal to the ECU?
#14
~17 MPG
iTrader: (2)
I wouldn't worry about those voltage fluctuations, it looks like the reading in your second video is between 0.135V to 0.138V which is probably less than 1% throttle position. I wouldn't expect to see that reading with the sensor disconnected, but I'm not familiar with Haltech input circuits.
Assuming this is not a simple vacuum leak, my next steps would be the following:
1. Learn how to configure your ECU's datalogging, so you can record the throttle sensor raw voltage, idle duty cycle (final result including any idle feedback settings), engine speed, battery volts, MAP, CLT, and IAT. In case there is a harness problem, watching for jumps or spikes in the IAT/CLT signals can help troubleshoot and identify some problems (CLT/MAP/TPS/IAT are likely to share the same sensor ground wire, but only MAP/TPS are likely to share the same sensor 5V supply wire).
2. Double-check the throttle sensor by connecting the throttle sensor and taking another video while slowly sweeping from full closed to full open with the engine off. Get familiar with viewing the ECU datalogs so you can watch to make sure the trace is 'smooth' without weird jerks or steps or jumps. If you press the throttle three times while datalogging, you should see three smooth 'bumps' in the throttle sensor reading.
3. Once you have datalogging working, connect all the sensors and then record a datalog while you tap/shake/bump the harness wires near each sensor and near the ECU. Watch the datalogs to see if any of the signal readings change.
4. If you don't find anything when shaking the harness, drive the car while datalogging and try to capture a log of the problem happening. Of have a passenger record a video of the laptop screen while the problem happens and hope the camera is pointed at the relevant readings.
5. Might not be related, but the ECU's indicated BattVolt value was 11.7V near the end of the video. Check with a multimeter to see how closely this matches your actual battery voltage. I would charge the car's battery if it's actually lower than 12.2V when sitting, if you don't already have a trickle charger it's worth getting.
Assuming this is not a simple vacuum leak, my next steps would be the following:
1. Learn how to configure your ECU's datalogging, so you can record the throttle sensor raw voltage, idle duty cycle (final result including any idle feedback settings), engine speed, battery volts, MAP, CLT, and IAT. In case there is a harness problem, watching for jumps or spikes in the IAT/CLT signals can help troubleshoot and identify some problems (CLT/MAP/TPS/IAT are likely to share the same sensor ground wire, but only MAP/TPS are likely to share the same sensor 5V supply wire).
2. Double-check the throttle sensor by connecting the throttle sensor and taking another video while slowly sweeping from full closed to full open with the engine off. Get familiar with viewing the ECU datalogs so you can watch to make sure the trace is 'smooth' without weird jerks or steps or jumps. If you press the throttle three times while datalogging, you should see three smooth 'bumps' in the throttle sensor reading.
3. Once you have datalogging working, connect all the sensors and then record a datalog while you tap/shake/bump the harness wires near each sensor and near the ECU. Watch the datalogs to see if any of the signal readings change.
4. If you don't find anything when shaking the harness, drive the car while datalogging and try to capture a log of the problem happening. Of have a passenger record a video of the laptop screen while the problem happens and hope the camera is pointed at the relevant readings.
5. Might not be related, but the ECU's indicated BattVolt value was 11.7V near the end of the video. Check with a multimeter to see how closely this matches your actual battery voltage. I would charge the car's battery if it's actually lower than 12.2V when sitting, if you don't already have a trickle charger it's worth getting.
#15
RX-7 Bad Ass
iTrader: (55)
If the TB is cracked open slightly and you calibrate the TPS for that position you'll have weird things happen. When the TPS reports the throttle body is closed it HAS to be totally closed.
Dale
Dale
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Manny_Apex (03-02-21)
#16
Juris Doctor
iTrader: (3)
I'd recommend as many have, that you should check your throttle plates and check for any vacuum leaks. It is always easier to check for the mechanical issues first then move on to the electrical.
You should next recalibrate your TPS sensor. There is a step-by-step calibration in the Mazda FSM.
When I first took delivery of my RX-7 it was having idle and backfire issues. Immediately recognized it as being a TPS issue and once I had the PowerFC installed, I recalibrated the TPS. All the problems went away.
You should next recalibrate your TPS sensor. There is a step-by-step calibration in the Mazda FSM.
When I first took delivery of my RX-7 it was having idle and backfire issues. Immediately recognized it as being a TPS issue and once I had the PowerFC installed, I recalibrated the TPS. All the problems went away.
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Manny_Apex (03-02-21)
#17
rotorhead
iTrader: (3)
You're just on the learning curve for how ECU tuning works. You basically got thrown into the deep end. This isn't a modern car with a stage 1 reflash/"chip" tune.
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Manny_Apex (03-02-21)
#18
Rocket Appliances
iTrader: (11)
I'm the tuner here.
This has been an odd one. A good number of months ago I remotely tuned the car and it was cranking/cruising/boosting all cleanly and consistently across the entire range. Fast forward a month and it starts having this odd issue where the idle wanted to stumble, but only during warmup. I revisited all the settings and tuned it back to stable several times through modification of the ISC settings, however with time it would always seem to revert back to the stumbling after some time and THEN on the same file it started having the issue where the idle would 'hang' high.
To me, it isn't an issue with the ISC as that valve simply doesn't flow enough to push it to a 3000 rpm idle even at full flow given the normal no-isc active idle is right at 1000 rpms. I've thought that there has to be something in the mechanical throttle linkage that is sticking OR a massive vacuum leak somewhere.
Skeese
This has been an odd one. A good number of months ago I remotely tuned the car and it was cranking/cruising/boosting all cleanly and consistently across the entire range. Fast forward a month and it starts having this odd issue where the idle wanted to stumble, but only during warmup. I revisited all the settings and tuned it back to stable several times through modification of the ISC settings, however with time it would always seem to revert back to the stumbling after some time and THEN on the same file it started having the issue where the idle would 'hang' high.
To me, it isn't an issue with the ISC as that valve simply doesn't flow enough to push it to a 3000 rpm idle even at full flow given the normal no-isc active idle is right at 1000 rpms. I've thought that there has to be something in the mechanical throttle linkage that is sticking OR a massive vacuum leak somewhere.
Skeese
#20
~17 MPG
iTrader: (2)
I re-watched your video today, and it almost looks like your car still has the factory thermowax / fast idle cam. If you've still got that installed, it's basically a variable throttle stop depending on the coolant temperature of that thermowax valve. Learning how to use the ECU datalogs would help catch this, the calculated throttle position should be about 4-10% higher when the thermowax is cold. If you accidentally calibrated the ECU's throttle sensor when the thermowax valve was cold, the measured throttle position might do weird things when the engine is warm and you're pressing the throttle very gently.
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Manny_Apex (03-02-21)
#21
Update:
I thank all of you for your input. I took the TB off once again to reset everything to make sure there was nothing mechanically wrong with the TB itself and to confirm that my TPS is aligned correctly. We're about to take another stab at it so we'll be back with you momentarily.
I thank all of you for your input. I took the TB off once again to reset everything to make sure there was nothing mechanically wrong with the TB itself and to confirm that my TPS is aligned correctly. We're about to take another stab at it so we'll be back with you momentarily.
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Manny_Apex (03-02-21)
#23
So we had an interesting break today that ultimately led me back to square one...but pointed me in the right direction.
So I called Skeese on Facetime earlier and we narrowed it down to an electrical issue.
First I tried starting the car to get some logging data...wouldn't start. Last time I tried it, it started but it was really rough, so somehow I've gone backwards. Called Skeese and we tried to figure out what was happening when he suddenly had a eureka moment. So to rewind a few months, this past summer I pinned the WBO2 gauge into a male connector to plug into the female WBO2 connector off the wire harness. After looking over my wiring allocation, Skeese discovered the voltages didn't match up. So with the key still in the on position, I unplugged the connector and boom....everything stabilized. So we came up with a game plan, decided to de-pin the ground, relocate it to a chassis ground, plug the connector in and see if that fixes it.
Thought we'd found the problem? Wrong again. After I hung up the phone and de-pinned the ground, relocating it to a chassis ground I tried again. Turn the key on and everything started going haywire again. TPS is fluctuating between 0-100, just like in the videos. Voltages are going crazy across the board for all of my sensors...BUT...something I remembered from our conversation, Skeese mentioned that all of the sensors that were going haywire were sharing a common ground...the ECU ground. The only issue I'm having now is now that the ECU ground and WBO2 are not sharing a common ground, shouldn't one or the other be more stable? I know this is hard to fathom without seeing the issue in person for you guys, but can some of you point in the direction of your aftermarket grounding setups? Since this problem has reared its ugly head, I've added approximately 4 chassis grounds in hopes they would resolve my situation and this has not been the case. Should I remove them all and start from scratch? What do you guys think?
So I called Skeese on Facetime earlier and we narrowed it down to an electrical issue.
First I tried starting the car to get some logging data...wouldn't start. Last time I tried it, it started but it was really rough, so somehow I've gone backwards. Called Skeese and we tried to figure out what was happening when he suddenly had a eureka moment. So to rewind a few months, this past summer I pinned the WBO2 gauge into a male connector to plug into the female WBO2 connector off the wire harness. After looking over my wiring allocation, Skeese discovered the voltages didn't match up. So with the key still in the on position, I unplugged the connector and boom....everything stabilized. So we came up with a game plan, decided to de-pin the ground, relocate it to a chassis ground, plug the connector in and see if that fixes it.
Thought we'd found the problem? Wrong again. After I hung up the phone and de-pinned the ground, relocating it to a chassis ground I tried again. Turn the key on and everything started going haywire again. TPS is fluctuating between 0-100, just like in the videos. Voltages are going crazy across the board for all of my sensors...BUT...something I remembered from our conversation, Skeese mentioned that all of the sensors that were going haywire were sharing a common ground...the ECU ground. The only issue I'm having now is now that the ECU ground and WBO2 are not sharing a common ground, shouldn't one or the other be more stable? I know this is hard to fathom without seeing the issue in person for you guys, but can some of you point in the direction of your aftermarket grounding setups? Since this problem has reared its ugly head, I've added approximately 4 chassis grounds in hopes they would resolve my situation and this has not been the case. Should I remove them all and start from scratch? What do you guys think?
#24
I wouldn't worry about those voltage fluctuations, it looks like the reading in your second video is between 0.135V to 0.138V which is probably less than 1% throttle position. I wouldn't expect to see that reading with the sensor disconnected, but I'm not familiar with Haltech input circuits.
Assuming this is not a simple vacuum leak, my next steps would be the following:
1. Learn how to configure your ECU's datalogging, so you can record the throttle sensor raw voltage, idle duty cycle (final result including any idle feedback settings), engine speed, battery volts, MAP, CLT, and IAT. In case there is a harness problem, watching for jumps or spikes in the IAT/CLT signals can help troubleshoot and identify some problems (CLT/MAP/TPS/IAT are likely to share the same sensor ground wire, but only MAP/TPS are likely to share the same sensor 5V supply wire).
2. Double-check the throttle sensor by connecting the throttle sensor and taking another video while slowly sweeping from full closed to full open with the engine off. Get familiar with viewing the ECU datalogs so you can watch to make sure the trace is 'smooth' without weird jerks or steps or jumps. If you press the throttle three times while datalogging, you should see three smooth 'bumps' in the throttle sensor reading.
3. Once you have datalogging working, connect all the sensors and then record a datalog while you tap/shake/bump the harness wires near each sensor and near the ECU. Watch the datalogs to see if any of the signal readings change.
4. If you don't find anything when shaking the harness, drive the car while datalogging and try to capture a log of the problem happening. Of have a passenger record a video of the laptop screen while the problem happens and hope the camera is pointed at the relevant readings.
5. Might not be related, but the ECU's indicated BattVolt value was 11.7V near the end of the video. Check with a multimeter to see how closely this matches your actual battery voltage. I would charge the car's battery if it's actually lower than 12.2V when sitting, if you don't already have a trickle charger it's worth getting.
Assuming this is not a simple vacuum leak, my next steps would be the following:
1. Learn how to configure your ECU's datalogging, so you can record the throttle sensor raw voltage, idle duty cycle (final result including any idle feedback settings), engine speed, battery volts, MAP, CLT, and IAT. In case there is a harness problem, watching for jumps or spikes in the IAT/CLT signals can help troubleshoot and identify some problems (CLT/MAP/TPS/IAT are likely to share the same sensor ground wire, but only MAP/TPS are likely to share the same sensor 5V supply wire).
2. Double-check the throttle sensor by connecting the throttle sensor and taking another video while slowly sweeping from full closed to full open with the engine off. Get familiar with viewing the ECU datalogs so you can watch to make sure the trace is 'smooth' without weird jerks or steps or jumps. If you press the throttle three times while datalogging, you should see three smooth 'bumps' in the throttle sensor reading.
3. Once you have datalogging working, connect all the sensors and then record a datalog while you tap/shake/bump the harness wires near each sensor and near the ECU. Watch the datalogs to see if any of the signal readings change.
4. If you don't find anything when shaking the harness, drive the car while datalogging and try to capture a log of the problem happening. Of have a passenger record a video of the laptop screen while the problem happens and hope the camera is pointed at the relevant readings.
5. Might not be related, but the ECU's indicated BattVolt value was 11.7V near the end of the video. Check with a multimeter to see how closely this matches your actual battery voltage. I would charge the car's battery if it's actually lower than 12.2V when sitting, if you don't already have a trickle charger it's worth getting.
1. I've done that already under the guidance of Skeese. I've gained a significant amount of knowledge regarding the configurations of the ECU. Now I haven't gotten into the tuning aspect of it all just yet because I feel as though the rotary is too delicate for a novice like myself to toy around with, but one day when the car is running fine, I will.
2 & 3. So I'm not sure if I've already mentioned this, but my TPS is brand new. The problem is every time I calibrate the TPS, the voltage values on 0 and 100% change. One time they might both be .02, and this last time they were both 0. However I like your idea of shaking the harness around near various sensors and the ECU. I'll have a friend come over this weekend and give me a hand with that.
4.If only I could get her to start.
I'd recommend as many have, that you should check your throttle plates and check for any vacuum leaks. It is always easier to check for the mechanical issues first then move on to the electrical.
You should next recalibrate your TPS sensor. There is a step-by-step calibration in the Mazda FSM.
When I first took delivery of my RX-7 it was having idle and backfire issues. Immediately recognized it as being a TPS issue and once I had the PowerFC installed, I recalibrated the TPS. All the problems went away.
You should next recalibrate your TPS sensor. There is a step-by-step calibration in the Mazda FSM.
When I first took delivery of my RX-7 it was having idle and backfire issues. Immediately recognized it as being a TPS issue and once I had the PowerFC installed, I recalibrated the TPS. All the problems went away.
What you are seeing is normal electrical noise. A tiny voltage fluctuation like that is not indicating a problem. Now there may still be something going on, but from the video, I don't see any obvious electrical issue.
You're just on the learning curve for how ECU tuning works. You basically got thrown into the deep end. This isn't a modern car with a stage 1 reflash/"chip" tune.
You're just on the learning curve for how ECU tuning works. You basically got thrown into the deep end. This isn't a modern car with a stage 1 reflash/"chip" tune.
I re-watched your video today, and it almost looks like your car still has the factory thermowax / fast idle cam. If you've still got that installed, it's basically a variable throttle stop depending on the coolant temperature of that thermowax valve. Learning how to use the ECU datalogs would help catch this, the calculated throttle position should be about 4-10% higher when the thermowax is cold. If you accidentally calibrated the ECU's throttle sensor when the thermowax valve was cold, the measured throttle position might do weird things when the engine is warm and you're pressing the throttle very gently.
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Manny_Apex (03-02-21)