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My car is a 1988 RX7 GTU. It's N/A, and S4. All stock for the most part except for some deletes.
WARNING: LONG READ (WOULD APPRECIATE ANY HELP I CAN GET)!
Short version of story:
Took car around the block, died when I went wide open throttle at about 5k rpms (just flat out stopped making any power at all and didn't run, seemed like ignition or fuel was suddenly cut).
Detailed version of story:
The car has no exhaust, air pump, or rats nest for the most part. Seems it was all deleted in the laziest way possible.
I got the car for free from a dude who was getting out of the army who just dumped it on me. It didn't start but I changed out the battery and it ran after a good 15 seconds of cranking. Immediately changed the oil, premixed some fresh gasoline into it (was nearly empty) and I used 1oz per gallon of 2 stroke to start with. The mechanical OMP was not hooked up in the engine bay so I assumed it was broken, came to find out it seems to work. I'm using 10w30 full synthetic and I keep the OMP disabled and just premix 1oz per gallon.
That all being said it would start, rev to 3000 and then idle rough and die if I didn't hold it above 1500 rpms with the throttle for a couple minutes and then it would idle rough but stay running. It seemed to run fine though. The clutch slips under WOT a bit after first gear.
So last week I was driving home from work, I went on a little adventure and did a bunch of donuts and got on the highway right after, did about 80mph and arrived on Fort Bliss. I went to my barracks parking lot, let it idle for about 5 minutes and then turned it off. I talked for about 45 minutes with some friends and then started it back up, got going out of the parking lot and then gave it wide open throttle down the street and before it got to 5000rpm the engine cut out on me and wouldn't start again.
It has never had a problem hot starting even in 100 degree weather after driving around and pushing it hard for several hours at a time. I did a compression test and I'm getting 89 and 90 psi respectively for front and rear rotors. All the puffs sound even, and it isn't flooded.
The tachometer and voltmeter work in the dash. The speedometer, and oil pressure gauge do not work. The fuel gauge works but reaches "empty" when I am at half a tank roughly.
First I pulled plugs, they are not burnt and smell normal. I am getting spark to leading coils but it seems weak, cables have about 12k resistance. I got out the multimeter and tested the plug going to the leading coil, it was outputting about 3.44 - 4v or so when cranking the car.
So I am not sure if the fuel system is the culprit but the previous owner had just replaced the fuel pump just before I got the car, along with the filter. I unplugged the filter and turned the car on and it would pulse fuel out the line just before the filter and it looks clean.
The AFM is also a brand new part, and he had three old junkyard ones in the back for no reason. The exhaust is the headers, and nothing after from where the cats are supposed to be. That is it. Very loud.
I checked and it gets spark at the igniters, and to the end of the plugs, as well as the spark plugs when put into the connectors for the plugs.
Main relay clicks once when I turn key from off to on, all the fuses are good as well (both under the dash and in the engine bay).
So I got a set of known working coil and igniters, replaced both leading and trailing. Went for start and it acted like it got ignition and then instantly died again before even getting an idle.
I have not a clue as to what the problem could be, any insight would be helpful.
Sounds like you're off to a good start with the troubleshooting. As you know, you need fuel, ignition, and compression to run the engine, and sounds like you've already verified two of those three things, but if I read correctly you only verified fuel during cranking.
One of the things the AFM does is output a signal to latch the fuel pump after starting (when the flapper door is opened). The pump is enabled by the starter circuit during cranking, and then enabled by the AFM when running.
There is 2 pin a yellow "check" connector on the passenger side engine bay with a solid black and solid brown wire; you can jumper this connection to force the pump to run, as well as leave it jumped if you want to try that in an attempt to start the car. More scientific, you can also check the fuel pump is getting voltage and probe around the fuel pump relays. Do you know how to use a multimeter and do you know how to look up/interpret the schematics in the FSM?
Sounds like you're off to a good start with the troubleshooting. As you know, you need fuel, ignition, and compression to run the engine, and sounds like you've already verified two of those three things, but if I read correctly you only verified fuel during cranking.
One of the things the AFM does is output a signal to latch the fuel pump after starting (when the flapper door is opened). The pump is enabled by the starter circuit during cranking, and then enabled by the AFM when running.
There is 2 pin a yellow "check" connector on the passenger side engine bay with a solid black and solid brown wire; you can jumper this connection to force the pump to run, as well as leave it jumped if you want to try that in an attempt to start the car. More scientific, you can also check the fuel pump is getting voltage and probe around the fuel pump relays. Do you know how to use a multimeter and do you know how to look up/interpret the schematics in the FSM?
Yes I've been scouring the FSM's from Rotaryheads but I have not been focused on the fuel system admittedly. It seems to have fuel pulsating from the line leading to fuel filter under the car when cranking but I had not checked anywhere else. The injectors and whatnot should be fine and not sticking because it cut off when it was running I had assumed although that's not relevant to what you're asking me to do.
I'll do what you said about forcing the pump on with that jump and yes I have a multimeter, it's a basic cheap one from autozone. Voltage (AC/DC), Ohms, and some other basic stuff.
I did not get it to start after jumping the two pin connector (green I think it was) with the black and brown wires coming from it. I audibly heard the fuel pump kick on when I put the key in the on position this time though. Turned over but did not want to ignite or actually start.
-edit-
It seems to be the same as before, may have flooded engine again but I did de-flood before doing this with the fuel pump disconnected and the 15amp eng fuse pulled. So that wouldn't have been the issue I think unless it was severely flooded.
What concerns me is that I'm only getting like 3-4v at two pin plug that plugs into the main (leading) coil instead of 12v like the FSM suggests. It does not say what to do if it is not getting 12v, it just says "ensure it is getting 12v"
Are you talking about the thick black/yellow wire? That is the supply wire, and that would be a problem. Where are you grounding your probe for reference? Also that should be a sealed connector IIRC, so ensure you are making solid contact with the pin.
As you know from looking at the FSM, that circuit is fused by fuse 4, and goes through the main relay. I would start by checking B/Y at the main relay and see if you already have the voltage drop. If not, there is a junction by the firewall (you will need to unwrap the harness bundle and you will find a factory splice wrapped in blue tape around the B/Y wire. Check to ensure that isn't damaged or corroded.
Also for grins unplug the condenser which will have the same color wire and be nearby with a 1 pin connector (I think it's just a few inches from the splice).
Are you talking about the thick black/yellow wire? That is the supply wire, and that would be a problem. Where are you grounding your probe for reference? Also that should be a sealed connector IIRC, so ensure you are making solid contact with the pin.
As you know from looking at the FSM, that circuit is fused by fuse 4, and goes through the main relay. I would start by checking B/Y at the main relay and see if you already have the voltage drop. If not, there is a junction by the firewall (you will need to unwrap the harness bundle and you will find a factory splice wrapped in blue tape around the B/Y wire. Check to ensure that isn't damaged or corroded.
(snipped the pic out)
Also for grins unplug the condenser which will have the same color wire and be nearby with a 1 pin connector (I think it's just a few inches from the splice).
I'm getting 3-4v at the yellow / green wire when cranking, 12.24v at the black and yellow wire. I ground it on the strut shock tower. I re-read the FSM and checked the correct wires this time. I think it should be 5v at the Y/G though but it's not. It's around 3.44v and maybe (almost) 4v at some points when cranking.
Resistance in the plug wires is about 10k as well, they say it should be 12k but I can't see less resistance as being a bad thing.
-edit-
Going to check power to the Y/G wire further back and see if it at any point loses voltage or meets some resistance.
No loss of power from main relay to coil, B/Y gets 12.24v, Y/G gets around 3-4v intermittently when cranking. Fuel pump is audibly running when key is in on due to the jumper. Air filter is clean and car was running and then just shut off. No clue what to look for since I have fuel, air, and spark. It's not extremely flooded by any means and I have deflooded it several times and not had any luck getting it to start.
Did some more simple diagnostics. There is fuel reaching the fuel rail, and it is pressurized. Not sure how to check the injectors themselves.
I pulled the plugs and put them back in the cables. Set them on the shock tower and all four plugs are getting spark.
The air flow meter is relatively new (to me) and doesn't look dirty or anything.
Could it be the crank angle sensor? I re-checked all my fuses once more and none are blown.
I'm getting 3-4v at the yellow / green wire when cranking, 12.24v at the black and yellow wire. I ground it on the strut shock tower. I re-read the FSM and checked the correct wires this time. I think it should be 5v at the Y/G though but it's not. It's around 3.44v and maybe (almost) 4v at some points when cranking.
Resistance in the plug wires is about 10k as well, they say it should be 12k but I can't see less resistance as being a bad thing.
-edit-
Going to check power to the Y/G wire further back and see if it at any point loses voltage or meets some resistance.
No loss of power from main relay to coil, B/Y gets 12.24v, Y/G gets around 3-4v intermittently when cranking. Fuel pump is audibly running when key is in on due to the jumper. Air filter is clean and car was running and then just shut off. No clue what to look for since I have fuel, air, and spark. It's not extremely flooded by any means and I have deflooded it several times and not had any luck getting it to start.
Pretty confident the injectors will not fire if there is no CAS signal. Do you have an oscope by chance? If not, you could probably see the injectors firing with an LED (current limited with the appropriate resistor of course). Or do it the simple way and physically remove the injectors and watch them spray fuel.
Pretty confident the injectors will not fire if there is no CAS signal. Do you have an oscope by chance? If not, you could probably see the injectors firing with an LED (current limited with the appropriate resistor of course). Or do it the simple way and physically remove the injectors and watch them spray fuel.
If I'm getting spark, and the fuel pump is on, and fuel is going to the rail.. I assume the injectors aren't firing or the timing is off maybe? The car stopped running when I gave it WOT and it reached like 5k rpms would this be able to even cause that issue?
I do not have an oscilloscope or an LED, nor do I have a ride or someone who can take me to go get any of this at the moment. Miles from any auto parts stores or places that sell stuff like that because I'm on base at the moment.
Is there another way to check the injectors without removing them? I don't even know how to do that but I guess I can scour the FSM a bit and find out.
If I'm getting spark, and the fuel pump is on, and fuel is going to the rail.. I assume the injectors aren't firing or the timing is off maybe? The car stopped running when I gave it WOT and it reached like 5k rpms would this be able to even cause that issue?
I do not have an oscilloscope or an LED, nor do I have a ride or someone who can take me to go get any of this at the moment. Miles from any auto parts stores or places that sell stuff like that because I'm on base at the moment.
Is there another way to check the injectors without removing them? I don't even know how to do that but I guess I can scour the FSM a bit and find out.
The only other thing I can practically think of doing is to listen to each injector with a stethoscope (or a makeshift one). This wont tell you if fuel is physically spraying out, but it will tell you the injectors are firing.
UIM removal is typically considered very involved for a first timer, but if you're mechanically inclined it should not be something to fear if you wanted to physically remove/inspect the injectors.
I am curious about what's going on. It sounds like there's been some sort of mechanical failure that caused your sudden issue. As you know, these cars love to rev, so a trip to 5k rpm in and of itself should not have killed the car .
In regards to your question about timing, is your CAS (crank angle sensor) secured? In case you didn't know, the timing is adjusted by rotating the CAS, much like rotating a distributor on a piston engine. You could always try to re-"stab" the CAS; this is the term used for removing, aligning, and reinstall. That search term will bring up a bunch of pictures and tips. It basically involved aligning two marks on the CAS and installing very carefully (it moves easily).
The only other thing I can practically think of doing is to listen to each injector with a stethoscope (or a makeshift one). This wont tell you if fuel is physically spraying out, but it will tell you the injectors are firing.
UIM removal is typically considered very involved for a first timer, but if you're mechanically inclined it should not be something to fear if you wanted to physically remove/inspect the injectors.
I am curious about what's going on. It sounds like there's been some sort of mechanical failure that caused your sudden issue. As you know, these cars love to rev, so a trip to 5k rpm in and of itself should not have killed the car .
In regards to your question about timing, is your CAS (crank angle sensor) secured? In case you didn't know, the timing is adjusted by rotating the CAS, much like rotating a distributor on a piston engine. You could always try to re-"stab" the CAS; this is the term used for removing, aligning, and reinstall. That search term will bring up a bunch of pictures and tips. It basically involved aligning two marks on the CAS and installing very carefully (it moves easily).
I'm trying to figure out how to align the gears in the CAS itself after pulling it out, I found the red and yellow notches on the pulley and lined them up. Not understanding how to line the CAS up before putting it back in and whatnot. It seemed to be pretty solid in place before removal and the gear doesn't look worn or anything at the very bottom.
I'm trying to figure out how to align the gears in the CAS itself after pulling it out, I found the red and yellow notches on the pulley and lined them up. Not understanding how to line the CAS up before putting it back in and whatnot. It seemed to be pretty solid in place before removal and the gear doesn't look worn or anything at the very bottom.
there is a mark on the body that aligns with a mark on the gear. It can be hard to see:
there is a mark on the body that aligns with a mark on the gear. It can be hard to see:
Sweet! I found it, but the oil made it hard to see. When I install it I just turn until the pointers match up top?
Also, I managed to break the stud off that you use to tighten the CAS down. Any easy solution to this? I have no welder, and there isn't enough left on there to fit two nuts. Can I tighten it down some other way once in position? Any ideas?
Sweet! I found it, but the oil made it hard to see. When I install it I just turn until the pointers match up top?
Also, I managed to break the stud off that you use to tighten the CAS down. Any easy solution to this? I have no welder, and there isn't enough left on there to fit two nuts. Can I tighten it down some other way once in position? Any ideas?
I can try one of those but it's gonna be a pain in the ***. Just need something to hold it in place so I got a bolt that fits and a nut and I can screw it into the spot if I get it out, if not, I can put it in the slot and hold it in place from just outside the place the other bolt threads in.
It came off, luckily, with a vice grips. Picked up the same size bolt from Autozone / Oreilly's and I'm good to go. May be back with more issues, let's find out.
I just checked the diagnostic box because I previously thought it used the dash lights to indicate errors but read up further on that now. All it's showing is 3 flashes and then nothing for 2 seconds in DCC1. I guess this means it's saying the water thermo sensor is bad?
I don't know if it's relevant but I had an incident where the car "stuttered" like fuel was cut and then after I let off the throttle it was back a couple of times randomly when trying to do a donut or similar. Not sure what would cause that but it happened once or twice in about 1000 miles of driving and doing burnouts / donuts in parking lots or whatever.
I don't know if it's relevant but I had an incident where the car "stuttered" like fuel was cut and then after I let off the throttle it was back a couple of times randomly when trying to do a donut or similar. Not sure what would cause that but it happened once or twice in about 1000 miles of driving and doing burnouts / donuts in parking lots or whatever.
sounds like fuel slosh. Happens pretty easily in these cars with a partial tank.
Try and start it two or three times. Take the trailing plug out -Is it wet? If you're getting fuel it should be soaked.
It seems to not be getting fuel. I ran it close to dry the day it happened I think and I put 5 gallons in right after it happened (I keep a 5 gallon jug) and still wouldn't start. I didn't think I ran it out of gas but I'm starting to think that is possible. I doubt that would kill a brand new fuel pump would it?
It would idle like this on a cold start and smooth out just a bit when warm, not sure if this sounds abnormal or not. Some people say it sounds rough, others say it's fine.
05-30-20, 12:43 AM
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