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-   -   Rtek TPS Issue, Car starts, then breaks up ~10 seconds in (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/rtek-tps-issue-car-starts-then-breaks-up-%7E10-seconds-1066105/)

RevinRx7 06-20-14 07:26 PM

Rtek TPS Issue, Car starts, then breaks up ~10 seconds in
 
So I am confused.

The problem as it stands now is that my car idled steady, and the TPS read accurate on the Rtek 2.1 AND had an AFR of ~13, but I found one of the injectors was leaking. I then fixed the leak, and now the Rtek 2.1 ONLY reads 74% regardless of TPS position and an error is reported on the "Error" screen in the form of "TPS: Narrow Band" AND the AFR stumbles from 15.5 to 20.

Now for how I got here:
This winter I installed a:
FMIC,
what I thought was 850cc Hi impedence injectors,
Rtek 2.1,
Wideband O2 (replacing the original O2 wire with a Simulate Narrow Band from it at the ECU),
Profec A Boost Controller,
Hybrid Turbo

Before all this my car ran fine and and idled flawlessly.
So when I installed my Rtek, I found that my TPS was idling at 70%. This prompted me to calibrate my TPS. I verified that there were no dead spots in the travel and set it to 20%.

From here when I would turn the car over it would start and sound as if it were to idle normally. Then around 10 seconds in, the car noticeably bogs and starts running super lean ( I should mention the 850cc inj were set to the proper 720/720 setting in the Rtek here, however I pulled about 5% fuel in vacuum under 2k RPM since they were so large).
Through process of elimination I found out that the injectors I had purchased were HIGH impedance and chose to modify an extra resistor pack I had laying around and removed the resistance so the ECU would see the appropriate impedance.

No change in how the car ran.

Then I swapped back to the stock ECU to determine if I had a bad ECU. Car still would not start with the 850cc's in. So then by process of elimination I put the stock injectors back in, and added the resistor pack back in. Walaa!! The car started and ran significantly better. To be sure, I place the Rtek back in and it ran just the same as the stock ECU. There fore I surmised that it must be the used injectors I bought. As I looked up the PN's on the side I found that they read 195500-1370 on the side, but had no keying feature anywhere to be found. This seems to tell me these are only 550cc High Imp???
WHATEVER

So now I'm back to the Rtek, get it warmed up a little and it decides to idle. TPS reads accurate etc. In fact here's what it was doing:

This is when I noticed my fuel injector spewing fuel on the top of the motor. Obviously shut it off immediately and "fixed" the problem. After re-checking this about 4 times I was satisfied that I had sealed the injector holes up properly ( when inserting the injectors ALL the way into the fuel rails, the bottom grommet was loose on the injector ports on 3 of 4 injectors. (seals are still soft too)

Car is still doing the same thing where it starts idles fine for ~10 seconds then breaks up, but now I can't get past 2k RPM. The more throttle I give, the more it breaks up. This is when I checked the Info coming from the Rtek again. My TPS is stuck at 74%.

I went to re-calibrate the TPS and found that resistance across A-B is 1.3k ohms ( I'm embarrassed to say I pushed the TPS the wrong way and got .3k ohms I'll need to recheck that later)
The voltage from pin A to ground is 0, pin B to ground is .25-.27 (again actuating full range the wrong way), and pin C is 4.84.

I'm so lost at this point. When logging multiple parameters, I couldn't see any one event that I could link this too.
I really need some fresh eyes on this.

Craze8 06-21-14 01:15 AM

If the ecu is seeing a weird reading for the tps and you know the tps is good. Do a resistance measurement on the wires from the tps to the ecu. Wiggle the wires as well, my bet is you will find your issue there.

RevinRx7 06-22-14 09:19 PM

I checked the signal wiring (GR) from the TPS plug to the ecu, 0 ohms.
Tested the the wiring at the ATP sensor as well, since they share a common voltage/ ground.
BrB 0 Ohm 0 V
BrW 150 Ohm 4.84V
BW 390 Ohm 11.73 V
GY Infin Ohm 4.37V

Resistances were taken with car off.
I rechecked the TPS, idle is at 1.3 kOhms and WOT is about 6.9 kOhms.
Certainly out of spec, but I'm still confused as to why this happened all of a sudden.

Car still will not maintain idle.

Craze8 06-22-14 09:46 PM

Manufacturers say simply only a 1.0 resistance increase over each connection on a circuit. So if there are no connections in the circuit you shouldn't see anymore then 1 ohm between the tps plug and the ecu with nothing connected at all.

As for the tps going bad? Its a plunger and they do develop dead spots. Thats why on newwer cars they use a sensor that sweeps instead of plunges in and out.

barkz 06-22-14 10:01 PM

have you flipped the rtek to one of the 550/x presets? were both having idle issues at the 720 preset but mine will idle perfect on either of the 550/x

RevinRx7 06-22-14 10:07 PM

Thing is, it doesn't have dead spots, its only out of range by a good 1K.

As I stated before (I think) The Rtek sees the 74% TPS signal even with the TPS unplugged from the harness. Which is leading me to believe its a bad ECU now...

RevinRx7 06-22-14 10:08 PM


Originally Posted by barkz (Post 11756924)
have you flipped the rtek to one of the 550/x presets? were both having idle issues at the 720 preset but mine will idle perfect on either of the 550/x

Yeah, I reset it to 550/550 when I swapped the injectors back. Have the right resistor pack too.

barkz 06-22-14 10:13 PM

but can you get it to idle with the 850's while on the 550 preset? it looks like others have this issue too and have just tuned from the 550/x preset with a larger injector

RevinRx7 06-22-14 10:21 PM


Originally Posted by barkz (Post 11756934)
but can you get it to idle with the 850's while on the 550 preset? it looks like others have this issue too and have just tuned from the 550/x preset with a larger injector

I see what you're saying. I'll give that a look tomorrow,

barkz 06-22-14 10:28 PM

it works for me. granted this is just idle, i have yet to drive it/get the secondaries to kick on. im assuming ill be able to get it tuned from the 550/720 setting. what i really need is my own dyno lol

RevinRx7 06-23-14 11:55 PM

Found my problem, now the cause
 
Well after searching around, I decided the only place left to check was the ECU. Sure enough I blew a trace on 2R. Now I just have to figure out why.
https://scontent-b-dfw.xx.fbcdn.net/...75915077_n.jpg
https://fbcdn-sphotos-g-a.akamaihd.n...77183779_n.jpg

What I don't understand is that it looks like someone failed with a soldering iron on the 334K100 capacitor there. Well on both of them. I wonder if turbo2ltr could tell me if they are around those during modification???

Then some more over heating/ garbage soldering??? on the back of the board. I can't tell
https://fbcdn-sphotos-h-a.akamaihd.n...50174309_n.jpg

Anyways, the resistor with the blown traces just happens to be on the 2R Pin which is the ground pin that is attached to most of the engine sensors.
Now I just have to figure out what could be causing such a large load to go through that circuit. The grounding to the engine is clean??? I don't get it.
https://www.rx7club.com/attachments/...x7-na-ecu2-jpg

RevinRx7 06-24-14 08:51 AM

So after thinking that I had found the issue, I had the board X-rayed to see if the traces were still intact. They are. The resistor still reads 4 Ohms like the rest of them do. and I have negligible resistance from the top of the diode all the way to PIN R on the header.

So without power, that part of the ECU checks out.
My next step is to try and figure out why the ECU still sees 74% with/without the TPS sensor plugged in.

BACK TO SQUARE ONE!!

satch 06-24-14 09:28 AM

How about backstabbing the TPS plug with another ground to see if this improves the sensor's reading.

RevinRx7 06-27-14 06:06 PM

I ended up back stabbing the TPS connector for voltage and then again at the ECU. The voltages matched.
I cleaned up some grounds under the coils and moved a ground I had for my boost controller and O2 sensor off the ECU, plugged it in and Walla it started.

The timing still seems a bit rough under 2k. I may have to look into modifying that.
Also in other news, my car spikes to 14 psi really quickly. Hope my motor held together...


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