R34 GTT won’t start

[trel]

On 26/01/2022 at 6:03 AM, Bigpad said:

Well I bought a pink label MAF off a low mileage r33 spec 2. I’m told they’re the same? Plugged it in and started the car. It fired and ran just fine (I didn’t take it for a spin as it’s cold and dark and I haven’t done up all of the hose clamps or brackets). 
However, despite the car seemingly running fine all of the dash lights are still lit up. I won’t know how she runs for sure until the weekend but I’d really like to get those dash lights sorted? Any help or advice would be appreciated! 👍

 

Also….. Is this what I need:-

 
and then download the data scan 1 software?

thanks again. 👊

I have that same unit. Works very well with my laptop via USB running Windows 11.

[Bigpad]

Thanks. Just need to wait for it to arrive so I can give it a go. 

[Bigpad]

So I’ve taken the car for a bit of a drive. It starts and drives just fine. I still have the dash lights on so have bridges the two pins on the diagnostic port. I’m getting code 21 which from what I’m reading is suggesting a coil pack issue. I’ve obviously done the coil packs, spark plugs, MAF and CAS. That doesn’t rule these out of course but the fact that the car starts and runs fine suggests they’re all good. Bridging the pins further and shutting the car off has not gotten rid of the warning lights!

Any help/advice would be appreciated. 

[joshuaho96]

On 1/30/2022 at 5:51 AM, Bigpad said:

So I’ve taken the car for a bit of a drive. It starts and drives just fine. I still have the dash lights on so have bridges the two pins on the diagnostic port. I’m getting code 21 which from what I’m reading is suggesting a coil pack issue. I’ve obviously done the coil packs, spark plugs, MAF and CAS. That doesn’t rule these out of course but the fact that the car starts and runs fine suggests they’re all good. Bridging the pins further and shutting the car off has not gotten rid of the warning lights!

Any help/advice would be appreciated. 

Code 21 means the ECU isn’t seeing the right resistance on one of the coilpack primary side circuits. I got it once when my ignitor unit had a slightly loose connection. 

[Bigpad]

The R34 doesn’t have an igniter unit does it? 
could the issue by the coil pack harness? 

Edited January 31, 2022 by Bigpad

[Ben C34]

On 1/31/2022 at 10:02 PM, Bigpad said:

The R34 doesn’t have an igniter unit does it? 
could the issue by the coil pack harness? 

Correct and yes.

[joshuaho96]

On 1/31/2022 at 3:32 AM, Bigpad said:

The R34 doesn’t have an igniter unit does it? 
could the issue by the coil pack harness? 

R34s shouldn't, but the logic is the same. The ECU sees the primary side wiring from the ECU output all the way out to the coilpack pins and back to the ground point. If it sees open circuit it sets a code 21. Short circuit you would probably detect pretty rapidly regardless of whether the code is reported or not.

[GTSBoy]

On 2/1/2022 at 7:06 AM, joshuaho96 said:

The ECU sees the primary side wiring from the ECU output all the way out to the coilpack pins

That's true of the R34s, but only inasmuch as it is also true for engines with a separate igniter. The ECU is not actually connected to the coils at all, on any of them. It is connected to the igniter. So the ECU's diagnostics on the "primary side" is actually only to the transistor that is the igniter. True for both older separate igniters and for integrated igniters.

The ECU does not see the primary coil of the coilpack.

[joshuaho96]

On 1/31/2022 at 3:47 PM, GTSBoy said:

That's true of the R34s, but only inasmuch as it is also true for engines with a separate igniter. The ECU is not actually connected to the coils at all, on any of them. It is connected to the igniter. So the ECU's diagnostics on the "primary side" is actually only to the transistor that is the igniter. True for both older separate igniters and for integrated igniters.

The ECU does not see the primary coil of the coilpack.

Good to know, when I was thinking about this issue for a while I had a feeling that was the case but I checked all the connections from the PTU to the coils anyways. My circuits professors are probably shaking their heads right now.

[Bigpad]

So……

Ive been able to plug the car in but don’t really know what I’m doing. I was able to isolate each cylinder in turn and the car behaved as I would of expected. Reset the ecu via the laptop but all warning lights stay on. 

Ive now replaced the coil pack harness as I wanted to rule it out but still no joy. The car is running ok but it seems to have a ‘stutter’ every few seconds on tickover. 
 

Can anyone advise as to where I should be looking next? It’s really bugging me now. 
 

Thanks. 

[Duncan]

I think you've changed the spark plugs, coil packs and coil pack loom so far? Which coil packs did you install? Can you swap the best of your original coil packs in one by one and see if you can identify one of the new ones is not OK? Also, what plugs did you install?

Also, you've mentioned it has a miss at idle. How does it run for normal driving and at full throttle, is it smooth or does it still break down?

I'm assuming the issue is on the spark side since that is what you got from the ECU....but of course it could still turn out to be a fuel or timing issue

[joshuaho96]

On 3/1/2022 at 12:47 PM, Bigpad said:

So……

Ive been able to plug the car in but don’t really know what I’m doing. I was able to isolate each cylinder in turn and the car behaved as I would of expected. Reset the ecu via the laptop but all warning lights stay on. 

Ive now replaced the coil pack harness as I wanted to rule it out but still no joy. The car is running ok but it seems to have a ‘stutter’ every few seconds on tickover. 
 

Can anyone advise as to where I should be looking next? It’s really bugging me now. 
 

Thanks. 

When you say stutter every few seconds do you mean the idle dips and recovers? If so make sure you are 100% sure you can trust the provenance of your spark plugs. I have gotten counterfeit ebay spark plugs before and while it mostly drove normally I noticed that at idle it would stumble and then catch itself cyclically. I have no explanation as to why that happened but replacing the spark plugs with OEM plugs sourced from a trustworthy source the engine ran normally again.

Does the ECU report any codes when you check via the laptop? You're going to have to figure out whether the control module is actually reporting error codes that should cause the warning lights to turn on or if it's something wrong with the cluster/wiring harness.

[Bigpad]

I bought all the replacement parts from reputable companies here in the uk but you’re correct, that doesn’t rule them out as still faulty. 
 

does the ecu report any codes you ask? Hmmmm that might of been some valuable info to include. 🙈🙈

 

[joshuaho96]

I would start looking for line breaks in the cylinder 1 injector circuit. That's a pretty simple circuit to follow. It is very strange to me that your engine runs at all with that ignition circuit code, when I had it my car straight up would not crank over at all. It's possible that it will go away if you clear it but if it doesn't you probably shouldn't ignore it. The other mystery error codes are kind of concerning, not sure what's going on there. Could be a lot of things causing it.

[Bigpad]

Well the saga is over. I bit the bullet and bought some splitfire coilpacks. While I was fitting then I replaced the cold NGK plugs I’d fitted for ones recommended by a member on here. Started the car up, the dash lights are off and the stutter is gone. Thank f**k!

thanks to everyone who commented. I really appreciate the help. 

[niZmO_Man]

coilpacks... who would have guessed

[Duncan]

Thanks for closing the loop, that will help the next person