[Derrick Laming]

Hello

I have been trying to figure out this problem for months. I cant seem to get the GTM to start.

When I try to start the engine, it fires and dies. I took the fuel injectors out and tried starting it and the would pulse twice and then stop. I have spark and my fuel rail pressure is adequate. After the one fire the engine will just crank.

Background on the car

06 GTO LS2 engine
LS1/LS2 harness that I chopped and put back together.
98 pcm
the engine has a 24t reluctor
I have done everything that someone would do for an ls1 to ls2 swap.

When I run my OBDii, no codes appear. Not even expected codes. It does however show what my sensors read my no codes.

I double checked to make sure my injectors were all wired right.

I sent this computer to FFR twice to have the VATS removed so I am confident they have had it removed. :glare:

Tried new crank sensor and when I crank I get normal rpm on my OBDii reader.

Please help and ask any questions I will provide all the info.

 

[GTMKris]

The way that the injectors pulse and then quit consistanly still makes me think that its something turning them off. Maybe someone with more knowledge then me will chime in.

 

[Nitetrain]

This maybe obvious, but have you looked at the thread about wiring the ignition switch correctly. The FFR build manual is not correct.

Just incase you have not tried that yet. Your problem sounded a little like my first one.

After that, if you have a tuner that will let you do it, make sure the steering wheel lock is off.

Good luck

Dave

 

[Derrick Laming]

I ended up fixing that ignition problem recently. It caused me a lot of trouble. I havent found a tuner yet.

I dont know much about the steering wheel lock but I thought that with vats and assumed with that steering wheel lock that it would run for a few seconds before shutting off

this just fires once and dies

thanks for the replies.

I just need to find what would cause the fuel injectors to quit. its obviously a pcm communication that is causing them to stop

 

[Derrick Laming]

I figured I would ask this too.
I havent even touched these parts yet, but I dont see why I need them

http://www.factoryfive.com/table/ffrkits/GTM/images/donorparts/80%20Ignition%20switch.jpg

http://www.factoryfive.com/table/ffrkits/GTM/images/donorparts/81%20Ignition%20&%20lock%20cylinders%20with%202%20keys.jpg

maybe someone can tell me when I have to use these

 

[GTMKris]

I figured I would ask this too.
I havent even touched these parts yet, but I dont see why I need them

http://www.factoryfive.com/table/ffrkits/GTM/images/donorparts/80 Ignition switch.jpg

http://www.factoryfive.com/table/ff.../81 Ignition & lock cylinders with 2 keys.jpg

maybe someone can tell me when I have to use these

I dont know what the first part is. For the second, I used the Factory Five ignition that came with the kit.

 

[msteen]

I had a very similar problem and what I found was that when I pulled out the relay controlling the MAF Sensor, the motor would run, but backfire a lot. Supposedly this was due to an uncalibrated MAF, but when I got it back, the package had a new computer in it. Everything works now.

Murray

 

[Derrick Laming]

I just wish it would give me a code. I have nothing to work on except maybe a loose ground, but I checked all the grounds for the computer. It could maybe be VATS but I sent it to FFR twice to make sure it was off, Or if it was a toyota it could be that the igniter is not sending a signal back to the computer saying it fired.

wouldnt the MAF problem cause a code to read?

 

[claybags]

Just a thought...does the LS2 use a different ECM? I know the early 98-2000 ECM's for the LS1 wre improved after that.
FWIW Cheers, Jeff

 

[VD2021]

When I first tried to start my engine it fired but would not start. My problem was the G105 ground of the engine harness that I missed and did not ground.

 

[Derrick Laming]

Thanks VD2021 I will look for that ground immediately.

Yes the LS2 has a different ECM, I have that ecm but thought it would be easier to do everything for an LS1 engine and do an LS2 conversion.

I also heard of such trouble with the older PCMs but no one has ever given me exactly whats wrong with them

 

[Derrick Laming]

I am checking all the grounds. I hope that I missed one

 

[Ron565]

It sounds like the VATS is still operating. Have you disabled the VATS in your PCM?

Ron

 

[spytech]

Are you using a larger throttle body or intake manifold by chance?

I recall others had lots of problems with the 98 PCM - might be worth ebaying it and getting a 99-04 PCM instead just to avoid any of those issues.

 

[Derrick Laming]

I sent it to FFR and had them disable it and they sent it back.

I sent it to them again after i got it because i thought that it was the problem.

I would imagine one of those 2 times the disabled it. I have no way of knowing for sure

 

[Derrick Laming]

I have heard of people having issues of said year of this pcm but no one has told me what exactly was wrong with them.

I still have the ls2 ecm from the GTO but thought it would be easier this way.

 

[Derrick Laming]

oh and I am using the same manifold and throttle body that came with the GTO. I have read all the troubles you were having

 

[Derrick Laming]

spytech, I know that you put an ls2 in yours. How is the harness and computer setup? Did you use an LS2 ecm or an LS1 pcm? how did you do it?

I am still unable to start it

 

[squee]

This might sound obvious, but you DID repin the connectors, right? You can't use the 98 PCM with the newer wiring harness without repinning it. Usually, people go the other way, since the 98 PCM is far inferior to the 99+. The 98 is much more limited in the tuning aspect. Your tuner will thank you for using the 99+. I can almost guarantee that if you swap to a 99+ with the VATS turned off, it'll fire right up.

 

[VD2021]

When I first tried to start my engine it fired but would not start. My problem was the G105 ground of the engine harness that I missed and did not ground.

The way I tracked this down was by the fuel fuel pump relay not operating. Is your fuel pump coming on? If not pull the relay and use a few inches of wire to jumper from Pin 30 to Pin 87. This should power the fuel pump. If it does and was not coming on when you tried to start it, you've missed a ground.