Classic FAST Help Needed, will not start sporadically??

[BIGONTS]

I am having an intermittent problem with my car, 1987 GN. I just came out of nowhere this winter. Did not make any changes to the car or tune. For some reason, it shuts off after about 12.5 minutes of idling or driving and will not restart for some time after that, bout 10-20 minutes. I tried diagnosing it withy Cal and we narrowed it down to the box, we believe?? When it does not start, it shows rpm, has spark and fuel, and 12V at the injectors, but for some reason they are not firing, tested with NOID light. Cal suggested I reach out to Craig Smith to take a look at the box, but I can’t get a hold of him.

Does anyone have any thoughts on this or recommendations? I appreciate anyone’s input. Going to try a different ignition module as that might have something to do with it, right?

Thanks

 

[BIGONTS]

An update, the car will not start at all now? Perfect start to the summer

 

[pacecarta]

you could always send it in to FAST
fuelairspark.com

did you check the injector harness power feed wire for 12v

 

[BIGONTS]

you could always send it in to FAST
fuelairspark.com

did you check the injector harness power feed wire for 12v

Yes getting 12v. Will check again since its not starting at all now.

Not sure if fast services these old units anymore.

Thanks.

 

[pacecarta]

they do ,
friend just sent a classic sequential in that he bought off the board for a checkup because it would not run well at all on the car
turned out two inj drivers were bad , which they were able to repair (cheaply too ) as well as the O2 was dead

 

[BIGONTS]

they do ,
friend just sent a classic sequential in that he bought off the board for a checkup because it would not run well at all on the car
turned out two inj drivers were bad , which they were able to repair (cheaply too ) as well as the O2 was dead

That sounds great. For some reason I heard otherwise. I will give them a call once I'm 100% sure it's the box. Thanks

 

[BIGONTS]

Did the same test and same results, not start I sent the FAST box out to get it inspected. Hopefully it's something minor.

Quick question. Can I just plug in a stock computer and try to start it? I have 83's and have only a chip for 50lb injectors? I don't care how it runs and will not drive it, just want to confirm the injectors are/aren't firing. I don't smell gas out the pipes when cranking it?? Not sure what would happen with no mass air meter and the way the MAP sensor is spliced in. If so, would I do it after the harness or take the jumper harness out? Thanks.

 

[XXQUICK6XX]

I wouldn't try anything until you hear from fast. And see if they find anything wrong with it.

 

[BIGONTS]

NEVER MIND, PROBLEM CAME BACK!!!! Good news everyone. Got it figured out thanks to Steve XXQUICK6XX. He recommended trying the crank sensor and I had nothing to loose but about ten minutes of time. Must admit i was very sceptical. I had this old beat up crank sensor from a parts motor that I was not sure even worked. First crank and it fired right up and runs perfectly. The one I took out looked new??

About two weeks ago, I sent the box out to lance ward and the computer ran flawless with all the test he put it through. Got it back and it still didn't start. Got very frustrated.

Should I have seen some kind of code? Nobody else suggested the crank sensor. Thanks again.

 

[HighPSI]

I didn't suggest a crank sensor because you said the FAST showed rpm when it wouldn't start. The FAST gets it's rpm signal from the crank sensor. You also said you had spark, which meant the CCCI was seeing a crank signal. I have never seen a bad crank sensor that still sends a signal out If you're not going to use it, I would be interested in putting this sensor on a scope. Something just doesn't add up.

 

[BIGONTS]

I agree Cal. I do appreciate all your and everyone's help. I wouldn't thought of it because I was seeing rpm. Luckily I didn't throw it put or smash it with a hammer and will send it to you.

 

[BIGONTS]

Another update. My problem is back again. Same thing happening. Car dying and will not restart. I buttoned up everything I took apart previously and was going to go for a nice long cruise and it died about 5 blocks away from the house when it warmed up. Would not restart until about 10 minutes and I made it about 2 blocks further and dies. Would not start after that and had to tow it home.

I took it for a few longer drives around the neighborhood before this and it ran fine. The car runs awesome when it does?

After about 4 hours of sitting and before the tow, I tried starting it again. It started right up, idled for a few seconds and when I put it in drive it died out. Would not start again. Any ideas?

 

[norbs]

CCC module, they have a tendency to crap out after heat gets in them, or just plain intermittent. Sand the mounting bracket down where the bolts attach.

 

[BIGONTS]

CCC module, they have a tendency to crap out after heat gets in them, or just plain intermittent. Sand the mounting bracket down where the bolts attach.

Will do. Trying to get ahold of one to test. My lower intake and the bracket are powdercoated. Would that interfere with the ground?

 

[BIGONTS]

Here's a quick update. Had some time yesterday to try a known good module and coilpack. It would not start before the swap, or after . I tried turning the cam sensor 1/4" each way, TurboBuRick recommend this in one of this threads when swapping ignition modules?? BTW, here's a pic of my module. Looks pretty bad. Wires are melted into the thing, normal? Could this caused anything else to fail??

The nigh before, it started right up. I pulled it out and let it idle for 15+ minutes. I turned it off. About 2 hours later I tried to pull it back in, it started for about 2 seconds and shut off, would not start back up. Had to push it in.

Lance Ward tested the ECU and all the injector drivers are functioning as they should. I'm going to try to determine if the injectors are acutally firing. Any suggestions how to do this? Lance recommended the fuel pressure way. Build it up, disconnect pump, crank and see if FP is going down. Or get extra injector and watch is pulse while cranking??

Any other recommendations??

Thanks

 

[kidglok]

that module is shot

 

[Chuck Leeper]

Are you monitoring Fp while this is going on??

 

[BIGONTS]

Yes, FP is good. Stays around 40-43 when cranking.

 

[Chuck Leeper]

Yes, FP is good. Stays around 40-43 when cranking.

What happens when the engine starts to act up??
[I'm wondering if there's a pump issue when hot, or if the tank vent is insufficient, and after running it pulls a vac on the pump intake....]

 

[BIGONTS]

What happens when the engine starts to act up??
[I'm wondering if there's a pump issue when hot, or if the tank vent is insufficient, and after running it pulls a vac on the pump intake....]

It does not act up, just shut off. No signs of it coming. Actually, the car runs great. After it shuts off, it's still showing 40-43psi when cranking? It also primes when key on/off?