Hi,
I have a 1989 GTA (all stock) 350 auto. A couple of months ago I was having some problems re-starting it while hot and the only way I could do so was to ground the A & B terminals while cranking and it would fire up???. The symptoms were identical to a flooded carb and having to hold your foor all the way down on the pedal to get it going.

After about 2 weeks of that intermittent problem the fuel pump gave out on me while driving it while I was diagnosing it using TTS ALDL software. At the time it died the fuel mix was maxed lean 160, and everything else was normal.

After I changed the fuel pump I could once again hear it building pressure like it was supposed to and I also checked the pressure at the fuel rail (approx. 45 and holding). Car would not start. I have a factory shop manual and performed all the troubleshooting tests, and it basically said replace ECM.

I put a different ECM into the car, and also a different hypertech chip (I bought it off eBay to fit my '89). After I swapped the computer, the car started and ran fine for about 8 seconds, then died.

The only way I can get it started now is to pour some fuel directly into the intake, put the rubber boot back on, and it will start up and run strong for about 2 seconds, then die.

I checked an injector with a noid light and it light up but does not appear to flash. I also had the coil checked at the parts store and it checked out ok.

I have VATS, but the security light goes of after a couple of seconds.

I thought that I might have burned out a relay or something while I was initially diagnosing the fuel pump. I have since replaced the distributor, new fuel pump relay, O2 sensor 3 mos old, fuel filter 6 mos old, battery brand new, new GM Ignition cylinder a few mos old.

I need some ideas from anyone who has had a similar experience with their TPI.

I have had a lot of GM Camaro's & Firebird's over the years and this is the first time I have ever been stumped?

I have also spent a few days reading posts on groups, and every time I find anything remotely similar, the person with the original problem never leaves a final post with their solution??

All I can figure out is that their must be some sort of stuck relay or solenoid that is affecting the ECM's injector driver circuits (If they were not already burned out (twice?))

Another possibility I keep hearing about is the fuel regulator causing a no-start? If the regulator was bad, and my pressure was constant would this even be a possibility?

Also, could the ESC module be at fault on the firewall. I would assume that it is still good since the car will run after manually adding fuel?

Could something as simple as a coolant temp sensor cause a no-start?...or possibly a bad TPS(voltage checks out ok though)

Any help would be appreciated.

Thanks?!?

Jeff

 

Do you have a stck GM L98 EPROM module you can plug into the ECM? The HyperScrap PROM introduces too many variables and wildcards to be able to diagnose the problem effectively. It might even be an LB9 PROM.

Since you have the cable and software, what are the injector pulse widths while cranking?

 

Hi,

I am not reading any injector pulse width while cranking

I probably need to switch the prom back to a stock L98, and I contacted "GMPartsDirect.com", and a new one was fairly reaonable. ($45). I just hate to pay the $ and have it immediately burn out.

I have considered buying a chip burner and getting a "Craig Moates" adapter + some flash chips , so I can hopefully keep it running long enough to diagnose what might be causing the glitch, wiithout paying a fortune for a bunch of new proms just to troubleshoot.

Do you think the chip burner idea is ok?

From what I understand, the injector driver circuits are on the prom, not the ECM...is this accurate?

Could I actually be shorting out my ECM by having a short, or would it only affect the chip?

I appreciate the help.

Thanks,

Jeff

 

No injector pulses while cranking... TPS showing Wide open (to the ECM) Injector fuses blown, no refrence pulse to the ECM from the distributor (possible wiring problem there).
I would suspect the hypercrap chip as being at fault.

Getting a Prom burner and chips would be a good idea..especially if you plan on modding the engine in the future. But you'll still need a stock Calpack (the item you were going to order from GM) to hook to Craig's adaptor, I wouldn't trust the hyperjunk calpack at this point.

 

I spent the whole day (re) doing electrical checks on my 89 GTA that won't start. Everything checked out fine except for I found an injector that had almost no resistance... #3 had .8 ohms!

the other 3 on the bank had 16.1,13.2, and 12.5

the other bank had 16.2,16.4,16.1,16.1


I actually got the car to run a couple of weeks ago after changing the computer and the Memcal at the same time. The car ran great for about 8 seconds, then died. I can now only get it to fire briefly after I pour gas directly in the plenum.

My question is:

Could the very low resistance injector cause the original ECM to go bad, and could it cause the second one to short out in less than 10 seconds? I understand the injector driver circuits are somewhat (fragile?)

I have ALDL + TTS. Unfortunately I was not taking readings when I changed the to the second ECM. I currently do not get any injector pulse width.


I have spark, TPS fine, Coolant sensor ok, O2 sensor new, I have dist ref pulse to the ECM, fuel pressure ok, new fuel pump, new distributer, new fp relay, maf diagnostics and MAF relays check ok, and yes...I checked all the fuses.


If anyone has any help or suggestions, I would appreciate it.

Thanks,

Jeff

 

I can't believe it was so simple. I read Vaders advice to try to start the car with the one bad injector disconnected (I first reset the ECM) , and the car started right up (a little rough on 7)...unbelievable. The car has been sidelined for 2 months now.

Vader,

Thanks again!