I hope some one can help or provide some information

Real quick, 1991 L98 Car stalled and would not restart. over the next 3 days would start and drive randomly. Now just will not start at all, Turns over and will catch for a second then immediately dies.

I followed all of the diags listed in the starting sequence. I checked fuel pressure 44+, Pump is working and holding pressure, replaced TBS, MAP sensors. Wanted to wait on FI replacement till I got the car running.
Since I just bought the car and do not have a good mechanic yet, I took it into the Chevy dealer.

Here is there diagnosis so far.

Basically they diagnosed a bad PCM, injectors had 12v on both wires, they repalced the PCM and car started and fried PCM again. They claim I have #2 & #3 injector that are shorted out and this is what fried the PCM. replaced #2&3 FI and car started now another shorted injector?

Do you have an opinion as to what would casue the FIs to short? I find it hard to belive that 3 FIs all short out by themselves at the same time. something else must be casuing the FIs to short right? Also, is it normal for a shorted FI to fry the PCM?

I am not a mechanic but I did by the FSM and can work on the mechanical stuff, I just could not diagnose the electrical issues I am now into

Now they want to replace all 8 FIs for $1700. I told them I wanted after markets put in cause 1700 is way too much. other wise I will just have it towed home and I can put a new PCM and FIs in it for less than $1700. They are gonhg to call me in the morning and see what they can do on the price!

Just was wondering if you have any thoughts on if they are correct or what else may be casuing the no start condition or if it is rational that a FI would fry the PCM?

 

First of all, the PCM did not come on the seen till 94. 93 and earlier used the ECM. I believe the injectors in those years around 91 measured 12 ohms. They should at least be tested to see if they are anywhere near correct. Usually the lower resistance will cause poor injector performance. Also, if they checked shorted what is the value? But more so, those injectors in those years that go bad, the resistance usually goes down with time. I have heard that many on the Forum had defective injectors but never heard of the injectors shorting out the ECM. The ECM basically closes the ground circuit or the low side or the injector coil thus completing the circuit causing the injector to spray. I would think if there was a short of some sort, it would take out the fuse on the supply side (+12) of the injector coil.

If two or three injectors have low resistance and does not measure the same as the others, then all should be replaced. Many have said the engine runs a whole lot better.

But it seems like your whole root cause of your problem might be missed according to your information. Do they know what part of the ECM is going defective? Has anyone ever used a noid light the check injector pulse. Ever checked for spark? Under normal circumstances its hard to believe the injectors are causing the ECM to go bad, but all I know is what I can read. Maybe you need a second opinion.

 

When 3 Of My Injectors Went Bad I Replaced Them All With Accels And They Screwed My Computer Up When They Went Bad But Not Totaly Just My Instant Average And Miles To Empty Is Goin Berserk But Fuel Injectors Can Definitly Fry The Cpu U Should Have Replace All 8 Injectors The First Time

 

PCM ECM VCM THEY'RE ALL THE SAME WITH DIFFERENT NAMES

 

The ECM became the PCM (powertrain control module) with the electronic control of the 4L60E trans. There is a difference.

 

Pc Is Right About The Resistance Droping And That They Should Be 13.7 Ohms Or Close To It And I Have Not Seen One Shorted Yet My Self Have Seen Them Open Though

 

I Dont Use Them. AND YES THERE IS A DIFFERENCE BUT YOU KNOW WHAT THE GUY IS TALKIN ABOUT WHEN HE SAYS PCM ECM WHATEVER

 

And get that caps lock repaired.

 

Replace the injectors yourself-it is not that hard. There are fuses for the injectors they should burn up before your ECM does. If your injectors are shorted out that's why your car won't run (high current condition exists - but not high enough to pop the fuses) your bad injectors require more current to open them than the ECM's ground switching pulses can provide. This condition shouldn't burn up the ECM unless you have multiple problems. Replace all the injectors at once then if the ECM are still burning up look for another problem.

Good luck!