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Re: 90 Indy starts and stalls immediately

Posted: Sat Sep 16, 2017 11:57 am
by AeraBell
I'm having the same problem with my 91 gt.. how do I test the injectors? It's the 3.1l

Re: 90 Indy starts and stalls immediately

Posted: Tue Sep 19, 2017 10:03 am
by ifixalot
You have to put an ohm meter across the terminals of each injector. It should read about 11-12 ohms.
I'm not sure if there is a harness that you can disconnect but then you'd need a pin-out for the harness.
On the 3.1, I think you need to pull the upper plenum to get at the injectors.

Re: 90 Indy starts and stalls immediately

Posted: Tue Sep 19, 2017 6:52 pm
by GT_Indy
3X00-Modified wrote:One injector can kill a whole bank on MPFI... I know it made it nearly impossible for my Indy to run with a bad one.


I believe its also supposed to shut off the injectors if an injector coil goes bad.

Re: 90 Indy starts and stalls immediately

Posted: Wed Sep 20, 2017 10:40 am
by 3X00-Modified
It's not "supposed" to do that, it's just the fact that they are wired in only two banks/circuits front and rear the injectors are in parallel on each bank. So if one goes bad then the whole bank is compromised, resistance on the whole thing changes. SFI engines have a individual circuit for each injector so if one goes bad then it only kills that one circuit, not the whole bank.

Re: 90 Indy starts and stalls immediately

Posted: Wed Sep 20, 2017 11:22 pm
by GT_Indy
Yah I remember seeing the wiring diagram, 2 banks each bank has 3 injectors together.
I have to look in the book again, I remembered reading somewhere a long time ago that the ecm checks the injectors resistance by looking at the voltage/current somehow and disables the drivers to prevent damage to the ecm/engine. I also remember pulling the plug off 1 injector on a working set and the engine wouldn't get any fuel on any cylinder by doing that. It was an 88 beretta gt, 2.8 auto, like 15 ish years ago.