Ok so I have swapped in a 96 Roadmaster LT1 and the PCM I am using is a 95 Fbody M6 Flash. I have a t-5 behind the motor (no comment).

Anyways. Here is what was removed from PCM and a list of what sensors I have left.

PCM items Removed
VATS
AIR
A/C
EVAP
CAGS
EGR

Sensors left
Both O2's
TPS
IAC
IAT
Opti
Coil
ICM
ECT
VSS
Alternator
MAP
Knock
MAF

I don't have the fans hooked up, and one of the O2's doesn't have it's bung welded up yet.

Am I missing anything that could cause the injectors not to fire.

I had the PCM scanned and it showed the PCM firing the injectors. And I have 12V to the injectors on the pink wire.

I can test fire the injectors straight from the battery. and the car will start and idle for 1-2 secs and then die. (using up test fired fuel).

I am suspect of grounding issues, but is there anything else that can cause this problem?

I get good clean blue/white spark. just no injectors. Fuel pump primes and runs correctly as well.

Any Help will be GREATLY Appreciated.

 

Judging from what you've gone over, I think you've got the answer, you just need to find it. Grounds. If the PCM is showing that it's firing them, and they've got 12V, I would definitely be thinking grounds at that point.

 

Ya, that's what I have suspected. Also I have been going over the Diagrams on Shbox, and from what it shows and what I have it appears that I have sensor grounds tied into my PCM grounds, now I would assume (because I don't know wiring very well) that that could be a problem, but on the safe side I plan to run the 4 PCM grounds and tie them off how it shows in the diagrams and tie off the Sensor grounds as they show it.

 

That would probably be the best way to go about it.

A thought: It could be just one bad ground connection. Have you tried going back through everything and cleaning the ground area and seeing what happens??

 

not yet, I plan to gring off paint and use Dielectric gel to help.

 

The injectors could be physically stuck if the engine has been sitting for a while. That's what happened to mine.

Also, I hope you changed the knock sensor in the block with an OBDI one if you're using a 95 PCM and 95 flash.

 

KS was changed and the injectors, I have all "test" fired with wires from the batt and 7 out of 8 work. I have the #4 injector unplgged as it doesn't fire, but all 8 show 12 ohms resistance

 

when i did my swap i had a simular problem. I just had a brain fart. The 12v source i used for the injectors was not constent while cranking. That meant no juice. It took me a week to figure that out because i was working solo. Hope that helps.

 

that is interesting, I will have to check into that one as well. Should be no harm in constant 12V power when key on, just don't want constant 12V all the time. Course that is what it should have anyways. But another thing to check.

So Grounds and 12V constant while cranking.

But was your harness mutilated? mine I pulled myself from the donor car and only cut the wires far inside the car.

 

Ok rewired abit and results are the same but I have new information.

Here is what I did (I followed the 95 Fbody diagrams on Shbox.com)

4 PCM Grounds tied together and straight to the coil stud

O2 MAF and ICM straight to the coil stud.

IAT and MAP wired together and to B16

IAC TPS and ECT wired together and to B6


I put 12V from the battery to where the two injector fuses are tested and 12V was on the injector wires, I pulled one of the pins of an injector from the PCM clip and grounded it and I didn't get the injector to fire. it made sparks but would not fire.

I find this odd that I can use wires off the batt and it fires but if I use the existing wires and try to get it to fire it won't.

if there is any +V going into the ground from anywhere can this cause enough to stop the injectors from firing?

My next step is to ground the PCM to the ground point on the block that is share by the -B Term. and to replace all the injector wires and tie them into bundles of 4 use inline fuses and tie them directly into the Pink Ignition 12V wire.

Can anyone offer some insight into this!!!!

 

I still question if something is up with the injectors themselves.

They did run around baking in a Propane situation for who knows how long.

Possibly they will pull the pintles with a direct 12 volt source and a direct ground but the resistance through the PCM drivers will not pass enough current to run them.

" put 12V from the battery to where the two injector fuses are tested and 12V was on the injector wires, I pulled one of the pins of an injector from the PCM clip and grounded it and I didn't get the injector to fire. it made sparks but would not fire."

That kind of supports this theory

Maybe buy a set of O rings and steal the injectors out of the RM to try.

Your PCM runs in my car with "A25" pulled so I can't see it being VATS

 

Ill be "borrowing" some injectors out of the RM this weekend, but I did try another way of powering the injectors and didn't get good results.

So far, if I power them direct from the batt they open and "fire" but I used the existing wiring, and pulled one of the pins from the PCM and grounded it, and the injector didn't fire. I checked 12V from the injector plug from the fuse box and so on. And it did ground (couple little sparks when you rub it on metal) but no firing? Ill post results this weekend when I try the other injectors.