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vortec 96 problem

2K views 7 replies 2 participants last post by  '45 Ford 
#1 ·
Hallo ,I'am driving a 96 astro awd,a few months ago i did a v8 swap.The v8 i put on was a rebuild one with L31 64cc heads with 1.94"I/1.50"E valves and a com cams extreme energy 268XE cam.
On this engine i put a 96 vortecinjection included pcm and all parts of a 96 pick-up.From in the beginning i had problems with cilinder 8 getting all the time fuel,so i checked the pcm and injector and wiring,the problem seems to be in the pcm it grounded cil.8 so it gets all the time fuel.I tried two other pcm's with the same result always cil 8 no good.To could drive the van i connected the pcm output for cil 1 together with cil 8,the timing is not perfect but i drive(not very good).Here in Belgium there's nobody who could help me with this problem(not enough expirience with this newer engine's).I had to change also the timecover in a cover of a 96 with a crankschaftsensor ,i was getting always a P1345 code on it,i think i solve this problem with setting the distributer a thoot in advance.So are there some gm techniciens who have expirience with this problem and will explain it to me.
Thanks on advance
 
#3 ·
Against my better judgement I'll try to help you. I am a GM tech. and am familiar with this system.

I won't even bother to ask why in the world did you put a V8 in your Astro.

First, you say the #8 is getting fuel at all times. Is that to say the injector is spraying fuel into the cylnder at all times? Is it hydro-locking the engine? Do you have a wiring diagram that you can work with me on? It sounds to me like the #8 injector control wire is grounded somewhere. It's not likely that the PCM is grounding it all the time.

Try this, remove the #8 injector control wire DR-BLU/WHT wire from the PCM and run the engine. Is #8 still fuel fouling? If not, disconnect the injector connector on top of the engine and check for continuity to ground on that wire. You should have NO continuity, if you do. Look for the grounded wire.

As for P1345, you've got the dist out of time with the crank. You'll need a scanner to adjust that properly and then clear the code.

Let me know what you find.
 
#4 ·
Thanks for the reply.I have checking out the wires for a triple time , i even replace the 8 wires for each cilinder.It's the pcm who's giving the signal,because if i connect injector 8 together with the pcm's outlet for cil 1 the injector do his job,if i measure the pcm outlet for cil 8 (- at connector 5 of C2 red and + at batery +)i become 13.8 volts all the time. with the engine running and not running.It's now the third pcm i tried and they give all the same grounding cil8 so i think there schould be a reason why?
So i hope you see what i mean it's not in the wiring of the injectors,i checked all the wires of the pcm by diagram and couldn't find anything diffrent.
Thanks
 
#5 ·
You mentioned checking terminal #5 @ the C2 (red) PCM connector. I might be looking at a manual mistake, but I'm showing #8 injector drive circuit being @#5 terminal of the C1 (blue) connnector. It should be a DK-Blu/Wht wire.

All injectors recieved B+ voltage on the Pnk wires @ the injector housing connector. You can remove the top of that connector to access the termianls. Remove it, connect a test light to B+ and touch the test light to the #8 wire with the engine running. It SHOULD not be on all the time. It should blink. Does it? If it's lite all the time and you've made sure the wire has NO continuity to ground, the PCM must be bad.

Good luck
 
#6 ·
Hallo thanks for the advice,tomorow i check the wire on possition 5 @ the blue connector.I hope your wiringdiagram is the right one because on my diagram there is no wire on 5 @ blue.Maybe if i get result with connecting the dk/blue wire on blue it schould be fine when you mail me your diagram ,so i can check all the wires again on your diagram.The diagram i use is also mailed to me it has a gm code(1w84 1w85 1w86 1w87) i 'm not schore if this is the right one.If i get result i let you now.
Thanks
 
#7 ·
A thousand Thanks you are rigth(like always i think)youre diagram is the rigth one ,my diagram i'm gonna use to put the wood on fire .By the way are there diffrences between the oxygensensors of a V8 and aV6(i'm getting no code for this just want to check)??
Thanks again:thumbup:
 
#8 ·
Am I to assume you got it running on all 8 cylnders now?

No, there is no difference between H02 sensors for a V8 vs V6. There is a difference between the sensors that go before and after the converter though.

Glad to have been of some assistance to you.
 
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