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No start 95 S

Do you have voltage at the solenoid? If so it may be too low due to a high resistance connection. I recall another member had the wiring harness completely burn up under the intake. At this point you are checking the pins at the ECM to make sure the ECM is ok by eliminating wiring problems. Voltage test at solenoid and then following the wiring diagram check voltage at ECM connector. Fix any resistance or opens between the two points by any means necessary including running a new wire clear back to the ECM.

Again the thread pitch of the solenoid is the same as a kitchen faucet aerator.
 
WarWagon said:
Do you have voltage at the solenoid?
Click to expand...

Have 12.? at the solenoid.

WarWagon said:
At this point you are checking the pins at the ECM to make sure the ECM is ok by eliminating wiring problems. Voltage test at solenoid and then following the wiring diagram check voltage at ECM connector. Fix any resistance or opens between the two points by any means necessary including running a new wire clear back to the ECM.
Click to expand...

I'm assuming I should check pins C16 and D15 dkblu/white where the enter the ECM.
How would you suggest checking resistance? The distance between the 2 ends is well over the length of my multimeter cables.
 
Back probe the Fuel Shutoff Solenoid wiring connector on the solenoid side to make sure you have voltage through the connector. It's possible that the connector is bad. As far as the ECM goes, use some 18ga stranded wire to extend your leads.
 
Sounds like you have a wire problem on the ground side going back to the ECM . If the wire from the ignition switch has one wire in the strand , it will still read good and have 12 volts but not be able to carry the current . Did it throw any codes after you ran it ?
 
Just checked the wiring diagram in Mitchell again.
It shows the wire coming from the fuel shutoff solenoid splitting and going to C16 and D15.
Also states the split occurs ( Eng Harness, apprx 11cm from I/P harness breakout)

Is the IP harness breakout the big plug or where it goes through the firewall?
 
The IP harness goes underneath the intake manifold to the big plug that attaches to the FFM bracket.
Would you think the breakout would be ~11cm from the plug, 11cm from where the plug wires branch from the main bundle, or 11cm from where they go through the firewall?

I'm trying to minimize the amount of wire loom I tear into.
 
There is only 1 bk blu/white wire into plug and there is power there. There is no power on 1 line after the split so the bad spot is between where the junction of the 2 dk blu/white wires and PCM.
 
Glad you got that far. Hopefully you figure out the rest and somebody with more knowledge on the wiring chimes in.

At least it will run now

Depending on the overall condition of your harness, I would get a new harness and swap it.

When I have been installing new harnesses, I run them outside the intake on the right side as I was advised to do several years ago.

All of my harnesses have been a little worse for wear.

I would also add the extra grounds - if you haven't - especially the ground from the heater blower ground to the dash mount bolt just inches away
 
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From the above description IP harness breakout sounds like it would be 11 cm past the plug, Engine Side, on the big connector by the fuel filter.

That's 4.3" putting it under the intake... and means you are pulling the intake manifold. You can check at the engine connector by the FFM to make sure the problem is under the intake and not the connector itself. I would at least inspect the connector pins in the plug for corrosion first.


@jsravoie advice for the wiring is good.
 
Forget that noise! This much of a runaround, take 45 minutes and pull all the covering off the haness section. Inspect it all in 15 minutes. And rewrap it in 30 minutes. That leaves 30 minutes to fix any actual problems and you are into it 2 hours for the repair. Still less actual repair time than this thread, and you know 100% it is good going foreword.
What, save 1 hour out of 2 and MAYBE there is another problem 1 inch away from where you stopped unwrapping?
 
I don't know what vehicle's wiring harness Mitchell used for a 95 C1500 but the only wire the correct color in the correct place was the DK Blu/White going to C16. According to the published wiring diagram where I didn't have a signal was between the PCM and plug at the FFM.

I checked the in engine compartment harness from the plug to where it turns back to the passenger side where it goes through the firewall below the heater box. Then because I had not found the fork started checking inside before I dug the wiring out from behind the engine. When I pulled the harness from behind the glove box so I could easily work on it I found that one of the wires that Mitchell said was Dk Blu/White was solid blue. I printed out the diagram and the only wire that matched was the Dk Blu/White going to C16. I went to a buddies shop and pulled it up on his AllData the colors matched and the DK Blu/White wire going from the Fuel Shutoff Solenoid to the PCM only went to C16 there was no branch going to another terminal.
 
Following the correct diagram. I have a complete circuit from the ignition switch through the wiring in the PCM plug. If the Dk Blu/White wire is connected to ground the solenoid functions correctly.

The PCM is not properly actuating the solenoid.
 
IIRC, the ECM grounds that lead to in turn apply power to the FSS to provide fuel to the IP. This may be a ground issue all along. I know we harp on grounds, grounds, grounds, but check the grounding point on the back of the passenger head and the one under the dash on the passenger firewall as these are the two main grounding points for the ECM. If you haven't thrown the dreaded "ECM Dead" code, check your grounds before dropping some serious money on a new ECM & PROM.
 
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