Engine/Transmission (1994 - 1998) Hard Starting to No start

[norcalram]

yes that is the 50 amp ignition/run fuse? it has 12 v

 

[Dave M]

im only showing millivolts grounded to 85.

That would indicate a bad ground.

 

[Dave M]

im only showing millivolts grounded to 85.

Pin 86 should have 12v from neutral switch when cranking and with pin 85 at GND the start relay will energize..... only while cranking... but there always should be GND on pin 85.

 

[norcalram]

85 is at ground with ignition off but showing Mv with ign on. 86 has nothing when cranking or with ign on or off

 

[Dave M]

85 is at ground with ignition off but showing Mv with ign on. 86 has nothing when cranking or with ign on or off

We are on the start relay. . Right. If there is no 12v on pin 86 (Yel/red wire) when cranking then the neutral switch and/or ignition switch is not supplying 12v to the start relay. Refer to the schematics I sent earlier. You have a PM from me.

 

[Dave M]

I helped "norcalram" figure out his no start problem. He had 12v on pin 86 and pin 30 of the start relay but the GND was bad on pin 85 so the relay could not energize. I had him attach a seperate GND to pin 85 and the starter fired. So it was a bad gnd in the start relay socket of the Pdc.



Troublsshooting the fuel relay he had both 12v signals into it but we never finished looking at the output of the relay. Then we worked on the start problem above and the fuel solenoid pull circuit started to work. He is going to post back and let us know how it has been working.



I recommended he buy a fuel relay in case it goes bad and pull the fuel solenoid and clean and lube it.

 

[Dave M]

I've been taking another look at the schematic for the starter relay and I believe your ground problem is in the Park/Neutral switch. On my manual transmission the schematic has the Clutch switch engaged and sends the 12v to pin 86 of the start relay in PDC to energize that relay and pin 86 of the starter relay is always GND but not so for your auto transmission.



For the Auto transmission the GND is supplied thru the Park/neutral switch to pin 86 (the GND part of the starter relay in PDC). Thats why you had no gnd at pin 86. The Park neutral switch supplies the GND when it is working properly. Check for GND at the park/neutral switch like I showed you using the red lead or positive of voltmeter on a good 12v signal and black lead or negative of voltmeter on the park/neutral switch output which is a Black/white wire on my 97 schematic.



It looks like you have a problem in that Park/neutral switch or the associated wiring.



Dave

 

[AKington]

Thanks for all the information Dave. I did not troubleshoot anything yet, I caught a nasty strain of flu and I'm just starting to feel better. I will test the parts and give an update as soon as I can.

 

[Dave M]

Thanks for all the information Dave. I did not troubleshoot anything yet, I caught a nasty strain of flu and I'm just starting to feel better. I will test the parts and give an update as soon as I can.

I had the flu and was home from work and getting over it when I helped you last. I am still coughing and not over it yet (2 weeks now). I hope you get better soon.



Dave