91 No Start

[R C Cola]

I'm not too good with schematics and need help on diagnosis questions. Had an occasional failure to start spread over a 2 week time frame. Not sure if it is neutral safety or ignition switch or other ? Push to start works fine. Dash lites come on. Lites dim when I turn key to start. Voltage at batt is 12. 85 . Runs fine when it does start till it is shut down. 1. Color of wire going from ignition switch to starter or start relay and then on down to starter. ? and is it a hot lead or a ground ? 2. Neutral safety switch wire at the clutch, hot or ground and can I just jump it for a test of switch. ?

 

[pepecat]

when I activate my neutral safety switch I don't get any dimming at all.

 

[Tippin Spotted Cow]

I've had a loose battery cable that could power the headlights full bright, but everything dimmed when you turned the key and the truck wouldn't start.

 

[pepecat]

I've had a loose battery cable that could power the headlights full bright, but everything dimmed when you turned the key and the truck wouldn't start.

same here... clean the grounds as well

 

[R C Cola]

Connections

Thanks... . checking those now, been needin to do that anyway. Fuses all good.

 

[MMeier]

R. C. , be sure to pull off the ground cable that attaches to the engine block and clean real ggod, also the small wires that come off the battery and attach to the radiator header panel.

 

[R C Cola]

Cables and grounds

Connections good at ground and starter. 12,8V at the starter terminal. Need to check the neutral safety switch and possibly the key switch contact. Ground is good at the header panal.

 

[Bob4x4]

IIRC the wire to the starter solenoid should be a 14 gauge brown wire,the ground wire from the nuetral safety swith should be brown with a yellow tracer to the starter relay. The start wire from the ignition switch should be yellow and will go to a clutch switch if manual trans or have a jumper there if an auto truck,I beleive it may change color there to yellow with black tracer out to the relay. The Battery feed to the relay will be about a 12 gauge red wire through a fuse link to the batt. Maybe an orange fuse link don't remember 100% It's been a few years since I have worked on a first gen.



Bob

 

[R C Cola]

No start

Thanks, now have checked those and they all checked out fine. Used a jumper to bypass the neutral safety switch and she started right up. Tested the switch and it was OK, now what ? Back on no work, pulled up manually and works fine. The switch body was too short. Placed a spacer between the switch and the firewall now works perfectly. Apparantly with wear over time internal parts wore enough that the switch was now too short. wow !

Repair cost, material 10 cents, time invested in education of self 3 hours.

 

[Paychk]

You may want to check the clutch master cylinder rod where it attaches to the clutch pedal. Over time the eye will wear and not actuate the rod enough to trip the neutral switch. Pull the rod from the pin and check the eye for an egg shaped hole and see if the plastic bushing is still there or if it is missing.

 

[R C Cola]

Egg shaped you bet

If I caught it right, the hole is supposed to be round and snug with very little play. There is at least 1/4 inch of movement before the rod starts to travel. Seems to have some type of keeper I will need to remove, but I cannot see how it comes off. My guess is bushing long since worn out and gone. Only 600k whats with the wearing out etc. ? Oh well call it maintenance.

 

[PToombs]

RC, it's just an E clip. Pop it off with a smallish screwdriver. When you get it off, you better look at the pin on the pedal good. If it moves as far as you say, the pin is worn about 1/2 way thru.