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

[Dave M]

This is very strange. I am having the same problem on my 98. just started today. When I turn the key to start, nothing at all happens. batteries are more than fine. i ran a jumper from the battery to the starter and it engaged fine but engine would not start. i checked the starter relay and have proper voltage. i also swapped some relays around and still when i turn the key nothing happens. will the shutdown relay or solenoid actually keep the started from engaging or just keep the engine from firing due to no fuel. also if it is the Park/neutral switch, where is this what color wire do i look for?



Thanks.

Is your 98 a 12v valve? If 24 valve it may not have a fuel solenoid. This description is true for my 97 12v. If your starter is firing it only has the BRN wire as common between the starter solenoid and the fuel relay... . they are the same wire. If its cranking then you may have a fuel solenoid/relay problem.



The neutral/park switch powers the starter relay. If you get the starter cranking then the neutral/park switch is fine. The output of the starter relay is the BRN wire which goes to the starter solenoid. The BRN wire also splits off and goes to energize the Fuel relay on the firewall. The fuel relay's purpose is only to energize the "Pull" circuit of the fuel solenoid. The "Hold" circuit of the fuel relay is powered directly off Fuse #9 of the fuse panel underdash.



Once the ignition switch is off of the cranking position the "Pull" circuit is out of the picture since the Hold section of the solenoid should keep the fuel solenoid up... if the fuel solenoid is working.



You can try cranking starter while physically pulling up the fuel solenoid plunger. This will bypass or help the Pull circuit which is very high current and could be bad (the solnoid or the fuel relay or the blue fusible link off the battery are all needed for the Pull circuit to work). If it starts and the fuel solenoid stays up when it is started and is released then the fuel solenoid "Hold" section is working and the "pull" section is not. Then you can troubleshoot the "Pull" circuit like is happening is this thread.

 

[norcalram]

I can only get the starter to crank by jumping from the battery to the small lead on the starter (brown wire?) i can't get any response with the key in ignition. i held the solenoid up while turning key and still nothing. ???

 

[norcalram]

Solenoid will not go up on its own but will stay if i push it. when it is up, starter still will not crank. when i turn ignition off, solenoid releases. it also feels pretty warm when i push it up manually.

 

[Dave M]

If Fuel solenoid stays up then fuse #9 is good and the Hold circuit of fuel solenoid is good. You need to look at the Pull circuit.



Since the starter is not cranking unless you jumper it you could have a bad neutral switch or starter relay or a bad fuse that powers the starter relay. The starter relay is in the PDC underhood on drivers side.



First you are not getting 12v on the BRN wire on starter solenoid. That indicates a possible bad starter relay, fuse #2 in PDC I believe powers the starter relay, or neutral switch or associated wiring or bad ignition switch.



Pull out the starter relay and probe pin 86 for 12v when the neutral switch is engaged and cranking position on ignition switch. That will verify the neutral switch. If that is good then probe pin 30 for 12v from the 30 amp Fuse #2 in PDC. If bad then fuse 2 is bad, if good then you need to trace the output of the relay which is the BRN wire going to the starter solenoid or its a bad relay. Look for a burnt BRN wire near the starter or a open somewhere in that BRN wire. Pin 85 of the starter relay should have a good GND also for it to work and pin 87 is the 12v output of the starter relay (BRN wire) that goes to starter solenoid and splits off also to the fuel relay on firewall. That spilt BRN wire is not shown on the schematic but it is there.



Dave

 

[norcalram]

Thank you so much for the info and time. relays look good. I will have to search out the brown wire tommorow. its time for bed!!

 

[Dave M]

Thank you so much for the info and time. relays look good. I will have to search out the brown wire tommorow. its time for bed!!

Once you get the BRN wire figured out then it's time to look at the Pull circuit. I'll be here to help if you need it. I'll be leaving for church tomorrow morn at about 8:30 AM and back online about 12:30 PM Here is another schematic:



Good Luck,

Dave

 

[Dave M]

I would consider the starter and fueling 2 seperate problems and fix the starter problem first then the fueling problem.



However, the BRN wire goes to both the starter solenoid and the fuel relay. The Pull circuit of the fuel solenoid gets its 12v thru the fuel relay using that BRN wire to energize the fuel relay during the cranking portion of the start function. Fixing the BRN wire for the start solenoid may also fix the BRN wire of the fuel relay.



You can verify whether the BRN wire to the fuel relay works by cranking and testing at the fuel relay (relay in or out for the test) on the BRN wire of the relay.



There are 2 relays on the firewall (one is 30 amp, other is the 70 amp fuel relay that is closest to the drivers side fender). Try swapping these temporarily to determine if the relay is bad. I'd prefer troubleshooting the pins to see where the real problem is first.



Also, if the problem appears to be the fuel solenoid then first try removing it and cleaning the bore/plunger with braker cleaner and lube with silicone spray and re-assemble and test it. That is what fixed my problem.



Let me know how you make out.



Dave

 

[MLee]

It was suggested a while back if you are haveing a start problem, and you think it might be the ignition switch, or area, move the steering wheel up and down while trying to start the engine, to see if it might be the wires there, they might have worked loose, or might be in a broken state in the insulation.

 

[Dave M]

It was suggested a while back if you are haveing a start problem, and you think it might be the ignition switch, or area, move the steering wheel up and down while trying to start the engine, to see if it might be the wires there, they might have worked loose, or might be in a broken state in the insulation.

Very true. But you can verify it is not the ignition switch but testing for 12v at the start relay on pin 86 Yellow/Red wire. If you have 12v there while cranking you will know if the ignition switch is good or bad. Then if the neutral switch is good look at the steering column wiring. I have heard of problems there due to the tilt function causing the wires to rub and wear.

 

[norcalram]

I have two solenoids on the firewall however only the 70 amp has any wires going to it. i don't see anything hanging there to indicate that there ever was anything going to the other one. on a side note, i manually lifted the fuel lever and jumped from the battery to the starter and she started fine. My brown wire comes out of the box and connects to a connector clipped on the outside of the box. i unplugged it there and found no voltage while cranking. i have swapped all solenoids around except for the 70 on the firewall.

 

[norcalram]

I have 12 v on the brown wire on the fuel relay.

 

[Dave M]

I have 12 v on the brown wire on the fuel relay.

Good. That will be used to energize the fuel relay. The 12v that is switched thru the fuel relay to the fuel solenoid Pull circuit is on the Red/Blk wire of the fuel relay pin 1. That 12v comes off the PDC fuse #9. Do you have 12v there... try it with the key on... not sure if it matters?

 

[Dave M]

I have two solenoids on the firewall however only the 70 amp has any wires going to it. i don't see anything hanging there to indicate that there ever was anything going to the other one. on a side note, i manually lifted the fuel lever and jumped from the battery to the starter and she started fine. My brown wire comes out of the box and connects to a connector clipped on the outside of the box. i unplugged it there and found no voltage while cranking. i have swapped all solenoids around except for the 70 on the firewall.

Your 98 may be different than my 97 regarding having the 2 connected relays on firewall. The BRN wire coming out of box... . do you mean the PDC? I'd try to connect to the starter relay output directly somehow which is pin 87 (or BRN wire). Do you have 12v there when cranking? That is your feed to the starter solenoid.



Edit: My other firewall relay is the Fuel Heater Relay.

 

[norcalram]

i dont see #'s on the fuses but my 9th is a 50 amp diesel start and yes i have 12v there. I have 12v to all pins in the starter relay but 87. if i jump 87 to the battery the starter will crank.

 

[norcalram]

i have . 8 ohms from the brown out of the pdc to the starter.

 

[norcalram]

no i dont have 12v on the red/blk fuel relay

 

[Dave M]

i dont see #'s on the fuses but my 9th is a 50 amp diesel start and yes i have 12v there. I have 12v to all pins in the starter relay but 87. if i jump 87 to the battery the starter will crank.

Sounds like a bad starter relay. You might verify the GND connection to the relay on pin 85 by (remove the relay) putting your gnd volt probe on pin 85 and positive voltage probe on the battery positive lead. If you read 12v then you have a good GND and it appears the starter relay is bad and is not connecting it's 12v on pin 30 to pin 87 to fire your starter.

 

[Dave M]

Also did you try swapping the starter relay?

 

[norcalram]

im only showing millivolts grounded to 85.

 

[Dave M]

no i dont have 12v on the red/blk fuel relay

The source of that 12v is the blue fusible link off drivers side positive battery in my 97 but it may be a fuse for you.