Ignition Troubles - FIXED

[ubertalldude]

Hey, everybody. Did some major work this weekend trying to fix an intermittent start and figured I would share my story and findings.

So, truck starts acting worse and worse when I try to start it, sometimes requiring that I be in neutral, sometimes starting while still in gear with the clutch not applied, sometimes needing an extra hard turn of the key, or just not responding to the key input at all.

I head a small relay clicking over in the passenger fender when I turn the key, so I figure the relays are probably OK and decide to replace the starter. Old starter needed to be done, the commutator bars on the rotor had all melted together (no wonder it sounded to strained when it actually WOULD turn over) but even with a new starter, problem persists.

SO! I think, "Starter is good and still fires sometimes, maybe it IS that relay I thought it was!" and also note that on the starter I pulled from the truck there's a sticker saying something to the effect of "recommended to replace Inhibitor Relay when replacing this starter". On the manual transmission model the Inhibitor Relay called the Interlock Relay, and in effect it's a relay that will not allow the ignition circuit to be completed unless the truck is in neutral or has the clutch applied (or in park for an auto trans). The part is located in the passenger side fender well, a few inches rear of the battery, and it's the only blue relay that has 2 connectors coming out of it. I order the part from a Nissan dealership ($30 or so) and replace it. Same issue! I'm getting flustered at this point.

New relay doesn't solve the problem, so I check the components attached to the interlock relay, which are the clutch interlock switch (clutch pedal), the neutral switch in the transmission, the emergency clutch interlock switch (in the cab below the steering wheel) Lo and behold, the clutch pedal switch has been removed and jumpered with a wire so it's always switched on, thus defeating the interlock relay's function. Since it's already been defeated, I decide to bypass all that extra circuitry and just jumper two electrical terminals located within the bigger of the two plugs which go to the interlock relay. This effectively bypasses the whole interlock circuit and allows the ignition switch to directly trigger the starter. This DOES create a dangerous situation where the truck can be started in gear, so do this at your own risk.

So, no more clutch interlock, nothing standing in the way between the ignition switch and the starter, this should be perfect! Of course, though, it is not. When it does want to start, it starts quicker because it doesn't have to wait for the clutch interlock relays to kick over, but is still intermittent. WHAT THE HECK. So I do some more research and find a lot of complaints about Nissan ignition switches going bad and requiring the key to be jiggled to actually kick over. I test it, and this is how mine is! So I take apart the steering column, look at the ignition tumbler, and realize that the back end of it is loose from its housing. When I hold it in and press it back into the ignition tumbler, it works fine. If I don't touch it, the truck won't start.

After all was said and done, I spent about $120 on a starter and relay, when all I really needed was to zip tie my ignition switch back together with $0.45 worth of zip ties.




I kept the interlock jumpered, too, because this is an offroad toy and I also know better than to start it in gear, so if you're in need of an interlock relay/inhibitor relay, I've got 2 working units.

[k9sar]

thanks for sharing your story. I'm sure it will help some other folks who wander in here looking for ignition/starting solutions.

 

[Charlie_Brown]

Thank you for sharing. My ignition seems to be slowly going out where I have to jiggle the key to turn over so I'll have to look into this problem.

[ubertalldude]

next time I decide to do some work on it or have some free time I'll take a few pics of what I did to give you a better idea of how I zipped it all up

[russwf77]

Ubertalldude, I am interested in the pics. My '94 is having trouble starting too, and the ignition switch is VERY loose. Already replaced starter and starter relay.

 

Thanks in advance

[russwf77]

Ubertalldude, I am interested in the pics. My '94 is having trouble starting too, and the ignition switch is VERY loose. Already replaced starter and starter relay.

 

Thanks in advance

[ubertalldude]

Ubertalldude, I am interested in the pics. My '94 is having trouble starting too, and the ignition switch is VERY loose. Already replaced starter and starter relay.

 

Thanks in advance

 

Sorry for the late reply! I haven't checked this thread in a while. I'll try and get pics as I'm working on it, but right now I'm chasing a sputtering issue with the engine so it may be a bit!

[SpecialWarr]

 

Sorry for the late reply! I haven't checked this thread in a while. I'll try and get pics as I'm working on it, but right now I'm chasing a sputtering issue with the engine so it may be a bit!

 

MAF wiring or a sketchy ground? Mine was a Idle Air Control Valve that was super dirty. I took it and the throttle body apart and cleaned them... truck ran fine afterwards... I also find that pulling the two battery terminals and touching the main positive and negative wires to each other seem to get everything back to factory settings.... mind you you do need to fiddle with every button and switch afterwards while the truck is running which is a bit of a pain.

[ubertalldude]

my MAF wiring was almost certainly suspect. The engine was dying at lights,so I added a new ground wire which made the truck run TERRIBLY for 3 drive cycles, but now has no stalling issues. IACV is working fine from what I can tell, the truck high-idles fine and then idles down to ~750rpm when warm and doesn't fluctuate much.

 

I also have new plugs/wires/cap/rotor, so the main things I think that would leave for sputtering would be injectors or the O2 sensor. Had plenty of injector cleaner run through it since I bought it, and it had a stuck thermostat which makes me think the engine seldom got to operating temps (leading to excessive carbon buildup and rich running), and the PO didn't mention having replaced the O2 in the service history of the truck (now at 245k miles) but that is an easy check once I get around to pulling the passenger seat and doing ECM diagnostics.