Confusing Starter Problem

[andrew3563]

I have a 92 isuzu mu which when I bought several months ago would sometimes wait several seconds with the key on crank before it would turn over, then run fine. After a few weeks it stopped doing this and started first pop every time. The other morning after driving it down the road and parking. It wouldn't start for half an hour, and did the same thing today.

I have checked the terminals, tried jump started it and made no difference. Also ran a second set of jumper leads from the battery terminal to the block incase of a bad earth which did nothing.

When I try crank the motor, the voltage needle will drop ever so slightly below 12v then straight back up to about 12.5, and the stereo will turn off, and the dash lights will all stay lit. Once off crank, the stereo turns back on and the dash lights all stay lit as they have been the whole time.There is also no click noise of a relay or solenoid from either in the cab, or engine bay.

Another interesting thing to note is the tail gate release will not work if the car is not starting. Once the car has started and been turned off again, it then works fine. Or if the car is running it will function correctly.

The starter motor also works first pop once the engine is up to heat.


Has anybody got any suggestions as to what it may be?

Thanks,
Andrew

[pig75]

Could be a problem with solenoid on the starter. It also might have a immobilizer thats faulty
The tail gate release will not work if the park break is not on

[turnturn]

I'd also be thinking solenoid (or power supply to it)...... or ignition switch?
Re the stereo (and possibly other things) turning off during cranking......I think that it is supposed to do this.
Tailgate release should work where ever the ignition is as long as the handbrake is on, this caught me out in the first few months of Mu ownership. Thought that I had an intermittent fault, duh.

[geeves]

if auto it must be in park

[Hamzzz]

hah turnturn! i had the same thing, first time I went out 4 wheeling, I was in 2 I think with the engine off, and was all like what the crap? no tail gate? took me a couple of months to click. stereo is meant to go off when turning ignition, when the engine starts and the alternator starts working, it can send out a small spike of electricity, which in turn, if something has not had a fuse put on it, can damage it over time. as far as weird starting problem, it sounds like it might be starter solinoid or ignition, as others have said, might be time to head down to the ol' wreckers

[andrew3563]

I was thinking it would be the solenoid, but when i turn the key to start it there isnt even the noise of a relay clicking to power the solenoid. I'm wondering if there is something that is able to inhibit starting and has become faulty? Its also interesting the tailgate only has a problem when the starter wont work which makes me think they are somehow related? Does anybody have wiring diagrams for an Isuzu mu?

[turnturn]

Is your Mu manual or auto? There is a switch that prevents the autos being started with the selector in the wrong position.

[andrew3563]

It is an Auto, but I have tried moving the selector up and down before cranking to move a sticky switch, but doesnt make any difference. Do you know where this switch is?

Just had a thought. When I put it in reverse sometimes, the reverse lights/and beeping dont come on. Could this be the same sensor that detects if its in park?

[Hamzzz]

Funny thing, just started having the same problem, basically your starter motor and/or the solinoid is stuffed. Get a 1m steel pole and hammer, if its not starting give the starter a tap. When you can, take the starter motor out and get it re-conned or just buy a new one

[andrew3563]

I'm sure its not the starter, tapping it makes no difference at all, and if I wire the solenoid trigger to +12v it will turn over. Its something in the inhibitor circuit from the auto trans. I just need to find this circuit in the loom and its park sensor but not sure where to start

[Natek235]

Did you ever locate the issue? I'm having the same issues, I just replaced the starter motor but still doing the same shit. So definitely not the starter. My reverse lights also don't always come on. I could run a switch from starter but would rather locate the issue if I can.

[geeves]

inhibitor switch controls reverse lights dash display and enabling starting in only park and neutral.