Simple question from a layman.

RedAphex

New Member
I've got myself a '90 Integra that has issues starting. I've tried everything I can come up with both on the advice of various mechanics & good ole' Google. First here's my question: Would a damaged PCM prevent the starter from cranking?

Here's a fun list of everything I've messed with and/or inspected.
  • Replaced starter
  • Replaced battery
  • Replaced alternator
  • Replaced clutch-interlock switch
  • Verified 12V at ignition
  • Verified 12V at starter
  • Verified 12V at Distributor
  • Took a test light to all fuses, inside & out.
  • Blk/Wht wire to starter (solenoid?) gets less than 1V while ignition is being cranked.
  • Verified Blk/Wht wire has perfect continuity end-to-end
Trying to start the car results in absolutely no response from the starter or any other engine components (aside from a brief hum which I believe is the fuel pump.) Everything else electrical appears to work (excluding the parking lights.) Check engine light goes off after ignition is turned as it should.

Sadly, I'm about to scrap the car. I've invested far more time in it than I care to and it's causing obvious problems in it's ability to transport me. Any advice is greatly appreciated.
 

RedAphex

New Member
Thanks for your response.

Since my last post I've pretty much ripped the whole engine wiring out, re-ran wires that didn't test well on continuity, and re-wrapped the whole bloody thing.

It's my understanding that verifying the spark plug power & fuel injection isn't relevant at this point. Somewhere between the battery, ignition, and starter I seem to be having a problem. I jumped the starter off of the battery today and it does indeed work correctly. So maybe I'll just run the solenoid wire into the cabin and trigger it off of a 12V switch from the local hobby shop.

Ghetto as hell but if it gets it working...
 

MrBean

New Member
So turning the key does not engage the starter.
Manual transmission has a starter relay.
Automatic has a neutral safety switch (ON: P and N Position)
If one of these does not work right you won't get voltage to the starter solenoid.

Could also be the ignition switch, but they usually start OK just don't hold the circuit when the car is running.
Maybe also a bad ground to the starter itself. When you checked for voltage was the meter on a known good ground, or on the starter itself? Could be the 12 volt control side is OK, just a bad return.
 


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justincpowell

1991 Acura Integra GS
yup check your grounds for sure it doesnt take much corrosion to cause a problem and considering all the years it could have set up over its time to run them down lol.
when you turn the key what exactly happens?
 

RedAphex

New Member
Mr. Bean

My car is a Manual transmition. When you speak of the starter relay, you're referring to the one under the dash...the main relay? If that's case then yes, I've tested every fuse on it both relating to the starting system and otherwise. When I tested the solenoid voltage I used the negative battery terminal.

justincpowell

When I turn the ignition to 'On' everything works as you would expect (wipers, lights, dash lights, etc) and I hear a brief hum from the engine compartment. Turning the ignition results in nothing...though the beeping noise it makes when you first turn it on (the one that alerts you that the car is on) goes off. Like if I just switched it to 'Off' and back on again.

I ask about the PCM because a friend of mine had a similar problem with a slightly newer model Integra ('92 I think) and replacing that unit is what resolved it. His car actually had a dash light for the PCM which often would not come on when the car was initially started. My car doesn't have this light and the Check Engine light should come on from what I understand.
 

emd513

New Member
have u checked the actual key switch it self. i have a push button to crank my car thats ran to the starter but i have to turn the key to the on position to get it to crank. dont ask why i bought it like that. but i had a similar problem with a couple of cars and that ended up being it
 


MrBean

New Member
Starter Relay gets power to close when ignition switch is turned all the way. It's closer to the center of the dash - between passenger and driver(book says right of heater unit). I can hear mine click inside the car.

But I don't think that is your problem because you have 12 volts at starter. The other end of the meter you say is on the negative battery. Just because you supply positive 12 to the starter does not mean you have a good return path (the negative side).

Start at the battery negative terminal and clean it well. Check the edges of the plastic covering on the wire. Sometimes the wire corrodes under the wire jacket. I had to replace the negative cable to the battery because the wire was down to a few good strands under the plastic. Then follow the cable to the next ground post and make sure all connections are clean and tight. I don't know how many connections are between the battery negative and the starter negative.

There is a PGM-FI main relay left of the drivers knees. That's probably not you problem. It turns on for 3 seconds to prime the fuel pump (hum) and then turns off along with the CEL. If the PGM is bad then the car will die for no reason. PGM supplies power to fuel pump and injectors. Even with that bad the car should turn over, (starter is engaged) but it just won't start. (Somebody correct me if there is some way the starter will not engage if the PGM is bad - I just don't think that is case.) I had the PGM soldier joints go bad, the car would not run, but I think it turned over no problem.
 
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lowazzteg

3rd Super Mario Bro
You have to depress the clutch in order to start it.

:lol:

My idea has already been ruled out. You hear the hum of the fuel pump so the main relay is ok. Good luck.
 

RedAphex

New Member
DagoAcura92

I haven't tried that, I'll go check it out. I did replace the clutch interlock switch itself though.

lowazzteg

Woohoo that fixed it!
.
.
.
.
I wish it was that simple ;)
 

RedAphex

New Member
Alright, so the Clutch Interlock Switch doesn't have power running to it. The wires themselves run from the Cruise Control unit (which has never worked properly.)

So I'm thinking maybe I'll use the red & black wires to the cruise. I looked them up and the red one powers the cruise control dash light so I don't really give a crap about that...and the black one is a ground. Tested them both and they have 11V running through them.
 
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MrBean

New Member
When the clutch is all the way down the "Clutch interlock swtich" is closed. It has a blk wire to ground and a blk/blu wire from the starter relay.
When the clutch is pushed down a little the "Clutch Switch" opens and turns off the cruise control. It also has a blk wire to ground and a pink wire to the cruise control unit.

If you changed out the upper switch instead of the lower switch, then I need to rethink the ground problem from the battery. It's the lower switch that you can short together and bypass to see if starting works again.
 

RedAphex

New Member
So I wired it to the cruise control and it gets full voltage now but still no starter action. The cruise control light is stuck on and goes off when the clutch is pushed hahah. I can live with that if it's a means to an end.

Mr. Bean
So you're saying there's 2 clutch switches? I suppose that explains why all the diagrams I've read show BLK/BLU and mine is BLK/PNK...I always thought that maybe mine was different because someone else messed with it. I haven't tracked down the starter relay yet either. You'd think my Haynes manual would at least mention that relay if the car did have one. It wouldn't be called anything else would it? Does anyone have a picture of it so I can identify the part before I go ripping stuff out?
 
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