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Still Can't Get this Thing to Start #2

OldCarNewTricks

Well-known member
Joined
Oct 23, 2016
Location
Oregon
My 1983 242 just doesn't want to cooperate. What I thought was just a fuse corrosion issue is no longer true. I had it running and driving for a total of maybe an hour over a couple days. Yesterday it stopped running while I was trying to air up the tires so I can finally drive it home.. grr, so frustrating.

I started with the AMM, added sleeves to the ICM pins that needed them and replaced the fuse holder with a waterproof one. Alot the wiring was replaced in the past, except for the light related wiring, alot of that needs replaced.

I wiggled the wires around the ICM and the distributor and it ran two seperate times for maybe 10-20 seconds each. Not sure if that's because I wiggled the wiring or if because of residual fuel. I can feel and hear both relays opening, they are both new, as well. What could cause the car to run, sitting stationary for 20 minutes and just die with no intention of starting again? Hall Sensor?

My distributor has a circular plug.

Also, the injectors are not receiving +12v to the Yellow/Red wires. When they had voltage, it ran.
 
I would start with the basics. Get a can of starter fluid and spray it into a vac line in the intake then try to start the car. Does the car start and run on the starter fluid? If yes, you have a fuel problem so diag further. If no, you have a spark issue so diag further.
 
Runs on starting fluid. And it ran extremely well when it was running.

So the injectors only receive +12v when the engine is turning? I thought they were to receive voltage whenever the car is on..
 
Rule number 1 did you change out the fuel pump fuse and clean the contacts?
 
The only fuse I changed was the 25a main power. I've spun them in their holder several times and I've gone through and I've cleaned any corrosion I found.
 
Also, the injectors are not receiving +12v to the Yellow/Red wires. When they had voltage, it ran.

Also, fuel pumps work. Fuel press. regulator still functions, etc.


If you're getting power to the pumps but not to the injectors there must be a break in the wiring. The pumps and the IAC valve get power from the same pole on the relay as the injectors. I'd suspect the junction where the 4 injector wires split from one.

LHJetIIPowerPath.jpg
 
power to the pumps but not to the injectors

1984 diagram shows two electrical contacts in relay...one to the pumps and the other to the injectors. Two separate wiring paths, as viewed here.

OP Question - "injectors only receive +12v when the engine is turning?"

Answer - Correct

ECM activates a ground to the relay when the ECM detects engine rotating. When this ground is turned on by ECM, then the injectors and pumps should have 12 volts...if relay is working, and if relay has 12 volt pwr, and ignition switch is sending 12 volts to it. See diagram here.

Relay is under the passenger side dash...towards center console area. Fuse #13 must be good. Via 1984 diagram, there are three Yellow-Red wires coming out of relay and going to fuel pumps and injectors...with a test light, I'd check to see if 12 volts is on these wires when starter is cranked. Relays go bad.
 
A break in wiring would make sense. I've stripped off all the split loom in the engine bay, and all the wires look good. So I'll have to check for continuity on that wire from the relay to the injectors.

I had the injectors out with bottles taped on them before I got it running the first time. It's weird because the injectors has +12v to them when they actually started working, and this was without the engine turning.

I'll have to see if they get +v when cranking the motor.

I had already suspected relays, and they are both brand new Bosch units, although the factory ones were still OK.

I'll check all my fuses again.
 
Take the cover off the relay and verify that when energized the relay is making contact.
 
Take the cover off the relay and verify that when energized the relay is making contact.

Better to use a jumper wire connected to Red and Yellow-Red wires on relay's receptacle...with male spades on this jumper wire to insert into receptacle's terminals, as I recall.
 
The only fuse I changed was the 25a main power. I've spun them in their holder several times and I've gone through and I've cleaned any corrosion I found.

:nono:

Change the fuse for the fuel pump and take sand paper to the contacts before putting in a NEW fuse.

If you haven't done that you are missing the #1 starting/no start issues with our early model Volvos...

I carry those fuses in my car in case I see a Volvo on the side of the road, I've sent quite a few happy people on their way after doing the steps outlined above.

Simple and at least gets that out of the way.
 
:nono:

Change the fuse for the fuel pump and take sand paper to the contacts before putting in a NEW fuse.

If you haven't done that you are missing the #1 starting/no start issues with our early model Volvos...

I carry those fuses in my car in case I see a Volvo on the side of the road, I've sent quite a few happy people on their way after doing the steps outlined above.

Simple and at least gets that out of the way.

WELL, it can't hurt to do! Thanks for the suggestion.

Also, the relays are brand spanking new Bosch units. The old ones, with the covers off, still worked just fine. I am keeping them as backups.
 
WELL, it can't hurt to do! Thanks for the suggestion.

Also, the relays are brand spanking new Bosch units. The old ones, with the covers off, still worked just fine. I am keeping them as backups.

Ya it's a no cost five minute box check in terms of trouble shooting - but you'd be surprised how often that is the cause of no start issues.

:wave:
 
WELL, it can't hurt to do! Thanks for the suggestion.

Also, the relays are brand spanking new Bosch units. The old ones, with the covers off, still worked just fine. I am keeping them as backups.

Do not use sand paper on contacts. A fine brass wire brush will remove the corrosion without damaging the contacts. Any paint store/hardware store carries them.
 
Well, I switched the fuses. No luck there. However, I purchased a Bentley manual recently and it has been helpful. I tracked the issue down to the ECM not providing ground to the injectors. The relay is functional and provides 12v to the injectors.

So I'm guessing maybe a bad hall sensor isn't picking up engine rotation?
 
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