Rough Idle then no start

Post by **Ozark Lee** » 27 May 2011, 01:51

Port A-6 is used for the ignition system on the Jetronic LH 3.2 system. '95 was a transition year between the Jetronic on the NA cars to the Motronic system. The Motronic system combined fuel and ignition into a singe ECU and it didn't talk to port A-6, only port A-2.

The short answer to your question is that no codes from port A-6 is likely not a bad thing.

I'm with the rest of the guys here, check your fuel pressure at the end of the fuel rail.

...Lee

Squat2011 · Post by **Squat2011** » 27 May 2011, 12:20

Can somebody take me through a quick tutorial about how to check fuel pressure at the end of the fuel rail? Much appreciated thanks

Srini850 · Post by **Srini850** » 27 May 2011, 15:11

The quick one is the Schrader valve test I outlined in my last post.

Squat2011 · Post by **Squat2011** » 31 May 2011, 14:34

Ok so I checked pressure at the Schrader valve and it has good fuel pressure. I also checked all the power with a multimeter all the way down to the starter solenoid and its all getting full power. After talking to my wifes uncle who happens to be an auto mechanic and owns three volvos he is saying PNP Switch? Any feedback on this? When you actually turn the key to start the car it gets nothing. Not even the fast click you hear from the solenoid.

Squat2011 · Post by **Squat2011** » 31 May 2011, 16:26

Also, does anyone have a picture of a bad PNP Switch? And the main symptoms that would go along with it? Thanks!

Post by **Ozark Lee** » 31 May 2011, 18:54

The typical symptoms of a bad PNP switch vary a bit.

#1 (Usually in the dead of winter) the car won't even crank. You hit the key and nothing happens

#2 The flashing Up arrow comes on and the car starts off in third gear. That is its limp home mode and you feel like you are dragging a safe behind the car. If at all possible avoid driving in that condition as it is very hard on the transmission itself.

If you suspect a bad PNP try rowing the shifter, quickly, from park to low a couple of dozen times. If things start to work again then consider it a shot across the bow and you will need to deal with it sooner rather than later.

A bad PNP switch will have no effect at all on how the engine runs though. It will not cause the engine to idle poorly.

...Lee

Swedish Chef · Post by **Swedish Chef** » 08 Jun 2011, 17:05

I dont know if you've solved this problem yet but my wife's wagon did the same thing other than the running rough problem, on occasion for the past 3 or so years it would just refuse to send power from the ignition key to the starting system, I tried boosting / shifter rowing / key cycling but the only thing that would work was time and after about 30-45 minutes it would start like nothing happened and continue to start for the next 8-12 months until it would do it again, unfortunately it happened about 4 weeks ago and i am not in the same part of the country as home only this time it gave the big F$^#*^ You to my wife for several hours, after getting the call i i had it towed to another mechanic friend who works on Saab's, he diagnosed it as being the PNP switch after ribbing me about it, as a licenced mechanic im sure im gonna hear about it when i return home

Squat2011 · Post by **Squat2011** » 14 Jun 2011, 17:48

Ok so it has been a couple weeks now and im still lost. Here is my status up to today. Multimeter reads full power (normal and cranking) all the way down to the solenoid. Yet when I turn the key I get nothing. As in no start, no crank not even a fast click from the solenoid. Nothing. All the lights are working and everything on the dash turns on. You can hear the fuel pump priming when you turn the key on and fuel pressure is good. I replaced the PNP switch after being told that is the only thing left it could be by a couple of people I trust. Had no problems replacing it and I got it aligned to where all the gears match up and the reverse lights come on when I put the car in reverse. STILL NOTHING! I am back to where I started. ANY ideas?? Also, Swedish Chef, It never quit before this it would only take forever for the starter to catch so we replaced it. After replacing the starter and solenoid it just ran crappy until one day it just wouldnt start,crank, or click.

Squat2011 · Post by **Squat2011** » 14 Jun 2011, 17:52

Ozark Lee wrote:The typical symptoms of a bad PNP switch vary a bit.

#1 (Usually in the dead of winter) the car won't even crank. You hit the key and nothing happens

#2 The flashing Up arrow comes on and the car starts off in third gear. That is its limp home mode and you feel like you are dragging a safe behind the car. If at all possible avoid driving in that condition as it is very hard on the transmission itself.

If you suspect a bad PNP try rowing the shifter, quickly, from park to low a couple of dozen times. If things start to work again then consider it a shot across the bow and you will need to deal with it sooner rather than later.

A bad PNP switch will have no effect at all on how the engine runs though. It will not cause the engine to idle poorly.

...Lee

Ozark Lee, Thanks for all the help. But I never suspected the PNP until the one day it just wouldnt start, crank, or click at the solenoid. Am I correct in saying that the only things that could keep the starter from turning are a bad ignition switch, battery, Starter/solenoid, or PNP switch? That is why i am frustrated because as of right now all 4 of these things are now installed and brand new on the car.

Post by **Ozark Lee** » 14 Jun 2011, 23:14

You can narrow things down by using a jumper wire to the "Service Starter Connector" It is a connector sticking out of the main wiring harness near the driver's side strut tower with a green/red wire. If you jumper that with positive battery voltage the car should crank.

If it does crank then that eliminates the PNP switch and the starter.

Your problems are starting to sound like a bad overload relay. The overload relays are the ones that are marked a J under the fuse box cover. They are dirt cheap to replace in relative Volvo terms.

...Lee