1993 940 RPM drops and stalling

bjgol · Post by **bjgol** » 21 Sep 2008, 08:35

Hi folks:

Just yesterday our 940 with 168k started exhibiting erratic behavior. Our RPMs will drop to 0 and we will get no response from the engine for a few seconds and then it will jump back. About 10% of the time the engine won't come back and we will glide to a stop. It seems to happen at all speeds and starts up after we have been driving for about 20 minutes. This is not good and we are very nervous about taking it into a dealership and getting soaked. Would love some feedback and any suggestions. Thanks!

Post by **billofdurham** » 21 Sep 2008, 11:33

Welcome to Matthew's Volvo Site.

Have you checked for any fault codes that may have been set as this happened?

Your vehicle is fitted with an On-Board Diagnostic unit (OBD) in the engine compartment. Using this you can see if any codes are there.

To use it see:

https://www.matthewsvolvosite.com/chat/p ... c&start=12

The instructions do cover your car.

Check this first and let us know if fault codes are there. If not, we go back to basics.

Bill.

bjgol · Post by **bjgol** » 22 Sep 2008, 19:22

Thanks for the reply. Do you have a diagram for the 940 that shows exactly where this onboard diagnostic tool is? I was looking under the hood without success today. Unfortunately, I am pretty inexperienced with this type of thing.

Thanks.

Post by **billofdurham** » 23 Sep 2008, 11:56

It is behind the left strut tower and looks like this:

It should have a cover on it but sometimes they go missing.

Bill.

bobbyz · Post by **bobbyz** » 23 Sep 2008, 21:51

Thanks for the self-diagnosis info you've given here, billofdurham.

My '91 940 has hot stalling problem

The diagnosis code given was 2-3-2. The sheet says lambda adjustment: check intake manifold, check fuel pressure.

Where shall I start?
The plugs, fuel & air filters were replaced couple of weeks ago.

Thanks

Post by **billofdurham** » 24 Sep 2008, 12:30

To test the intake manifold start the engine and spray a small amount of water or WD40 along the gasket between the manifold and the head. If the engine starts to die there is a leak.

To test the fuel pressure you need a fuel pressure gauge to do it accurately. It is something that any self respecting small shop owner would do for you - not a Volvo main dealer - or you could buy the gauge and DIY. Probably cheaper to have it done as it is not something you should be doing every week.

Bill.

bjgol · Post by **bjgol** » 23 Nov 2008, 15:08

I finally figured out where the diagnostic box was. Here is what I did.

I plugged it into slot 2 and it returned "111".

I plugged it into slot 6 and it returned "144."

Should I plug it into any other slots? Thoughts on the "144"?

Thanks!

Post by **billofdurham** » 23 Nov 2008, 15:29

1-1-1 means no fault codes have been stored.

Socket 6 tests the ignition system. Code 1-4-4 is "Fuel System Load Signal".

Go back to the link for the on-board diagnostics, scroll down to pages 7 & 8 to find out how to check this.

There are no other sockets used on your car.

Bill.