91 940SE Stalling

gyrene · Post by **gyrene** » 03 Apr 2009, 07:13

HELP!!! My 91` 940SE turbo is stalling, I mean it just shuts down. I hit a hard bump in the road and the engine died, but restarted but now it will go only about 1 to 5 miles and will stall again. It normally will restart each time but won't run long. I changed the fuel filter and fuel regulator w/ no results. I could flounce (middle Tennessee for search LOL) around for ever not being a tech (or really want to be). What are some things to zero in on?

gyrene · Post by **gyrene** » 03 Apr 2009, 15:13

I ran a diagnostic test and retrieved two codes, 1-2-1 ( MAF sensor signal faulty or missing) and 3-1-2 (no knock enrichment signal from DI system). What in the world is the DI system? I am hoping against hope I will not have to buy a MAF but...... What do you think billofdurham, I know you have an answer.

Post by **billofdurham** » 03 Apr 2009, 15:59

Your faith in me is touching, thank you.

DI? Dependency Injection (DI) in computer programming refers to the process of supplying an external dependency to a software component. ...

NO, it can't be that. The only DI I know in the engine world is direct injection. My book on 3-1-2 does not mention DI so I shall admit I don't know and move on.

The MAF may have a bad connection or it may simply need a spray of MAF cleaner. However, 1-2-1 also includes the fuel injection main relay.

How to test all of these components is in the attached:

940 MAF and Knock.pdf: (285.96 KiB) Downloaded 251 times

Before hauling out all the test equipment check all connections to the sensors as your initial post made me think immediately of a loose or dirty connection.

Bill.

gyrene · Post by **gyrene** » 03 Apr 2009, 17:46

Thanks Bill for answering so quickly, I do appreciate you sharing your knowledge. Now, let me mention that I unplugged the MAF and the engine smoothed out nicely, I understand that puts the engine in I think you said elsewhere the "limp home mode" then when I plugged it back in the RPMs increased and the car just shut off. I will post again when I get some MAF cleaner and recheck the connections. Oh, where is the fuel injection main relay, or maybe what color is it.

gyrene · Post by **gyrene** » 04 Apr 2009, 11:32

I removed the MAF cleaned it with the proper cleaning spray and reassemble, I get 12 volts across the proper points (why am I using the word proper so much

) anyway still will not idle. I think maybe the in-tank fuel pump. Can anyone tell me how to access it on a station wagon? I also disconnected the battery to reset codes, started the car and when it died I rechecked the codes I get 1-1-1.

Post by **billofdurham** » 04 Apr 2009, 11:58

Lift up the carpet in the luggage area and you will see an inspection plate. It is under there.

How to remove the fuel tank unit:

940 tank unit.pdf: (1.05 MiB) Downloaded 183 times

Draining the fuel tank - Volvo, naturally, use a suction pump with a pipe down the filler. If you don't have much fuel in the tank and don't intend striking matches to see what you are doing you can probably skip this. I haven't drained a tank yet and I am still here to tell the tale.

The retaining nut - special tool for removal thereof. I have always managed with an adjustable wrench or pipe pliers.

Bill.

gyrene · Post by **gyrene** » 07 Apr 2009, 15:21

Bill if you are there I need help again.(LOL) I replaced the MAF car starts and runs, however, it now idles at between 2000 and 2500 RPMs. I took the IC motor off and cleaned it tested it by hooking to 12 volts on the bench and it runs. Put back on car still no change. Cleaned throttle body etc etc ......... I have no clue.

Checked codes 1-1-1

Post by **billofdurham** » 07 Apr 2009, 16:02

There's no pleasing some people. Car won't run - not happy, car runs - still not happy.

Things which can affect the idle:
Fuel injectors.
Intake system leak.
Coolant temperature sensor. Not the one for the gauge. The FI temp sensor is under the intake manifold about the position of #3 cylinder. I have done a write up recently about how to check it. https://www.matthewsvolvosite.com/forums ... sor#p81428
Throttle switch and connector.
Idle valve ensuring the airflow arrow is pointing in the right direction.
Distributor.

As you have cleaned the throttle body is it possible that you have knocked something out of adjustment? This will help you to check:

Throttle Body and Throttle Position Switch Adjustment.

1. Checking the Throttle Body (Plate and Throttle Position Switch) Adjustment

Connect an accurate tachometer then warm up the engine. Let it idle in Park with a/c off. Pinch off the hose between the air intake and the IAC valve (don’t damage the hose with something sharp!) Idle speed should drop below 500 rpm, or the engine may stop: both are normal. If idle speed does not drop, adjust as below. First remove the hose clip.

2. Adjusting the Idle Speed

On the side of your throttle body, there is an adjustment screw. Loosen the lock nut. Start the engine and turn the adjustment screw until idle is 480-520 rpm. Switch off the engine and tighten the lock nut while holding the adjustment screw so it doesn't turn.

3. Checking the TPS Adjustment.

Check the gap between the adjustment screw and the throttle lever with a feeler gauge. Insert a .45mm feeler gauge. There should be no click from the TPS when the throttle is closed. Then insert a .15mm feeler gauge. There should be a click from the TPS when the throttle is closed. If these are incorrect, then adjust as below.

4. Adjusting the TPS.

Loosen the TPS adjustment screws. First turn the TPS clockwise (away from the electrical connector) until it stops. While keeping your finger on the throttle disk so it won't move, turn the TPS counter-clockwise (toward the connector) until you hear or feel a "click". Continue turning until it stops, then tighten the screws. Go back to step 3 above to check the adjustment.

The TPS should throw code 1-3-3 but I have seen them go out without a code.

Bill.

gyrene · Post by **gyrene** » 08 Apr 2009, 07:03

ROFL

But thanks for the info. I'll beee baaaack!!

Post by **billofdurham** » 08 Apr 2009, 15:21

To bear out my thoughts on the throttle body clean causing the high idle I found this on SwedishBricks:

Poor Idle; TB Cleaned; Now Idle is Too High. [Query:] Well my problem is certainly gone. It now idles at 1600 rpm, but that's a steady 1600. Did I do something wrong, or was the crud in the throttle body masking another problem? The barrel of the actuator rod is threaded on both ends, did I loosen an end accidentally? Should I take it back off and remove the spring assembly from the side of the body? Since mine had a very short assembly on the side, is that the idle adjuster? How is it adjusted? Thanks for any help anyone can provide. [Response: Evan] Nope, the crud WAS the problem. Crud makes the car idle lousy and slow. Lazy mechanics simply dial up the idle to mask the problem, rather than fixing it. You just need to dial the idle back to spec. On the end of the butterfly shaft, the end where the spring is, there's a stamped metal plate. It has a 'leg' bent down that rests against the idle stop screw. The screw is held in place with a lock nut. loosen the nut and adjust the screw.

Hope this helps further if you can stop ROFLing.

Bill.