My 93 volvo 940 base is still dying. Last time I changed the fuel pump relay, cleaned the MAF sensor, and gutted the catalytic converter. This was to see if it would stop dying.

1. When driving twice the car shuddered then seemed to stop accelerating. I pulled over, it died. I restarted, then it drove fine.
Today I was driving, i felt it stop accelerating, pulled into the middle lane, coasted a bit then pressed the gas and it picked back up and went, then no more problems.

2. My overdrive light had been flickering on and off now for a week or so along with being dim then getting brighter. Then after some point after 5-10 minutes it shuts off. Do you guys recommend the overdrive bypass kit for this problem?

 

1. sounds like it /could/ still be fuel pump related, but its hard to say. also still could be an MAF problem but those typically throw codes you can read on the OBD-I module, and most of those codes will light the 'check engine' light on the dash.

re: question 2, is it kicking in and out of OD when the light is flickering (assuming your cruising somewhere over 40 MPH with light throttle at the time). if the problem is with the OD relay, or button wiring, instead of doing the solenoid bypass, you could try pulling the OD relay, and shunting pin 1 to pin 3 on the socket (pin 1 is also called '15' on the relay, and pin 3 is '87'), this shunt will activate the solenoid always, so you'll always be in OD mode (the actual OD is automatic inside the transmission... depowering the solenoid disables OD). the light will be off as long as the relay is removed, since its powered from pin 5 (87A) [and is inverse logic... ground to pin 5 lights it]

 

For issue #1, I would check your crank position sensor. It is located at the top of the bell housing where the engine and transmission are joined. It has a thick black wire that goes to a connector on the firewall. If the insulation is cracked and fraying, its time for a new one.

I believe that 940s have a radio suppression relay as well that should be checked. As I don't own a 940, I am not as familiar with the location of the relay but you can do a search on the forums here and you should be able to locate it and how to diagnose.

 

the RP relay on a 940 is near the left suspension tower. easiest way to test it is to unplug an injector, turn the ignition on (without starting engine), and measure the voltage from one of the injector connector pins to engine ground. if the relay is working, you should see 12V on one of the pins (nada on the other). if you see 12V, the relay is working, if you don't, time to figure out why.

 

*Update*
I replaced the crankshaft position sensor and had no problems for a couple weeks. Then it died again, so I replaced the Radio suppression relay(which looked original). My car drives great now except it still is stalling out.

It died driving and while stopped. It sometimes shudders, and the rpms drop down to zero, lose power steering, and it shuts off. So i put it in park, try to restart and it doesn't always want to start sometimes waiting 5 minutes.

It happens when the car is cold, so no overheating problems. I pull out of my driveway and within a minute it shuts down. It seems random, and no specific things I can attribute to it.

 

when it doesn't start, does it crank over and just not catch, or does it not even crank ?

You need to figure out if its spark or fuel thats missing.

a 1993 940 could be Bosch LH2.4, or Regina/Rex fuel injection and ignition. troubleshooting varies between these two systems. Bosch systems have a traditional round 'beer can' ignition coil, while Regina/Rex systems have a rectangular ignition coil that looks like a transformer and has the power module integrated into it.

 

It cranks over and doesnt catch.

I have a Regina system and the ignition coil was changed last July.

 

I'd start with this checklist.
Engine Tune and Performance

 

Thanks pierce, ill get right on that!

 

I think I found/fixed the problem. One of the fuel injectors was getting pinched and got it to die by wiggling it a little bit. So I let it get free a little bit and it hasnt died in two days.

 

Main problem now is the car dying at stops. I have these codes. 2-2-3(IAC Valve), 1-3-2(battery voltage too high/low), and 1-2-2(Air temp sensor).

2-2-3 (Signal missing to/from idle valve) . I tried cleaning it to see if it would help(it didn't). I believe that my IAC might be dead from what I read. Before I drop money on a new one, is there anything I can do to confirm that this is the problem.

 

the diag box has a test mode, and one of the tests it runs cycles the idle air valve on/off/on/off .... so you hook it up when its not bolted in and blow through it, if it chops the air, its good, if it doesn't, its not.

see 'DTM 3' here, on socket 2 => Engine and OBD Diagnostic Codes

 

While doing the IAC valve test(Which works). I found a cracked leaking fuel line. Do they sell these rubber hoses at the auto parts store? And is there anything I should do, probably disconnect the battery, when changing this?

 

make sure you get high pressure fuel injection lines, and not low pressure fuel hoses. its a metric size, 6mm? I forget. BMW fuel hose is what I used on my motorcycle (also fuel injected), a local VW-centric parts shop said they use that for everything, sold it by the foot.

 

Correct me if I'm wrong, but the line circled in the picture is a low pressure return line. You should be able to get that at an auto parts store.

 

it is the return line, but I still think you should use fuel injection rated hoses for the whole fuel system. if the return line plugged up somehow, 50+ PSI of pressure could develop in that line.

 

I replaced the return line. And now my idle is at around 100. Perhaps that could be something with the IAC test yesterday. Before I replaced the line I relieved the fuel pressure(by disconnecting the fuel pump relay). The car started fine then the idle dropped to the 100 mark. After putting everything back together, it still remained at the same level. What recommendations now? lol

 

sure the IAC is plugged in? it should be idling around 600-700rpm

 

gah yes. silly me. it wasnt all the way clicked in, just lying there lol. thanks for the help pierce, master mechanic lol.