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Hi Guys,
Got a 1995 940 B230 with 140k with what I think is a rain/moisture problem.
Today on the drive home, she died and simply would not start. This happened about a week ago, and a few other times in the last year.
The engine dies, only when driving in rain/damp conditions. I replaced cap, rotor, and wires about a year ago. When it dies, it dies INSTANTLY. Then, it starts back up after 15-20 minutes, idling fine. However, it dies when you apply throttle. After idling about 10 minutes, it runs fine. I suspected something getting wet, as it only happens when damp conditions/rain are part of the situation. It also happened when I pressure washed the engine.
This time, it simply will not start. I had it towed home, put in my tiny garage, and I cranked up Qty 2 Salamander Kerosene ‘torpedo’ 50,000 BTU heaters. It was 110 degrees F in the garage for about an hour this evening.
My plan was to smoke out the water issue, but it still will not start.
I checked the timing belt, and it is ok.
Any other ideas? It cranks fine and everything looks ok.
I am stumped. Any other ideas?
I also turned out all the lights while my wife cranked the ignition, and cannot see any spark grounding out.
Jeremy in Central Massachusetts
1991 940, 1995 850, 1995 940, and my slightly rusty 1971 142e(under the tarp, but running ok)
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Well guys,
The brickboard is an asset of tremendous value. Your help allowed me to finally solve the problem. It was indeed the Bosch Ignition Amplifier, as everyone pointed at. I trundled off to my local boneyard in Worcester, MA. (Sam’s pull-a-part on Granite Street) and got another one for $5.
Same as this part:
http://www.eeuroparts.com/Main/PartDetail.aspx?id=3501921A
They have usually 3-8 940’s, a few 700’s, and this week had about 10 850/S70’s.
By the way, I really like eEuroparts.com, those guys are great. The only problems is that I need the part immediately instead of overnight sometimes.
I plugged in the new Ignition Amp and it fired up perfectly. I put a thin coat of heat sink compound on the back, cleaned the inner fender, and seated it as it should be.
Systematic, logical, troubleshooting help is what you get here on the brickboard.
Happy Holidays and many thanks again to all who helped me solve this one.
Jeremy
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Good going!
Don't forget you have a low-mileage distributor cap laying around as a spare.
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i live in central mass and will give you hand if you get real stuck.
our family has several 940's in the fleet
have your verified you crank sensor is good.
your problems is either a missing signal or some other electrical problem. i seriously doubt fuel is the cause.
the instant killing of the engine strongly yells electrical.
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No, I have not yet verified that the crank sensor is either good or bad.
When I crank the engine and try to start, the tachometer never moves at all.
In the 700/900 FAQ, it is mentioned that the tach moves when the "Hall effect sensor" is working, but does not mention the crank sensor
I will read the crank sensor test procedures and see if I can test it.
Thanks for your help!
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you do not have a hall sensor.
remove the connector on the firewall near the upper rear middle. the connector connects the cranks sensor to the harness...the sensor can easily be seen on a 95 940. it is the wire which bolts to the top of the transmission bell housing. anyway disconnect that and get a multi meter and set for 200 or so ohms and read the ohm between 2 of the 3 spades. i forget which two. a good sensor should read around 180 ohm.
if you have an open ohm reading the sensor is dead.
alternatively get someone to start the car while you jiggle the sensor wire on the bell housing and see if it starts for you.,
http://www.eeuroparts.com/Main/PartDetail.aspx?id=3547847
on top of the bell
while this one is on inner left front fender
http://www.eeuroparts.com/Main/PartDetail.aspx?id=3501921A
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Found it with no problem, just as you stated. I measured 167 ohms between pins 2 and 3. Connector is at the top of the firewall and plugs right into the harness.
Sounds like it is ok, right? Where next.......
Ideas?
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Determine if you are lacking spark of lacking fuel.
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I pulled 2 plugs. Both are wet with fuel, and I smell fuel when cranking. Must be spark, right? Ideas?
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I'll assume you have a non-turbo with Rex-Regina engine controls....
Take the coil pack apart and clean the internal contacts and all mating surfaces including the unit's contact with chassis ground. It doesn't cost anything to do this and it's a known source of ignition problems on these cars.
Also consider the Crank Position Sensor (alias RPM sensor) may be going bad. Reading out the error codes via the OBD display may give hints of this. The instructions are in the the 700/900 FAQs if you've not done it before.
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Hi Chris,
Mine is a Bosch system, as I checked the 700/900 FAQ to confirm. I also checked the coil resistance with my fluke, and it is within specifications. 0.9 ohms from 1 to 15 and 7.3k ohms from 15 to the high side.
I know how to pull the codes from the On board diagnostics, and there are no codes shown.
I am going to test the RPM sensor next, but still at a loss…. I took today off work to try and get her going again.
Many thanks for your help. It is greatly appreciated.
Anybody else have any ideas on why this thing will not start?
jeremy
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I believe one of the weak links in the Bosch ignition is the ignition amplifier. I'm not positive about your car, but it may be mounted to the LH inner fender, just behind the headlight. Someone more "940 Bosch" familiar might shine some light on that location. People have reported problems with that part particularly when it heats up. I've also read where unscrewing it and cleaning the mounting surface helped. (Also a very light coating of dielectric grease between it and the fender panel has been mentioned to help promote more efficient heat-sinking to the chassis.)
Have you looked inside the distributor cap lately to see if all is well in there? No oil leakage out of the rear cam seal?
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Hi Chris,
Yes, I am just now starting checking the ignition amplifier out. I found it just behind the air box as noted on the 700/900 FAQ.
This is the animal:
http://www.eeuroparts.com/Main/PartDetail.aspx?id=3501921A
I plan to check pins at this connector next. It is a mad dash to get it running again!
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Hi Chris,
I went ahead and purchased another complete new distributor cap and rotor and installed this afternoon. Still no spark....
When I pull the coil wire off the distributor cap and place the end near a good ground conductor on the car, there is no spark. I am having a friend crank the car while I watch during that test.
The crank sensor tested out ok, perhaps the engine computer is next.
I am at a loss now.... ideas...?
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Check to make sure you have voltage at fuse #1. That fuse supplies the ICU. If there is voltage there, replace the ignition amplifier.
If you cannot get spark after the replacing the amplifier, then suspect a bad ICU. Unusual though as they are fairly reliable. Have you checked all the various susceptible grounds(2 fuel rail, behind battery etc)? PS. The Bosch ignition amplifiers when blown are dead, cleaning and regreasing wont help, need new.
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This was it! I had 12v at Fuse 1 just as you asked. I went to the boneyard to get another Ignition Control Module (Bosch Amp). See post above and many thanks!
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"...Have you checked all the various susceptible grounds..."
Good point. If you look at the inner fenders again, just behind the headlights, you should find some ground lugs that are attached there. Both the lug spades and/or the attachment to the inner fender can be points of failure (or intermittant continuity. I'm not sure if these grounds play into the ignition system or just the fuel injection.
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