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post #1 of 13 (permalink) Old 10-08-2012 Thread Starter
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940 turbo won't start, lots of troubleshooting already done. I'm stumped.

I am having a problem with our '94 Volvo 940 turbo. It had no problems with it Friday, and it was running fine when my wife parked it at about 9:00 PM. Saturday morning, the battery was dead. Not completely flat, but only had about 6 volts. I couldn't even get the car to crank on the heavy duty charger. I left it to charge for about 3 hours, and it took no charge. She mentioned a couple days before that she smelled sulfur, which I attributed to a cat going bad. When I pulled the battery out, it had no water in it at all.

So, I put in a new battery, and now the car was cranking fine, but wouldn't start. IT wouldn't even sputter. Thinking it was possibly flooded, I pulled all the plugs which were totally soaked with gas. I cleaned the plugs & dried the cylinders by lighting a grill lighter by the plug holes (I know, bad idea, but I learned it from an old school mechanic & it was all I had the patience for at the time...). Still nothing.

I checked that it was getting spark by plugging a boot from each wire onto a plug and laying it across the intake manifold and cranking the engine. All were getting good spark. Still nothing.

I replaced the obviously worn cap & rotor, still the problem persists.

Our gas door broke off a while ago, and once my wife forgot the gas cap when it was raining, and we got a bunch of water down in the gas tank. I thought that maybe since these have a little area that tends to hold water that may have held enough water to seep in under the gas cap (we got a LOT of rain Friday...). So, I drained all the fuel and refilled the tank, still to no avail.

I have also checked the fuel pressure & all the temp sensors, all are fine.

So, after all this, I still can't get this thing running again. Any thoughts?
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post #2 of 13 (permalink) Old 10-08-2012 Thread Starter
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Update:
I farted around with this thing, pulling the plugs and thoroughly cleaning the plugs and drying the cylinders out. I hit it with some starting fluid and it sputtered and finally caught, misfired like mad, and smoothed out.

It still will not idle, and misfires occasionally if I hold it around 2k RPM. I have a fuel pressure tester, and part of the assembly has a transparent tube with a petcock on it to allow flow (this is how the fuel was drained). The position of said tube was where there was some fuel left in it, and I noticed little bits of bubbles flowing out of the closed (but apparently not totally sealed) petcock. I opened it up, and severely aerated fuel started flowing through it.

I may have a leak of some sort in the in tank plumbing, as I have no external fuel leaks. Is there an access panel or do I need to drop the tank?
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post #3 of 13 (permalink) Old 10-10-2012 Thread Starter
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Update 2:
I pulled the sending unit out, thinking the hose from the in tank pump to the flange may be leaking, and it is not. I double checked the pump, and it is also running fine. I will put it back in tonight and see what happens.

Another question. Why does the unit have that section that slides up and down? What purpose does that serve?
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post #4 of 13 (permalink) Old 12-18-2012
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What did you end up finding wrong with it ??
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post #5 of 13 (permalink) Old 12-18-2012 Thread Starter
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Nope. I did charge the battery and change the plugs, and it did start after that. But it still runs rough and takes spells of not starting, especially when it has been raining.
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post #6 of 13 (permalink) Old 12-18-2012
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You might want to try some "Heat" or isopropyl alcohol in that fuel to take out any remaining water that may have settled in the bottom of the tank. That and replace the filter as water may be hiding in there.

The fact that's it's hard to start or poor running when it's raining sort of fits with bad ignition wires. With insulation that's starting to crack the electrical energy "leaks" out and jumps to ground instead of across the plugs gap. Just a thought.
If you take a spray bottle with just plain water and mist the wires with the engine running later in the day when it's dark if they are bad you will hear and maybe see that spark snap to ground.
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post #7 of 13 (permalink) Old 12-19-2012 Thread Starter
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Quote:
Originally Posted by kiss4afrog View Post
You might want to try some "Heat" or isopropyl alcohol in that fuel to take out any remaining water that may have settled in the bottom of the tank. That and replace the filter as water may be hiding in there.
The thing is, the car has been running "OK" for several weeks now with only minor hiccups.

Quote:
Originally Posted by kiss4afrog View Post
The fact that's it's hard to start or poor running when it's raining sort of fits with bad ignition wires. With insulation that's starting to crack the electrical energy "leaks" out and jumps to ground instead of across the plugs gap. Just a thought.
I have done this, and there are no sparks.

I am leaning toward some computer getting wet or a bad sensor.
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post #8 of 13 (permalink) Old 12-19-2012 Thread Starter
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Speaking of which, where the devil IS the crank sensor on this car?
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post #9 of 13 (permalink) Old 12-20-2012 Thread Starter
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Since my wife got stranded 30 miles away from home today with her mom and our toddler, I decided to replace the crank sensor

Found & replaced the crank sensor.

Let's see if this fixes it.

Here is the old one...


'94 volvo crank sensor wires by rtuite81, on Flickr
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Not sure what's in your picture but for anyone who comes across this post the crank sensor is sticking straight up from the transmission where the bell housing connects to the block. Straight up with a loom coming out of it.
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post #11 of 13 (permalink) Old 01-05-2013 Thread Starter
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My picture is the wiring pigtail from the sensor to the harness. The insulation was crumbling off, and the shielding layer was ineffective as it was no longer being held around the wires.

I did finally find it. It is not visible unless you can look strait down between the firewall and the back of the head. I found it by tracing that pigtail down to the sensor.

I am happy to report that since changing that sensor 2 weeks or so ago, we haven't had any problems.

It still "stutters" idling, especially in gear, but it has done that since we got it. I believe the IAC is at fault there.
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post #13 of 13 (permalink) Old 01-23-2013 Thread Starter
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I don't think this is related, but I am going to post here anyway because the history of what I have done should be included.

The car quit again a couple weeks ago, and got stranded again. This seems different though because there was no spark. Before there was spark, but it just wouldn't start. It was getting a bad signal from the crank sensor and not able to time the injector pulses.

Finally got into checking it out Sunday night, and there was NO voltage to the injectors or the coil. Traced the problem down to the fuel injector system relay. Pulled the cover off of it and there were several cold solder joints, so I reflowed them all, put it back in, and the car started right up! Literally, cranked for 5 seconds, and it started and ran great.

The car wasn't driven Monday, and we got a severe cold snap here in central Indiana. Our ambient temps are 5-10 farenheit, and wind chills of -5 to -15 (though wind chill doesn't affect cars so much...) Anyway, I went out and the bugger wouldn't start. It woiuld occasionally sputter, but just not start. After 5-10 minutes of cranking (not continuously) it finally started. Once it started, it ran fine.

Is this an issue with the coolant temp sensor? Sounds like the computer is trying to flood the car. Is there a separate sensor that feeds the computer information than the gauge? I know my old '86 BMW has like 5 coolant sensors for different systems, but I would think this was a little more advanced.
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