93 850 the dreaded warm start problems, cranks but no start Topic is solved
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93ForMe
- Posts: 30
- Joined: 17 May 2020
- Year and Model: 1993 850
- Location: Portland
- Has thanked: 6 times
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Maybe. I should know tomorrow if it is good. Since I pulled the Engine Computer and put it back in, my 850 has been running and starting very rough all the time. The intermittent problem went away, now it is bad all the time! The coil arrived yesterday and I just put it in. Still really hard to start and stalled out just idling. The coil tested within spec, so I think that I can rule that out as the problem.
I then pulled both computers, pulled apart the entire computer compartment and got down to all the wiring. Some of the wires were coated with an oily substance that seemed to be leaking from the back of the computer bay. I soaked all the connections with electronics cleaner, let it dry, then blew it all out with compressed air and put it back together. After that the volvo started right up and ran very smooth. I turned it off and restarted it five times. Each time it started right up without any hesitation.
When the car reached operating temperature I did the voltage drop test between the positive battery cable and the starter motor and got a reading of 0.03V which, from what I am reading, is within spec.
So if tomorrow I can start it up, drive it two miles, turn it off and it starts again, my weird problem may be solved!
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93ForMe
- Posts: 30
- Joined: 17 May 2020
- Year and Model: 1993 850
- Location: Portland
- Has thanked: 6 times
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I just took it out for a test drive. It has been about 24 hours since I last started it after I cleaned the wiring in the computer bay.
It started right up first crank. No hesitation from the starter, no hard starting from the engine at all. I took it on the two mile loop in my neighborhood that I have found can cause the problem symptoms 100% of the time. My 850 accelerated so smoothly, no choppiness at all. It was also idling beautifully, very smooth. I reached the end of the loop back at my home just as the temp gauge reached center. I turned it off and waited three minutes before attempting to start.
Crank-crank-crank Catch, Chug, stop. Then just crank-crank-crank
I went inside for 30 minutes, came back out, went to start it, and it started just fine, first crank. I waited for it to warm back up to the needle at center, turned it off, waited three minutes. Starts right up, first crank, no hesitation.
I still have my problem!
I really don't think that it could be the starter at this point. It operates flawlessly and the car starts easily every time except for when I drive 2-4 miles the first time each day.
It does seem temperature related, albeit in a very narrow range. I cleaned the wiring on both the ECT side and the computer side. Perhaps somewhere along the way resistance is increasing and the car thinks it is colder than it is. Would this cause it to dump too much fuel into the warming engine which would keep it from starting?
Or maybe it is computer related?
I found en exact match for both the Engine and Ignition computer online for less than $30 combined, so since I have tried almost everything else I will try this avenue while I also look to find a wiring diagram for the ECT to see if there are more connections to spray out...
It started right up first crank. No hesitation from the starter, no hard starting from the engine at all. I took it on the two mile loop in my neighborhood that I have found can cause the problem symptoms 100% of the time. My 850 accelerated so smoothly, no choppiness at all. It was also idling beautifully, very smooth. I reached the end of the loop back at my home just as the temp gauge reached center. I turned it off and waited three minutes before attempting to start.
Crank-crank-crank Catch, Chug, stop. Then just crank-crank-crank
I went inside for 30 minutes, came back out, went to start it, and it started just fine, first crank. I waited for it to warm back up to the needle at center, turned it off, waited three minutes. Starts right up, first crank, no hesitation.
I still have my problem!
I really don't think that it could be the starter at this point. It operates flawlessly and the car starts easily every time except for when I drive 2-4 miles the first time each day.
It does seem temperature related, albeit in a very narrow range. I cleaned the wiring on both the ECT side and the computer side. Perhaps somewhere along the way resistance is increasing and the car thinks it is colder than it is. Would this cause it to dump too much fuel into the warming engine which would keep it from starting?
Or maybe it is computer related?
I found en exact match for both the Engine and Ignition computer online for less than $30 combined, so since I have tried almost everything else I will try this avenue while I also look to find a wiring diagram for the ECT to see if there are more connections to spray out...
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Ocelot
- Posts: 172
- Joined: 4 October 2018
- Year and Model: 1998, S70
- Location: Hattem
- Has thanked: 61 times
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Okay, I might have a suggestion, don't know if it will work for you. I had a similar problem with a friends Ford Sierra. He replaced pretty much all parts you mentioned. But the car wouldn't start with a warm engine. We got so desperate we went to our old teacher (from the mechanics school) for help. He said to look if there's not too big a gap between the crankshaft sensor and the flywheel. When the gap is too big (and it was) the ECU doesn't get any signal. Another suggestion he gave us was to look if the camshaftsensor wasn't drowned in oil due to a faulty oil seal. We also found that the positive cable from the starter was way close to the crankshaft sensor, possibly interfering it with it's magnetism. I'm really grinding my gears trying to figure out your problem, I hope this somewhat helps!
'Hij die zonder zonde is, werpe de eerste steen. Ik buk wel'. Simon Carmiggelt
Recent car
'98 Volvo S70 2.5 10V Europa edition (Freya)
'83 Volvo 340 DLS 2.0 redblock (Loki)
Previous owned Volvo's
'96 Volvo 440 Si 1.8
'87 Volvo 340 GL 1.7
'85 Volvo 340 DL 1.4
Recent car
'98 Volvo S70 2.5 10V Europa edition (Freya)
'83 Volvo 340 DLS 2.0 redblock (Loki)
Previous owned Volvo's
'96 Volvo 440 Si 1.8
'87 Volvo 340 GL 1.7
'85 Volvo 340 DL 1.4
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93ForMe
- Posts: 30
- Joined: 17 May 2020
- Year and Model: 1993 850
- Location: Portland
- Has thanked: 6 times
- Been thanked: 1 time
First of all, thanks for helping me think through this! This problem has been driving me crazy
Is there a way to measure this distance on an 850? The sensor just gets inserted into a hole and screwed down. I have tried two Volvo sensors, both the same length.
When I switched out the camshaft sensor, the port that it mounts in was clean and dry.Another suggestion he gave us was to look if the camshaftsensor wasn't drowned in oil due to a faulty oil seal.
I have been doing my best to keep wires tied away from each other and away from heat sources wherever I can.We also found that the positive cable from the starter was way close to the crankshaft sensor, possibly interfering it with it's magnetism. I'm really grinding my gears trying to figure out your problem, I hope this somewhat helps!
All your suggestions really help me. I did not know very much about the inner-workings of cars before I embarked on this problem, so every idea opens up a new path for me.
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93ForMe
- Posts: 30
- Joined: 17 May 2020
- Year and Model: 1993 850
- Location: Portland
- Has thanked: 6 times
- Been thanked: 1 time
So I have a bit of an update:
The Engine computer arrived. I installed it. No change.
I have been thinking a lot about the things that misha had said about the ECT sensor. I have cleaned the hell out of the connectors on both the ETC side and on the Computer side. However this problem just seems so temperature related, I decided to dive a bit deeper.
I pulled apart the connector that the ECT plugs into and saw that the female barrel connectors were surrounded with a translucent rubbery substance. This means that all the spaying into the connector may not have cleaned things as well as I had first thought.
https://photos.app.goo.gl/sAuQm4zu57SCzML48
At the base, this material was beginning to crumble. I cut away at it with a knife to reveal where the stranded copper wire is crimped to the barrel and saw quite a bit of green corrosion.
https://photos.app.goo.gl/A6L7hAsM6KQSJ7jXA
I soaked the barrels in vinegar for a couple of hours, then neutralized with baking soda. I then sprayed it all out with Electronics cleaner.
When I reassembled the connector, the barrels just pushed out when I tried to plug the two connectors back together because the rubbery material was no longer as long as it used to be. I probably could have thought of something better, but I just bulked up the end with electrical tape and crammed everything back together.
It had been six hours since my last test drive, so I did another two mile loop, turned my 850 off, went to start it, and it started right up!
I am not going to call it fixed yet. I am going to let it sit overnight and do the 2 mile loop in the morning under the conditions that have given me 100% start failure. We'll see what happens then...
The Engine computer arrived. I installed it. No change.
I have been thinking a lot about the things that misha had said about the ECT sensor. I have cleaned the hell out of the connectors on both the ETC side and on the Computer side. However this problem just seems so temperature related, I decided to dive a bit deeper.
I pulled apart the connector that the ECT plugs into and saw that the female barrel connectors were surrounded with a translucent rubbery substance. This means that all the spaying into the connector may not have cleaned things as well as I had first thought.
https://photos.app.goo.gl/sAuQm4zu57SCzML48
At the base, this material was beginning to crumble. I cut away at it with a knife to reveal where the stranded copper wire is crimped to the barrel and saw quite a bit of green corrosion.
https://photos.app.goo.gl/A6L7hAsM6KQSJ7jXA
I soaked the barrels in vinegar for a couple of hours, then neutralized with baking soda. I then sprayed it all out with Electronics cleaner.
When I reassembled the connector, the barrels just pushed out when I tried to plug the two connectors back together because the rubbery material was no longer as long as it used to be. I probably could have thought of something better, but I just bulked up the end with electrical tape and crammed everything back together.
It had been six hours since my last test drive, so I did another two mile loop, turned my 850 off, went to start it, and it started right up!
I am not going to call it fixed yet. I am going to let it sit overnight and do the 2 mile loop in the morning under the conditions that have given me 100% start failure. We'll see what happens then...
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93ForMe
- Posts: 30
- Joined: 17 May 2020
- Year and Model: 1993 850
- Location: Portland
- Has thanked: 6 times
- Been thanked: 1 time
So this morning I fired up the 850 and did the two mile loop that has allowed me to replicate the crank but no start issue 100% of the time. I turned the car off for three minutes, then went to start it. It started right up! No hesitation at all. I think that I have finally found the issue and solved it.
What I am guessing was the source of the problem was that due to the corrosion on the wiring harness side of the ECT sensor connection, the resistance increased, causing the computer to think that the engine was cooler than it really was. When I tried to start the warm engine, the computer would dump too much gas into the combustion chamber, which would cause it to not ignite. If I waited for it to actually cool, it would start right up again.
All the other things that I fixed along the way did seem to improve things as I was doing them. I think fixing the vacuum leak, cleaning the MAF, cleaning the idle air control valve all narrowed the range of when this issue was a problem. And once the engine was heated up all the way, the range between the ECT sensor reading and the reading that the computer was getting through the corrosion was close enough that it didn't throw things off nearly as much.
If my Volvo had been in tip top shape and I lived somewhere where I needed to drive more than six miles to reach a destination, I would never know that I even had this problem until the corrosion got worse and made it not start when fully warm, I am guessing.
I wonder if this corrosion is the source of many warm/hot start issues that have been unresolved over the years?
One thing I am not too happy about was the way I repaired the female end of the ECT sensor connection. I just wrapped it in electrical tape and jammed barrels into the housing and taped it all together. I did spray the wires with DeoxIT D5, which should provide some corrosion protection, but I'm not sure how long it will last. I will probably get a connector from a junkyard and refurbish it, then splice it into my 850.
I'll do the test drive for a couple more days just to be sure before I call this completely solved, but right now I am feeling pretty good about it!
What I am guessing was the source of the problem was that due to the corrosion on the wiring harness side of the ECT sensor connection, the resistance increased, causing the computer to think that the engine was cooler than it really was. When I tried to start the warm engine, the computer would dump too much gas into the combustion chamber, which would cause it to not ignite. If I waited for it to actually cool, it would start right up again.
All the other things that I fixed along the way did seem to improve things as I was doing them. I think fixing the vacuum leak, cleaning the MAF, cleaning the idle air control valve all narrowed the range of when this issue was a problem. And once the engine was heated up all the way, the range between the ECT sensor reading and the reading that the computer was getting through the corrosion was close enough that it didn't throw things off nearly as much.
If my Volvo had been in tip top shape and I lived somewhere where I needed to drive more than six miles to reach a destination, I would never know that I even had this problem until the corrosion got worse and made it not start when fully warm, I am guessing.
I wonder if this corrosion is the source of many warm/hot start issues that have been unresolved over the years?
One thing I am not too happy about was the way I repaired the female end of the ECT sensor connection. I just wrapped it in electrical tape and jammed barrels into the housing and taped it all together. I did spray the wires with DeoxIT D5, which should provide some corrosion protection, but I'm not sure how long it will last. I will probably get a connector from a junkyard and refurbish it, then splice it into my 850.
I'll do the test drive for a couple more days just to be sure before I call this completely solved, but right now I am feeling pretty good about it!
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93ForMe
- Posts: 30
- Joined: 17 May 2020
- Year and Model: 1993 850
- Location: Portland
- Has thanked: 6 times
- Been thanked: 1 time
Okay, I'm back to say that my entire attempt to fix this problem has been a HUGE red herring. I can say that I have now fixed the problem and it has been over a month , and the problem appears to be gone for good. Here is what happened:
So, as I posted earlier in the thread, I thought that the issue was fixed, except every now and again there would be a slight hick-up. I told myself that it was nothing and went along happy as could be. It was getting into the summer months, warm and dry. One morning I got up and it had been raining, first time in weeks. I went to start the Volvo and it was hard to start, but finally did. Wow, worse than before. I put it in gear and started driving. It lurched and stumbled for about 1.5 miles before it died completely. I coasted into a parking lot and it would not start. I waited a half an hour, turned the key in the ignition, and it started right up and ran fine the rest of the day.
The next morning, still raining, I started the car and drove around the block a couple times, got back home and turned it off. I then tried to restart it, but no luck, crank-crank-crank, almost start, die.
I took off the distributor cap and there was moisture inside! My old mechanic had just replaced the distributor and it was brand new, so I didn't look at that during my original troubleshooting. Big mistake! What was causing this moisture? I then removed the rotor and I tried to remove the plate that the rotor was mounted to, but it was completely stuck. Two days and a lot of Kroil later, I was able to pry it off. Where the plate mounted to the engine was badly corroded. The rear-cam seal behind it looked fine, and it was not leaking oil. I pulled it and saw on the side that it looked compromised on the upper part. There was a line of varnish from the back to front. I replaced it, put everything back together and everything has been working flawlessly ever since.
What I think was happening was in the morning when I first started the car, moisture in the engine was being forced out the compromised rear cam seal into the distributor causing arching and the car to miss. By the time things got bad enough to stall, the engine was already partway warm. If the car then stalled, the heat of the engine evaporated all the moisture in the distributor over a half an hour or so. After that the car would start just fine and run just fine the rest of the day.
I think that I can now call this truly solved!
So, as I posted earlier in the thread, I thought that the issue was fixed, except every now and again there would be a slight hick-up. I told myself that it was nothing and went along happy as could be. It was getting into the summer months, warm and dry. One morning I got up and it had been raining, first time in weeks. I went to start the Volvo and it was hard to start, but finally did. Wow, worse than before. I put it in gear and started driving. It lurched and stumbled for about 1.5 miles before it died completely. I coasted into a parking lot and it would not start. I waited a half an hour, turned the key in the ignition, and it started right up and ran fine the rest of the day.
The next morning, still raining, I started the car and drove around the block a couple times, got back home and turned it off. I then tried to restart it, but no luck, crank-crank-crank, almost start, die.
I took off the distributor cap and there was moisture inside! My old mechanic had just replaced the distributor and it was brand new, so I didn't look at that during my original troubleshooting. Big mistake! What was causing this moisture? I then removed the rotor and I tried to remove the plate that the rotor was mounted to, but it was completely stuck. Two days and a lot of Kroil later, I was able to pry it off. Where the plate mounted to the engine was badly corroded. The rear-cam seal behind it looked fine, and it was not leaking oil. I pulled it and saw on the side that it looked compromised on the upper part. There was a line of varnish from the back to front. I replaced it, put everything back together and everything has been working flawlessly ever since.
What I think was happening was in the morning when I first started the car, moisture in the engine was being forced out the compromised rear cam seal into the distributor causing arching and the car to miss. By the time things got bad enough to stall, the engine was already partway warm. If the car then stalled, the heat of the engine evaporated all the moisture in the distributor over a half an hour or so. After that the car would start just fine and run just fine the rest of the day.
I think that I can now call this truly solved!
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