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93 850 the dreaded warm start problems, cranks but no start

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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Jaydiesel
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Joined: Fri Aug 04, 2017 6:58 am
Year and Model: 95 850 T-5R, 00V70R
Location: Florida
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Jaydiesel

Re: 93 850 the dreaded warm start problems, cranks but no start

Post by Jaydiesel » Sat May 23, 2020 3:21 pm

Have you resolved your issue yet?

93ForMe
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Joined: Sun May 17, 2020 4:46 pm
Year and Model: 1993 850
Location: Portland
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93ForMe

Re: 93 850 the dreaded warm start problems, cranks but no start

Post by 93ForMe » Sat May 23, 2020 3:46 pm

Jaydiesel wrote:
Sat May 23, 2020 3:21 pm
Have you resolved your issue yet?
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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Jaydiesel
Posts: 10
Joined: Fri Aug 04, 2017 6:58 am
Year and Model: 95 850 T-5R, 00V70R
Location: Florida
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Jaydiesel

Re: 93 850 the dreaded warm start problems, cranks but no start

Post by Jaydiesel » Sat May 23, 2020 4:46 pm

Sounds like your getting super close. keep us posted. Interested because all the different warm start issues everyone has over the years.

93ForMe
Posts: 13
Joined: Sun May 17, 2020 4:46 pm
Year and Model: 1993 850
Location: Portland
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93ForMe

Re: 93 850 the dreaded warm start problems, cranks but no start

Post by 93ForMe » Sun May 24, 2020 2:37 pm

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...

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