1995 850 GLT long cranking to start, esp when hot

Post by **cn90** » 20 Sep 2013, 07:27

The answer is YES.
Remember the dash temp gauge is buffered so some changes in the "perceived" temp as registered by the ECT may not show a change in the dash gauge but enough to cause ECU malfunction (wrong fuel/air ratio).

The ECT is a very common issue in most modern cars. After 120K-150K in many cars, the ECT usually goes bad.

In fact, later year Volvo tstat is a combo of tstat and ECT in the same unit. This way when one replaces the tstat, one likes it or not, the ECT is replaced too. The engineers design it that way to simplify trouble-shooting process. For example 2007 V70 tstat assembly PN 31293698 is a combo of tstat and ECT.

Post by **jblackburn** » 20 Sep 2013, 08:02

Yeah, my temp sensor went bad too and make starting almost impossible when hot.

Post by **E Showell** » 20 Sep 2013, 12:00

+1 on the ECT. Always replace the thermostat when replacing ECT since a bad ECT can cause thermostat failure.

jrc1995wagon850glt · Post by **jrc1995wagon850glt** » 21 Sep 2013, 14:24

Thank you all so much, guys. I am not looking forward to dealing with a completely destroyed torx bolt that is among the pair holding the tstat housing on, but I will win and will be addressing the issue by monday hopefully. I have a now have a known good used ect on hand to try it out at least to diagnose (easy enough job- once i get the destroyed torx bolt out and replace with a good hex head) that I'm not too concerned if I have to do the job again soon- better than risking paying $50 to find out that it is something else. I will report back immediately upon confirmation one way or another. Thanks again and have a great weekend.

jrc1995wagon850glt · Post by **jrc1995wagon850glt** » 23 Sep 2013, 13:21

NO LUCK!!!! So frustrated!!! Swapped ECT with known good unit and zero difference in problematic symptoms. At least I replaced the torx bolts- one of which was destroyed and had to be drilled and extracted- with hex head bolts... ANY more ideas, anyone? Stumped beyond belief and no idea where to turn now...

Post by **jblackburn** » 23 Sep 2013, 13:24

Bummer.

Don't give up hope. I can think of a few other possibilities, and I'm sure others can as well.

Next time it's hot and doesn't want to start, take a towel, go to the fuel rail under the plastic cover @ the throttle body. Remove the cap, push on the valve with a screwdriver, and let a little fuel out.

If there IS no fuel pressure there...that's another problem.

There's also an EVAP purge valve near your battery on the radiator shroud. 3 thick black hoses connect to it, one going to the front of the intake manifold near the vac. tree. If it's not starting, disconnect that one and tape off the end so as to not create a vacuum leak. Try again.

Post by **erikv11** » 23 Sep 2013, 14:00

Have you yet tried swapping in the coil from the parts car? How about plug wires? Although that should give misfire codes. Oh, maybe the coil wire, try that.

When I see "won't start when hot" I think of resistance, which goes up with temp. So if something has a poor connection, then it will be exacerbated when hot. E.g. was very common for the 80s and 90s Camrys to have the starter fail only when hot, due to worn contacts creating a thin circuit connector (high resistance).

So anyway, you also want to make sure all the connectors are good with no frayed wires (I know, easy to say, nightmare to check ...). Can be a little easier I suppose if you focus on things related more to starting than to running in general, as you have posted.

Post by **rspi** » 23 Sep 2013, 20:41

Here is a video on pulling bad bolts.

jrc1995wagon850glt · Post by **jrc1995wagon850glt** » 24 Sep 2013, 07:20

Hello gentlemen, I have the opportunity to spend a little MORE time (UGH!!) trying to fix this and upon further inspection of air intake pathway, I noticed quite a bit of wet fuel and a bit of deposit build up at the the port which accommodates the flame trap (at least I'm just about positive that's the part that I'm looking at - immediately on engine side of flex hose from airbox/MAF assembly, positioned on portion of tube facing rear of vehicle, with a large and a small vac line on it, adjacent to throttle cable linkage). Shouldn't this be dry???!!! If so, please advise as to best manner to address the problem. Again, I really appreciate the insight from you all. Thank you again!!

Post by **rspi** » 24 Sep 2013, 08:28

You likely have a clogged PCV system. If you pull the cover off the top of the motor, is there oil up there around the spark plugs?

1995 850 GLT long cranking to start, esp when hot

Re: 1995 850 GLT long cranking to start, esp when hot