1995 850 GLT long cranking to start, esp when hot

jrc1995wagon850glt · Post by **jrc1995wagon850glt** » 17 Sep 2013, 17:40

Hello,

my '95 850 GLT (N/A) has myself and the local volvo specialist stumped. The car will start great most times if it has sat for 24 hours plus. Otherwise, it often requires holding accelerator to the floor while cranking (for anywhere from 5-15 seconds) until it catches and fires up. A few revs and it smoothes out and runs pretty well, but with poor fuel economy and certainly running rich (occasional black smoke and significant odor). Car runs like a dream on the highway and overall well anytime the car is given throttle. At idle, rpm will drop to about 450 then surge to about 1,100 before returning to normal idle speed. This seems to happen at about 10 second intervals. Brought it to local reputable volvo specialist and he said fuel pump was culprit due to sporadic loss of fuel pressure (indicated check valve built into pump). I replaced fuel pump and absolutely zero difference in behavior of the car and he confirms that rail is now holding perfect pressure. In checking this forum, I decided to check and replace with known good parts the following common issues: fuel pump relay, cam position sensor, crank position sensor, MAF sensor. No difference. All of these were from a friend's '96 850 N/A parts car, which runs excellent but has junk suspension and body. Of note, my dad's '98 V70 was having very similar issues starting and running rich, and the problem has been fixed by swapping out the MAF from my friend's donor car. The V70 is still starting and running great after 2 weeks. I did put brand new oem spark plugs in as well- also zero difference in behavior of car. The volvo specialist is now recommending a rear oxygen sensor ($220 part), as he "thinks it may be contributing to hard start issue" and is "likely a significant factor in running rich, stumbling and poor fuel economy". He did show me real time O2 reading with a Volvo reader while car was running and rear 02 sensor occasionally read negative voltage values (i.e -0.027V or similar value rather than +0.027V or similar), which he says should never happen. The values on both sensors did fluctuate a bit while running and he indicated that this is normal, but the negative voltage reading is absolutely not normal.
My understanding was that 02 sensors never cause difficulty starting because their inherent purpose only comes into place once the car is running. Any thoughts on this problem are greatly appreciated... Please, I am getting desperate with this thing!! Ha!! I have literally dozens of hours of wrench spinning and research into this, along with $85 for diagnostics to inform me to purchase and install a fuel pump, which I was able to get for a great deal thanks to my brother in law (manager @ parts store able to order OEM for me) for $100. If I figure my time being worth a meager $15/hr, this problem has already set me back at least $635 with parts and time and I have made zero progress!! As we know, the car is only worth a couple grand... I love the car, but getting to my wit's end with it!!! Thank you all so much in advance, your input is GREATLY appreciated!!

Post by **rspi** » 17 Sep 2013, 18:44

Does the car have a CEL?

Post by **rspi** » 17 Sep 2013, 18:47

Just reading the title made me think the coolant temp sensor is bad.

jrc1995wagon850glt · Post by **jrc1995wagon850glt** » 17 Sep 2013, 18:55

Sorry, forgot to mention that CEL indicates 02 sensor only, according to Volvo specialist. Using a cheapo universal OBDII reader I did get get a high voltage MAF code, but it did not return at all following clearing it out. Also, if it is ECT sensor would it be possible for it to malfunction and still indicate temperature accurately on dash gauge? It seems to operate as it always has- normal operating temp @ 3 0'clock and normal timeframe from start up to achieve same. Thanks again everyone!

Post by **Ozark Lee** » 17 Sep 2013, 19:38

The rear oxygen sensor really has nothing to do with starting and it has very little to do with the engine performance after the car is running. Its main purpose is to be a tattletale on catalytic converter efficiency. The rear sensor may or may not be bad but I would sort out the other starting issues before you just throw more parts at it.

Do you get black smoke when the car finally starts?

Does the fuel pressure hold after the car is turned off?

A leaky fuel injector could explain the problem since it would basically just drip fuel until the fuel pressure bled off. Similarly a bad fuel pressure regulator could cause your issues. To check the fuel pressure regulator just take the vacuum line off of it and see if it is dry. If it is wet and smells like gasoline then the diaphragm has ruptured which sucks raw fuel into the intake manifold.

...Lee

jrc1995wagon850glt · Post by **jrc1995wagon850glt** » 18 Sep 2013, 06:26

Hello Ozark,
Yes the fuel pressure holds at all times, whether running or off. I do get some black smoke at times, but not consistently. It appears that pressure regulator is good, considering pressure holds exactly at all times. My initial thoughts mirror yours in that I suspect something other than oxygen sensor causing hard starts- and I definitely do not want to throw parts at it, unless I now they are parts required to fix my problem- hence bringing to the local reputable Volvo specialist to accurately diagnose (though it seems that he has no clue hat the actual problem is either)... Really frustrated with this, its been a couple months of putting significant time into figuring this out to no avail. Again, thank you everyone who may have a thought on this...

Post by **shiloh51933** » 18 Sep 2013, 08:41

rspi wrote:Just reading the title made me think the coolant temp sensor is bad.

I had same thought after reading initial post and then I see your post...coincidence maybe.

Post by **cn90** » 18 Sep 2013, 08:59

I think rspi is right.

I had the same issues, a new ECT (Volvo or SWF brand only) is $45 at Volvo dealer.
There is a DIY in forum (just undo the upper rad hose) to gain access.

jrc1995wagon850glt · Post by **jrc1995wagon850glt** » 18 Sep 2013, 10:16

Hi guys,
Thanks for the input, it's greatly appreciated. Just to clarify, is it possible for the ect to be the culprit while it still shows temp accurately? Would it not show temp out of normal range if it were malfunctioning in any way? Could it malfunction and not throw a code? I am really hoping to avoid the continuation of throwing parts at the car to no avail... thanks much!

jrc1995wagon850glt · Post by **jrc1995wagon850glt** » 20 Sep 2013, 06:40

Hello gentlemen,
I'm hoping somebody mat be able to follow up re: possibility of ect issue (will it still show normal temps if it's malfunctioning?) and/or any other possible culprits with my 850?? Thanks everyone!!