'02 V70 Turbo w/126K cranks and cranks and then starts

skisix38off · Post by **skisix38off** » 03 Dec 2010, 06:34

Hi all,

I'm fairly new to this forum but not new to cars, I mostly work on restoring my 1978 Pontiac Trans AM, and enjoy a trouble free ride on my '02 V70 turbo with 126K miles- until recently.

I've searched through this forum to find answers and I have found some leads to pursue and those have not yielded any positive results.
Here's the situation; I get into the car first thing in the morning and I turn the key and it turns over a couple times and fires. After sitting from my morning commute by lunch time I get in, turn the key and it will sometime, not every time, crank and crank but not fire, then throws a "reduced preformance" message and then has always started. After it does fire, the exhaust smells very rich for a bit. It runs normally and eventually, within minutes, the "reduced performance" message extinguishes and it run normally.

Things I've done- I replaced the evap purge valve, the spark plugs, not long ago the fuel pump and battery were changed.

I've read that some people have had luck changing the coolant temp sensor- my dashboard gage reads normally but, where is this sensor and I can try it.
Any other suggestions? I don't find service shops/dealers to be very useful on intermittant issues like this and they get very expensive...

Thank you and I look forward to your suggestions.

Post by **jblackburn** » 03 Dec 2010, 06:52

Welcome, I've moved your post to the newer V70 (2001-later) section, so that's where you'll find replies. A link will remain here to it for a little while.

The coolant temp. sensor is located just under the thermostat housing where the top radiator hose goes into the engine. If you go to replace it, change the thermostat at the same time anyway.

Another thing I would check is your fuel pressure. There's a schraeder valve at the drivers side of the fuel rail. Flip the key to position II, then turn it off and check the pressure. It should hold; if it drops to 0 immediately, you've got a bad check valve on the fuel pump housing.

skisix38off · Post by **skisix38off** » 03 Dec 2010, 08:22

Sorry for posting in the incorrect area., thanks for getting me straightened out.

Is there a way to check the sensor- Does anyone have a chart of temp versus resistance or something like that. I have a DVM and could easily check that before I go buy more parts that don't yield results.

Thanks.

Post by **jblackburn** » 03 Dec 2010, 10:52

No problem - it happens a lot.

I do have resistance values, but they are for the 93-2000 cars. The sensor was the same on yours as the 1999 & 2000 models, so this might be the same.

ENGINE COOLANT TEMPERATURE SENSOR RESISTANCE TABLE

Temperature F ( C) Ohms
32 (0) .............................................. 7300
68 (20) ............................................. 2800
176 (80) ............................................. 300
212 (100) ............................................ 150

skisix38off · Post by **skisix38off** » 06 Dec 2010, 06:00

Ok, then my coolant sensor seems to function properly..... Hmmmm.
Anybody have any other checks to help me run this down?

Post by **jblackburn** » 06 Dec 2010, 06:45

Have you checked the fuel pressure?

skisix38off · Post by **skisix38off** » 06 Dec 2010, 11:08

I haven't checked that yet. Is that a typical schrader valve? The reason for not checking is that if I had a leak in the fueld delivery system, the car wouldn't run well after starting either because it wouldn't be able to build full pressure. After starting the car runs very well and is as strong as it ever was.

I could be wrong in my line of thinking here- please tell me if I am....

Greg

Post by **jblackburn** » 06 Dec 2010, 11:18

If it is just a problem with the fuel pump check valve, it will only have trouble starting since it has to build up pressure from 0 all the way to the front of the car, but it will maintain fuel pressure perfectly fine after it's going.

skisix38off · Post by **skisix38off** » 07 Dec 2010, 06:31

Ok, that makes sense. Thanks for teaching me something new!

Scudder02V70xc · Post by **Scudder02V70xc** » 08 Dec 2010, 16:57

Hi, New to MVS and am very grateful for everyones posts.

I have a 2002 V70 XC w/124,000 on it and had the same problem. No CEL came on but had "reduced engine performance" about 2-3 times a week and more oftern when warmer out. Had to take to dealer for service and mentioned it to them. Pulled codes that only they could read from memory.

Turns out that it was the RPM(aka crank sensor) that is located just below the cam sensor area. It is under all the turbo hoses and wiring harnesses. Tech pulled it our and showed me what appeares to be 124,000 miles worth of starter/flywheel wear that collected on the magnetic sensor. Aparently all the little metal pieces built up enough to cause intermitent signal problems. He recommended cleaning it and blowing out the area while it was out to reduce likely hood of it happening again.

After removing, cleaning, reinstalling, clearing all other codes car cranks fine every time. This was the most expencive($230) cup of Coffee and carwash I ever had but at least the car works properly again. Hope this helps if you havent found the cause yet.