2000 c70 2.3 HP Turbo rough idle in drive

jmenard · Post by **jmenard** » 10 Aug 2020, 07:13

Hello I really hope there's someone out there that can help me
I have a 2000 C70 HP Turbo that has a rather rough idle when I come to a stop in drive as well as in park but considerably less vibration. I have just recently cleaned the throttle body ( This is a rebuilt throttle body with the hall sensor that I did myself )
I also replaced most of the vacuum lines. And checked the PCv system and seems clean. The car seams responsive and more or less normal but I notice that the idle is around 1100 in park and once its shifted to drive the idle drops to 9000ish.
i'm pretty good with engines but im starting to lose sleep over this I live in NYC and have tried several "experts" that have caused more problems than solving.

Any will be greatly appreciated. JR

Post by **bmdubya1198** » 10 Aug 2020, 09:13

It sounds like you have worn engine mounts. Check the passenger side mount under the crank pulley.

If it's engine related, check for vacuum leaks. How old are your spark plugs, and are they the correct type and correctly gapped? Only run blue box Volvo, Bosch FR7DC/FR7DPP, or NGK BKR6E.

jmenard · Post by **jmenard** » 10 Aug 2020, 10:27

Hello and thanks for responding

I replaced all of the motor mounts including the top one about six years ago and replaced most 99% of the vacuum lines yesterday with silicone hoses. The only one I didn't replace is the one on the turbo thats facing the motor. I ordered new spark plugs and expect them later in the week. Checked the valves on the intake side and they seem fine. I started it up with the MAF unplugged the motor definitely didn't like that so I'm assuming that is functioning possibly not sure what i'm looking for. Is there a procedure for checking for vacuum leaks?

Thanks JR

Post by **misha** » 10 Aug 2020, 15:34

Usually....the engine should run ok with Maf disconnected.
What are the codes?

Post by **bmdubya1198** » 10 Aug 2020, 21:47

You can smoke test to find vacuum leaks.

jmenard · Post by **jmenard** » 11 Aug 2020, 07:44

Hi
Thanks for all the input so I ran VIDA again this morning after getting ECM light on the dash I should mention I have the ABS module out of the car at the moment as I'm having it rebuilt. The only codes that came up that are possibly relative would be ECM 430C EVAP small leak, and ECM 644A Camshaft control fault position. NOTHING ELSE ?
Im at a loss

Post by **misha** » 11 Aug 2020, 08:54

Camshaft control fault position can be the reason for rough idle.
I'm surprised that it runs with that code.
It's either that camshaft is at wrong position or camshaft sensor is faulty.

Post by **bmdubya1198** » 11 Aug 2020, 09:24

I believe that code is for the VVT solenoid. That will certainly cause the rough idle.

How old is your timing belt? Before running the car, make sure everything is where it should be and it hasn't jumped timing slightly. You may have caught it just in time. From what I can see, this code will appear when either the timing is incorrect, or the VVT solenoid is failing.
If everything looks good on the timing belt, replace that solenoid with the updated part. Only genuine Volvo for that, the Dorman/other cheapo replacements fail very quickly.

jmenard · Post by **jmenard** » 11 Aug 2020, 10:19

Thanks

This seems to be an intermittent problem I replaced the timing belt and its associated parts about 4-5ish years ago less than 60,000 mi on it
I'll check it out . I believe it's possible to test in VIDA not sure what the value should be for correct operation?

JR

Post by **bmdubya1198** » 11 Aug 2020, 11:44

I don't know that they have a set position, but you can test it in VIDA. If you look at the fault tracing for that code, it will walk you through testing. Basically, the value should change as you rev the engine. If not, it's definitely bad. If it does, it still could be bad, just won't be keeping up with the ECU's demand.