2000 S70 2.4t Rough idle/ stalls P0300, P0342

[socals70]

Hi All,

I recently got a 2000 S70 GLT SE. At the time of purchased it had a bad head gasket and was hard to start and stalled. I assumed the latter problem was due to the bad gasket. I have since changed the head gasket, piston rings(honed cylinders), all sump seals, head resurfaced, valves cleaned and lapped, intake/ exhaust gaskets, spark plugs.

After I got everything back together the car still has a lot of trouble starting and idles very rough and will stall unless I keep my foot on the gas. If I keep it above 2K rpm it runs ok, though the exhaust smells like it is missing.

It has two fault codes
P0300- Random mulitple cylinder misfire.
P0342- Cam position sensor low input.

Things check so far:

1. All five plugs have good spark.
2. fuel pressure is about 52psi.
3. Compression is about 160psi in all cylinders. New rings still havent seated all the way.
4. Replaced cam position sensor and tested the new one:
a) with the key on and engine not running I get 5V on two of the sensor wires and the third is ground.
b) has continuity from the connector to the pins at the ecu and the connector is good.
c) while turning the engine one of the 5V signals alternates from 5v to 0v.
5. Tried disconnecting MAF and cleaning it, no change.
6. Cleaned throttle body and replaced gasket.
7. Timing seems to be good. both cam marks line up with notches on cover and crank mark lines up with mark on the block.

Any ideas or help would be greatly appreciated

thanks,

Chris

[Ozark Lee]

What procedure did you use to set the CVVT preload? What color is the sticker on your electronic throttle module? Have you checked for spark on all of the coils? Normally you would get individual cylinder misfire codes along with the multiple misfire code.

What codes, if any, did you pull before the engine rebuild?

...Lee

[socals70]

Thanks for the reply. I believe the sticker was white, I can check for sure when I get home. Yes I checked all five plugs. The P0300 is the only misfire code no specific cylinder codes.

I am not familiar with the CVVT preload procedure, please explain. Prior to rebulid it had a code for the cam solenoid on top of the "valve cover" and also the misfire code. The prior owner had used rtv gasket maker on the cam solenoid instead of the gasket so it was all plugged up, I cleaned it and used the proper gasket and that code has not returned.

[Ozark Lee]

Your car has Continuously Variable Valve Timing (CVVT). The CVVT control valve is the cam valve above the exhaust cam that you referred to. As you may have noticed when you did the engine rebuild the sprocket on the exhaust cam moves independently from the hub that bolts to the camshaft itself and, as such, it isn't proper to simply line up the timing mark on the exhaust camshaft when re-installing the timing belt.

The way the system works is that the CVVT hub will advance or retard the cam timing, independent of the timing belt sprocket position, by utilizing engine oil pressure that is controlled by the CVVT valve. The CVVT valve modulates the amount of oil pressure that goes to the hub based on an electrical signal from the ECU.

The preload procedure positions the camshaft in a mid-range position so that the camshaft timing can be either advanced and retarded. The ECU looks at the camshaft position sensor signal and compares it to what it expects the signal to be in terms of the camshaft timing that the ECU has requested. If the camshaft timing "limits out" then it will typically post a camshaft position error code and the CVVT system is disabled.

That may be more information than you wanted but that is the basics of how the system works.

The method that you use to set the preload depends on whether or not you removed the CVVT hub from the camshaft itself at any point during the engine rebuild. If you did then you need to use a cam adjustment tool to lock the camshafts in the timing mark position from the rear of the camshafts and then slightly tighten the center Torx screw on the hub slightly and rotate the sprocket and the hub, clockwise, so that the sprocket is at its stop and the timing mark is 1 tooth removed, counterclockwise, from the corresponding timing mark on the timing belt cover. At that point, with the sprocket still at its limit, the Torx screw on the hub gets tightened to 120 Nm (88 ft lbs). From there the timing belt is installed with the CVVT hub being held at its clockwise limit while the timing mark is at its proper mark. You hold the hub at its limit by using a Torx bit on the oil cap that covers the CVVT mounting bolt.

Once the belt is on, and the cam adjustment too is removed, the mounting screws for the outer sprocket on the CVVT hub should not be at either limit after the engine is hand cranked over a couple of revolutions.

The procedure is detailed here:

Turbo CVVT Camshaft Seal Replacement.pdf

(815.09 KiB) Downloaded 763 times

If you didn't remove the CVVT hub from the camshaft the procedure is much easier. All you need to do is rotate the engine clockwise and go 90 degrees past the timing marks and then rotate the engine back, counterclockwise, to the timing marks. At that point loosen the timing belt tensioner and remove the timing belt from the camshafts. As you re-install the timing belt adjust the outer sprocket on the exhaust camshaft so that the sprocket timing mark is lined up with the timing belt cover timing mark as you thread the belt back on. Reset the tensioner and you should be good to go.

The white sticker throttle modules are a problem and it may be more at the root of your issues than the camshaft timing. It is normally pretty good about lighting up the ETS light when it is mad about things though. Does the ETS light come on with the key in position II? If not it could be burned out or it could have been removed.

ETS errors don't directly show up as typical powertrain (P) codes but resultant engine performance problems will show up as P codes.

...Lee

[socals70]

I did not remove the sprocket or hub from the cam shaft, but it is possible the pervious owner did. I did the procedure as if it hasnt been removed and the car runs marginally better but the stumbling and stalling still happens.

I looked at the ETS again and the sticker on the front of the ETS while installed facing the front of the car is Yellow not white. The ETS light does come on while the key is in the number two position but does not come on or flash while running.

I am also now getting a P0102 code for the MAF sensor. I get this code when it is unplugged and now also while it is plugged in but the engine stills stalls either way.

[Ozark Lee]

Is there any chance that something got pinched in the intake manifold when it was put back on and it isn't sealed all the way to the head? The camshaft and crankshaft position sensors plug in just below the manifold and I have had to move those wires out of the way when re-installing the intake manifold.

The yellow sticker throttle module is a good sign. They still have problems but nothing like the white sticker versions. Since the ETS light works but isn't coming on I would rule out the throttle module as the source of the problem.

...Lee

[socals70]

It is possible something got pinched. I will pull the manifold tonight to be sure it is clear and nothing is pinched. I do hope the ETS is good, from what I have seen they are pretty pricey. I will post an update later tonight.

Again, thanks for your assistance so far.

[socals70]

I pulled the intake yesterday night and did not find any pinched wires, but I do believe I found the problem. The clamp that goes on the intake tube that goes from the throttle body to the intercooler was jammed up with dirt and was stripped. So when tightening it the screw would get hard to turn as if it were tight but the clamp was still very loose on the tube. It was loose enough on the TB side that I could easily slip the tube off of the TB by hand. I had tightened the clamp when the intake was already installed before so I had not noticed it.

I plan on getting the intake back on today with a new clamp and testing it out. I really hope this solves the problem, I will post an update once I try it.

[socals70]

The intake is back on, the car runs smoother than before but still stalls and won't idle. I no longer get the p0300 misfire code. It still has the p0342 cam sensor code and the MAF code.

Could this possibly be a ECU problem? I'm getting ready to take it to the dealer if I can't figure this out soon.

[abscate]

Doubtful its the ECU. I would try a harvested MAF to see if that is the problem. Bosch only on the MAF.