996 idle and power problems

[IBR COMPETICION]

Hello,

I'm new around here.

My name is Ivan.

I have a 996

3.4

2001

manual

The problem is that the idle is erratic, ranging between 720 and 830 rpm.

It has electronic throttle, I've cleaned, I have changed o2 sensors, MAF, ignition coils, spark plugs, injector cleaner, and does not improve.

Ever hear the exhaust noise as if a cylinder fails.

MAF Sensor: 24 Kg / h

RKAT: - 4.20

RKAT2: -2.10

CAM DESVIATION: -9,80

Sometimes, when you go, the engine run out of power and you accelerate, gives small explosions from the exhaust.

Excuse my English, but I'm Spanish.

Thanks for all.

[Loren]

Nine times out of ten this is caused by a dirty throttle body. Use some spray carb cleaner or spray fuel injector cleaner.

It should clear up.

[IBR COMPETICION]

I clean the throttle body 4 times, and no improvement.

I have check the camshaft adjustment.

I have found that keeping the engine revs to 2500, I hear the exhaust failure.

[Loren]

What is the MAF reading at 3000 RPM?

It should be 50-80 Kg / h -- if it is not replace the MAF.

[IBR COMPETICION]

At 3000 rpm 70 kg/h. I replaced maf,ignition coils, spark plug, o2 sensor, cleaned the egas, changed inyectors, and the problem continue.

[Loren]

Any fault codes or pending fault codes?

[IBR COMPETICION]

This is the problem. No fault codes.

[wvicary]

I clean the throttle body 4 times, and no improvement.

I have check the camshaft adjustment.

I have found that keeping the engine revs to 2500, I hear the exhaust failure.

How did you verify the camshaft timing? Are you hearing a backfire through the exhaust?

[IBR COMPETICION]

Because the cam desviation with durametric is 9,80 °.

I think that is out of correct value.

For the exhaust i hear sometimes ignition fails.

[Loren]

Because the cam desviation with durametric is 9,80 °.

I think that is out of correct value.

For the exhaust i hear sometimes ignition fails.

If that is true you should have fault codes.

[IBR COMPETICION]

No fault codes,

with durametric:

Maf: 22 to 26 kg/h

Cam desviation: - 9,80

Rkat: -4,20

Rkat2: -2,10

Temp: 90°c

Rpm idle: ranging between 700 to 820 with small ignition fails.

[logray]

Curious there are no codes. I wonder if one of your variocam actuators is marginal or on it's way out (going bad).

That is pretty far out of time, 9.8 degrees, and since your car sounds like it is ROW, we might not have the other bank's timing information. I would correct the timing and see if it continues to have a slight misfire.

Also did you say you cleaned the injectors (removed, cleaned, and reinstalled), or did you buy new injectors, or did you just use fuel injector cleaner in the gas tank?

[Dharn55]

A failing cam actuator should not affect the idle. Could be a failing throttle body on an E-gas car. Mine failed this summer after displaying surging, bad idle, etc.

[logray]

A failing cam actuator should not affect the idle. Could be a failing throttle body on an E-gas car. Mine failed this summer after displaying surging, bad idle, etc.

Agree on the throttle body, but if there is a slight miss (at idle and/or higher rpms) I would bet the engine would be a little rumbly and could search a little.

[IBR COMPETICION]

Hello,

I can see that the CAM 2 is 1,5 mm rotated respect to the head plane.

Can be this the problem?

tomorrow i will have a new E-gas.........we will see what happen.

I will keep you informed.

[Dharn55]

Are you saying that you removed the green plug on the intake cam an with the engine at TDC the slots on the cam are 1.5mm off. If so this is a significant numbers of degrees (remember that the cams only rotate once for every two rotations of the crank.

[IBR COMPETICION]

No is the intake camshaft, is the exhaust camshaft.

[Dharn55]

Sorry my mistake, haven't benn in my engine for awhile now. It is the slots on the end of the exhaust cam that are used to set the timing on 3.4 engines. When the engine is set at TDC on the proper rotation of the crank the slot on the end of the exhaust cam should be straight up and down with the narrow side out. It this is off by 1.5 mm I think that is potentially a significant timing issue, although it is hard for me to visualize exactly what you mean by 1.5mm. But each 1degree of error at the cam is equal to 2 degrees at the crank. Have you checked both sides?

[IBR COMPETICION]

Yes, i checked both sides, the exhaust camshatf 1 is OK, but the other one no is aligment with the plane of the head, is a little rotated, about 1,5 mm respect the plane of the head.

[RFM]

As already mentioned by other forum members, at such an exemption fault codes must occur. Unless the MIL bulb is defective or removed by a fun person.

[logray]

Cams are probably in spec then.

What does the spark plug look like in that cylinder? Did you do a compression and/or leak down test?

[IBR COMPETICION]

The new E-gas is installed, but the idle still the same.

Corrected adjustment of the camshaft and worse.

Also heard noise in chains to accelerate, when hot.

At startup, once heard, the sound of chains.

The engine has 2347 hours of operation.

Not to do, but the engine runs very poorly, with -9.8 in the camshaft worked better thannow, because the correction has gone from -9.8 to -11.5, I can not understand.

The compression cold are 9 bar and 10.5 bar hot.

[logray]

150psi compression is really very poor.

This could be attributable to timing (still sounds like it's not corrected), or other spark/fuel/cylinder/piston problems.

Have you also performed a leak down test?