2004 Cayenne s 8 cylinder 5 of 8 plugs wet with gas

[Renzo511]

5 of 8 plugs wet with gas. Idles fine but hesitates when driving mainly shifting into lower gears. This is automatic transmission. Also strong gas smell when I come to stop and put in park.

 

New coils and new plugs. Put new in because when I pulled last plugs 50 miles ago with same problems I assumed plugs were bad..

 

Black dry soot in tailpipes. My assumption is it's running rich. 

How can I balance this fuel issue ?

 

Get misfiring codes. No other codes. 

Checked injectors for leaks they are ok.

Could it be bad O2 sensor (s) . 

[lewisweller]

4 hours ago, Renzo511 said:

5 of 8 plugs wet with gas. Idles fine but hesitates when driving mainly shifting into lower gears. This is automatic transmission. Also strong gas smell when I come to stop and put in park.

 

New coils and new plugs. Put new in because when I pulled last plugs 50 miles ago with same problems I assumed plugs were bad..

 

Black dry soot in tailpipes. My assumption is it's running rich. 

How can I balance this fuel issue ?

 

Get misfiring codes. No other codes. 

Checked injectors for leaks they are ok.

Could it be bad O2 sensor (s) . 

Low cylinder compression also needs to be ruled out. 

How many miles it's done? 

Maf sensors been cleaned ever? 

 

[Renzo511]

140k miles, mafs cleaned recently. Compression is around 170 on all 8 Except number 8 is 158

[JFP in PA]

You need to scan the vehicle for fuel trim levels.

[Renzo511]

140k miles, mafs cleaned recently. Compression is around 170 on all 8 Except number 8 is 158

13 minutes ago, JFP in PA said:

You need to scan the vehicle for fuel trim levels.

JFP ...Should I check them at idle ? What would be normal on the 2004 Cayenne s 8 cylinder ? 

 

My hunch is it's running very rich 

[wizard]

I would have thought that five 'rich' cylinders from the eight (with three cylinders normal, presumably) surely suggests an injector problem on each of those five cylinders?

[JFP in PA]

I'm away from the shop at the moment, so I do not have access to nominal trim values, but I'm sure someone can chime in with them.

 

 

[JFP in PA]

Just now, wizard said:

I would have thought that five 'rich' cylinders from the eight (with three cylinders normal, presumably) surely suggests an injector problem on each of those five cylinders?

I would also expect that five overly rich cylinders would trigger codes............

[wizard]

Indeed ...... misfire codes.

 

 

[Renzo511]

I did have multiple random misfire codes .  Cleared them along with CEL

[Renzo511]

What would cause 5 injectors to be problems ?

[JFP in PA]

If you are getting misfire codes, the plugs are wet from misfires, not richness.  If the mixture was so rich, you should throw codes associated with being overly rich.

[Renzo511]

3 minutes ago, JFP in PA said:

If you are getting misfire codes, the plugs are wet from misfires, not richness.  If the mixture was so rich, you should throw codes associated with being overly rich.

140k miles, mafs cleaned rece

1 hour ago, JFP in PA said:

You need to scan the vehicle for fuel trim levels.

Any advice what could 5 cylinders to misfire....Plugs and coils are new

[JFP in PA]

Loose harness connection or a short.

[Renzo511]

Any way to diagnose ?

[lewisweller]

47 minutes ago, Renzo511 said:

Any way to diagnose ?

Go back to basics first. 

 

Are the coil and plugs correct oem parts? Bosch multiple electrode is standard for the S I think. These come pregapped. What torque did you use on the plugs? Is any oil in the plug holes?

Recheck and also make sure the coils are seated well and tightly screwed without going crazy and cracking the coil plastic. 

Earth wires to block clean and tight on the Allen bolt near the number 2 coil and number 7 coil?

 

Try swapping coils from misfiring cylinder to non misfiring cylinder, moving misfires will identify coils fault or installation issues. 

Inspect the harness for damage or frayed wires. 

 

Fuel? Maybe low fuel flow and or pressure. Have you tried Switching to the right pump by pulling the left pump fuse? And restarting the engine afterwards. Was the filter ever changed? 

 

Pictures of "wet" plugs would be helpful are you sure it's not oil? 

 

This seems more ignition related I think. 

 

[JFP in PA]

1 hour ago, lewisweller said:

This seems more ignition related I think. 

 

 

That is where I am leaning............

[Renzo511]

I agree that it seems more ignition related.. is there some diagnostics I can do to pinpoint the cause ?

 

 Cylinders 2,4,6,8 and 3 are the wet plugs 

[lewisweller]

5 hours ago, Renzo511 said:

I agree that it seems more ignition related.. is there some diagnostics I can do to pinpoint the cause ?

 

 Cylinders 2,4,6,8 and 3 are the wet plugs 

Do the above mentioned checks and then report back. 

[RFM]

Are you sure the plugs are wet with gasoline? The system works as follows: after a number of misfires the system will shut down the injectors concerned, it is therefore not evident that they are wet with gasoline. There are still more options as motor oil, coolant, gasoline contaminated with gas oil or other fuel. Be sure, first of all, that this pure gasoline. 

[Renzo511]

It's definitely gas. The engine chugs and sputters while driving. Somewhat loss of power.

 

When I come to a stop or park ,there is a strong gas smell from engine area and there are no.leaks.

[lewisweller]

37 minutes ago, Renzo511 said:

It's definitely gas. The engine chugs and sputters while driving. Somewhat loss of power.

 

When I come to a stop or park ,there is a strong gas smell from engine area and there are no.leaks.

That doesn't rule out ignition problem. 

Have you tried blocking off or clamp purge valve pipe to eliminate that additional fuel entering? 

I think you need to get the tools out bud and whip out the plugs and coils inspect picture and reinstall being 100% everything is spot on so this can be set aside for the moment. This forum ain't gonna fix it, only advice can be given some good and some bad. Good luck. 

[Renzo511]

Is there anyway to check each cylinder is getting spark ? 

Not to familiar with coil.packs, it seems all the gas is not combusting. I have tried a few different plugs and same results

[JFP in PA]

To see the plug firing voltages, you need an oscilloscope.

[lewisweller]

15 hours ago, Renzo511 said:

Is there anyway to check each cylinder is getting spark ? 

Not to familiar with coil.packs, it seems all the gas is not combusting. I have tried a few different plugs and same results

Pico 4 channel scope required, which is why physical checks was advised. 

Have you switched between left and right pump it may just be a weak fuel pump. Takes 2 mins to check this.