Running rich on stock engine, cel is on? please help me out!

[tomcat80]

Searched the topic but it didnt help me alot, so here goes.

I had my car to a workshop to check the emission co2 readings, and it came out reading 7,5% on idle where it is supposed to read max 0,5%, so it must be running too rich.
It's also hessitating while throttling, and the exhaust smells bad.

The cell is on:
-P0325 knock sensor
(checked, and there is goo running down my block, waiting for new one)

-P1105 fuel pressure solenoid
(possible to check? the el connections was covered in white powder so i cleaned them out)

The engine is stock, besides a Greddy type S bov wich is vented to the intake. Spark plugs and wires has been replaced 2 months ago, as you can see from the pictures they now are dark and smoggy.

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Where should I start my troubleshooting?

 

[Dream On]

First, resize your pics so they aren't over 700 pixels wide before you get attacked by the moderators. Second, do a boost leak test. If you have a logger, check to see if it's cycling at idle. Mine was dead and it didn't throw a CEL all the time for some reason.

 

[scottsee]

this has to do with tuning how?

 

[tomcat80]

First, resize your pics so they aren't over 700 pixels wide before you get attacked by the moderators. Second, do a boost leak test. If you have a logger, check to see if it's cycling at idle. Mine was dead and it didn't throw a CEL all the time for some reason.

Sorry about the oversized pics, I forgot to adjust them down. I'm going to do a leak test and then we will see from there. I don't have a logger, and what do you mean by "cycling on idle"? thanks for your help...

 

[tomcat80]

this has to do with tuning how?

If you have a better suggestion of where to place my post please let me know, if not don't fill my post with information I can't use of any good.
My post takes up 3 or more of the topics in the forum heading so I would guess it's where it's supposed to be? knock, datalogging, fuel trims

 

[steve]

Where should I start my troubleshooting?

I assume those were platinum or Iridium spark plugs, time to replace the knock sensor and a fresh set of the standard BPR6ES copper plugs.

The knock sensor code will cause the ECU to retard the timing all the time.
The platinum fine wire electrodes don't seem to work in out cars.

Steve

 

[tomcat80]

I assume those were platinum or Iridium spark plugs, time to replace the knock sensor and a fresh set of the standard BPR6ES copper plugs.

The knock sensor code will cause the ECU to retard the timing all the time.
The platinum fine wire electrodes don't seem to work in out cars.

Steve

So you think the mailfunction knock sensor could be the reason for the rich mixture in it self combined with these type of spark plugs? what about the o2 sensor?

 

[scottsee]

If you have a better suggestion of where to place my post please let me know, if not don't fill my post with information I can't use of any good.
My post takes up 3 or more of the topics in the forum heading so I would guess it's where it's supposed to be? knock, datalogging, fuel trims

Problem Diagnosis

So you think the mailfunction knock sensor could be the reason for the rich mixture in it self combined with these type of spark plugs? what about the o2 sensor?

The knock sensor won't change the A/F mixture, just the timing of the spark. It's a peice of the puzzle though and wouldn't drive much untill you get a chance to replace it. I would suspect your problems would be contributed to that FP malfunction. Do you have acess to known working 2g regulator?

When you say the car hesitates while throttling, do you mean while feathering the throttle at idle, or durring closed loop cruising conditions. Are you experiencing idle surge, low throttle hesitation, or misfireing durring acceleration?

 

[zippyshoe]

Sorry about the oversized pics, I forgot to adjust them down. I'm going to do a leak test and then we will see from there. I don't have a logger, and what do you mean by "cycling on idle"? thanks for your help...

The "cycling at idle" is referring to what a healthy O2 sensor does while at idle or at cruising. A healthy O2 sensor will output a voltage which bounces back and forth between roughly 0 volts and just under 1 volt. On the other hand, a dying or dead O2 sensor will typically output a nearly constant voltage close to 0 volts. Unfortunately, without a logger, you will not easily be able to monitor this signal. When the ECU sees this constant low voltage, it believes that the engine is running lean and continues to increase fuel delivery to compensate - this will cause the engine to run rich and should (eventually...) throw a CEL.

The purpose of the fuel pressure solenoid is pretty limited - all it does is temporarily raise your fuel pressure when you start the engine when the engine is hot. After the engine has been started, it serves no further function.

 

[tomcat80]

Problem Diagnosis



The knock sensor won't change the A/F mixture, just the timing of the spark. It's a peice of the puzzle though and wouldn't drive much untill you get a chance to replace it. I would suspect your problems would be contributed to that FP malfunction. Do you have acess to known working 2g regulator?

When you say the car hesitates while throttling, do you mean while feathering the throttle at idle, or durring closed loop cruising conditions. Are you experiencing idle surge, low throttle hesitation, or misfireing durring acceleration?

I have no access to other 2g's, as my is one of very few in Norway...we need to import these cars from the US. But I have done some reading and found that the FPS not really is needed, so I have bypassed it with running the line from the intake straight to the fuel regulator. (the FPS plug is still connected)

When feathering the throttle at idle I don't feel any hesitating, only when loading while crusing and full throttle. I'm sorry but I'm not shure what idle surge is. The idle sometimes goes a bit up and down as an wave though, not much but you can hear it. There is no missfiring.

 

[tomcat80]

The "cycling at idle" is referring to what a healthy O2 sensor does while at idle or at cruising. A healthy O2 sensor will output a voltage which bounces back and forth between roughly 0 volts and just under 1 volt. On the other hand, a dying or dead O2 sensor will typically output a nearly constant voltage close to 0 volts. Unfortunately, without a logger, you will not easily be able to monitor this signal. When the ECU sees this constant low voltage, it believes that the engine is running lean and continues to increase fuel delivery to compensate - this will cause the engine to run rich and should (eventually...) throw a CEL.

The purpose of the fuel pressure solenoid is pretty limited - all it does is temporarily raise your fuel pressure when you start the engine when the engine is hot. After the engine has been started, it serves no further function.

So you agree that bypassing the FPS is ok? just to eliminate one possible cause.
So what do you think should be my next step. I'm still waiting for the knock sensor, but when I have installed the new one I guess I still will have the same problem with A/F mixture.
Thanks for the answres so far guys...

 

[dsm-onster]

When feathering the throttle at idle I don't feel any hesitating, only when loading while crusing and full throttle. I'm sorry but I'm not shure what idle surge is. The idle sometimes goes a bit up and down as an wave though, not much but you can hear it. There is no missfiring.

Sounds alot like a boostleak. A connection that seals somewhat ok at low throttle but the onset of boost blows it open. I'd do that boost leak test you plan on doing. . .

 

[zippyshoe]

So you agree that bypassing the FPS is ok? just to eliminate one possible cause.
So what do you think should be my next step. I'm still waiting for the knock sensor, but when I have installed the new one I guess I still will have the same problem with A/F mixture.
Thanks for the answres so far guys...

I don't believe that bypassing the FPS is causing the problems you are describing, as long as the vacuum hose you have connected from your intake manifold to the fuel pressure regulator has no leaks.

As a next step, I would also recommend performing a boost leak test, as dsm-onster pointed out. A boost leak could definitely effect your A/F ratio. I would also recommend investing in a logger - otherwise, you are "flying-blind" when you try and diagnose problems. With a logger, you could see what is going on with your front O2 sensor as well as your fuel trims.

 

[romeen]

1) I agree with everyone else regarding the boost leak test. Make sure there is no leak in the vacuum line between IM and FPR (as zippyshoe mentioned). A leak here can interfere with accurate function of the FPR causing increased fuel pressure.

2) If you have a multimeter the easiest way to check an O2 sensor is by checking resistance (continuity test) across terminals 1 and 3 on the sensor's electrical connector. More accurate than that is to use a voltmeter along with jumper cables from the battery while the engine is running to check for cycling of the sensor's voltage output as mentioned previously. If you need details on how to do this let me know.

3) Make sure there is no kink in the fuel return line.

4) If everything else checks out ok then consider the possibility of your FPR not functioning correctly. I don't think that this is common but it does happen.

 

[tomcat80]

Thanks for all your answeres so far. I have done some work since i posted last time, here is what I have done:

-Replaced knock sensor. A pain in the ass
-Replaced front O2 sensor.
-Boost leak test.

The boost leak test uncovered a severe leakage in the plastic elbow that goes from the intercooler behind the air filter/fusebox and to the hose that ends at the throttle housing. http://members.shaw.ca/dsm.1000q/Engineprimer/2G/uicpipe.htm
It leaks in one of the plastic weldings, so I tried to seal the hole with a small blowpipe to try to melt it in but it didn't help. I also tried to seal with sealing compound and ducktape, but it can't take the pressure so it leaks in a while.

I guess and hope this leakage is what causes the rich a/f mixture, do you guys agree? so the next step will probably be to replace this plastic elbow. But where could I get one?

What about this one? http://www.diamondstarmotorsport.com/intakeparts.shtml "Greddy 2G Upper and Lower IC Pipes". A bit expencive though.

 

[DirtyBirdRacing]

You could probably try to jb weld the intercooler pipe. Hopefully that will fix your problem.

Bill

 

[tomcat80]

Had my car on a emission test today and it went through with no remarks, I have also bypassed the FPS with the el connection still connected and the CEL dissapeared.
The problem was the leak in the intercooler pipe that has now been replaced.

All right, runs great now...thanks for all your help!