hello guys and gals. I am been trying to track down this Rich condition that I am having. Here is some info on the car.

Its a 2007 with 90k. I have injen cai, test pipe, and tuned flashpro.

The issue lately and has been on-going is the car stalling out when coming to a stop light. It appear to only happen at idle.

Seeing I have a 2006+ S2k which there is no IAVC to clean as its controlled by the ECU.

I have done a compression test on the car and it all looked good with number consistently at 230 across the board.

I have replaced the primary o2 sensor, pcv valve, and replaced the MAP sensor with a brand new one from Honda.

I haven't had a chance to do a fuel pressure or adjusted the valve clearance yet.

It has thrown a P0172 which is a rich condition in bank 1. I'm thinking its because of the MAP sensor reading high at idle.

I have logs from last year (when it wasn't having issue) and compare it to the current log.

I notice that the MAP sensor from a dead cold start is higher now than before. Seeing the ECU uses the O2 sensor and the MAP sensor to determine fuel delivery. With the high valve showing from the MAP sensor, its causing the ECU to add more fuel than necessary which I believe it causing the car to run rich.

Here is a picture of last year log:



And here is a picture of the current log done this morning:



As you can see last year on a cold startup is at 400 mbar versus the current at 550 mbar. I have been monitoring it and comparing logs and it seem to run higher reading cruising and so forth. My MPG has dropped from 28-29 down to 21-22 without any change in driving behavior. The MPG is done on the freeway!


So question is, what can cause the MAP sensor to read high.

Can one bad injector cause it to run high?

Can it be a valve adjustment (valve set to tight) cause this issue. I will be doing the valve adjustment for the first time this week. The car is 5 years old so I need to order the seals and stuff before I can start unless do you think I should be okay? I purchase the feeler gauge and adjustment tool already.

Fuel pump issue? I can't imagine this to cause a high map reading. Wouldn't a bad fuel pump cause the car to run LEAN instead of RICH?

Anyways, let me know your thought on this. Thank you.

 

another thing I was thinking. Can it be a intake manifold gasket leaking?

would a bad gasket cause a MAP reading to be high?

 

It could be a lot of things, I would imagine even weather being one of those. What does the service manual say? And have you checked all the basics, how do your plugs look? Etc. I gotta ask what happenes when you disconnect the map sensor?

 

oh yes i have done all the basic. Spark plugs was replaced as well.

What happens if I disconnect the map sensor? do you mean unplug it? or pull the map sensor with the connector still attached?


everything points to maybe a tight valve clearance making the map sensor read high which in turn make the car run rich.

If its not the valve clearance then next step would be to get a reading on fuel pressure. If that checks out then fuel injector.

 

ngk plus and make sure you check the gap and torque them properly. when you unplug the map sensor. also make sure you have the little oring and the hole is not clogged.

 

thank you for the response starchland. I have done everything as you mention. Gap and torque the spark plugs correctly.

I replaced the map sensor with a brand new one from honda. It came with the oring and made sure its on there. I also coated the o-ring with clean motor oil to give it a better seal. I don't think it is a MAP sensor issue.

 

I dont think so either.

Just saw that you have a flashpro...I want to say this has something to do with it. Did the problem appear shortly after your tune? Is it possible to go back to oem ecu or map and see what happens. Im sure someone with more experience will chime in />

can you monitor your fuel trims?

 

yes i tried to go back to stock map and it still happens!!

and of course i can monitor fuel trim. Trust me, I did everything and research as much as possible!!

Just thought maybe someone has a clue that isn't the norm and point me in the right direction without throwing money at it!!

I'll be doing the valve adjustment tomorrow night.

Does anyone think its my APP (accelerator pedal position) sensor? its sensor that read the throttle input.

If someone has the troubleshooting method for that, let me know. I have a 04-05 service manual. So if you have a 06+ service manual and have that procedure, please PM me.

Thank you again.

 

just want to update everyone. After doing the valve adjustment tonight, it resolve all my issue. I haven't driven it but have taken a log of cold startup and what do you kow, the MAP reading is now back to normal. Woo Hoo. What a great feeling it was to see that.

All of the exhaust valve except one was all TIGHT!! I had a .009 feeler gauge and could not put it in there!! It should be .10 to .11. Anyways adjusted all of them to .10.

On the intake side. Only the first cylinder was tight. The other one were lose or perfect at .009. I adjusted all of them to .009.


Now I'm hoping I didn't burn a valve or anything like that for running like this for over a 5-6 months!

Glad I didn't have to purchase injector or diagnose it further.

What a great relief!!

Hopefully if someone had issue, this can cure it.


To summarized, TIGHT VALVES will cause a HIGH MAP reading.

Who need a brand new map sensor!! let me know. haha.