Boost / System to rich issue(Car reeks of fuel)

[Grip99]

My 2000 threw some codes. Just to let you know, I've done searches on this and only came up with a torn TBB for the p1157.

P1557 (Charge Pressure Control - Pos Dev)
P1137 (Bank 2 (add) System too rich).

My car has these upgrades:
APR stg 2
APR Bi-Pipe
stock DVs (tested and are working fine)
034 3 inch Dps
rear o2s coded out
EVAP "coded out"
NEW primary o2s


The car has a rough idle, and my boost gauge would sometimes drop to -15 vac from the normal -18/-19 vac. I feel the car lost some boost pressure as well. The car holds 13 psi under full load. The car is chipped with apr stg 2.

I performed a boost leak test at 15 psi, and i noticed that my N249 check valve was leaking out of the check valve seams after i sprayed some soapy water on it. I sprayed the green check valves as well and they seem to be fine. But i will check them more thoroughly. Would that leak in the N249 check valve cause the codes i listed above?

I ordered the new n249 check valve and will be throwing that in on sat. My EVAP system is "coded out" based on what the previous owner says, but when i run the readiness it says its ok. Also I also tested the N80 in vag and it works fine.

I checked my fuel trims in (032) as well as (033). The long term fuel trims were sitting at -3.1% and -4.9% (in order from first block) and the short term fuel trim (033) were fluctuating between + and - 2% on each at idle. I sprayed brake clean around all vacuum lines and other possible areas to see if the fuel trims will change, but nothing changed the values. I disconnected the Maf and the values changed dramatically as well as throwing a code.

Any help on this would be great. Thank you

[jaychen]

Few things to check/swap (in no particular order)

N75
Maf
FPR
Injectors (checked fuel pressure?)

[Grip99]

Few things to check/swap (in no particular order)

N75
Maf
FPR
Injectors (checked fuel pressure?)

Awesome thanks Jaychen. Ill work on these.

[Gotwake424]

Few things to check/swap (in no particular order)

N75
Maf
FPR
Injectors (checked fuel pressure?)

Happen to have a link to a FPR replacement diy?
Searched and didn't come up with a whole lot. I seem to remember one side being a hardline onto the fuel rail.
Unless you literally just pull out the clip and put the new diaprham in...(can't be that easy right?)

[jaychen]

Happen to have a link to a FPR replacement diy?
Searched and didn't come up with a whole lot. I seem to remember one side being a hardline onto the fuel rail.
Unless you literally just pull out the clip and put the new diaprham in...(can't be that easy right?)

You just pull the clip out, pull the old fpr out and put the new one in.

[Gotwake424]

You just pull the clip out, pull the old fpr out and put the new one in.

Cool, thanks


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[christianb5s4]

What about the green coolant temp sensor behind the passenger side head? Your symptoms sound very very similar to when mine went out, although my car was pretty much undriveable. Was running so rich I bet I could have lit the exhaust on fire with a match and idled badly.

[zillarob]

Check the fitting where the fuel line screws to the rail.
It is very common for them to leak in cold weather. Look for staining below on the vc or engine cover.
Tightening might help, but it may be from where it it crimped.

[Grip99]

What about the green coolant temp sensor behind the passenger side head? Your symptoms sound very very similar to when mine went out, although my car was pretty much undriveable. Was running so rich I bet I could have lit the exhaust on fire with a match and idled badly.

That sensor is fairly new. I believe i have another one sitting around. If so, ill put it in and check the fuel trims again.

[Grip99]

Check the fitting where the fuel line screws to the rail.
It is very common for them to leak in cold weather. Look for staining below on the vc or engine cover.
Tightening might help, but it may be from where it it crimped.

Ill definitely check this out also. I had unscrewed it when i did the aux pump under the intake. But i was pretty careful to use both wrenches when tightening it back up so that i wouldnt kink the line.

[V1nny]

Cool, thanks


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Be prepared for some gas splashing around while you removing the FPR. So smoking removing FPR would not be good idea. Keep handy few lint-free rugs or paper towels to clean FPR housing before sliding the new FPR in. I was surprised how much dirt was there when replaced main. Consider replacing tiny vacuum hose clamp or vacuum line as well.

Also consider boost leak test.

Another diagnostic tip for you: disconnect both downstream O2 sensors and see if car runs better. I know they are coded out, but if sensors are shorting internally or in the wires, it will affect the same circuit that your front O2 sensors use.

[Gotwake424]

Not diagnosing my car car. I just have low pressure at the rails
I'm running lean not rich


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[Grip99]

Update: I installed the n249 check valve and cleared the codes. I re-checked the fuel trims (032) and they were somewhat lower but still in the negative range. Bank 1 went from (-3.1%) to (-1.5%) and bank 2 went from (-4.9%) to (-2.1%) at idle. I know the range is + - 4.0%, but should i be sitting in the negative range in general?

I drove the car home from my shop, and the car felt great BUT still full boost spike 15/16 and holding 13psi (APR stage 2?). But when i got back into the city after a 15/20 mile drive home, i would be sitting at a red light, the cars idle would spudder almost like something was stuck open fuel-wise. Unfortunately, i dont have a copy of VAG on my own laptop to check if any codes came back. I will be out at the shop again tm to scan it and try and diagnose the problem again.

I am going to take out the fpr tm to see if it has fallen apart. If its bad, atleast its a "cheaper" part to replace. If its not that ill go after the maf. It also seems from the codes that the n75 could be acting up. But does anyone know what boost psi an APR stg 1/2 should be putting out?

Again, thank you in advance for your responses. Any help would be great.

[jaychen]

I think most people with APR tunes peak at around 16-18 and fall to 13-15ish (respectively)? I could be wrong though. Its been a while since i looked into that.

are you absolutely sure you don't have any vac/boost leaks?

[Grip99]

I think most people with APR tunes peak at around 16-18 and fall to 13-15ish (respectively)? I could be wrong though. Its been a while since i looked into that.

are you absolutely sure you don't have any vac/boost leaks?

Vacuum holds strong at -19 at idle. If im not mistaken, -18/-19 vac is normal at idle? When I did a boost leak test, only thing that showed signs of a leak was the n249 check valve, which i replaced. I did a log of (115) to measure boost pressure and (118) for N75. I was the only one in the car with rain and traffic, but i was able to get one pull: APR stg 1/2

[IMG][/IMG]

[IMG][/IMG]

[axnjaksn]

Vacuum holds strong at -19 at idle. If im not mistaken, -18/-19 vac is normal at idle? When I did a boost leak test, only thing that showed signs of a leak was the n249 check valve, which i replaced. I did a log of (115) to measure boost pressure and (118) for N75. I was the only one in the car with rain and traffic, but i was able to get one pull: APR stg 1/2

[IMG][/IMG]

how old is your maf?? just curious if you've ever replaced it.....common on a lot of older cars especially when you get sputtering at idle after driving a little bit. when MAF is on its way out, runs great cold, then when the MAF gets hot, the readings start to go out of spec and cause these issues and more.

[Grip99]

how old is your maf?? just curious if you've ever replaced it.....common on a lot of older cars especially when you get sputtering at idle after driving a little bit. when MAF is on its way out, runs great cold, then when the MAF gets hot, the readings start to go out of spec and cause these issues and more.

I havent replaced it yet. I m not sure on the age other than when i purchased the car 2 years ago. It could be on its way out.

[Grip99]

Replaced the n 249 check valve and seemed it fixed my boost leak. I performed a boost leak test after it was complete and nothing seemed to be hissing at 15 psi. Can anyone tell me if my n75 is working correctly based off my log and graph above just for reassurance? LOL

I also have these codes:

P1139 - system to rich
fuel trim: Bank 2 (add)

P1137 - system too rich
fuel trim: Bank 1 (add)

2000 S4. O2's are new. Could it be a maf at this point? I have an apr chip

Thanks

[jaychen]

MAF will definitely cause those codes, do you have one you can swap in?

[Grip99]

MAF will definitely cause those codes, do you have one you can swap in?

I actually had ordered one this past monday. It arrived this morning and im about to put it in now. Ill clear the codes and drive it for about 50 miles. Hopefully that will be enough mileage. Ill report back then.

Thanks for your help, jaychen.

[jaychen]

No probs. report back with update!