Ongoing A/F problem

[hardcorandy]

So I've had A/F questions post up previously. Now I really have a problem with the car getting leaner. Running stock fuel with a 14b at 14psi. For the past month or so my A/F will get a little worse by the day. Started out at 11.5-1 and now is hitting 13s on some pulls. Finally hit fuel cut tonight so this has to get fixed. If I do a 3rd gear pull it'll be 12-1. Ill do another pull and it'll be about 12.7. Not consistent what so ever. The weird part is when I start a pull the wideband will go into the 11s then jump up right away.

I turned the boost controller all the way down tonight and got a 12-1 on 9psi. WTF I still dont like that because I know the problem will continue. Temp outside was 35* and my coolant temp was sitting at 195*.

Not sure if this is related but as this problem started the hot starts have been really lean in open loop (if thats the loop that runs off the ECU) and idles really low and sounds like crap. Itll sit in this loop all day long if im idling. Will not change to closed loop until i give the thing some gas. Then the idle is back to 14.7-15.2 and sounds happy again. It has also kicked me out of closed loop (o2 cycle) a few times while sitting at a light. The rpms drop to 500 from 750.

Ive BLTed this thing more times then i can count and used soap and water. Have a little bit of a leak into the oil as the turbo has a little bit of play. No smoke though. No exhaust leaks to throw wideband off. o2 sensor has 20k on it. Coolant temp sensor has 20k on it. Caps have been replace in the ECU and i just checked it to be sure its not leaking again. Just put a new fuel filter in after 10k on that.

I really need to get to the bottom of this. Would it have anything to do with it getting so cold outside? I wouldnt think it would make THAT much of a difference. Im just looking for a little input before i just go buying parts and guess.

 

[hardcorandy]

Update.

Cleaned out the mass with no change. So i went and replaced to o2 sensor and checked to o2 housing for leaked. Now after replaces the o2 and resetting the ECU, Im hitting a solid 13 A/F at 14psi. I turned the boost down and did another pull. 12.5 A/F at 10 psi. Problem got worse. WTF is going on?

Talked to a buddy of mine and he said something about the MASS and o2 pretty much fighting each other causing everything to be out of whack. Possibly a dying MASS? Im gonna try another 90 ECU tonight to possibly rule that out.

 

[97ebaygst]

Have you test your fuel pressure? It could be the pump slowly going out.

 

[Arthris]

Pump or regulator. Replace Filter thats cheap and if it works it works. Always a good thing to do first.

 

[spyderturbo007]

Talked to a buddy of mine and he said something about the MASS and o2 pretty much fighting each other causing everything to be out of whack. Possibly a dying MASS?

Tell your buddy he's on crack.

At WOT (Open Loop), the ECU disregards all feedback from the O2 sensor, so even if your O2 sensor was going crazy, it wouldn't change anything.

Finally hit fuel cut tonight so this has to get fixed.

This helps a little. Fuel cut is caused by the ECU cutting fuel delivery in response to airflow. So, we need to look at things like boost creep or an airflow metering issue. Do you have access to another MAS you can try?

 

[bradselph]

check these.

Fuel pump, fuel pressure, mass, wideband, ecu.

 

[hardcorandy]

Thanks for the replies.

I bought a MAS a few nights ago. Didn't change a thing. So here is a rundown of everything that has been changed to try and fix this. ECU, o2, MAS, Fuel filter and Coolant temp sensor.

Ive been taking it easy on the car as of lately. Did a WOT to see if anything has changed and sure enough its even worse. Again A/F will dip low as soon as I hit 13psi and then lean out. It leaned out to 12.7, stayed steady for a second then went to 15.0 in the snap of a finger. Broke up but did not hit fuel cut that time. I let off right away.

I do have boost creep but not till about 5500 and all these problems are well under that RPM.

Im ordering a 255 pump and a FPR tomorrow along with a 20g hopefully. Link v3 is coming in 2 weeks. Worst case Ill be able to find the problem with link if its not the pump. I plan on getting the 20g as my 14b has some side to side play. Doesnt smoke but its enough that I cant really do a solid BLT. Ive sprayed every fitting and such with soap but the oil seal on the turbo leaks air into the drain pretty bad. PCV is a brand new OEM but i have oil blowing out of a few places as I think I have too much pressure building up in the engine and the PCV cant keep up. Everything that has went south on the car Ive upgraded, so this is why I have this plan.

Sound like Im on the right track?

 

[TurboAnything]

Sounds like you have a pressure leak in the tank. I have seen the O-ring seal between the pump and cradle go bad and start spraying fuel out thereby reducing overall volume. Or If the cradle bell was cut off and a piece of hose used the clamps or hose could leak. Same thing as above reduction in volume.

Only thing that does not add up is you hitting fuel cut. That makes me think leak or metering issue in the intercooler piping.

 

[bryanwheat]

Sounds like you have a pressure leak in the tank. I have seen the O-ring seal between the pump and cradle go bad and start spraying fuel out thereby reducing overall volume. Or If the cradle bell was cut off and a piece of hose used the clamps or hose could leak. Same thing as above reduction in volume.

Only thing that does not add up is you hitting fuel cut. That makes me think leak or metering issue in the intercooler piping.

I was thinking along the same line here, the o ring on the pump is leaking pressure back into the tank. As for the supposed fuel cut, i am thinking that you might actually be running out of fuel supply because of the o ring being bad at the higher load levels that you are running the engine so lean that it is cutting out and giving you the effect of fuel cut. I would definitely look into checking fuel pressure, and pressure under a load.

 

[hardcorandy]

The problem with the O ring theory is that its not lean on the first couple pulls. If I fully warm up the car off of a cold start and do a pull its perfect. Then it starts going downhill from their. Still have a hot start issue that may be related as these 2 problems popped up the same time. Today it actually stalled on a hot start. I restarted the car and gave it some gas which kicked it into o2 loop and then itll run great.

Im not so sure its the pump or the FPR at this point. I would always have problems no matter what situation I would think. I bought a multi meter tonight and decided to play around a bit. The only problem I found was the TPS. The reading at closed throttle is fine and so i know its set correctly. The book says move the throttle fully open slowly and check to make sure the ohms climb steady from 1100 to 5600. Mine climbs smooth but only goes from 1100 to 4500. I would think being that far off would cause a major problem right?

 

[hardcorandy]

I have replaced the TPS. Wants to going richer WOT but still not right.

I know when I BLT, I lose all the pressure through the oil drain of the turbo. Have side to side play. No smoke. Im creating tons of crankcase pressure under boost. PCV is brand new mitsu. PCV isnt open under boost, but the crankcase would see the same pressure as the manifold in my case right? The nipple on the side of the VC is ran to the intake tube to the turbo. The only way im relieving pressure is through all my oil seals.

I had a thought tonight and I wanted to test it. I ran a temporary catch can and vented it to atmosphere. Did a few third gear pulls and got 12.5 every time. Kept the car running and put everything back to stock setup. Pulled a few more times and saw 13s. So am I right thinking this all the turbos fault? That .7 AF difference is huge for all that crankcase pressure pushing through a small hole.

Id really like input on this. Thanks