jmmillerfzr

I've been fighting the P0171 and P0174 lean conditions for a while now. I can clear the codes and within a 100 miles they come back. Car seems to be running well. I've replaced the pvc valve in the past and found a torn diaphragm, not really hearing any sucking sounds around the pvc, but opened it up and found everything in order. I've read a MAF sensor could be at fault with this CEL and have cleaned it with no change. Can this be tested with vagcom? Any other ideas? Thanks.

jmmillerfzr

Well poked around and think I have a intake gasket leak. Could hear a faint sucking sound at back of the motor. Checked a few intake bolts and some were a little loose, Allen or torque bit in a nut driver an easy a quarter turn. Still thought maybe pcv valve so removed it and put a pipe between the hoses. Restarted and sucking sound is worse. When spraying carb cleaner on back drivers side of intake, sucking sound stops and idle improved. So thinking intake gaskets. What else should I order for this project? Fuel injector orings? Throttle body gasket?

Any links to a good instruction?

jmmillerfzr

Well started digging in this weekend. The might as wells started pilling up. With the intake off I could get to the o2 sensors and I had bought some when they were being cleared out, not a easy job. Then decided to check the pass cam adjuster, I had a pair of replacements when drivers side went out, went well. Found a vacuum pipe that runs under the manifold seemed lose, replaced with oring and a little gasket maker. Rubber hose was clean. Replaced throttle body gasket, original was cracked. New gasket was a three layer metal gasket. Need to get injectors in tomorrow and hopefully no more vacuum leaks.

jmmillerfzr

Got the fuel injectors and everything else put back together tonight, fired up and ran alittle rough, cleared its throat and seems to run great now. A few observations.
Victor reins throttle body gasket is three layer metal and great, much better than stock. I believe this was the root of my problem. There intake gaskets were paper, stock were metal. Replaced the lower oring on the injectors, upper one I checked on one and looked new compared to ones that touch the intake. Also noticed valve stems were clean and shining. I have ran seafoam and injector cleaner in the past. Nice to have it all back together.

BrianC72gt

I'm glad you got your issue sorted. While it is running well, it's a good idea to make note of the fuel trim in both banks through VAG com or even Torque app(free or $3.00) and a cheapo bluetooth OBD2 plug ($20). You'll get small numbers all around. Then, if you get a leaking hose, both banks will jump up, but a leaking manifold will show differences from one bank to the other.

jmmillerfzr

Thanks for the tip. I'll do that once I get the new issue sorted, just love that word. I'm getting a miss P0306 cylinder 6. I think it much have something to do with the injector as I did not touch that side of the motor. Would be good to confirm that cylinder 6 is the second cylinder from the front on the drivers side of the car. I'm guessing injector as I had to remove the injectors and rail when removing the manifold. As luck would have it the injector for cylinder 6 was the one I pulled to check the upper oring. The upper oring was perfect and I opted not to replace the uppers, only the lowers on the injectors. Not sure why this would cause a problem. I'm thinking damaged wires leading up to injector. I'll check it out this weekend.

BrianC72gt

The injectors all get a constant hot in, and the ECU switches the ground side from open to grounded to complete the circuit. The only way I know of to test it would be a noid light ( or an oscilloscope - but who has one of those anymore) or you could listen to it compared to its neighbors using a mechanic's stethoscope. A simple multimeter isn't fast enough to detect the opening and closing of the ground side.

Also, swap the #6 coil with one of its neighbors and see if the miss moves or stays in place. All of my original coils died at some point, and the aftermarket replacements can be spotty. I carry two cheapo spares in the trunk. The hot ticket is to swap in later model red top turbo coils which run about $20 each. I think ECS makes $shiny bits$ to make that mod plug and play. Or you could be a cheapskate and make the bits yourself.

jmmillerfzr

I did not get a chance to look at it last night and I only drive two miles to work. I did look around last night and found a refurb/cleaned bosch injector on ebay for $23 delivered. I looked at the red coils and much cheaper than the black ones. I saw whole sets for $120. I also saw replacement ends pretty cheap for a set. Just a wire splice to replace the ends? I work at a aerospace machine shop and could make adapter plates pretty easily. Are the red top coils better? Last longer? Would be an interesting upgrade.

jmmillerfzr

Did a couple of 500+ mile days and found no check engine lights and got 26mpg running about 74mph. Pretty happy with the car right now.