[eastsidaz]

Originally Posted by 335xiE90

Alright folks. A smoke test showed my charge pipe and map sensor needed new o-rings. Once I did that a smoke test showed no leaks. But I ran into the same exact issue, once the car gets warmed up it starts surging in first gear badly. Not sure if it helps, but here's yet another log. https://datazap.me/u/matthew-pinola/...=50x50&sc=3-21. Could the surging be caused by a bad HPFP? I'm pretty sure I'm running the original still.

Yes, Rail pressure barely gets over 700psi even at 4000rpm. 700psi at idle is normal and increases with RPM so it's no good.

Weird thing is rail pressure was ok in earlier logs

[lookalikehuuh]

Originally Posted by 335xiE90

Alright folks. A smoke test showed my charge pipe and map sensor needed new o-rings. Once I did that a smoke test showed no leaks. But I ran into the same exact issue, once the car gets warmed up it starts surging in first gear badly. Not sure if it helps, but here's yet another log. https://datazap.me/u/matthew-pinola/...=50x50&sc=3-21. Could the surging be caused by a bad HPFP? I'm pretty sure I'm running the original still.

yeahh... this is weird... Rail pressures were perfectly fine before but now I would expect them to be around 1500ish+ while you are on throttle.

Fuel trims are still extremely high, we are approaching 30 when you combine the LTFTs and STFTs. Its somehow acting as if there is unmetered air coming into the combustion chamber.

[335xiE90]

I'm going to reset adaptations again tonite and try and get a 2-3 gear log.

[335xiE90]

Alright. So in the last 2 1/2 weeks I've replaced the boost solenoids, MAP Sensor and coolant temp sensor. All of them went out, one after the other. Does anyone have any ideas on narrowing this down a bit? The car ONLY does this when the oil temp is > 160. It drives perfectly normal with a cold engine.

[TunafishE93]

Whats your blow off valve situation?

[335xiE90]

Originally Posted by TunafishE93

Whats your blow off valve situation?

I'm running a tial BOV.

[TunafishE93]

How close are you to target boost, the last graph with seeable surges doesn't have that parameter.

[335xiE90]

Originally Posted by TunafishE93

How close are you to target boost, the last graph with seeable surges doesn't have that parameter.

I'm going to try and go out saturday morning to get some new logs. I will make sure to log target boost as well!

[TunafishE93]

Originally Posted by 335xiE90

I'm going to try and go out saturday morning to get some new logs. I will make sure to log target boost as well!

What turbo do you have?

[335xiE90]

Originally Posted by TunafishE93

What turbo do you have?

Factory turbos w/ 160k miles!!! They have some wastegate rattle and i plan on replacing them VERY soon. I just want to resolve this surging issue first.

[335xiE90]

Big update. I was driving the car and it was doing it's normal surging in first gear, but something new happened. It started smoking like crazy. Come to find out the ground wire on the #1 coil backed itself out and shorted out on the coilpack. I think this really has to be the issue at this point because there's literally nothing else that could be causing this from all the research I've done.

Anyhow, I plan on picking up a new wiring harness for the coils this weekend if all goes well.

[335xiE90]

I was wrong the surging persists. Here's a 2-3 log I got this morning at WOT. Here's a log - https://datazap.me/u/matthew-pinola/...x50&sc=3-11-21.

Things to note with the surging - It only happens after oil temp > 160, only felt between 1800-3400 RPM when not WOT.

[CarAbuser]

You probably need to replace the secondary O2 sensors. Your surging is caused by the DME running O2 sensor diagnostics, you can see it in the logs.

The secondary sensors are just as important as the primaries for a smooth running engine.

[335xiE90]

Originally Posted by CarAbuser

You probably need to replace the secondary O2 sensors. Your surging is caused by the DME running O2 sensor diagnostics, you can see it in the logs.

The secondary sensors are just as important as the primaries for a smooth running engine.

Noted. Those sensors probably have never been replaced, ever. I'm just gonna order them tonite, because everything else has been replaced one way or another.

[Gizm0]

Originally Posted by 335xiE90

I was wrong the surging persists. Here's a 2-3 log I got this morning at WOT. Here's a log - https://datazap.me/u/matthew-pinola/logs/cmoebz0wd0001i806wqf73dfa?channels=21x3&sizes=50x5 0&sc=3-11-21.

Things to note with the surging - It only happens after oil temp > 160, only felt between 1800-3400 RPM when not WOT.

Cylinders 1, 4 & 5 pulled a lot of timing when you shifted into 3rd.

High and low fuel pressure look good. Someone said earlier HPFP pressures were low, but the couple of logs where the pressure was in the 700psi range were partial throttle. HPFP will only push about 700psi at idle or low throttle input, and will increase to 1500+ psi at WOT so your HPFP is fine. I doubt your secondary oxygen sensors are the culprit. You’re running open loop in WOT so o2 sensors don’t have any effect there. They will affect how the car runs in closed loop though, at idle or low pedal input when the AFRs are close to 14.7:1.

STFTs are a little high, but within +/- 10% so not alarming.

Your WGDC is doing something weird, jumping up and down. Boost solenoids might be getting tired/sticky?

[CarAbuser]

Originally Posted by Gizm0

Cylinders 1, 4 & 5 pulled a lot of timing when you shifted into 3rd.

High and low fuel pressure look good. Someone said earlier HPFP pressures were low, but the couple of logs where the pressure was in the 700psi range were partial throttle. HPFP will only push about 700psi at idle or low throttle input, and will increase to 1500+ psi at WOT so your HPFP is fine. I doubt your secondary oxygen sensors are the culprit. You’re running open loop in WOT so o2 sensors don’t have any effect there. They will affect how the car runs in closed loop though, at idle or low pedal input when the AFRs are close to 14.7:1.

STFTs are a little high, but within +/- 10% so not alarming.

Your WGDC is doing something weird, jumping up and down. Boost solenoids might be getting tired/sticky?

Open loop at WOT?? The only time the DME is open loop is when there is a O2 sensor fault or at startup.

He's also not having the surging issue at WOT, because diagnostic routines are mostly disabled at high DME CPU load.

[Gizm0]

Originally Posted by CarAbuser

Open loop at WOT?? The only time the DME is open loop is when there is a O2 sensor fault or at startup.

He's also not having the surging issue at WOT, because diagnostic routines are mostly disabled at high DME CPU load.

Yes, at WOT, the DME is ignoring the secondary narrow band sensors. These are only used for emission compliance to reach stoic under low throttle. Primary wide band sensors are used to target rich fuel mixtures.

[CarAbuser]

Originally Posted by Gizm0

Yes, at WOT, the DME is ignoring the secondary narrow band sensors. These are only used for emission compliance to reach stoic under low throttle. Primary wide band sensors are used to target rich fuel mixtures.

DME is running closed loop at WOT.

Secondary sensors are used to calibrate the primaries, for trim control and for primary sensor and catalyst diagnostics.

[335xiE90]

Update - got the rear oxygen sensors ordered. I should be installing them next weekend. I'm going to be replacing the turbos anyways, so I'm just waiting on parts to come in.

[Aode06]

Originally Posted by 335xiE90

Alright everyone I flashed back to stock and it still surging. The weird thing is it does not do it when the car is cold. It's mainly felt during initial acceleration in 1st gear then in the lower RPMS in 2nd gear.

160k miles
Stage 2+ tune for 65k miles
VRSF DP
VRSF 7.5 IC
Index 12 Injectors
Eldor Coil Packs
1 Step Colder Plugs

Newly replaced:
Cam Ledges
Both VANOS solenoids
LPFP
Oxygen Sensor (Upstream/Rear)

Swap the exhaust and intake Vanos connections they could be crossed.
Send us full clear pics of the top your index 12 injectors,where did you buy them?
What brand plugs do you have? where did you buy them?
what brand lpfp do you have and ratings? Where did you buy it?

[335xiE90]

Originally Posted by Aode06

Swap the exhaust and intake Vanos connections they could be crossed.
Send us full clear pics of the top your index 12 injectors,where did you buy them?
What brand plugs do you have? where did you buy them?
what brand lpfp do you have and ratings? Where did you buy it?

Injectors are from FCP
Brand new 1 step colder NGK plugs from FCP
The LPFP is this one - Brand new Precision Raceworks bucketed pump bought here - https://www.bmptuning.com/products/p...40083515244662

I've swapped the LPFP for a brand new stock one during my testing and found no difference between the two.


EDIT: Swapped the vanos with no luck.

I'll swap the Vanos tonite and let you know how that works out.