I'll try and make this simple. I have a tune and an accessport, and my car kept losing power. Well I started watching my AFR's and the car is leaning WAYYYY out when it does this. Im talking 15-17 WOT, then usually drops back down to high 11's/low 12s as it keeps revving, I shift and its way back up until the RPMs climb again. I dont want to pop my motor but I've been messing with stuff trying to fix it, take it for a hard run, and the same thing will happen. I have a track day in about a month and want this fixed asap so I dont have to cancel. I am getting a P0076, and have read on here that the car will lose power with this code/valve not opening, but no one has mentioned (from where I can find) that its leaning out when this code is thrown.

Sooooo would the P0076 cause the car to lean out?? I'd like to replace the solenoid, but want to make sure my leaning out issue is taken care of first. Two bird, one stone if it is the solenoid, but I can't find proof.

Car is tuned, catless, new plugs/coils/wires, 13k on motor, RE-A intake, brand new fuel filter and sock, but mostly stock power wise aside from that.

By the way, this only happens after running the car very hard roughly over 5 minutes.

 

Load the stock tune to see if it goes away....

if it does it's the tune 😎

If it doesn't you have a fuel delivery issue...so fuel pump ( check pressure ), injector issue, MAF issue, pump resister....there are lots of option's 😊

 

I've flashed it back to the stock tune twice and the issue was stil there. I've been thinking it's fuel related but this code likes to come on and I was reading how it can cause power loss, just no one has mentioned if it's a power loss due to the car leaning out.

 

The fuel pump was JUST replaced yesterday. Brand new unit. That's why I took it out on a hard run to see if it fixed the issue. Nope... lol

 

D0076 is a VDI solenoid valve error. Likely a wiring issue or a problem with the solenoid valve. It is a low VOlathe error so if you have a broken wire it will do that.

Usually the valve doesn't open till higher RPM operation so it usually doesn't cause too many issues with power loss until above 7K

If you have a new pump then temporarily rule that out


Do you have a scanner to check fuel trims? I would expect with a MAF error you would get trims where it isn't reading appropriately. In closed loop it should try and add fuel to make the mixture correct. If the error is in open loop area then it wont self correct. You might want to unplug the MAF and see what happens. The PCM will revert to an open loop map and if it runs better the you can maybe try a new or loaner MAF to see if that helps.

Did you check the injector wiring if your engine has been out before....but usually it won't idle well with them backwards

If you have a Sec or P2 injector failing you can get funky AFR''s in the transition areas where they are coming on as well...

Start someplace and systematically confirm that that part of the system is good and then move on

If you have a way to post a log....run one with the problem logged and as many parameters as you can. Post it and we can have a look 😊

 

Shew that was a lot of info, but i needed it. I have an OBD reader on my phone, and my accessport to scan stuff, but never thought to check if I can read fuel trims with either. I've been running the car hard since break-in was over on this motor, and havent had issues until maybe 1,500 miles ago, so i have kinda temporarily bypassed the injectors/wiring to them as well. MAF is on my list for sure right now, as well as the solenoid. I CAN post a log, but the issue doesn't happen right away. Its gradual and gets worse and worse until i have to baby the car to death. I could try and post a data log when it gets bad if you'd like.

 

When it gets bad...run an Accessport log and post it here or PM me and I'll give you my email address to send it to me

"so i have kinda temporarily bypassed the injectors/wiring to them as well" What does that mean?

 

I bypassed that because the past 8-10k of track time since the motor, I haven't had an issue. I'm down to send you a data log though. I can still check the wiring on the injectors, but that's all I meant. Not saying the injectors aren't having an issue now, but I'd figure if it was the wiring, it would have started a while back.

 

Ya....if it ran properly for a while it wouldn't be the injectors wired incorrectly.

Nothing worse than an intermittent electrical issue to try and diagnose

 

PMed

 

Bump.

Still no luck guys. Pulled my intake plenum off and checked the injectors/wiring, sent some data logs in, checked the MAF and o2, and I still can’t figure it out. The car won’t throw a code