So i've been getting codes P1128 and P1130, which are O2 codes so I decided to do a leak test. I tested at the airbox connection and heard a substantial leak coming from either around the TB or the DV's. I've checked the F-Hose and the DV's (they're new and working great) and sprayed leak test fluid (snoop) over the area and couldn't see anything. Any ideas where it might be coming from? I think it may be coming from the Y-hose from the other side of the DV's.

Here's my current plan of attack:

- pressure test from the turbos, if it's the Y-Hose, i shouldn't hear any leak.
- remove F-Hose and DV's, plug the Y-Hose and cap the TB. Pressure test from the intake.

I'm somewhat worried it's the hoses from the airbox to the turbos, and that'll require dropping the engine to fix. At any rate, any other ideas?

 

codes 1128 & 1130 are:

P1128

•

361 Oxygen Sensing Adaptation, Idle Range, Bank 2 -

Below Limit

Diagnosis conditions

•

Oxygen sensing system active

•

Time elapsed after engine start-up: 250 to 350 seconds (USA)

•

Time elapsed after engine start-up: 302 to 402 seconds (RoW)

•

Engine temperature greater than 60 °C

Possible fault cause

♦

Incorrect signal from MAF sensor

♦

Fuel pressure too high

♦

Fuel injector leaking
♦ EVAP canister purge valve open

Those codes don't sound like an air leak, faulty MAF perhaps as its on both banks but not an air leak.

What pressure did you use??

I have this nagging feeling that its possible to get false leaks when pressurising from the filter pipe, I just cant remember what it is that can cause the false leak, but Im sure I read on 6speed some time ago about this.???

Anyway, interesting to hear what the problem is. Have a look at the code descriptions I posted there from the w/shop Manual.

 

When I did the dv's I decided to drop the engine about 4 inches. And when I did the leak check I was able to reach the maze of sense lines. I have found a couple of them leaking.... See Rolfjahn post https://www.6speedonline.com/forums/...-engine-2.html

 

Thanks so much for the help. I've looked this up before and this site: http://forums.rennlist.com/rennforum...e-opinion.html points to an intake leak.

I pressure tested at 3psi, and given that i can hear a leak in that vicinity, that's why i suspect it's an intake leak. I've cleaned the MAF sensor a couple times and replaced the o-ring on my oil cap for good measure, but i'm hesitant to buy and install a new MAF if it won't solve the problem...

One other thing of note: I suspect there isn't much of a leak on the turbo side. It boosts up to .6-.7bar no problem.

 

From reading your posts you obviously never did this before...
the piping from airbox to to turbos is not high pressure thus not leak proof...

stop imagining things and do it right the first time....
get a boost leak tester ... turbos are 2.25" OD... you block one turbo off and pressure test from the other side... dont worry about what happens to the hoses you took off the turbo... try to get 20 psi.... and it should not drop more then 1 psi per 30 seconds...

if you do this and find the leaks.. fix them and your worries will be over...
OR get someone that knows what he's doing( good luck lol)...

 

Thanks Markski. You're right that I haven't done this before. I asked a question in another thread wondering why you suggest doing it this way, but the FSM suggests doing it at the airbox connection (page 620).

What would I do if the leaks are on the non-pressurized side? You're saying that it's less likely you'd get these codes from an issue on that side of the intake?

Thanks for your help.

 

In case anybody happens onto this via google, my issue was a faulty MAF as well... The thing runs so smooth now that that its been replaced.