M35 Lean Now Not Lean Strange Codes

[zelda]

Hey everyone,

Having some issues with the stagea i cant quite figure out.

Dont like starting a new topic and iv done some extensive searching on these forums so heres the rundown

Car has HDI kit, custom bov pipe ( 3inch from kit ) kompact bov, changed vac hoses except one with restrictor going to WG actuator, boost solenoid blocked off so should be running on wg pressure, scottys dump pipe and a walbro 255 not yet on 12v constant.

Somewhere along the line it threw a lean code on bank 1 P0171, i had the fuel pump done along with filter etc thinking this might clear it but to no avail, however the car still idle fine just bleeds off boost around 9psi according to the tyrbosmart guage not the usual 12ish it used to even after ditching the solenoid.

So i dropped it off to a reputable auto lekky and had him throw the scanner on it and run some tests, he found a couple of small leaks and while i was there i had the injectors flow tested and serviced for peace of mind.

Got the car back, the code had gone but still bleeding off at 8/9 psi and still rather whiney ( as always ), about a week later the CEL came back and gave me the lean code again along with Electronic throttle control ( guessing TB ) and throttle or pedal pos sensor, assuming they both go hand in hand.

Unfortunately i needed the car for the week and couldnt get it back to them to investigate further

Strangely enough two days later i start the car and now the codes are gone? It feels like its got a little more grunt now too but still bleeding off early!?

Sooo im scratching my head, could the AFM be going? Or the wastegate opening early? Heat is not proving to be a factor with the gate AFAIK, the idle is always 650 once warm, idle inHG is around 18/20 ish as mentioned drives fine untill that 8/9psi mark then just spins no more and is a sluggy sounding whistle really.

Anyone willing to throw in some input is greatly appreciated,

Ps will change the lower rubber pipe before intercooler not supplied with hdi kit to this dolphin hard pipe when it arrives.

Cheers!

[stripey]

Does it sound like this kind of whine ?

[BoostdR]

Check fuel pressure, check manifold for leaks or cracks. Lean code could also be a misfire. Coil packs or plugs.

[zelda]

Does it sound like this kind of whine ?

https://youtu.be/P9tT4yApVes

Hard to say in comparison but yes similar

[zelda]

Check fuel pressure, check manifold for leaks or cracks. Lean code could also be a misfire. Coil packs or plugs.

Checked for leaks, although it wont hurt to do it again, plugs have been done LFR7s iridium if i remember,

Is it worth putting a FPR with a gauge on ? Relatively cheap and harmless to do i would imagine - whats the standard pressure about 44psi ?

Cheers

[BoostdR]

I haven't checked OEM pressure, I would assume 43.5 psi with the vac line removed. Would be worth checking the spec.

I would also check the Oxygen sensor...is it average on fuel?

[zelda]

I haven't checked OEM pressure, I would assume 43.5 psi with the vac line removed. Would be worth checking the spec.

I would also check the Oxygen sensor...is it average on fuel?

I would hope the o2 sensors good as the dump pipe was only put on about a month ago, pretty comfortable my mechanic would of pointed it if it was the case, he did mention it was in a way more sensible place haha, yeah the fuels about right ~ 650km per tank mixed driving

Ill see if i can find the spec for the FPR and give that a go othewise im leaning towards rebuilding the turbo ?

[scotty nm35]

When you say checked for leaks, did you pressure test the intake at 20psi+? I have seen many leaks that would never be found using a smoke tester or visually, 20 psi into the intake usually sorts them quickly.

The other common issue is the fuel reg hoses, they commonly fall off as there are no barbs. Make sure you cable tie both ends. Checking the reg at base fuel pressure you will need to remove this vac hose.

Other than that, before you start swapping turbo's, have you tested the test device? I have seen more boost gauges fail or reading wrong than wastegate actuator problems.

[zelda]

When you say checked for leaks, did you pressure test the intake at 20psi+? I have seen many leaks that would never be found using a smoke tester or visually, 20 psi into the intake usually sorts them quickly.

The other common issue is the fuel reg hoses, they commonly fall off as there are no barbs. Make sure you cable tie both ends. Checking the reg at base fuel pressure you will need to remove this vac hose.

Other than that, before you start swapping turbo's, have you tested the test device? I have seen more boost gauges fail or reading wrong than wastegate actuator problems.

I'll have to check with my auto spark, he found the leaks and didnt mention weather it was pressure tested or otherwise,

As for the reg hoses they are tied on and im always checking just in case one does pop off, checking for the base pressure im assuming it can be either one scott?

As for testing the tester, well i still run the factory gauge ( not much to go off i know) as well as the AM one which is a brand new unit, T'd off just before the factory boost gauge sensor, since the problem arose the factory gauge has never hit the same mark ~1bar

I think the next most sensible step is to make a boost leak tester and rule it out for myself, although iv been vigilant in sealing everything and tieing all hoses etc it needs to be seen with my own eyes, and ill let you know how it turns out, any one got any pics of there home made boost tester suited for the stag?

Thanks again!

Zach

[datmoo]

I'll have to check with my auto spark, he found the leaks and didnt mention weather it was pressure tested or otherwise,

As for the reg hoses they are tied on and im always checking just in case one does pop off, checking for the base pressure im assuming it can be either one scott?

As for testing the tester, well i still run the factory gauge ( not much to go off i know) as well as the AM one which is a brand new unit, T'd off just before the factory boost gauge sensor, since the problem arose the factory gauge has never hit the same mark ~1bar

I think the next most sensible step is to make a boost leak tester and rule it out for myself, although iv been vigilant in sealing everything and tieing all hoses etc it needs to be seen with my own eyes, and ill let you know how it turns out, any one got any pics of there home made boost tester suited for the stag?

Thanks again!

Zach

[zelda]

Is there any reason i couldnt pressure test it at the suction pipe and cap off the bov return? I might sound stupid but would this in theory test through the turbo for leaks and save me getting under the car? Just a thought cheers

[datmoo]

Is there any reason i couldnt pressure test it at the suction pipe and cap off the bov return? I might sound stupid but would this in theory test through the turbo for leaks and save me getting under the car? Just a thought cheers

Give it a go. Mine was more to do with pipe size as I already had this made for my Datto.

[zelda]

So still havnt managed to get the boost tester on it yet, but engine light came back on again today after drving open roads for about 150ks

P0171 is back left bank lean

P0120 throttle position switch

P1122 any one got any clues to this one??

Thanks again for your input guys

Zach

[joshm35]

http://www.autocodes.com/p1122_nissan.html