I'll check everything you've said chrispy, still doesn't make sense that a boost leak would make it run lean, if airs escaping then it'd be rich?? I've pulled plugs, every cyl looks the same, I can put pics of all the plugs up if necessary. Gunna have a look at the AFM too. The Hotwire might be damaged??
When off boost the engine will pull a vacuum. Leaks in this case will make it run lean. Though looking at the original dyno run it was making boost from quite lowdown. Something funny going on anyway.
Here are the plugs pulled from the engine the day before the dyno day. The third from the right looks leaner than the rest to me. Chrispy, prockies ECU scanner thing said my TPS was at .46 at idle.
Nah mate, that's the only graph I have when the previous owner owned it. Could be an injector given the fact that the plugs look a bit different?
No idea. I'll have to pull the current set of plugs and see. They should have enough use to see if it's lean, had 6 pulls on the dyno yesterday and a couple hundred km driving.
OK, I have determined 100% that I have fuel pressure. Took the return line off and ran it into a bucket, it's pumping very fast and the gauge is reading over 70psi at full throttle. Rob260 had a theory that my car may have been tuned to run without 02 sensors and someone had connected them post tune. One of the cars at the dyno day was running excessively lean with 02 sensors connected and with the 02's disconnected it ran fine, it had a nistune ECU as well and Rob's theory is that the tune that was written onto that particular cars ECU was designed to not utilise the 02 sensors. Now, interestingly enough I found that the drivers side 02 sensor on my car wasn't connected, in fact I could only find one connector on the drivers side, the male plug was nowhere to be found. The passenger side WAS connected. I disconnected it and the car ran the same, it didn't really change anything, so I'll leave it disconnected for now. It can't hurt anything. Given the fact that the male plug on the drivers side has been removed, I believe that Rob's right and the car may have been tuned without 02's and someone has just reconnected the 02's on the drivers side thinking they were doing the right thing. I bought some contact cleaner and cleaned the AFM, it was quite dirty. Will reinstall it on the car tomorrow. The only thing left to do is a vac leak test and I'll pull the plugs after a few more miles to see if one of the plugs is still showing signs of running lean. If it is, I'm fairly certain an injector has shit itself. If that's the case I'll have to get them flow tested. I'll test the connectors with a multimeter first, of course If the injectors are good then there's really nothing it could be other than the ECU/Tune. Strange, but at least I'm eliminating things.
If the o2s were tuned out it wouldnt matter if they are connected or not since the ecu is not referencing them. rip the tune and email it to me and ill tell you. also, make sure you plug the o2s into the correct plugs, not the cam sensors
You're putting my abilities up on a bit of a pedestal, Mike I don't have the equipment to pull the tune and I wouldn't know how anyway. It'd be nice if I could, that way I'd know if it's a physical factor or not... I DID take it to UAS when I first got it, the mechanic told me it was running rich (excessively at idle) and he leaned the idle map out. He then opened up the old tune and said the current one was the same, so idk????
Hey man. I'm going through this exact process haha. I think I created a boost leak installing bovs and have a dodgey injector. Starts missing if I jiggle the wiring. Also did my fuel filter. Had black stuff coming out the back when I gave it a good tap.
im witrh the above, the issue really only seems to be on the transition from off boost to on boost (3500-4500) as far as AFRS are concerned.. even below that its a bit all over the show just do the basics, electrical connectors tensioned and clean, base timing, boost leak test, most of the other systems on the car aren't in operation during a WOT throttle run failing that a tee-kay test for head gasket and compression test fuel pump, filter, regulator and injectors are fine given its hold 12.5 AFRS to redline
That is possible. If the fuel maps were rescaled and the closed loop section was not reviewed and the O2's were plugged in after it is possible it will pull fuel to try and meet stoich. Get that tune pulled and send to Mikey. But if that was done I don't hold high hopes for the rest of the tune...
Frustrating hey, but that $50 pull was worth every cent. I'm fairly certain that any boost leak before the plenum will cause the car to run rich, as the ECU is putting in a certain amount of fuel for a specific amount of air, yet that air is escaping before the plenum, so I can't see how your bovs would make you run lean. I'm going to boost leak test mine, though. I don't think I've got a boost leak as I have no problem seeing 21psi on the e-boost. minivan, what's a tee-kay test? I've had a coolant chemical test done on my last car.... I compression tested this car when I first got it, all cylinders were between 165 and 170ish whilst cold (cheap compression tester so it probably reads a little high, but it showed 145 on my old engine and also showed 110 psi on one cyl of my mates skyline, so I'm sure it's good enough to determine that my compression is fine). Chrispy, if it's just the tune I'll be happy. Can easily rectify that, lol.
Will put the feelers out on the fb page. You'll have to familiarise me with wtf I'm doing though, lol.
Just rang a local shop to get a coolant chemical test done to check my head gasket and he said if I'm not going through water then there's really no point and it wouldn't make me run lean anyway. He did mention that the 02's could do it if they weren't supposed to be connected. He also told me about a bmw he worked on recently that kept on cutting out under load like it hit a fuel cut, he put a new AFM in it which fixed it. Now, my car has done this but only VERY intermittently. Sometimes under high load it will just cut out. I mentioned to him that my AFM was dirty (the mesh was completely black, as was the hotwire, after spraying it with contact cleaner it was silver). So I'm going to OHM test my injectors, test my injector wiring, reinstall my afm and try to get a voltage reading from that, then the only thing I can do is a leak test and it'll have to be the tune?
My old afm made my car run lean as. Fixed it with a new one. If you wanna try mine for a diagnose your free too.
If the afm is sending the wrong signal to the ecu this could cause it to run lean or rich. So this could well be your problem.
Just OHM tested my injectors, all read .11 so they're fine as far as I can tell. One injector connector was glued onto the injector though and I broke it. Ordered another one from UAS, should get here this week if not tomorrow. Then I can put the afm back in and do a vac leak test. Next step as far as I can tell is putting it on the dyno. So far I've: Tested TPS voltage with the help of prockies ecu scanner thing Fixed broken vac line from manifold to FPR Checked fuel pressure and ran the return line into a bucket, pumping hard. Found that one side 02 connector was connected and the other side had a missing male connector. John at UAS said it's common practice for UAS and MRC to unplug 02 sensors. When I drove the car without it, I felt no difference, so I'm leaving the one side unplugged. Theory is that someone connected it thinking they were doing the right thing. I've cleaned the AFM, it was dirty enough that the mesh was black instead of silver, as was the hotwire. OHM tested the nismo 555cc injectors, they came to .11 - will look up later, but I'm fairly confident they're within spec. Tests to come: Vac leak test AFM voltage test - anyone got a link to instructions? From what I can gather I should measure it at the ECU, find which pin on the ECU is for the AFM, plug the pos wire from the multimeter into that pin maybe have to use a paper clip, then ground the other wire and test voltage, is this correct? Possibly find someone to get a copy of the tune so I can send it to Mike. I can't think of anything else other than putting it on the dyno after that. If I'm forgetting anything, please let me know
