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My Intake Pipe Design, Stalling Issue And Lean Popping


SargeRX8
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Yeah, literally haha. Such a weird problem. It seems only to happen when warm and only on idle. Anyway I fixed up my shonky BOV return pipe(it was a piece of heater hose, had 3 kinks in it which got worse lol) by putting in a few PVC 90 degree bends here and there. Got a nice pipe with no kinks. Started the car up and it sounded very smooth. Temps were around 61C. I didn't want to get ahead of my self but it did sound alot better. Switched it off and will test it properly with more fuel in the tank as I head out to work shortly.

Spoke with DVS JEZ on the phone. He suggested I add some latency to my injectors(16ms). It made a huge difference in the smoothness of idle but didn't really help with the lean popping. It seemed to work but what looks to have happened was it pushed the lean popping pattern higher up into the rev range. It wasn't popping much at 2krpm but more so at 3500 etc. Hopefully this pipe has some effect on it which is a positive effect and hopefully it eliminates my stalling when clutching in.

Two skylines drove past today while I was working on the car and both were lean popping when cruising lol, maybe I am just being too fussy.

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New bov return had no effect on lean popping... Something is throwing out the tune. It can't be the weather because it happens on warm days and even cold nights... I very much doubt it's misfiring. There is no effect at all when under load just idle and cruising low rpm...

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checked that it actually is lean with a wideband?

The intermittent pop is more often than not referred to as the lean pop. I think I'm going to buy a wideband. I tested it with the stock afm and same issue but that doesn't rule it out. It would be odd though that my afm is causing issues under no load... But I do hear an electronic buzz under the bonnet... I need it checked out...

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I've got a pfc so that consult port is useless I think. But on my pfc controller my timing is 15 degrees at idle which is normal. In all honesty its the stalling when clutching in between gears which is a problem and I feel the two issues are related because both started happening at the same time...

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Can you check your TPS readings please?

See if it gives consistent readings on the handjob.

On the pfc I'm assuming this is labelled thro, if so idle is constant 0.35v. Didn't check when I give it throttle but I will today. I'm going to clean my aac and spend some time looking for split vac lines...

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LOL nothing beats a good handjob sometimes.

Im not sure if the PFC shows THRO or TPS...... Ull need to have a good check and see whats what.

Ive had similar problems to what your having here with a dud TPS. It would show the right voltage at idle and at full throttle but in between it would give inconsistent readings.

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I just went for a drive, this problem almost certainly only happens when the car is warmed up... I never usually do this but after a minute or two of warming up I gave it just enough to create 0 boost and vacuum and backed off the throttle and it didn't stall nor come close to it. Once it was warmed I done the same thing again and it almost stalled(rpm was about 300 maybe 400). I went to buy carby cleaner to clean up the AAC as I think my issue may be there. From what I may have read somewhere, the AAC does not have any role until the engine is warm. Is this correct? I'm going to check all my lines while the engine cools down a little now.

The PFC shows THRO. If that is the same thing then yeah I kept an eye on it(dangerous shit lol) while driving slowly giving it petrol and it would slowly and consistantly rise from 0.35 and I saw it get to 0.88 before I had to start watching the road. There was no erratic change in numbers. Very linear.

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The AAC and the cold start valve both provide another way for air to enter the plenum (other than the throtle butterfly). The AAC is under the control of the ECU for idle speed control, the cold start valve is thermostatically controlled. It closes up as the car warms up. So it does tend to dominate idle speed control while it is open and as it closes up the AAC can start to gain some control.

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Judging by that then it would be safe to assume my cold start valve is fine as the car is perfect when its cold/warming up. It is only once the car IS warm it plays up. I cleaned up my AAC before, was filthy as shit. Lets hope later when I drive it, she goes fine. I checked everything over and over, I can't see any split or cracked hoses anywhere. I read on the net that you can spray carby cleaner directly onto vacuum lines n shit when the motor is running and if the engine makes a odd sound when you spray on a certain spot, its a good indication there is a hole or leak there. Is this safe to try on a turbo car?

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Yeah, safe - ish. Don't spray it onto your coils or other wiring connectors, because it is a highly flammable hydrocarbon and if you ignite it you'll ruin your eyebrows at the very least. Just a quick squirt on hose ends and other joints/gaskets will usually do.

Edited by GTSBoy
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Yeah, safe - ish. Don't spray it onto your coils or other wiring connectors, because it is a highly flammable hydrocarbon and if you ignite it you'll ruin your eyebrows at the very least. Just a quick squirt on hose ends and other joints/gaskets will usually do.

Ill probably give the idea a miss as I really cbf cleaning that shit off, and it smells weird lol.

I was thinking of something. If I built a small circuit consisting of a few LED's ranging from red to yellow to green which will receive the AFM voltage signal as the input and work in such a way that when the volts are low the lights are red and when the volts and air rises the lights will go to yellow and green, could I use this as a clear display for me to monitor when I am getting effects of reversion to determine if its an issue? I don't think it will take long to make and I should have all the parts I need. I can just keep my eye on my power fc hand controller afm voltage and see what happens. My idea is this. When you clutch in the flow against the afm should be nothing really and read about what I think its .3v or .5v on idle. What I can do is watch my lights(or hand controller) for retarded random fluctuations when the throttle is closed which should tell me if air is hitting the afm. If I don't see any air hitting the AFM and the voltage is stable until the stall point then I guess I can rule out reversion as being the issue here and start looking deeper into a vacuum leak.

Just tested this out quickly with the car off. I blew compressed air through my recirc pipe and read 1600mv. Not a good figure but also not something to base anything on considering the car was off, turbo not spinning and no vacuum from the engine.

Edited by SargeRX8
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