Desperate, about to throw in the towel

[Vincent Brick]

The stomp test works, it just hasn't been giving me any codes any codes.... until just now when i tried it again. Its been maybe a week since I last tried it, but just now I got a 1222 "Lambda Control System Bank 1: The ECM has been unable to maintain Lambda (fuel mixture or fuel trim) on Bank 1 (cylinders 1–3) of the engine." Could this be left over from the last brief CEL I got at a stop light on a day when I was playing with the AFM spring? Should I disconnect the battery and clear the code? Is there a better way than disconnecting the battery to clear the codes?

I did fail to mention that until recent smog my car has a fuel pressure gauge off the rail, and my roommate who knows M20s better than I said the pressure looked fine. I do still intend to check the fuel flow via the method described above.

I'm really thinking vacuum leak right now though after accidentally creating that other leak yesterday (already repaired) and having it not effect the cars running in the slightest. I need to get it back on a smoker ASAP.

[raudonis]

You don't need a smoke test to let you know if your m20 has a vacuum leak.
With the engine idling open your oil cap or pull out the dipstick.
No change in engine operation will mean there is a vacuum leak somewhere.

[Vincent Brick]

Good to know, but I imagine I probably will need a smoker to find the source of the leak.

I guess then I should check the seal on my oil cap and dip stick. Not sure I have owned a car where that stuff needed to be sealed, not something I would think to do. Thanks.

[Vincent Brick]

Remove oil cap and idle gets noticeably more rough, same goes for the dipstick, despite the fact I apparently have electrical tape sealing it in lieu of an O-ring. Apparently the o-ring size is 9x2.2mm so I'll try and cop one tomorrow, or pull the electrical tape off and replace it with some heat-shrink.

[efficient]

You don't need a smoke test to let you know if your m20 has a vacuum leak.
With the engine idling open your oil cap or pull out the dipstick.
No change in engine operation will mean there is a vacuum leak somewhere.

with the smoke machine you can see where the leak is instead of just guessing were it is.
or you can get the car hot at operating temperature and spray carb cleaner around the intake area. if when you spray and if it makes the motor change then you found your leak.

[bradnic]

IMHO do whatever jlevie recommends.

The parts you replaced.. Were they new? Def sounds like a vacuum leak. Def so the smoke test. Absent that replace the hoses. The hose connections to the TBhave press fittings on them - you can get leaks there. If the boot is cracked replace that too. At least you don't have an M42 lol.

And how sure are you the TPS is ok?

[crappycoco]

Um, I've heard bad things happen to those that play with the AFM spring. Its laser calibrated or so I've heard.

I don't have access to a known good DME. Would it be worth it to buy one?

NO. Try to borrow one and only buy another one if its broken =)

There are visible cracks in my intake boot, but my roommate (the BMW mechanic) says that is normal and as long as no smoke comes out it should be good.

Ugh. I hate this kind of mechanics. You'll fix one leak, pressure will build up on those cracks and they'll start leaking. From how you describe it I believe there is one "big" or several smaller leaks somewhere on the system. I had a mystery leak too - it was the ICV of all places. Yes the goddamn ICV was leaking air into the system from its connector. Don't ask me how =D

If I would do my troubleshooting again on my car, I'd start with replacing ALL of the vacuum hoses. With that out of the picture, check the ICV for leaks, swap a "virgin" AFM into the car and see how it runs with it.

But still, those will improve idle, not the kind of problems you're talking about while you're driving. So the guys pointing to the fuel pump, fuel filter and injectors might be on a better lead =)

[Vincent Brick]

All parts have been new except for refurbished injectors.

Last smoke test that revealed a leak it was the breather hose off the valve cover and I replaced it with a new one. I did the valve adjustment since then so maybe that is the cause, I'll try to get it on the smoker tonight.

I tested the TPS for continuity between the appropriate pins with a multimeter. It seems to activate the closed throttle and WOT at the appropriate times with a nice audible click. Is there any sort of test beyond that?

jlevie is the man, got it.

Thanks a bunch.

[Vincent Brick]

Oh, and after one more click leaner on the AFM its feeling a lot better as far as hesitation and overall performance. The idle has even cleaned up for the most part, its staying pretty solid at 1000rpm and no longer self-revving or anything. Idle is still quite rough, lopey like it has a small cam in it (PO said it might have a cam in it but I don't really buy it), but that's been very consistent and I imagine just a result of worn valvetrain components or something.

[Vincent Brick]

Smoke test now indicates vacuum leaks at crankcase vent lower seal above oil pan but mostly at the rear main seal(!?). The guys at my buddy's shop had never seen smoke pour out of a bellhousing like that before. It would seem this proves that checking for a vacuum leak by removing the oil cap or dipstick is somewhat unreliable.

Thanks for steering me in the right direction on the vacuum leaks, I was too quick to trust that first smoker. Replacing both along with my cracked oil pan on Saturday and I guess I will take it from there.

[crappycoco]

If I were you I'd do all the while you're in there parts too (you know, like the clutch, selector rod & output shaft seal, pilot/throwout/input shaft bearing), dropping the transmission isn't a small job after all, might as well do it while you have it out of the car. But thats just me =D

But please, if nothing else, do the selector rod seal if you didn't already. Those leak in 90% of e30's =D

[Vincent Brick]

Selector rod seal, the knuckle right there whatever its called, and the trans output shaft seal were all done maybe 2 months ago. I bought the car immediately after transmission replacement and the PO said clutch had life left. The TO bearing does make a knockknockknockkncokknock sound at idle with the clutch out, I'll see what my guru says, I'm sure those will be the first words out of my Dad's mouth too when i tell him we're yanking the tranny. I really can't afford to put a clutch in it right now if it doesn't absolutely need done right away though, I still have to buy a new rear end and do timing belt/cam seal/water pump/radiator/hoses/temp sensor in the immediate future as well.

After this weekend I will have fixed both of my transmission leaks and 2 of my 3 oil leaks, maybe soon there will be one less chunk of outdoor carpet in the driveway to keep the HOA off our asses about the oil stains (my roommate owns several air-cooled VWs.)