L-jet 323i - low power, fuel rail loses pressure in 5 minutes

[frankenbeemer]

Seems like a very good price on the wideband. I'll try to search out that book.

[kronus]

let me know if you find it. I am curious about what #1 Partial Throttle Switch does - there is a similar-looking sensor on Motronic engines, but it is a barometric pressure sensor and doesn't have a vac line running to it.

[bloodsnot]

Do you have the "2/3 way valve" (#8 in the diagram) on your car? I can't find that on mine..

[kronus]

I don't think I have #8 or #14. I'll take some photos when I'm down there tonight

[bloodsnot]

I'll take some photos when I'm down there tonight

That would be much appreciated!

[kronus]

well, it's not the timing belt being off, both marks are right on the dot.

I'm putting together a ghetto smoke tester and checking the distributor advance/retard lines.

[kronus]

So I built a smoke tester out of two vw hubcaps, some hose, an air sprayer, a zip tie and a rag:


you have to keep the air intake closed:


using that, I found that the distributor retard line was completely severed at the distributor. fixed, but didn't solve vacuum issue.

then, I read a lot about timing m20 engines with distributors and figured out that I did it drastically wrong the first time - I'd set it to sit at the O|T mark at 3k RPM, because I mistook it for the 19 deg advance line (Z mark), since both had convenient yellow lines drawn over them, and the distributor was maxing out its travel before getting to the correct advance setting.

I pulled the distributor out, advanced the rotor manually to give it enough travel, reset the timing to the correct 19 degree BTDC at 3k RPM, verified no more vacuum leaks, and went out for a test drive. Power felt better than before, but not great, and now it is backfiring a lot on power, idles at ~1200 and smells fairly rich. Ideas? Could this be just because I have the exhaust off pre-cat?


edit: did some reading. Backfiring could be due to running overly rich OR overly lean. It also could be due to too much advance, OR not enough advance. lol.

I'm going to see if putting the exhaust on will make the backfiring go away, and also check AFRs, although I'm not sure what can be done to fix AFR problems on an L-Jet engine.

Annoyingly, the idle vacuum has only slightly increased, from 5 in hg to 8 in hg. Running out of ideas, although the high idle continues to point to a vacuum leak despite the smoke test's inability to locate any after I fixed the distributor line.

[bloodsnot]

Did you try a different fuel pressure regulator?

Have you had your injectors ultrasonically cleaned and flow/leak tested?

Check for leaks around your manifold gaskets..?

[kronus]

the FPR is new, I've verified that the rail pressure is good when the car's running.

I haven't done the injectors yet, since I can't find a place that rebuilds low-impedance l-jet injectors.

smoke test showed no intake manifold leaks.

[bloodsnot]

I haven't done the injectors yet, since I can't find a place that rebuilds low-impedance l-jet injectors.

...:-?
Did not know L-Jet has special injectors. Do you know why/how the impedance would matter when cleaning and testing them?

[kronus]

they're a different generation of injectors... I don't think many people stock the rebuild parts for them anymore. Everyone uses the modern, universal Bosch style, which is why you can fit Ford 5.0 injectors to an M20.

[bloodsnot]

Okay. But the only parts they'd use would be the pintle caps and O-rings, right?

My car is an '85, perhaps it has the newer generation of injectors? I mean, they came back with new pintle caps that were identical to the ones I sent them off with when I had them cleaned/tested.

RealOEM gives me 13641284408 as the injector part number. I'd have to go pull the fuel rail to see if that's what's in there...

What p/n are your injectors?

It's possible that the previous owner swapped in some newer ones on my car, of the universal Bosch type, and this could be why they could be serviced. I don't know if they're a drop in replacement, though, or if they'd cause any issues for the L-Jet controller..

[kronus]

from various rumors on the internet running the wrong injectors is "bad". I don't know what the actual effect is...

to my knowledge L-Jet always uses low-impedance injectors.

what place did you use to get yours serviced?

I'll check my injector PNs tomorrow night.

[bloodsnot]

from various rumors on the internet running the wrong injectors is "bad". I don't know what the actual effect is...

Yeah, that's the general impression the internet has left with me over the years, too. I have this vague recollection of the previous owner talking about putting in higher flow injectors that gives me night terrors from time to time. I'll be pulling them out to take a look once my roommate's M-B diesel gets out of the driveway later this week; it's been bothering me for a while and this is a good excuse to take a look.

to my knowledge L-Jet always uses low-impedance injectors.

Would these low-impedence guys be available in the same form factor of a universal Bosch injector? "Low-impedance" would indicate to me a different signal requirement to operate at the very least but nothing about the fitment to the manifold or fuel rail.

what place did you use to get yours serviced?

I went to Dr. Injector (North). It was essentially a drop box in some dude's driveway that had envelopes and markers in there for you to drop off your injectors after paying over the phone with a card. He called a day later and I picked them up in the same box with a flow/leak test report and some candy. This cured a hard-starting-when-warm issue I had been having at the time (that has since reappeared).

I'll check my injector PNs tomorrow night.

Just navigating to your year/make/model on RealOEM, it would seem that you have injector part number 13641284408, different from what mine came from the factory with. Without knowing your VIN number I can't guarantee that to be 100% accurate. Would be curious to know what they actually look like if you could post pictures...

[kronus]

the injectors in my 323 are PN 0280150208:



oddly, this table says they're high-impedance.