My e30 318is s52 swap thread

[windsor318is]

ahhhh i thought you new the guy, my bad, hope its still on the lift

anyone know which of the 3 relays is the fuel pump one???

[windsor318is]

alright so my fuel pump is fucken, happy its that and nothing else stupid, he did a vacuum check and its perfect, so im assuming my fuel pump is why its running lean, well see what happens....

[mattdk318i]

considering the s52 had a larger volume pump in the E36.

[e30serg]

Good luck man! I hope it all works out for you....

[windsor318is]

alright so i installed the 325ix unit, its alot bigger, and all i had to modify was the vent pipe that was blocked off.
after that i sealed off the factory FPR and installed the BMP FPR set it to about 60 psi at idle and its still running lean, but the car runs now, the fuel pump was shot.next i think i might look for a 506 dme, lemme no if you see one around. im almost ready to burn this car, and so is my fiancee!!
next up is the booster issue, and install the exhaust, cant wait for that

[windsor318is]

alright so i installed the 325ix unit, its alot bigger, and all i had to modify was the vent pipe that was blocked off.
after that i sealed off the factory FPR and installed the BMP FPR set it to about 60 psi at idle and its still running lean, but the car runs now, the fuel pump was shot.next i think i might look for a 506 dme, lemme no if you see one around. im almost ready to burn this car, and so is my fiancee!!
next up is the booster issue, and install the exhaust, cant wait for that

also, it seems like it picks up a bit more power after 4000rpm, but not much more, anyone have this before?

[matt]

You don't need a different DME. How do you know it's running lean?

It sounds like you need a working oxygen sensor hooked up...

[e30s52]

the dme's are basicly the same. just stick with your 413

[windsor318is]

You don't need a different DME. How do you know it's running lean?

It sounds like you need a working oxygen sensor hooked up...

from the air/furel meter, and the butt dyno, its got about 160hp. would it run this poorly with a bad o2 sensor? might have to try another one. and it is in one bank in the headers if thats a reason as well?

[BigD]

from the air/furel meter, and the butt dyno, its got about 160hp. would it run this poorly with a bad o2 sensor? might have to try another one. and it is in one bank in the headers if thats a reason as well?

With a bad O2 it would be running in or equivalent of open loop mode - which is always rich. So if anything you'd have more power than normal, just shit fuel economy. So you confirmed that you have proper fuel pressure at the rail now?

[windsor318is]

With a bad O2 it would be running in or equivalent of open loop mode - which is always rich. So if anything you'd have more power than normal, just shit fuel economy. So you confirmed that you have proper fuel pressure at the rail now?

yup i got proper pressure now, as much as i wont, handy when i get the blower on there. so i guess its not the o2 then. im very close to driving this thing to RMP im sure they would sort this out. im going to let my mechanic finish off the exhuast and figure out whats going on with my brakes, then decide what to do. i dont think the dealership would like to tackle this, but i might talk to them.

[BigD]

I dunno man if your mechanic still can't figure this out, it's time to get a new one. With the debugging you've done, there isn't much left to check. You know you have the right amount of fuel at the injectors so from here it's either the injectors themselves or the timing (by this I mean everything the computer would be taking care of, including the pulse width, pulse timing etc). Get the injectors flow tested and cleaned if you haven't. If those are fine then it's something electronic. Maf (bad or backwards?), some sort of DME glitch (ask a buddy with an E36 to borrow one, don't forget to swap in your chip), dead TPS...

[matt]

If you have a working O2 sensor, it won't stay lean for long. It will adapt back to stoich. So, I would say you have an issue with either your narrow band O2 sensor or your meter is wrong. No/bad O2 sensor can cause all sorts of running issues. More importantly, it will prevent your motor from fixing its own issues by learning around problems (like vacuum leaks or non-stock fuel pressure)

With a bad O2 it would be running in or equivalent of open loop mode - which is always rich. So if anything you'd have more power than normal, just shit fuel economy. So you confirmed that you have proper fuel pressure at the rail now?

No no no.

Don't think of these ECUs as having "open loop" or "closed loop" modes. It doesn't work that way. At WOT, the ECU is ignoring the O2 sensor, yes... but it is STILL USING the adaptation data it obtained at idle and part throttle. Adaptation data is collected at idle and light load but applied globally. And it is not always richer, in fact I would say that most of the time the O2 sensor is actually adding fuel globally.

So... "Open loop" AKA no O2 sensor does NOT mean richer than usual. Richer than usual does NOT mean more power (leaner is more power).

[BigD]

Cool, my understanding of the way the ECU uses the O2 sensor is wrong then. I was always told that a dead or dying O2 sensor results in the ECU running it's stock mixture which is on the rich side. I've had bad O2 sensors on several cars, including my E30 when it was an eta. Some dead some not quite, never had one motor go lean, always running well and guzzling fuel like a bitch. But then none were engine swaps with the ECU learning from scratch.

Rich or lean isn't more power, I mean a little each way. But a little rich would be, especially when you goose it - and when you do goose it you should feel it because a lean engine will bog, whereas a rich one will actually clear up (if only for a little while but still).

By the way, I gotta ask, are you really saying that the "adaptation" is so significant that it can lean out the motor to the point of being as weak as he describes? I always figured this "adaptation" is a very very minor adjustment one way or the other, which is only really visible on the emissions report.

[matt]

Adaptation is a big deal. It can be the difference between a car that runs well and a car that doesn't. The ECU runs its "stock" mixture all the time (provided the MAF is working, and it has backup tables if the MAF fails) but it uses the O2 sensor feedback to fine tune the mix all the time, also.

The purpose of adaptation is to let the motor learn around issues that come up like vacuum leaks, fuel pressure or injector problems, and the programming of the chip not exactly matching the performance of the motor. So, it does the learning at part throttle and idle (when the target is ALWAYS 14.5-14.7) then it applies the adaptation globally (because WOT fueling will be effected by vac leaks or fuel system issues also).

In his case, the adaptation is not pulling fuel out... it's just not adding it back in. But I don't think that's the real issue. M50 motors will idle happily up to 17:1, they just fall on their faces under load if they stay that lean. I think there is some mechanical issue with the motor, fuel system, electronics.... not sure exactly.