Need some guidance for getting my m30 swap BAR legal

[McGyver]

Moving my questions to a new thread :

http://www.r3vlimited.com/board/showthread.php?t=408687

[TobyB]

Yeah, and that messes up the idle mixture and speed, so the car tries to compensate for the rpm fluctuation-
but the extra added air and fuel are rich enough, so the engine overspeeds, closes the IAC motor
and reduces fuel, and now it's lean again.
So it hunts.
It's what this dog does...

t

[McGyver]

In reading through your post, I was thinking 'lazy oxygen sensor'- they're cheap, I'd try it.

I can see that, especially since my O2 sensor is only looking at the air in 1 pipe, so only 1 bank. Also, I think I used a generic Bosch O2 sensor instead of a factory e30 one.

I'd also look for an air leak, just because it's hunting.

Wouldn't an intake leak (unmetered air) cause it to run lean?

[TobyB]

In reading through your post, I was thinking 'lazy oxygen sensor'- they're cheap, I'd try it.

I'd also look for an air leak, just because it's hunting.

fwiw.

t

[McGyver]

Smog guy didn't have time to help me today, so I go back on tuesday.

I hooked up a fuel pressure gauge and my 3.0 bar fpr was actually building 3.2 bar. So I swapped it out for a 2.5 bar fpr. I'm hoping that my Motronic 1.1 DME won't be able to adjust the injector pulse duration to account for the lower pressure and that I'll get it a little leaner. If not, I guess I'll get some E85 in the tank.

[nrubenstein]

This isn't quite the right spot to ask, but oh well.

I got a smog guy to look at my numbers and my m30b35 is running too rich. HC and CO are both too high. NO is super low.

I was able to lean it out a bit by messing with the spring in the AFM. Now it's closer, but will be clean for a few seconds, then run too rich, then lean itself out again. It seems like the DME is trying to compensate for me playing with the AFM.

Also, the engine originally came running Motronic 1.1 (150 yellow DME). The car will run on Motronic 1.3 (179 Maroon DME). Would 1.3 be more adaptive and help it to run in the correct range?

So far I have checked the plugs and they have super healthy spark. That makes me think the coil, wires, cap, and rotor are all in good shape. The plugs do look a little sooty from the car running so rich.

I plan on changing the coolant temp sensor (it looks super old) and I'm going to test fuel pressure to see if it's too high.

Other than that, what would cause the car to run rich all the time?

Also, my new o2 sensor is only reading off of 1 bank instead of having the cross pipe that would allow it to read both banks. Could that cause a problem?

High HC, low NO, add 30% E85 to the tank. It'll drop your HC and raise your NOx.

A bad coolant temp sensor will certainly make the car run rich, but the fact that screwing around with the AFM doesn't permanently alter things suggests that the O2 sensor is engaged and the car is getting into closed loop mode. I'd probably want to swap the AFM and the O2 sensor at this point. Newer DMEs may be a little bit cleaner, so it wouldn't hurt to run it.

[McGyver]

This isn't quite the right spot to ask, but oh well.

I got a smog guy to look at my numbers and my m30b35 is running too rich. HC and CO are both too high. NO is super low.

I was able to lean it out a bit by messing with the spring in the AFM. Now it's closer, but will be clean for a few seconds, then run too rich, then lean itself out again. It seems like the DME is trying to compensate for me playing with the AFM.

Also, the engine originally came running Motronic 1.1 (150 yellow DME). The car will run on Motronic 1.3 (179 Maroon DME). Would 1.3 be more adaptive and help it to run in the correct range?

So far I have checked the plugs and they have super healthy spark. That makes me think the coil, wires, cap, and rotor are all in good shape. The plugs do look a little sooty from the car running so rich.

I plan on changing the coolant temp sensor (it looks super old) and I'm going to test fuel pressure to see if it's too high.

Other than that, what would cause the car to run rich all the time?

Also, my new o2 sensor is only reading off of 1 bank instead of having the cross pipe that would allow it to read both banks. Could that cause a problem?

[reelizmpro]

All E30 325i have a check engine light. 87-88 is Motronic 1.1 and 89-91 is Motronic 1.3 with stomp test. If the E32 M30B35 had a check engine light, then it must work in your car as well.

[kronus]

i think it might have become easier to find relatively unmolested m10 shells recently, since the stance and drift kidz don't want 'em

[TobyB]

...plus, the M10 got smaller strut housings, and drum brakes...

I'd vote negatory on the m10 swap, unless you're planning on just using the shell 'cause it's in really good shape.

but I'm only an expert on the internet.

t

[kronus]

So would it be easier to swap a M30 to a E30 M10? Or it does not make a difference?

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easier if you don't feel like finding a different transmission (m10 240 bolts up, some argue it's weaker, though)

harder if you aren't good at wiring (late model m20 C101 is pin-compatible with M30 B35 harnesses, also late m20 harness can run an M30 with a little bit of work. m10 is totally different..)

[noypi2]

An M30 is literally an M10, just with 2 added cylinders. And sometimes a bore. And maybe a stroke. Depending on era.

The M20 is an orphan scion of the late 70's, early 80's fuel crisis.
Its bottom end lived on in the M4x and then M5x DOHC motors.

t
bored at work.

So would it be easier to swap a M30 to a E30 M10? Or it does not make a difference?

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[brandn]

Alright well I took the car for a little drive today out of boredom and it turns out that I think the CEL is working! Since it is an older car (and ECU), I don't actually think there is a stomp test - the light just flashes the codes when you put the key into the on position, which is exactly what it's doing! It's giving me 2 flashes, which is the code for the O2 sensor, which it what it should have been giving me since the sensor was unplugged. Only problem now is when I plug the sensor back in, the same code still throws... maybe it's because the sensor is not plugged into the exhaust? Not really sure, but I am kind of happy the light is flashing now lmao.

[brandn]

Wow, this is the perfect thread for me!

My 1989 325i vert with an m30b35 just got loaded onto a truck this morning in Richmond, VA and is on it's way here. I figured I would try to sneak it by smog first since it's a clean swap and everything is there, but I figured I would have to BAR it if I fail the visual inspection. So it's good to read a bit more about the process.

i already tried to sneak it past the smog tech, at multiple places, and nobody would do it unfortunately :( kinda glad to see someone else in the same situation as me though (as bad as it sounds haha). hopefully you don't have to do anything major to pass BAR! keep me updated man

as for an update on my car - still absolutely no luck with the CEL. i got some wiring diagrams from an ETM and still can't figure out exactly which wires were supposed to go to what... one of the ones that was going to nothing was for an oil pressure switch or something of the sorts, can't remember off the top of my head. as far as the exhaust goes, however, I got the whole system off other than the headers and i'm gonna start chopping shit up this week hopefully lol.

[McGyver]

Wow, this is the perfect thread for me!

My 1989 325i vert with an m30b35 just got loaded onto a truck this morning in Richmond, VA and is on it's way here. I figured I would try to sneak it by smog first since it's a clean swap and everything is there, but I figured I would have to BAR it if I fail the visual inspection. So it's good to read a bit more about the process.