SuperEta head swap problems

[G-man55]

Did the head swap a while back, and I've got some problems I haven't quite been able to work through yet.

-Getting about 10 mpg, white smoke out the exhaust at stop lights, loss of power up to around 4k rpm, bogs a little bit with a quick throttle input

-Had a really funny idle (idled at 2000 rpm), turned out to be TPS. Adjusted, the car now has a little bit of idle fluctuation between 7-900 rpm

-No redline! (will rev past 7k)

Used an unopened 173 ECU

I've tried finding vacuum leaks around the intake boots, throttle body housing, ICV, brake booster, etc.

The idle bypass on the AFM has been adjusted in the past.

The Pulse Sensor (on one of the spark plug wires) was pulled at the junkyard, not sure how to test if it's working or not.

TPS won't give me a stomp test (nothing happens)

Already changed out spark plugs, didn't help.

The Bentley isn't helping much, and trust me, I've tried the search function.
Anyone got any ideas?

[Julien]

does the car have a 4cyl cluster in it (7k redline issue)
sounds like you aren't hitting WOT (hence the hesistation issue around 4k RPM) I would bench test/adjust TPS


how much white smoke? hard start the morning after driving her?

[G-man55]

There's a bit more white smoke than you would expect from a cold start, not a straight up smoke screen, but it's noticiably more, and also happens when the engine has warmed up. After the new plugs, it did get a bit better (not sure if related)

I only swapped the tach, I kept everything else on my old cluster. I'm not sure whether the tach was out of a 318 or 325, how can I tell?

Would the TPS not reading right cause it to hesitate? I had the closed throttle part adjusted correctly, shouldn't that mean the WOT switch is in place as well? I'll check it anyway when I get home.

[G-man55]

Update: I never swapped the coding plug in the tach, so the tach is reading correctly.


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[jlevie]

Exactly what was done in the head swap?

White smoke from the exhaust once the engine is at operating temperature usually means a bad head gasket. The failure of the stomp test usually means that the DME isn't seeing both the idle and WOT switch closure of the TPS. Hesitation off idle is most commonly from intake leaks (have a smoke test run). The tach indicating a redline above 6200rpm will be a bad tach, wrong coding plug, or bad DME.

[G-man55]

All gaskets and seals were replaced, including head gasket. It stopped smoking a few days ago, either that or my friend pointed out the smoking while the car was warming up.
DME does see the idle, the engine rpm rises to 2000 on idle when the TPS is unplugged.
I'll swap in my friend's DME and see if that changes anything.


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[Regnar75]

Are you running an o2 sensor (early or late model one)?
Coding plugs vary greatly between 4cyl and 6cyl ALSO between E and I of 6cyl ( i think you want BMW 17, its a white plug )
do a compression test to eliminate HG being ruined.
definitely seems like there is signs of a vacuum leak.
what AFM are you using, can you try an untampered with one?
did you swap over to the 325I ICV?
actually, just list what parts you used from the 325I on this swap and if you have upgraded to motronic 1.3 so we can help diagnose better



look through my post ( #324) to see if any of those little qwerks are happening to you

http://www.r3vlimited.com/board/showthread.php?t=100939&page=22

[G-man55]

The car is the '88 SEta
The only "new" parts swapped were the manifold, injectors, rail, FPR, TB, AFM, TPS, valve springs, and ECU.
Original ICV swaps over, as does the o2 sensor.

I'll grab a coding plug off an I at the yard sometime to try and see if that fixes the problem.

I'll try a compression test and try a new AFM on Monday.


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[G-man55]

I checked out your post, I don't think I'm having any of those problems because I'm already on moto 1.3


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[jlevie]

Did you swap in the M20B25 cam along with the other M20B25 parts?

[G-man55]

Yes, cam and valve springs


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[G-man55]

Update: swapped in an I coding chip, now idles at 750 and redline is normal again. For future reference, SEta and I coding chips are different, even though they're both for a 6 cylinder engine


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[Regnar75]

coding plugs
62-11-1-377-368 Coding plug for 325e/eS -9/87 "06"
62-11-1-385-580 Coding plug for 325e, 10/87+ "19"
62-11-1-385-468 Coding plug for 325i "BMW 17"
62-11-1-381-699 Coding plug for M3 "12"

I guess i should clarify in my 2.7i post that BMW 17 is the 325I one, and that its different than the 6cyl E coding plugs.

[G-man55]

All good. Today I swapped on new (to me) afm, plug wires, and coolant temp sensor, all known to be working, and now it idles even funnier than before. F logic.


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[Regnar75]

Did the head swap a while back, and I've got some problems I haven't quite been able to work through yet.

-Getting about 10 mpg, white smoke out the exhaust at stop lights, loss of power up to around 4k rpm, bogs a little bit with a quick throttle input

Is this still happening, gas mileage fixed?

-Had a really funny idle (idled at 2000 rpm), turned out to be TPS. Adjusted, the car now has a little bit of idle fluctuation between 7-900 rpm

You said idle is still funny, funny how?

-No redline! (will rev past 7k)

this was fixed with coding plug?

Used an unopened 173 ECU

I've tried finding vacuum leaks around the intake boots, throttle body housing, ICV, brake booster, etc.

The idle bypass on the AFM has been adjusted in the past.

replaced with known good AFM

The Pulse Sensor (on one of the spark plug wires) was pulled at the junkyard, not sure how to test if it's working or not.

I did the same

TPS won't give me a stomp test (nothing happens)

did you adjust it right so that both "clicks" happen through full range of throttle body opening?

Already changed out spark plugs, didn't help.

The Bentley isn't helping much, and trust me, I've tried the search function.
Anyone got any ideas?

so it has funny idle now (most likely vacuum leak, if you cant smoke test you can try plugging the airbox quickly with your hand, if it doesnt stall or the air boot doesnt collapse then you definitely have a leak) not sure if this method is bad for the engine tho ;)

are you still getting bad smoke out of exhaust and terrible gas mileage? try running a compression test to make sure you didnt warp the head when you replaced the head gasket (head stud bolts are new but should be torqued in the order described in the bentley, to specs in bentley)

is it still cutting out power at 4k?

bogging a little with quick throttle is also another sign of vacuum leaks.