S50 rough idle/start after 3.5 MAF/injector install

[cfletch13]

I have been collecting parts slowly to basically do Turners Stage 2 Tune. Meaning the proper chip, 24# injectors, 540i MAF, and a new AFE intake.

Over the weekend I put in the new injectors and MAF and wanted to start it up for a brief second to see if I had any leaks with the injectors. Turned the key and it fired right away and ran pretty well, better than I was expecting it to without the proper chip. I then turned it off after checking each inlet for leaks. The following day, my friend had given me an RK tune chip, I didn't realized that it was meant for a different DME since I have a 413 silver label so I uninstalled it after attempting to start the car with it in. I had it crank but no fuel/spark. Anyways, come the next day I installed the stock chip again and wanted to start it again briefly just to be sure that all was good. It started, but ran extremely rough at idle, when I tried to hit the gas a little, it would jump up to 4k RPM and then go back down and possibly stall, or really struggle to idle for a moment then go back to the 'standard' rough idle.

I have not done much else to it since I am still waiting on the proper tune and intake.

Is it now running really poorly since I have made these changes and had the DME unplugged for a while thus the system lost its memory? Or is something else possibly wrong with what I have done thus far?

Edit: I sprayed some carb cleaner around the lines as well as the injectors and the idle evened out when spraying it around a particular cylinder. How likely do these orings go bad to the point where they do not seal? I removed and refitted them back and still had the same issue.

[Hova]

Has it rained in the last few days?

[cfletch13]

No, why?

[das borgen]

That's really strange. I guess there's no chance it's a vacuum leak since it was running fine before you put in that RK chip, yeah?

Have you gotten any ECU codes?

[cfletch13]

That's really strange. I guess there's no chance it's a vacuum leak since it was running fine before you put in that RK chip, yeah?

Have you gotten any ECU codes?

I do not think I am having any major vacuum leak to cause all of this considering it was running fine prior to me messing with the chip in the DME.

I did not really run the car long enough to pull any codes since it was sounding rather scary. I think collectively I ran the car for about 20-30 seconds after swapping back the OEM chip. Would having the battery disconnected for a few days allow for enough time to discharge the DME capacitors make it so their stored values are lost to the point where it would even run that poorly? Also when I removed the Stock chip again, I noticed that some of the pins were bent, they were still in their respective sockets, but who knows if that may have caused anything weird to happen too.

[cfletch13]

UPDATE: Got my turner chip, installed it and put it all back together. It still is running very poorly, the CEL is on and the code given is 1281- DME Memory unit supply... Anyone with thoughts?

[Hova]

No, why?

Early E36's have ECU compartments that can flood.

[Hova]

UPDATE: Got my turner chip, installed it and put it all back together. It still is running very poorly, the CEL is on and the code given is 1281- DME Memory unit supply... Anyone with thoughts?

https://www.bimmerforums.com/forum/s...5628-DME-issue


https://www.bimmerforums.com/forum/s...ry-unit-supply

[cfletch13]

https://www.bimmerforums.com/forum/s...5628-DME-issue


https://www.bimmerforums.com/forum/s...ry-unit-supply

Unfortunately none of those really seem to be similar to my issues, while they have that code thrown, it seems like they can drive. My car can barely stay alive idling let alone actually drive.

Still hunting

[cfletch13]

Just got out there again and sprayed some starting fluid around to see if the idle improves in case of a vacuum leak. I sprayed around 1 injector and the idle improved. I am thinking maybe it was not seated well? Does this all make sense

[E30s50dude]

if you take brake cleaner spray over the intake/injector and you have a change in idle that indicates a vacuum leak. Don forgot to check the ICV hose and make sure they're not cracked or unplugged.

[RRSperry]

I'll bet you that you have a bad/incorrect 3.5" MAF. Install the 3.0, and OE chip and see what happens. I'd bet you that it at least runs better.

[cfletch13]

I'll bet you that you have a bad/incorrect 3.5" MAF. Install the 3.0, and OE chip and see what happens. I'd bet you that it at least runs better.

I swapped to new injectors and still had the same issues with idle, checked the new code on the CEL and its going with 1215. I just swapped the maf back to stock 3.0 size and am waiting a bit with the battery disconnected so I can throw in the stock chip... sighh

[pbonsalb]

Did you use a real MAF or chinese copy?

[cfletch13]

UPDATE:

The older injectors were not even an issue. The whole reason why the idle fluctuated when I sprayed that specific injector was because somehow the top hose from ICV to manifold got disconnected? Since the injector was pretty close to the hose, it sucked it up and made me think it was that injector causing all the issues. I swapped back to the correct tune, intake boot, MAF and all runs perfectly. I went for a long drive and love the new feel of everything. Thanks for the suggestions you guys!

[RRSperry]

It's always the last place you look... Have fun...

[NeilM]

It's always the last place you look...

Well yeah, silly to keep on looking after you’ve found it!
;-)

Neil

[das borgen]

Well yeah, silly to keep on looking after you’ve found it!
;-)

Neil

yeah, you'd have to be an idiot to keep looking once you've solved a problem.

Glad it was a vacuum leak like I thought, OP!