Low rpm stutter... Suggestions?

[hasback]

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okay so my e30 always seemed to run a little rough. so i re did the valve clearance and put it away for the winter 3 months ago. just went out to start it up for the first time and it took a few tries to get it to start. once it started and i let it heat up to temp it seemed to have a bad miss fire. well i figured it would go away after it warmed up like it use to do. it never went away. here i have a video of what exactly it was doing. it would idle then miss, the check engine light would flash every time it missed. my question is, does this seem like a cap and rotor issue or something else. every time it missed i could smell gas. i pulled the plugs when i redid the valves and they all look fine. none were wet or discolored. i drive a 91 325i if that changes anything as well. any input would be awesome. so i don't start throwing money at the wrong issues.

bottom line. no check engine light, only when it actually misses. when it misses it loses total power. almost like every cylinder missed. it did have a tuneup about 20k ago. plugs, wires, cap, rotor.

http://www.youtube.com/watch?v=FgVJ9tRXCLU&feature=youtu.be

[efficient]

could be plugs, wires, cap, injectors clogged, break in the wire to the injectors.
you can do a balance test by pulling the plugs one by one and seeing it the car shakes then that cylinder is fine.
if it doesnt do anything then you found which cylinder is having problem. then you can see if that wire is getting spark by going underneath the rubber insulator with a light probe thing or you can get shocked and thats how you can tell if its getting spark. if you got spark it could be clogged injector or open injector wire .

[jlevie]

The behavior of the tachometer an econometer would suggest a lost of timing data or an interruption of power or ground to the DME. A new OE CPS, a new main relay, and a check of the DME ground (on the right strut tower) would be the first things I'd do.

[enigmaticdream]

The behavior of the tachometer an econometer would suggest a lost of timing data or an interruption of power or ground to the DME. A new OE CPS, a new main relay, and a check of the DME ground (on the right strut tower) would be the first things I'd do.

+1 on the CPS. You can check if it is in spec with a multimeter. I believe it is 525+-75 ohms. However, I'd check a Bentley to make sure.

[FLG]

The behavior of the tachometer an econometer would suggest a lost of timing data or an interruption of power or ground to the DME. A new OE CPS, a new main relay, and a check of the DME ground (on the right strut tower) would be the first things I'd do.

Exactly.

Though if I'm not mistaken generally a reset on the econometer points to a disruption in power or ground to the dme?

Either way I'd do all of the above. Make sure it's a bmw oe cps not a aftermarket one. Best bet is your dealer.



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[mpowerful]

Ive got five on cps. In for updates. Doesnt motronic store codes? Cant you stomp it after one has been set and gone off and the code will be in memory?

[hasback]

sorry this ohio weather has left me unable to work on the car yet. as soon as it warms up here a bit ill go try the pointers you guys recommended.. and no i have not done a stomp test yet.

[bmoores]

sub'd for resolution. Having a similar issue.

[FLG]

sub'd for resolution. Having a similar issue.

Resolutions gonna vary due to nature of the problem. Could be multiple sources.

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[bmoores]

Resolutions gonna vary due to nature of the problem. Could be multiple sources.

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I'm aware of that but I was curious what the resolution will be in this particular instance. :up:

[hasback]

okay... so i replaced the cps and nothing has changed. when the car misses it throws a code but then the car caught itself at idle for awhile and the code disappears. the stomp test showed no help as i just get code 1444 meaning no codes have popped up. im about stumped at this point. it keeps missing like this once its warmed up. the car has a slight miss through all rpm ranges but seems to miss on all cylinders at some points when the code flashes.

[jlevie]

No stored code in this case probably means a DME power/ground or START signal issue. But it could be a failing DME.

[FLG]

Do you have another dme you can try? Also check power coming to the dme, would be cheapest (free) option

Pins 18 (constant) and 37 (switched power)

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[hasback]

That was his thread tho I forgot I opens my own thread sorry.

[FLG]

Yep my apologies, I double checked and realized you weren't the op there.

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