So here's the deal. A couple weeks ago the car was throwing 2 codes: one a cylinder 5 random misfire; two a code for the gas tank evaporator motor. I diagnosed bad plugs as the reason for my misfire so I fixed them and reset the codes. Problem solved; not only did the misfire code go away but the evaporator motor code went away as well.
Fast forward a couple of days. One Problem remains, my car dies randomly at low speeds and stops. When I first fire up the car, it throws me an unknown error code of p1632; something to do with the throttle body, and promptly proceeds to notify me the error has been fixed. It will randomly do this while the car is running, but none of the service lights come on and are all off.
The car runs perfectly other than that and the rear differential bushing that needs replaced. I took apart the intake, cleaned the throttle body, and replaced the brake booster vacuum line, throttle body boot, and air filter. The disa and maf probably need replacing too. My question is, could my disa or maf be causing this? I know i need to replace them but I want to hone in on the possible problems first. My guess is its a poor air fuel mixture but I'm not sure how to find out. Any thoughts?
The DISA isn’t the problem. The DISA changes the effective length of the intake runners: long for low rpms, short for high rpms. It can cause a vacuum leak when its seal gets old.
The MAF can cause poor performance when it under- or over-reports. But the engine computer (DME) also uses the data from the pre-cat oxygen sensors to determine how much fuel to inject into each cylinder.
What tool are you using to scan the DME? How old are the pre-cat oxygen sensors? They need to be replaced every 100k miles. The post-cat oxygen sensors don’t affect the engine’s performance.
The P1632 code could mean the throttle body’s electronix are acting up. Are you having any other electronic or electrical issues with the car? How old is the battery? I ask as these cars are rolling computers and whacky voltages cause whacky issues.
You can't correctly diagnose your BMW using a generic p-code reader. P-codes suck. They are garbage bureaucratic emissions nonsense which rarely apply to the actual problem.
That said, if you insist on trying to diagnose your BMW with p-codes, you need a new throttle motor assembly.
Of course, you haven't identified the car, either, so no one knows whether you're talking abut an M52TU or an M54, which are very different, as far as throttle control.
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
Chris, his profile sez it’s an E46.
Indeed Mark, but early E46's had an M52TU, and a throttle cable. Later ones had an M54, with drive by wire.
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
Yeah, I forgot that.
Gotta love those threads without an ending!
I find P codes can sometimes be better than INPA codes
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