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DISCUSSION => Engine + Driveline => Topic started by: JoeDellio on February 07, 2011, 06:23:07 AM

Title: Engine bogs unless given full throttle.
Post by: JoeDellio on February 07, 2011, 06:23:07 AM: Ive read the other bogging threads. I have no CEL. Car bogs down unless I give it full pedal, this has gotten worse over the past couple weeks. I didnt think it was a fuel issue since it responds to full throttle, but I really dont know. Whats new is the fuel pump, fuel filter, plugs and wires, and a coil pack. I can unplug the AFM and it doesnt change anything, so I dont know whether to rule it out or anything. This problem sucks thanks to the absence of a CEL.
Title: Engine bogs unless given full throttle.
Post by: Janne on February 07, 2011, 09:38:26 AM: Quote from: JoeDellio;101220
Ive read the other bogging threads. I have no CEL. Car bogs down unless I give it full pedal, this has gotten worse over the past couple weeks. I didnt think it was a fuel issue since it responds to full throttle, but I really dont know. Whats new is the fuel pump, fuel filter, plugs and wires, and a coil pack. I can unplug the AFM and it doesnt change anything, so I dont know whether to rule it out or anything. This problem sucks thanks to the absence of a CEL.

Maybe it is bad THROTTLE VALVE SWITCH (part number 5.) :http://www.realoem.com/bmw/showparts.do?model=BE51&mospid=47425&btnr=13_0578&hg=13&fg=15
Title: Engine bogs unless given full throttle.
Post by: JoeDellio on February 07, 2011, 01:00:13 PM: Thats the TPS I was wondering about, I guess its worth a shot unplugging and investigating. Im torn between buying any new parts because I dont have a CEL, I guess the TPS is a cheap start, then Ill waste money on a rebulit AFM
Title: Engine bogs unless given full throttle.
Post by: B318M42W on February 07, 2011, 04:50:00 PM: you can test out the sensors using a multimetre... the e30 ETM has all the goodies! the tps has a linear continual voltage change.

I really dont think the AFM is the culprit since the car responds at full throttle. might also be ECU?

whats the idle like?
Title: Engine bogs unless given full throttle.
Post by: JoeDellio on February 07, 2011, 11:58:08 PM: I lost the link on how to test the TPS, I didnt know you could test the AFM, It idles fine 90% of the time, if I come to a stop after the cars starts bogging the idle is choppy but clears out if I give it gas and then will idle fine. So youre saying if the AFM was bad it wouldnt respond at full throttle?
Title: Engine bogs unless given full throttle.
Post by: JoeDellio on February 09, 2011, 05:27:52 PM: Well guys, got my new TPS today and problems seem to be solved. I didnt test the new one because I was so anxious to get it in. It fired right up and idled at 2k for a second and then idled smooth. It doesnt hesitate at all anymore even going up hills at 45mph in 5th gear. Sooo, my TPS was bad and didnt throw a code.
Title: Engine bogs unless given full throttle.
Post by: B318M42W on February 09, 2011, 06:56:46 PM: great to hear you fixed your problem!
Title: Engine bogs unless given full throttle.
Post by: JoeDellio on February 11, 2011, 10:05:02 AM: WTF, car ran fine for days after the TPS was replaced, but now it fell on its face in 1st once yesterday and its been fine since then. Its startin to do what it did before it was totally undrivable.
Title: Engine bogs unless given full throttle.
Post by: doitover on February 11, 2011, 01:51:53 PM: From a purely debugging things in the lab point of view,

If you still have the old TPS, test it. If it wasn't bad and the short term improvment was due to replacing the TPS, it would have to be the connection between the ECU and the TPS. Could be that the connector is corroded or there is an intermittent open or short in the wire.

Cars can be frustrating though, especially 16 year old ones. The improvement after changing the TPS may have been completely unrelated.
Title: Engine bogs unless given full throttle.
Post by: JoeDellio on February 11, 2011, 03:45:11 PM: Quote from: doitover;101364
From a purely debugging things in the lab point of view,

If you still have the old TPS, test it. If it wasn't bad and the short term improvment was due to replacing the TPS, it would have to be the connection between the ECU and the TPS. Could be that the connector is corroded or there is an intermittent open or short in the wire.

Cars can be frustrating though, especially 16 year old ones. The improvement after changing the TPS may have been completely unrelated.

The old ones numbers were really screwy, so thats why I bought a new one, though I didnt check the new one. I guess Ill take it out and check it out for the hell of it.
Title: Engine bogs unless given full throttle.
Post by: DesktopDave on February 11, 2011, 04:19:10 PM: How old is your O2 sensor? Does the trouble happen only when the car is cold, only warm or both? I'm asking because WOT disables the O2 sensor.
Title: Engine bogs unless given full throttle.
Post by: JoeDellio on February 11, 2011, 05:00:14 PM: Quote from: DesktopDave;101373
How old is your O2 sensor? Does the trouble happen only when the car is cold, only warm or both? I'm asking because WOT disables the O2 sensor.

Dave, oxygen sensor has 30k on it, took it out and it looks real good. The problem happens when the car is warm. Then when I shut it off for like a half hour it hiccups again real bad at start up, which makes no sense hot vs cold. Its got me stumped, I dont wanna pull a AFM out of my wallet if I dont have to.
Title: Engine bogs unless given full throttle.
Post by: JoeDellio on February 16, 2011, 12:13:13 PM: I have pinpointed the problem to only happen after I shut the car off after being warm. If it sits for say 20 minutes, it will then bog when I start to go, then I floor it and its fine. Weird.
Title: Engine bogs unless given full throttle.
Post by: colin86325 on February 17, 2011, 09:05:45 AM: You could have a lot of carbon build up. Try running some Techron through the tank when it's aout 1/4 full. You can also perform a "hot soak" with a produt called Sea Foam.
Title: Engine bogs unless given full throttle.
Post by: fiftytakedowns on February 22, 2011, 02:11:45 AM: Im having similar symptoms? any luck?
Title: Engine bogs unless given full throttle.
Post by: JoeDellio on February 22, 2011, 06:04:38 PM: The engine was seafoamed at 82k, its got 110k on it now, the way I drive carbon has no chance to build up, lol, but seafoam does wonders when it is needed. The TPS seemed to cure the problem, its ran like a top for the past week, no hiccups at all.
Title: Engine bogs unless given full throttle.
Post by: fiftytakedowns on February 22, 2011, 07:37:07 PM: didnt you drill out the TPS holes?