Greetings,
I have a 1995 E36 325i Automatic (GM 4L30E transmission) with 181k miles. The car drives completely normally: engine + gearbox + diff all smooth.
However, at around 60 mph (+/- 3 mph), the engine feels as if it's stuttering. Anywhere above or below this, all is good.
The "stuttering" also is independent of throttle applied or gas tank level.
The problem first came about 4 weeks ago, intermittently. Since last 2 weeks it is more frequent.
Could it be my transmission? I last changed tranny fluid and filter at 120k miles. Perhaps at this speed, as the auto tranny is shifting into overdrive it's clutches are worn. (I dont know how overdrive works)
Could it be engine? Perhaps caused by either fuel cut-off by MAF + Speed sensor malfunction.
I couldn't find anything through a search of this forum or internet in general. Any places to start searching, fellas?
Last edited by bobARC; 06-26-2018 at 06:58 PM. Reason: adding details
when did you last change the fuel filter? If always around 60mph then it's probably a bad or clogged sensor in the trans, crankshaft, vacuum perhaps?
I didn't think it would be a vacuum line, as the Tranny & engine is completely electronically controlled.
Trans sensor could be something but it's the engine that feels it's running outta juice ("stuttering").
I never changed the Fuel Filter during my ownership. Will do ASAP and reportI'd start with the fuel filter as well.
My old E36 was an auto and ~55 seemed to be the speed threshold between 3rd and 4th gear. It would do weird things, just above 55 in 4th gear, if I came up on a hill it felt like it had no power until I gave it enough gas that it would downshift.
My old E36 was an auto and ~55 seemed to be the speed threshold between 3rd and 4th gear. It would do weird things, just above 55 in 4th gear, if I came up on a hill it felt like it had no power until I gave it enough gas that it would downshift.
Can you check the RPM while driving at stable speed at 60 mph?
Can you double check if the problem exists in other gears at the same RPM (both lower and higher speeds)?
So, at 80 mph, no problem at all? If that's the case, then the odds of it being the fuel filter or fuel pump get quite low, as the car probably uses 20-30% more fuel at that speed compared to 60 mph.
Can you read the error codes? Connect a laptop with INPA?
I don't if it's possible, but perhaps the crank or cam sensor has trouble reading the teeth correctly at a certain RPM..
Does the problem persist with the MAF sensor disconnected? The M52 can run surprisingly well without the MAF connected, but I think the M50 should do an OK job at it too.
1997 E36 BMW 323i (European) 275k km (171k miles), with following small mods:
- Chip tuned DME (190HP/257Nm); 328i dual pipe exhaust (plug&play); Meyle HD control arms, Bilstein B4 shocks
- Fan delete mod: Stock 92C thermostat, 80/88C temp. switch, 80/20% water/coolant; INPA says temps 100% OK
- Throttle body coolant hose delete mod; Comprehensive ASC Delete option list; Solved: -30 additive adaptation values
RPM at 60 mph are anywhere from 2,000 to 3,500 depending on how I'm driving. Problem look to be independent of RPM
Yes, it's completely fine all the way upto 90 mph. Only at 60 mph (+/- 3 mph) does it "stutter" intermittently
That's why I myself suspected that it was something in the trans rather than the fuel system. But regardless I'm ordering a $10 fuel filter
OBD1 so can't run the more elaborate diagnostics. But using the brake pedal technique, no codes came up.Can you read the error codes? Connect a laptop with INPA?
I don't if it's possible, but perhaps the crank or cam sensor has trouble reading the teeth correctly at a certain RPM..
Could try that over the weekend, MAF sensor was cleaned just 65k miles ago. Air filter is super clean.Does the problem persist with the MAF sensor disconnected? The M52 can run surprisingly well without the MAF connected, but I think the M50 should do an OK job at it too.
Last edited by bobARC; 06-28-2018 at 09:26 PM. Reason: more detail
So one thing to check is to see if torque converter lock-up is working properly. When cruising at 60mph, watch the rpm needle, it should hold steady and not jump up or down (~200rpm), that would indicate that lock-up is slipping out (loosing lockup and then re-engaging). My converter did this and it was due to a cut o-ring on the input shaft seal going into the converter.
Second, while at 60mph (steady), give a small amount of gas, the rpm should stay the same, if it jumps then the torque converter is not locking up.
I would agree to do the fuel filter. Also if the ignition coils are very old or original they should get replaced. I just replaced my aftermarket coils and the car has better acceleration. The coils that I took out had "treeing" (dielectric breakdown) on the plastic.
Attn. NEWBIES: Use the search feature, 98% has already been discussed.
Click the search button, select "search single content type", select the "e36 sub forum" specifically, try the "search titles" then try the "search entire posts".
2 weeks ago: replaced Transmission fluid & filter. Problem persisted
1 week ago: replaced Fuel Filter. It doesn't stutter nearly as much at ~60mph, but there is clearly some faint "stuttering".
Time to look at my injectors, I guess?
Alright, used Lucas Oil and Chevron Techron injector cleaner. Still no luck.
So in conclusion: I guess my tranny is going to die soon? Welp!
EDIT: Shifting from 1-2 and 2-3 has been smoother (most likely thx to fuel injector cleaner). Better fuel consumption as well. Shuttering ~60mph still occurs, but I think I understand why:
And that explains (most liekly) what's going on. That O-ring is finally giving out after 185k mi
Last edited by bobARC; 07-24-2018 at 11:19 AM. Reason: more details.
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