BimmerFest BMW Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
Oh where to start...

Well lets start with the problem. I have a 318is (1994) and it is entirely COLD Blooded!! While still cold and not at or close to operating temperature, this car is a Champ! But it seems once it reaches operating temperature it just goes limp on me... The car will rev up just fine while it is cold, but when it starts to warm up it will not rev any higher then 2000 rpm. This is an "ANY SITUATION" occurrence and I do mean any! It runs fine when warm and under 200 rpm however should you attempt to pass or push 2000, this car will just laugh at you as it bucks jerks and shakes its way down the road. If you were to baby shift it once warmed up it can reach 45-50mph but that is your limit as the vehicle is a 5 speed manual and in top gear doing 1800 rpm that is simply all you get.

Now that we covered the problem, and if I was unclear or left something out I apologize but please feel free to ask about the problem as this is why I have started this thread.


Problem Solving!! Well not really... I have replaced the computers and MAF sensor, I have checked for vacuum leeks and found nothing, replaced CAM and CRANK sensors, switched knock sensors with known good parts, and afew other minor things have been tried just to endulge a friends "brilliance", or so he thinks, and nothing has changed for my little "Problem".:confused:


If anyone would like to give a Fellow E6 Enthusiast with my "Problem", Please post and post and post some more!:)
 

·
The Canadian Prick.
Joined
·
12,984 Posts
Check fuel pump pressure, change air and fuel filters. Clean MAF. Check spark.

Failing those basic maintenance issues, do a compression test.

Good well thought out question.

Welcome to the 'Fest,

Ed.
 

·
Registered
Joined
·
12,836 Posts
I suspect a MAF problem. While the engine is still cold and coming up to temp the fuel injection system is still in open loop mode. Once it's warmed up and switches to closed loop it's depending on input from all the sensors (MAF, TPS, O2) to determine how much fuel to inject. If the fuel injection controller is getting a bogus input it can restrict the fuel artificially. Try cleaning your MAF first as Ed suggested, and if that doesn't fix it try running with your MAF disconnected. If that doesn't make any difference, get a code reader and see if there are any fault codes stored in the computer. I'm not thinking the throttle position sensor (TPS) would cause this because I believe it's an active sensor in open loop, but I couldn't swear to that.
Usually you'll get a check engine light if the O2 sensor is bad so I'd put that last on the list.
If you had a fuel pressure issue I'd expect that to be there regardless of the engine being hot or cold, but it may be marginal and just come into play once fuel injection switches to closed loop.
Sorry for not being able to pin-point a single, solitary cause but the fuel injection system is fairly complex...................
 

·
Registered
Joined
·
4 Posts
Discussion Starter #7
Just able to get back online and read the posts,

thanks for all the input guys. i just wanted to add however i have already checked spark, changed plugs, filters, and replaced MAF (didnt clean it but its brand new it should be clean). i have monitered fuel pressures and commpressions of each cylinder. Unfortunetly on a 94 318is there is little to none diag capability as far as computers go. flash codes revealed nothing. it cannot be tranny or drivetrain, it must be the engine and/or ecu{Since the problem has started i have replaced the ecu, aswell as multiple sensors including MAF, CAMs, Crank, Knocks}. The problem does occur once entering closed loop. It cannot be anything past the flywheel as the problem happens in any situation including clutch engadged/disengadged, In and out of gear 1-5 and R-N. I put it on a lift at work and it does it in the air and on the ground{In the air the drivetrain has much less resistance to the engines revolutions then when on the ground} and there is no vacuum leaks i could find with ether or smoke.

Guys i hope this helps... I am out of ideas myself and if i havnt done it or havnt done it a certain way please let me know what it is i need to try. i am willing to hear any and all suggestions. Thanks for the help so far guys.
 

·
OEM Hoe....
Joined
·
1,828 Posts
Maybe just try cleaning your MAF, maybe it has some residue or something from the factory. Other than that, I'm not sure.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #9
sounds good to me killjoy, what should i clean it with? i normally use naptha or other solvants but i am fresh out.
 

·
The Canadian Prick.
Joined
·
12,984 Posts
Use an electronics cleaner.
 

·
Fireballs inc.
Joined
·
9,256 Posts
someone said once to put the maf in gasoline....


needless to say it was a bad idea
 
1 - 13 of 13 Posts
Top