Weak Acceleration! Need a diagnosis!!! - BMW Forum

dagli · 11-30-2005, 10:38 PM

Okay, here's my problem. I have a 1987 325es, and I've been happy with it for a while, but now it's just come to my attention that my gas pedal may be "sticking". You see, when I put it into gear and hit the gas pedal my car lags for a brief second or two, then goes ahead and pulls me forward. Is this one of the characteristics of the economy series; a weak, initial acceleration? Would a performance chip solve this problem?

What do I have to do to bring back a strong gas pedal like this car must have at one time had?

With a straight 6 under my hood I'd like to maximize it's true potential, but this lag in the the pedal to the engine proves to be a pesky problem.

ldsbeaker · 12-01-2005, 07:37 AM

I've had this happen a bit... I think my clutch is on it's way out.

325eXTATIC · 12-01-2005, 09:09 AM

you want to maximize all the links in the chain so to speak... Spark Plugs, Wires, Cap, Rotor, Throttle Cable, Air Filter, CLEAN YOUR INJECTORS!!! And as the Turtl3 mentioned... Could be your clutch starting to slip.

Just a few ideas!

Josh W.

Morgenster · 12-01-2005, 02:04 PM

Quote:

Originally Posted by 325eXTATIC

you want to maximize all the links in the chain so to speak... Spark Plugs, Wires, Cap, Rotor, Throttle Cable, Air Filter, CLEAN YOUR INJECTORS!!! And as the Turtl3 mentioned... Could be your clutch starting to slip.

Just a few ideas!

Josh W.

Yeah,

I got into some compound problems with my M40 316i. Lot's of different small fixes are now bringing the car back to life.
Vacuum leaks, electrical current leaks, and dirty engine insides can do that.
If you're lucky it 'll be an easy and cheap fix, but you'll have to post a little more info, like does it only happen in gear? Does the weather influence this? Does engine temperature influence this?, etc. I started from knowing absolutely nothing about cars four months ago...

WardJ · 12-01-2005, 09:29 PM

yeah i'm just reiterating what they said

could be:
spark plugs fouled
fuel injector malfunctioning
fuel filter clogged
ignition timing could be off
or worse, intake manifold air leak

dagli · 12-02-2005, 05:01 PM

Well, I Techroned the engine the first time I filled up when I got the car. As far as spark plugs go I havn't really tinkered with them all that much. As of lately I've just been detailing the paint/plastic off it.

Going into detail about the problem: it happens in all gears and is particularly more troublesome when it's cold out. I've been watching the tach closely while driving and I noticed that as I shift the RPM goes down, and fluctuates as I step on the gas. A half a second or so later, it picks up all of a sudden to a slightly higher RPM and drives normally. Since it's got down to the 20s here in Missouri, every now and then I smell exhaust/gas in the cabin.

In addition to checking the spark plugs and changing the air filter, and all that regular maintenance I think it may be something to do with the fuel lines. Is it an easy job to tighten the fuel line rings myself, or should I have one of my friend's dad's BMW mechanic guy who's worked on their various BMW's do it? Really, its a question of DIY or have someone who knows what he's doing do it.

Morgenster · 12-03-2005, 03:31 AM

Here's a few pointers to make it easier for you or a mechanic to pinpoint the problem:
-Let the car idle cold and hot to see how it does this and if there's any difference. listen to and feel the engine. Does the tach needle go up and down and if so, how much? Does the engine stumble or stutter? Also, step out of the car and listen to your engine out there or look under the hood.
-Hold the throttle steady in neutral and see if the tach stays at the same RPM. (also when the engine is hot or cold)
-Check your spark plug wires on both ends for corrosion. Mine were just plain dirty and caused a drop in power by almost 30%. Especially in cold damp weather.
If cold weather makes things worse I'd think it'll either be an electrical or vacuum problem.
The exhaust gas smell is a major alarmbell, though. I'm not sure if anyone here ever experienced this as normal, but I think it's a safety hazard.
If you do some checks yourself it'll be easier to tell a mechanic what's wrong with the car. It often cuts labour-time bills in half and makes the fix much more accurate.