Author Topic: Another power loss issue (Read 4319 times)

Systema · « **on:** October 01, 2009, 06:32:57 PM »

Hey all

I have a '91 318i that's been developing a bit of a problem over the past couple days. Every once in a while, when trying to take off from a light, the engine won't rev up past ~1500rpm. It seems to bog down as if it wasn't getting enough fuel. If I floor the pedal or (sometimes) shift into second, it'll struggle for a while before eventually catching and going through the rev range like normal. When cruising in fourth, I also lose power for a short while before it picks up like normal.

The oil is fine, not milky as would indicate a blown headgasket. I did notice a strong gas smell when I took off the oil cap, though I have no idea what that could mean. I also replaced the plugs about a month ago, but beyond that I'm at a loss. It just started doing this a few days ago, but had been running fine for the past four months I've owned it. It's probably worth mentioning, though, that I have been getting a CEL for the camshaft position sensor for a couple months, even after replacing the CPS and resetting the ECU.

bearsbmw · « **Reply #1 on:** October 01, 2009, 06:39:31 PM »

sounds like a Fryed/Leaking Fuel Injector

iamcreepingdeath · « **Reply #2 on:** October 01, 2009, 06:41:41 PM »

hmmm.... maybe clean your injectors? is the motor misfiring, or simply bogging, as if some invisible force was stepping on the brakes?

Systema · « **Reply #3 on:** October 01, 2009, 07:08:16 PM »

Bogging, like I was stepping on the brakes. And it sounds like it's struggling.

iamcreepingdeath · « **Reply #4 on:** October 01, 2009, 07:39:08 PM »

look at the fuel system. Sounds like a fuel restriction rather than a timing/ignition problem. Check fuel lines, filter, pump, FPR, and injectors. And not necessarily in that order.

bearsbmw · « **Reply #5 on:** October 01, 2009, 07:53:46 PM »

A stuck open fuel injector could begin to yield the same symptoms as the o2 sensor
will see too much fuel and lambda will try and fix it by pulseing the other injectors less causing a lean out and loss of major power in the three other cylinders

Would also explain the fuel in the oil

If it ends up not being the fuel system I would start looking at the AFM

Systema · « **Reply #6 on:** October 02, 2009, 10:53:03 AM »

Thanks guys. I read up on the injectors, and that sounds like the problem I'm having. I know my fuel pump is going, too, because occasionally the car won't start until I tap the pump a few times. So I'll probably be replacing that soon.

DesktopDave · « **Reply #7 on:** October 02, 2009, 10:56:26 AM »

Check the connector on the pump next time you're in there, they loosen up over time & seem like a bad pump. Crimp the pins a little to snug them up, maybe spray a little electrical contact cleaner or dielectric grease in there too.

fiftytakedowns · « **Reply #8 on:** October 02, 2009, 10:12:43 PM »

I have this same problem, still havent fixed it......

tell me what you do, and if it works.

///m42 sport · « **Reply #9 on:** November 10, 2009, 06:19:43 PM »

any updates on this?

emurepleses · « **Reply #10 on:** November 13, 2009, 07:30:13 AM »

Help I don�t know what�s wrong or how to fix it.

A week ago my E39 started to act up. At high RPMs 5000 to 6000 I get a sudden loss of throttle. It doesn�t matter if I am in sport mode or not. I then have to wait until the RPM�s drop below 3000 RPMs or shift into 5th or 6th gear to force the RPM�s to drop below 3000. Once the RPMs are below 3000 I get my throttle back however it doesn�t deliver as much power as normal. To reset the problem I have to turn the car off and back on.

Any ideas? Is it the computer? Would a BMW tech be able to plug it into his computer and find out the problem? Please help

Systema · « **Reply #11 on:** November 16, 2009, 12:02:26 PM »

^^ I don't know for sure, but that does sound like a computer issue if restarting the car fixes it.

I bought some new injectors, and went to install them. I ended up rounding off a nut on the intake manifold, so now I'm stuck until I can figure out how to get that off.

For anyone who has the same problem as me, check this out: http://www.m42club.com/forums/showthread.php?t=7757 It didn't help me, but it might be what's causing your problem.