Fuel problem

Bijan · 03-04-2009, 11:10 PM

I have a 88 325. Normally I get around 360 miles on a tank of gas. On this last tank I only got 190 miles. I can smell the fuel (burning lean) as I am driving and the engine is not running good. What could be the problem? Thanks in advance for any replies.

mrinfinit3 · 03-05-2009, 10:30 PM

Quote:

Originally Posted by Bijan

I have a 88 325. Normally I get around 360 miles on a tank of gas. On this last tank I only got 190 miles. I can smell the fuel (burning lean) as I am driving and the engine is not running good. What could be the problem? Thanks in advance for any replies.

What do your plugs look like? any tail pipe smoke or hvy water at NOT? (norm. operating temp)

allbmw · 03-06-2009, 01:27 PM

It is possible that your fuel pressure regulator is malfunctioning and gas is being sucked through it's vacuum line into the intake manifold. Take off the vacuum line and see if there is fuel in it, there shouldn't be.

Alan

Bijan · 03-11-2009, 02:12 PM

Finally I changed my spark plugs yesterday and went ahead and changed the fuel pressure regulator. Here is the condition of the plugs
#1 cylinder, the spark plug was severely burned and the tip of the electrode had broken off or burned off. #2 cylinder the spark plug was less severely burned but other wise OK. #3 was slightly burned and 4, 5 and 6 were OK.
Next I drove the car and everything seemed to be normal until the coolant temperature raised to normal level. At that point all previous problems started the car feels like is not getting any fuel and wants to stall and when I try to press the gas pedal while holding the clutch in it keeps misfiring and it feel like and air leek or lack of fuel. I have checked all the hoses for leek, I couldn't find any. I also changed the big rubber air boot next to the throttle housing.

I am thinking that probably the problem is from the coolant temperature sensor or some other sensor sending the wrong information to the computer and in turn the computer is compensating by sending less fuel to the cylinders.

What do you guys think. Thanks for the replies.

allbmw · 03-11-2009, 03:54 PM

Have you set the timing? What do you mean by the spark plugs looking burned? Where do you smell the fuel smell?

allbmw · 03-11-2009, 04:01 PM

I think that on an 88 325 you can't adjust the timing. Something is seriously wrong, though and I don't think it could be a vacuum leak. Don't start replacing parts until you know what is going on.

Bijan · 03-12-2009, 10:40 PM

before the car warms up every thing is normal. after it warms up that's when misfiring, wanting to stall, the smell of unburned fuel starts. I can smell the fuel inside the car while I am driving. As for the spark plug being burnt. Its burnt around the electrode area, the tip all the way around the treaded area.

allbmw · 03-13-2009, 08:14 AM

Quote:

Originally Posted by Bijan

before the car warms up every thing is normal. after it warms up that's when misfiring, wanting to stall, the smell of unburned fuel starts. I can smell the fuel inside the car while I am driving. As for the spark plug being burnt. Its burnt around the electrode area, the tip all the way around the treaded area.

The tip of the sparkplug should be a grayish color. If yours were black it could indicate that your engine is running rich. Is the tip of the exhaust pipe black? Is there any black smoke coming out when the engine is warm?

There may be a cold start injector that is not closing and is squirting gas after the engine has warmed up. It may be leaking. If you can afford it, get the Bentley repair manual for your car. It has a great deal of good information that would help you.

Alan

Bijan · 03-14-2009, 12:49 AM

I have a question. Since the spark plugs in cylinder 1, 2 and 3 are burned gradually less. (#1 burned more severely). It tells me it's hotter in the #1 cylinder. Assuming the cold start injector is stock open after the car warms up, shouldn't that cause the opposite (less burn on the spark plug)?

Thanks for all your replies

allbmw · 03-14-2009, 08:36 AM

I still have trouble understanding what you mean by burned? Is your car running rich? Where is the smell of gasoline coming from? There are sensors that tell your fuel injection system when the engine is warm, are they working? You can test your cold start injector to see if it is faulty. Don't just replace parts trying to fix the problem. Identify the cause of the problem and fix just that. You can spend a fortune chasing a cure by replacing lots of parts. The parts are very expensive for this car.