Cause of an occasional rough start?

[Severian]

Our '98 ti occasionally starts a bit on the rough side. It has happened about 7 times since we purchased it a month ago. By "rough start" I mean that immediately upon ignition the car rumbles a bit then konks out. Turn key to the "off" position, count to 3, start her up and give her a bit of gas for good measure, and everything's good. Usually the A/C happened to be on when this happened, so I thought they may be related.

This morning my wife started her car to hit her commute to work. The A/C wasn't on, and the car konked out just after starting. But then successive attempts to start it up failed. The car was turning over, but the sound that it made while turning over didn't sound 100% normal, and it didn't kick into a full start despite holding the key in position for 4-6 seconds at a time. I can't describe the difference, maybe it was all just in my head at the time (because we were running late as it was). But it was turning over.

Finally, my step son came down and while it was attempting to start up gave it some gas. The engine started up, and everything was back to normal. Do you guys have any idea what may cause the occasional rough start, despite A/C setting? (it seems)

We have:
1998 318ti, stock most things, not modded
Manual

My step son said perhaps we got some bad gasoline, because there weren't any other symptoms. We have been feeding it regular gasoline. He suggested we start using 89 octane +

Thanks!!

[L84THSKY]

My 2 cents:

Replace the gas filter and use higher octane gas.


Our '98 ti occasionally starts a bit on the rough side. It has happened about 7 times since we purchased it a month ago. By "rough start" I mean that immediately upon ignition the car rumbles a bit then konks out. Turn key to the "off" position, count to 3, start her up and give her a bit of gas for good measure, and everything's good. Usually the A/C happened to be on when this happened, so I thought they may be related.


This morning my wife started her car to hit her commute to work. The A/C wasn't on, and the car konked out just after starting. But then successive attempts to start it up failed. The car was turning over, but the sound that it made while turning over didn't sound 100% normal, and it didn't kick into a full start despite holding the key in position for 4-6 seconds at a time. I can't describe the difference, maybe it was all just in my head at the time (because we were running late as it was). But it was turning over.

Finally, my step son came down and while it was attempting to start up gave it some gas. The engine started up, and everything was back to normal. Do you guys have any idea what may cause the occasional rough start, despite A/C setting? (it seems)

We have:
1998 318ti, stock most things, not modded
Manual

My step son said perhaps we got some bad gasoline, because there weren't any other symptoms. We have been feeding it regular gasoline. He suggested we start using 89 octane +

Thanks!!

[Severian]

Thanks for the quick reply, L84THSKY. I found a Mahle fuel filter on Auto Doctor for $20.25 before shipping. How difficult is it to change one of these on my own? I'm a noob at car repair/maintenance. I do have some tools and a jack + 2 jack stands. Is this a job that I can handle, perhaps with some help from my more savvy step son? Or should I plan on having this done in a shop.

.:EDIT:.
I found this useful site to help me on my way. But I'm still curious, is this too difficult or risky?
http://www.unofficialbmw.com/e36/engine/e36_fuel_filter_replacement.html

[L84THSKY]

I replaced mine myself. Of course I had my car on a lift, so I could walk right under it. Not a hard job, just need basic tools. It's located below your drivers door. Just remove the cover and clamp off the lines during removal. Someone recommended removing the fuel pump fuse first, then crank the engine a few times. This is to relieve the pressure before removal.

Thanks for the quick reply, L84THSKY. I found a Mahle fuel filter on Auto Doctor for $20.25 before shipping. How difficult is it to change one of these on my own? I'm a noob at car repair/maintenance. I do have some tools and a jack + 2 jack stands. Is this a job that I can handle, perhaps with some help from my more savvy step son? Or should I plan on having this done in a shop.

.:EDIT:.
I found this useful site to help me on my way. But I'm still curious, is this too difficult or risky?
http://www.unofficialbmw.com/e36/engine/e36_fuel_filter_replacement.html

[Severian]

Okay, sounds good. I'll get my hands on two clamps and the fuel filter. If anyone has any more info about changing the fuel filter or about the original post on this thread I'm all ears. Thanks.

[Severian]

L84THSKY, I have a few more questions if you wouldn't mind the time. I checked out this site to find a diagram just because I'm a research freak. I want to know what I'm in for before I crawl under there:

http://www.realoem.com/bmw/showparts.do?model=CG73&mospid=47506&btnr=16_0345&hg=16&fg=15

1. This diagram shows the filter in the rear passenger side area. Weird?
2. Are there any nuts or bolts that attach the in-line filter? Or do the hoses hold the filter in place?

Thanks very much.

[aceyx]

i second switching up to 89. it's the recommended octane for this model (as noted on the back of the gas flap).

that failing, ICV?

[Severian]

i second switching up to 89. it's the recommended octane for this model (as noted on the back of the gas flap).
Gee...that's a terrific place to put info about what gasoline to use. But why didn't I think to look there??
:rolleyes:

I'll switch to 89+ types of gasoline, then see how things roll out over the next few weeks before I get a new fuel filter. Thanks guys!

[L84THSKY]

The filter is definitely below the driver side door...roughly. I installed my x-brace, Stromung exhaust and gas filter the same day. There is a cover that must be removed, and that's about it. Jack the car up and look underneath for the cover. The write-up you found shows the cover.

L84THSKY, I have a few more questions if you wouldn't mind the time. I checked out this site to find a diagram just because I'm a research freak. I want to know what I'm in for before I crawl under there:

http://www.realoem.com/bmw/showparts.do?model=CG73&mospid=47506&btnr=16_0345&hg=16&fg=15

1. This diagram shows the filter in the rear passenger side area. Weird?
2. Are there any nuts or bolts that attach the in-line filter? Or do the hoses hold the filter in place?

Thanks very much.

[aceyx]

there are diagrams and instructions from the TIS here:

http://www.unofficialbmw.com/e36/engine/e36_fuel_filter_replacement.html

i purchased hose pinchers from autozone or pep boys for about $4. it'll be a day until i can find out the manufacturer, but it's the one whose colors are red with white trim. lilly?

the filter cover takes 6mm allen keys IIRC, and you'll most likely have to spray them with pb-blaster or similar penetrating spray if you live north (where they salt the roads) or if you see rust. i've never found wd40 to work well for this application.

there are hose clamps that keep the fuel filter on (in addition to nubs that expand the hose). they take a flat-head screwdriver.

remember to keep a bucket to catch all the fuel that comes out of the filter, and wear gloves because you'll undoubtedly get some on your hands. i prefer nitrile over vinyl and rubber gloves.

[Severian]

Very helpful comments aceyx, everything I wanted to know. Thanks very much.

[KdCass]

Problem solved? I had the same issue with the start and die start and start and die.....one of the Vaccum hoses was popped loose. The hose is part of the cold start low emmissions gear. I also had another small rubber hose with small cracks in it.

I reconnected the larger hose hose and taped the small rubber hose. Presto starts and runs great.

-Dave

[Severian]

Our fix was easier...stop feeding it 87 octane gasoline. Since we started using 89 and occasionally 91+ things have been fine. But the car punishes me if I space out and give it 87. I did it ONE time and the car had 5-10 rough starts, even two tanks later. We're over the hump now though.