Disappearing power. M44 help!!!

[speedracerf4i]

I have a very strange problem and hopefully you guys can tell me what to look for.

I was driving on the freeway yesterday and all of a sudden, I lost power (50%). The engine still runs as if I was driving in neutral. A cell came up in which I found out to be "cylinder 1 misfire".

I was able to slowly drive home at max speed of 40MPH (5th gear) with my emergency blinkers on. There is no hesitation on the engine at all, just feels like there is a long accerelation lag and driving a 20 HP car.

I checked the spark plugs and they are firering OK, though the spark was kind of weak. I am not sure how strong the spark had to be. The engine was idling fine at 800 RPM smoothly even with 1 plug off.

The exhause smelled like unburned gas and from searching, I narrow down to a few possibble culprits.

1. Spark plugs - I checked all 4 and they are firering (pulsating).
2. Plug wires - If the plugs are firering, can the wires still be bad?
3. Ignition coil - I am getting sparks and there is no hesitation on the engine. Can this be bad?
4. ECU - This is an expensive unit with no way to tell if this is good or not right?
5. Fuel injectors - The unburn smell may suggest that it's delivering fuel OK. Will this throw a cell if bad?
6. Cam Position sensor - The engine has no weir vibration though.

Maybe I am missing something else. Please help!!!

Thanks

Leonard

[Will'sBimmer]

It could be a fuel problem or even a vacuum problem. The gas you are smelling from your exhaust could be from your car running to rich and therefore using too much gas and that is why your exhaust smells like gas. I would also check for a vacuum leak, or bad Idle Control Valve, a bad crankcase vent valve, or even a bad MAF which can make your car run too rich. I am not sure if this is your problem. Just throwing some suggestions out your way. I hope this helps in your search for what is wrong.

[speedracerf4i]

Wouldn't a bad MAF pull a cell?

How can I check if the ICV and Crankcase vent are bad besides replacing them? My idling seems fine though.

[marko]

yes MAF would throw a CEL... if you dont have a vacum leak & the plugs are igniting the fuel properly, then you may have a MAF problem.

Originally Posted by speedracerf4i

Wouldn't a bad MAF pull a cell?

How can I check if the ICV and Crankcase vent are bad besides replacing them? My idling seems fine though.

[Will'sBimmer]

A bad MAF would throw a CEL. Is your car not throwing a CEL at all???? I don't know if there is a way to check if your ICV is working properly. Mine threw a code and my idle and car runs like crap right now. Also I am burning more gas than I should be. Hence the smell from the exhaust. The crankcase vent valve I am not sure about either. But mine is venting more air than normal when it is idling. Or at least it sounds that way to me and my dad. I am about to replace my ICV on friday. So I could let you know then if it helps my car out. As for your problem, I am still stunned that your car hasn't thrown a CEL yet. Which plug did you have out when your car was idling fine at 800 rpm??? Was it the number 1 cylinder?

[b.u.ti-ful]

This thread might relate:

http://www.318ti.org/forum/showthread.php?t=24597

[marko]

also, when you pulled the plugs, did you notice anything strange? like discoloration from un-burned fuel?

check your cables too.. make sure they are not ripped/cracked I.E. arching. long shot, but hey...

Originally Posted by speedracerf4i

I have a very strange problem and hopefully you guys can tell me what to look for.

I was driving on the freeway yesterday and all of a sudden, I lost power (50%). The engine still runs as if I was driving in neutral. A cell came up in which I found out to be "cylinder 1 misfire".

I was able to slowly drive home at max speed of 40MPH (5th gear) with my emergency blinkers on. There is no hesitation on the engine at all, just feels like there is a long accerelation lag and driving a 20 HP car.

I checked the spark plugs and they are firering OK, though the spark was kind of weak. I am not sure how strong the spark had to be. The engine was idling fine at 800 RPM smoothly even with 1 plug off.

The exhause smelled like unburned gas and from searching, I narrow down to a few possibble culprits.

1. Spark plugs - I checked all 4 and they are firering (pulsating).
2. Plug wires - If the plugs are firering, can the wires still be bad?
3. Ignition coil - I am getting sparks and there is no hesitation on the engine. Can this be bad?
4. ECU - This is an expensive unit with no way to tell if this is good or not right?
5. Fuel injectors - The unburn smell may suggest that it's delivering fuel OK. Will this throw a cell if bad?
6. Cam Position sensor - The engine has no weir vibration though.

Maybe I am missing something else. Please help!!!

Thanks

Leonard

[marko]

good find - that actually sounds like it makes a lot of sense - limp mode FTL

Originally Posted by b.u.ti-ful

This thread might relate:

http://www.318ti.org/forum/showthread.php?t=24597

[speedracerf4i]

The spark plug is 1 year old and shows no oil and no abnormal discorolation.

The is no electrical arc visible except on the tip of the plug like it should.

Thanks for the link, at least I know that my car was running at safe mode and I didn't damage anything by limping my car home. I read the link, and it's link. First primary link says that the knock sensor was at fault and the secondary link says the O-ring relating to the cam positioning sensor was at fault.

I did not get any cell except P3001. misfire cylinder 1.

[speedracerf4i]

[QUOTE=Which plug did you have out when your car was idling fine at 800 rpm??? Was it the number 1 cylinder?[/QUOTE]

yes, cylinder 1 (furthest from the driver) and number 2.

[branden]

When is the last time you changed the plugs? Check the gap on them and make sure it is right or change them if needed.

Also, you should check the resistance on the wires. They need to be close to 15,000 ohms I believe.

I was just having similar problems and my spark plug gaps were off and they also looked pretty crappy so I threw in some new platinum plugs. Night and day difference.

[b.u.ti-ful]

Originally Posted by speedracerf4i

I read the link, and it's link. First primary link says that the knock sensor was at fault and the secondary link says the O-ring relating to the cam positioning sensor was at fault.

I did not get any cell except P3001. misfire cylinder 1.

Yeah, the o-ring thing was a pretty big fluke, but the knock sensor is more likely.

[speedracerf4i]

I tested the ignition coil with the a voltimeter and found out the the resistence was between 10-14 miliohms. According to Bentley, it should be 4-8 mili-ohms. I also found hair-line cracks on my coil so I am replacing the ignition coil and the plug wires to see if they will get me out of this limp-mode.

$250 total

[speedracerf4i]

My mystery has been solved!

I finally towed my car to a shop and after going over all the possible causes and came up fine.

The problem, as it turn out, was constipation. My catalytic converter was plugged up!!! Thus restricting exhaust from going out...

I heard that DEC can no longer sell a 50 state legal cat, so I guess I need to buy the OEM cat now.