slight engine miss

[andyman7931]

Haven't driven my ti in over a week until today and noticed a small problem. When accelerating hard with the 3/4 or more throttle when the engine is at low RPMs (2k) about 20% of the time there's a shudder that feels like 1 cylinder may not be firing. If I let off the gas and try again it almost always stops doing this. Also it won't do it at higher RPMs either. No CEL, no other obvious clues as to what's wrong. I'm planning to replace my plugs and wires next week after I get back from the UK, figured that's a good start. While I'm in there I'll do a compression check too. The car is a 98 and has 101k miles and I have no history on it since I bought it with 95k miles.

Anyone else have any ideas or thoughts?

TIA

[madfronter]

Maybe your coil pack is going bad. Maybe your fuel filter. I would try changing the plugs and wire like you said as well.

[andyman7931]

Originally Posted by madfronter

Maybe your coil pack is going bad. Maybe your fuel filter. I would try changing the plugs and wire like you said as well.

where's the fuel filter on these cars? maybe I'll just go ahead and change that too.

If none of that fixes it, I'll swap coil packs with the other ti and see if the problem follows it.

thanks for the suggestions.

[madfronter]

The fuel filter is located under the car.

[andyman7931]

I went to drive the car tonight, and now the CEL light is on and it drives very very rough. Just went around the block and took the other ti out instead. I got a code reader while I was out, so that's where I'm going to start.

[bullmand]

Crank position sensor?

[Blue318ti]

CMP (Camshaft Position Sensor) will cause it to stall at the lites or when decelerating. OBD is the place to start. Let us know ASAP (we're all experts here until it happens to us....lol).

[andyman7931]

the code was P0301 which said cylinder 1 misfire. I pulled the wires and found some liquid around the spark plug for cylinder 1 only, it's about an inch deep. The liquid has no significant smell (not gas) nor no significant thick viscosity (not oil) so I think it's either water or coolant. The question is, did water magically appear there from rain or some other source, or is something like my headgasket leaking and lets water get in there? Thoughts, comments, suggestions? Also if it's the headgasket, when I replace it is there any performance things I should do while in there? Is shaving the head a good thing for these m44s?

Edit: Also checked oil and coolant to be sure they didn't mix and both appear fine (normal colors and levels)

Thanks

[bullmand]

It could very well be water. I would carefully inspect that wire and boot. You might want to throw new plugs in and consider replacing the wires. That's not a very inexpensive prospect. On the bright side, it will give you a chance to get some of those BMW high performance wires

[andyman7931]

upon further inspection and thinking, I doubt it's a head gasket. There doesn't seem to be any way that the gasket would let water go into the spark plug area. The liquid definatley seems to have a greenish tint to it as well, so I'm almost 100% sure it's coolant. My guess now, unless someone has more direct input, is that it's probably a cracked head. Tomorrow I'll wipe up the coolant and take it for a drive and see how fast it fills up with coolant.

[andyman7931]

UPDATE: I cleaned out all the coolant from around the plug and took it on a test drive. It started missing after 1 mile so I headed home to find the coolant about 1" deep again. I'm thinking cracked head or something unfortunate. I'm buying another engine and going to swap it out. I've been wanting to collect parts to build a stroker m44, so I guess this is where I start.

What parts should I replace when I have the engine out? There's some plastic coolant fittings on the back of the head, right? I'm also going to get a new clutch and lightweight flywheel. Also are there any unusual tools I'll need? I've done a dozen or so m20 engine swaps and have all tools required for those, just looking for a heads up on potential weirdness.

[dave45056]

Maybe your spark plug coolant level is set too high?

[andyman7931]

Originally Posted by dave45056

Maybe your spark plug coolant level is set too high?

??? that makes no sense...

[SlickmisterN]

I think it was more of a light hearted joke.
Good luck with all the work ahead. Stroked M44 + Seam Charger = TEH WIN!!! LOLOLOL

[dave45056]

Yes it was a joke. In all seriousness, it sounds like you have a cracked head. A compression check, leakdown test, or even a coolant leak test (under pressure) could confirm it. I hope this is not the case, so I'm keeping my fingers crossed for you.

And if you do have to do the head, you don't need to remove the engine. You will need a few special tools... camshaft lock, flywheel lock, and a rigid chain tensioner. Oh and a e12 torx socket. Other tools are normal.

Good luck