Hi everyone. I've spent enough time lurking on here. It's time to come blinking into the daylight...

I'll try to contribute some useful stuff (not that I know much about anything), but for now I'm asking for advice. My car has a couple of problems.

 

1 (fairly consistent) - driving along at constant speed, boost needle is just under the half way mark, revs showing just under 3000rpm (between 2800 & 3000), speedo showing just under 80. I get a slight misfire. Not much, but annoying. As soon as I squeeze the accelerator, it stops spluttering and accelerates smoothly. All on private roads, of course.

 

2 (rare) - happened to me twice, both times in heavy rain on motorways. The first time was just before Christmas and scared the sh*t out of me! Driving along the motorway, rain was absolutely pissing down, and suddenly there was a huge mechanical shock that went through the whole car. I thought something solid in the drivetrain had just broken and jammed. But the car kept going fine. A few seconds later, it happened again. And several more times. (Imagine your car is attached to a big building by a big hefty chain. You drive along happily until the chain reaches its full extension, and then breaks. That's how it felt - imagine it was a beefy chain and you'll get the idea of the shock that went through the car.) So I pulled off the motorway and took the urban roads the rest of the way home - about 5 miles. After I came off the motorway, there were no more of the shocks (although I was still sweating all the way home).

 

The car is 1990 Jspec TT auto. No significant engine mods. Just a free-flowing exhaust. Knock sensor hasn't worked since I got the car about 8 years ago, but I always use high octane petrol and haven't ever heard any pinking (except a couple of times when I first got the car, and put ordinary unleaded in it). Erm, can't think of anything else.

 

Any ideas? I'm guessing they're two different problems.

 

Thanks everyone.

can't help on 1st one but the second is prob water that got into your air filter and upset your maf. We had this happen last year on the way back from Castle coombe. do you have an after market filter on

on

I didn't at the time, but I got one fitted a couple of weeks ago. A Blitz from Z Centre.

 

It hasn't p*ssed down since I got the new filter on, but hopefully you're right and the new filter will cure it. Thanks Scubie.

 

Anybody else? :D

do a search on missfire there is hundreds of posts on the subject :D

do a search on missfire there is hundreds of posts on the subject :D

 

Yep. Already done that chief (I'm a mod on another forum, so I always try to search before I post questions and wind up the regulars. :) ). I couldn't really find something that matched those symptoms (although I did suspect the MAF for the wet weather trouble).

 

Maybe I'm too much of a numpty. But I'll keep searching.

ok try cleaning the ECU temp sender, it gets covered in green shit whichplays havoc with the ECU and timing as it thinks engine is cold and adjusts timing, fuel etc as if engine is cold

any ecu error codes to go on?

ok try cleaning the ECU temp sender, it gets covered in green shit whichplays havoc with the ECU and timing as it thinks engine is cold and adjusts timing, fuel etc as if engine is cold

 

Thanks, I'll give that a go. Probably this weekend.

 

Ollie - there were none about a month ago, but I'll try again this weekend.

OK I can identify your 2nd problem as thats what i felt the other day. It was my gearbox.

 

If your sure its a missfire then go to Maplins and get a can of their terminal cleaner spray and clean every single connection.

 

Because you would of disconected your Battery to do this youl reset your ecu, always a good time to do the filters too at this point.

any ecu error codes to go on?

 

OK, just checked. Code 34 (det sensor, which I knew about) and code 11 (CAS)...

I fitted a apexi filter and it hates the rain due to my vented nose panel, I made a quick fix by fitting a rain shield out of half a bucket and fastening it above the filter and the problem has gone