THORPE

Alright I'll try to make this short.

I bought an 02 f4i from my friend. He bought it new and after a few years started having trouble with it cranking all of the sudden. It will start eventually or you can push it off. If you keep it running till it gets warmed up it rund pretty good but has a little hesitation on the low end.

he took it to the dealer and they gave him a bunch of different storries: MAP sensor, IAT ECT..... Then they said that it needed some sensor inside the throttle body that couldn't be removed and that he would have to replace the throttle body..

I bought it and found a full set of throttle boddies on ebay with the airbox, boots, inj, MAP, IAT Fuel rail intact. I swapped the whole set up, and it still does the same damn thing.

It reads a trouble code for the MAP but the sensor checked out fine.

I did clear the trouble codes after the swap and it came back

Could it be the ECU??

Any help or suggestions on something i didn't check / swap would be great!!

sprocketz

might want to check it with a vacuum gauge, the map sensor uses eng vac for a input if you got low or fluctuating vac readings it might throw a code. fluctuting vac could be caused by bad valves or mis adjusted valves or low vac might be retarded ignition timming, pluged exaust,vac leak etc anyways its jus a thought only takes a second to check it otherwise you might be right about the computer..... keep in mind though that it may also be the tps throttle position sensor if the tps reads hlf throttle and the map sensor reads 18inches of vac the computer may not know whos lying the map says idle but the tps says half throttle it might be throwing a map code when really it should be throwing a tps code anyways good luck i always start with the basics first before pulling out my hair......if you do think it might be a tps check the return wire voltage should be around 1volt and as you open the throttle it should increase up to 5volts

THORPE

If it is the TPS, Is it possible to swap it even though it's riveted?

sprocketz

i would think so, rivit guns are cheap but i have never done it myself on a f4i

THORPE

Still no luck, It keeps fouling plugs Those dam things are 70 bucks.

I reset the ECU afer I got it warm and running and rode for an hour. The Map sensor FI light never flashed but it still has trouble at idle and in the low end and now i've fouled another set of plugs trying to crank it.

It only seems to through a light while i'm tryin to crank it and i have the throttle gapped. makes me think maybe not FI related.

Could it be the Coil packs or whatever they're called?