The r1 Im working on (my friends) in having a slight problem, he went to the track a week or so ago and ran pretty good, but one run he missed a gear which was no biggie, never over revved or anything he just missed the 2-3... ever since that run the car has had strange off throttle problems. Its idle bounces from like 1500-3500 then settles to about 2200 then starts bouncing again. When you roll on the power everything works great (OCCASIONALY at 30% or less gas it surges at about 3k), but it pulls like it used to, holds 14 lbs (pettit ecu https://www.nopistons.com/forums/pub...IR like it used to. We changed a bad gasket on the o2 housing and checked all the vacuum lines on that side, everything aok. Reset the ecu, checked every possible vacuum line i could (removed manifold extension) but nothing seems bad. A shop did a compression check and said it was high in the spec range (8k miles on engine w/ beefed up apex seals), coolant level holds w/ no abnormal mixing or temps, holds oil like it always has. Nothing seems amiss. Any thoughts? Im buttoning up a 2row install on it tomorrow morning but before i get everything sinched up i was hoping maybe i could get some imput. Sorry for the book i just wrote, im baffled... maybe i should stick to pistons https://www.nopistons.com/forums/pub...R#>/unsure.png

Check fuel filter and plugs. What kind of gas was he running at the track? I'd be willing to bet the 2-3 missed shift is unrelated. Was that whe the problem was first noticed?



Kevin (the other Kevin)

Ya it was after that pass i made the idle started acting up. We have no idea. And i was on pump gas.

Compression good?

This is a shot in the dark but try the thermo-wax valve. It is behind the throttle body by the elbow. If it gets stuck, and it does over a few years, it will surge the idle and you wont be able to settle it down. Check that valve out. It is a dealer part about $80-90 but it could be the problem. It sounds like the engine is tight. It is going to be a SMALL problem and thats the problem with the 3rd gen. Small problems cause big problems.

Did you check the map sensor?

Oh, yeah... That thing too! https://www.nopistons.com/forums/pub...1047683473.gif

It was probably something from the race gas more than the missed shift, assuming (like you said) he didn't redline it when he missed. Check the things mentioned here: fuel filter (maybe you got some bad gas), plugs (reset gaps and check for buildup), then do the other things listed - map sensor is where I'm putting my money.



I get the feeling the car didn't like the difference in octane. But then again, I'm rarely right https://www.nopistons.com/forums/pub...#>/biggrin.png

And, check the fuel filter by yourself. Garages like to charge rediculous amounts because the filter is next to the rear diff which gets frigging hot under normal driving. A freind of mine got into a fight with a garage because they tried to charge him $700, which included 10 hours of labor. Bastards.

Well from what I've gathered, rpm surges can be caused from

running lean. Maybe the idle or light load fuel map is lean.

What ecu is the car running? Is it tuned correctly?

I had a similiar problem before my motor blew. It was surging

at low speed decelaration. Try changing the fuel filter. But, like

mentioned don't pay for it to be done. Its not that hard a job.