slight stutter under light load
 

The build is complete, roughly 4xx miles on it now. since I have started driving it after the rebuild I notice a very slight stutter, almost misfire like I've never driven a cammed car so is it possible that its normal? .ALSO just got the computer back from madz28 I'm now noticing a bad egg smell ever since I got the computer tuned, it was fine before hand not exactly sure what may have happened there.

Not familiar with your build, what's been done?

lt1 short block, polished crank new rings,bearings,seals timing set shaved and portmatched heads lt4 hot cam with the springs and 1.6 rollers. egr eliminate air eliminate, k&n cai, pace setter midlengths -y to magnaflow converter and muffler, new opti, newer coil and wires Stock injectors and rail

Is this a stick or auto car? When do you feel the studder and what RPM?

Are you sure the egg smell isn't from the bad Mexican you ate the night before? :haha:

its a stick, center force aluminum flywheel and clutch. and like 1200-1500 and under clears up instantly after that. no mexican for me. although i wish that was the case.. lol

1200-1500 you shouldn't be using the gas pedle and lugging the engine lol. However it can probably be ironed out in the tune. Mail order tunes are never exact unless you data log and send it back and fourth. My suggestion at the very least is log you car get/ watch a wideband and dyno it to see what's going on.

Also the smell is probably the cat going bad or from running rich/lean and getting in the cat

what do you mean by i shouldnt be using the gas pedal and lugging the car? the converter is brand new think its junk already?

At 12-1500 rpm other then when in forst taking off from a stop light you are probably loading up the motor. Even woth a lt4 cam that low of rpm is bad for it unless on highway or just starting off in 1st and even then should be minimul throtle. The converter may or may not be bad. May be whatever the tune is set to is making the cat smell. Or it could have made it go bad no way of knowing wothout knowing whatthe car is doing.

sounds like misfire

bad egg smell is usually a cat. I would data log it and see whats going on, my old car used to misfire and not throw an ses, but hooking up to HPT a few cylinders were having tons of misfires.

Since it wasn't doing this before the tune I would suggest contacting ION and let him know what it's doing. There may be a lean spot or a timing transition that needs to be smoothed out. I also agree with peeps above that you shouldn't be running RPM's that low. What do the specs on the cam look like? Another thing to look for is bad plug wires. If you open the hood at night while the car is running and inspect all of them you might be able to see if any of them are arcing.

Thanks for all the input. I'm definitely going to contact them I'm convinced it is running rich the exhaust is very potent and actually burns your eyes. I'm going to put a new set of wires in there for the piece of mind any how. As for the driving habits are you suggesting I tach higher while driving? The specs on the cam are 218/228, Lift .492/.492 112 lsa.

When using more then lets say 20% throttle you should be at atleast giver or take 2500 rpm and if flooring it keep rpms up

surprised nobody said it....



it's the opti...



lol

Brand new opti,coil,plugs,icm. I contacted madz28 the guys said with it running cooler (had them command fans sooner) it will run richer. I am going to use the sniffer on the inspection machine to get readings on the exhaust to see how rich or lean it is. Any body suggest adjustable FPR?

My suggestion is a dyno tune with your car there. A wideband before the cat. And maybe something to log.

I would have thought that he would adjust the AFR for cooler running temps. I wouldn't use and adjustable FPR to lean it out because that will lean it out all across the board. A dyno tune would be best or do some data logging and get it adjusted. Otherwise you'll have to live with it.

Playing with the fuel pressure wont matter, the ecm will always try to achieve stoich via the o2s.

Playing with fuel pressure is like adding larger or smaller injectors without changing the constants in the PCM.