I have a LS-V with Skunk Pro 1 Camshafts. High Compression Build on 91 Pump Gas. I just had the car tuned at Church Automotive and Testing. When driving off it started to make a stutter between 3 & 4000 RPM. Took the car back and showed Shawn. After changing out the Dizzy, Plug Wires, Spark Plugs and Injectors (Brand New 550 RC) still having this missing. Double checked the Valve adjustment 7 & 8 just a Skunk Recommends. Even did compression test 285 across the board? Shawn says it’s not the tune. I can figure it out at all. Pulled the spark plugs and it shows that # 2 Cylinder running a little richer from the evidence of black build up on the tread part of the spark plug. But the tip is brownish. Also when you start the car up and its cool it does not do the sutter but after 5 min or so when its warmed up a bit it starts the sutter. Not sure what’s going on. So if any one has any idea be glad to try them out. Thanks.

 

So many people read this post but no one has any info. Come on Honda Tech

 

You say it happens between 3k and 4k- do you drive at lower rpm's or is it usually 3k or above? We need to find out if there is a performance hole in the middle of the rpm range or at the beginning. List any unmentioned mods. Find out if the throttle position has any effect on the problem- does it happen more or less at WOT than at minimum throttle?

 

burn spot on the tps?

 

Burn Spot in the TPS. I will change it out and let you know what happends. Thanks

 

DelSolProblems I have tuned the car 3 times now. After changing the Injectors and dizzy the same problem. We took the car on a drive around town and when it sputters its consistent all the time between 3 to 4500 even when the car is sitting just throttle between those rpms. But when it does sputter the duty cycle and fuel pressure don’t change at all so I don’t believe it is a tune issue. At WOT the Car is strong all the way no problems just a low throttle.
Motor Build Mods
Port and Polished head
High Comp Cp Pistons
Skunk 2 Manifold
Aeromotive Regulator
Walbro 255 hp fuel pump

 

What's your Vtec set at? Does the problem happen at the top end of the non-vtec range and then stops when the vtec engages? How's the idle and what rpm are you idling at?

 

Vtec is set at 6000 and the car idles perfect at 850 and the problems is way before vtec hits i can drive it all day and never hit vteci if i really wanted to. Driving hard i dont have problems its strong all the way through. At lease i dont notice or feel it. Also when i drive the car around seems to be on the hotter days it will cut out like it cutting fuel or some thing. I have to let off the gas and then get back on. And this continues even at one steady rpm say around 4 or 5 when you are driving on the freeway

 

what ecu are you using?

have you checked the actual afr when this happens.

If the duty cycle does not increase with rpm that means that the engine is getting less and less fuel.... if the injector is open for 2ms at 2000rpm that would give you a duty cycle of about 3.3%. at 4000rpm the cycle is happening twise as fast so that 2ms is now 6.6%.
in order for it to stay at 3.3% you would have to have 1ms opening time on the injector, wich is half the fuel....

if you are actualy not confusing duty cycle with puls width i'd say it's all in the tune.

 

If a new TPS doesn't help I can't think of anything but the tuning as mh mentioned. Perhaps the vehicle was tuned only for maximum power (WOT) without considering partial throttle performance. Try checking the A/F ratio and ignition timing at the same throttle position and rpm that causes the problem.

 

OP, do you have datalogging and a wideband?

 

It is s100 and when we were driving the car around when the studder was happening the fuel was not messing up which would be causing the problem that's what I mean. I'm sure the duty cycle is fine.

 

Ugh, the source of the problem may not be injector duty cycle at all. The reason for datalogging and wideband is to see what your ecu is registering during the studder. With that information and a wideband you will be able to diagnose the source of the problem.

 

You need to datalog all sensors and see what is affected by the stuttering. Look at at every sensor one by one.

Also try adjusting your fuel pressure to see if that changes anything.

 

The fuel is good during tune we did mess with fuel psi and it didnt like it to much. I dont know so for a wide band what kind do you guys recommend?

 

good on the wideband or good in the datalog? widebands are not a good tool for diagnosing issues like yours. have you tried another ECU??? that would be the next simple step since you've replaced most typical items.

why did it not like fuel pressure changes???? explain. what is the fuel pressure now?

 

i have this same problem on my 99 si. it just feels like it doesnt want to accelerate and then right when it gets past it, the car throws you back from the take-off

 

typically a lean condition.

 

what is the easiest way to correct that with a very low budget and tools in the garage.

 

what is done to the car? ecu(stock or chipped)? cams? hondata? need more info.

 

its pretty much stock other than cold air intake and headers

 

I need to try another ECU i agree. Some one else also told me that it could be the Barow sensor. So im looking for a P28 or another ECU that i can use with Hondata. I have a P28 in the car right now.

 

any news yet?

 

try changing out your map sensor. i Hada similar problemon on a b16b rally car. when the driver let off the gas and put it back on again quickly while driving the motor spluttered. Changed the map sensor ,fixed it.

 

X2 map shifts can cause this kind of problem, but without data its just a guess.