Car is 98 ITR with stock motor. I am running a Zdyne ecu with a program that has run very well already so I know the program is ok but I now have problems.

Problem is: under boost in vtec the car pops and farts and stumbles badly. Under vaccum driving is perfect. There is also no detonation going on. I replaced the rotor and cap as well as spark plugs. I checked all the bolts on the turbo and they are all there and tight.

anyone have any idea what to check next? I know its difficult to diagnose a problem on the internet but any ideas would be helpful.

scott

 

what map sensor you running

 

What is your fuel setup?


Also, how do you know there is no detonation going on?

Say for example, you are running pretty rich, yet your timing is pretty advanced, You probably will not be able to tell its detonating by looking at the spark plugs.

Im not familar to the zdyne ecu, but did you get the program from another car? Often the same program will run totally different even on the same setup type cars.

 

"sounds" like the program is retarding too much under boost. the pops, farts, stumble description reads like missing to me. what gap and heat range on the plugs?

 

for the record the problem was fixed by gapping down the plugs