I have a friend that just got JUN III cams installed in his ITR motor. Currently he has a JUN ECU, Jun cam gears (0,0). Also has intake and exhaust on the car.

His car was running perfectly fine yesterday but it starting acting up after he got home. He said he started it up and it idles rough 500-800 RPMs and sounds like a domestic. He is running very rich right now too.

He also says that there is .5 second delay in throttle response.
"rev, and .5 seconds later it revs"

Will the ecu retard it since it's running rich? Timing is stock and running on 91 octane.

What should he do? What can he do to make it run normally?

 

He will have to drive like this for awhile because he is broke.

 

hm...i have the same setup. i hope this wont happen when i intsall them..

 

Isn't it true that only Jun can reprogram the ECU?

 

Not sure but I know that every JUN ecu is different.

 

jun might have great products but customer/sale service is the worst.

 

Sounds liike bent valves

 

my car is currently running extremely rich and untuned, and sometimes if I step on the gas, nothing happens and it just bogs down. It seems to run fine if not idling, but as soon as it idles, I dont think its burning enough fuel and starts to bog down. If its anything like my problem, Id say its a fuel issue.

 

Does the rough idle only happen when the motor is cold?

 

i heard it happened at every stop light or when idling, warm or cold..

 

Sounds like his valve lash might be off, too. Compression test first, and if that comes back ok, have him check the valve lash. Will idle and run ok until it gets to operating temperature, then the symptoms you mention will occur.

 

I just got done talking to him and he said that the valve lash was adjusted to stock specs, which was what JUN suggested.


[Modified by ExOdy, 7:42 PM 9/30/2002]

 

Here's what he said:
nope i dont think soo if i did the effect woulda been imediate yeah i shut off the car when it was running great then started it..then it ran like crap

The valve lash for the intake was 7 and the exhaust was 8.


[Modified by ExOdy, 7:48 PM 9/30/2002]

 

Okay, let me get this straight.

This guy got the JUN3's put in, with the Jun valvetrain. He has intake and exhaust. The car was running fine, then when he went to turn it on after a day of driving he noticed this??

Cam gears are okay, and it seems like the valve adjustment was done. Has he tried to check the timing. Maybe the timing is off. Would it be possible that the timing belt could jump a tooth and throw everything off??

 

another question does he what kind of i/h/e is he running

 

i'd like to know if a timing belt can jump a tooth...

 

Tell him to doublecheck the lash anyway. It can't hurt. Ditto on making sure the timing didn't jump and is still set correct. Start with the obvious and troubleshoot from there. Try putting in the stock ECU and see what happens.

Does his car have problems on immediate startup, or just when warmed up?

 

I think he is having problems at idle when the car is cold and even warmed up. Ya he should double check valve lash, and see if timing lines up. other than that i dont see why this should be happening, this is interesting.

Is there a possiblilty that fuel is off, maybe rich or lean?? Might wanna ask him that

 

My money is on the fact that the timing belt is off by a tooth. I know when i put my timing belt on last time i thought i had everything tensioned correctly, then i gave it a test spin using the crank bolt and the belt jumped by 2 teeth. I thought it was on right, but it was actually off which is why it jumped. I could almost guarantee this is his problem.

 

On my old motor, my cam gears slipped and I jumped a tooth on my timing belt, car idled really low, and hesitated like crazy. Once I figured out the problem, fixed the belt, and checked the timing, it ran perfect.

 

when your timing belt slipped, did it hessitate even while driving or just reving?

 

Does that only happen at idle or all the time? Does the probably go away when you drives it? If it does, its the ECU program, I and a bunch of other people have run into this when you start the car sometimes. It will run extremely rich at idle sometimes and then it will go away once the car warms up more. I think its a result of running in open loop all the time. The ecu will think the car is running cold and then will dump cold idle fuel, causing the car to lope and run like crap at first. If thats not his problem, check mechanical things like everyone else said.

 

Do you have any thing to back this statement up? Canuck has gotten GREAT customer service from JUN. I have know other people that have gotten similar positive experiences from JUN as well.

 

i think he said it happened all the time, warm and cold. my guess is his timing belt slipped..


just thinking, if the belt slipped, it probably slipped clockwise. so if he turns the cam gears clock wise a little, to match up with the belt, would that be a safe temporary solution to this?


[Modified by TypeR 599, 11:06 AM 10/1/2002]

 

I'll let him know. Hopefully he can get it fixed right away