i just installed my vortech kit with dw600 injectors(new), walbro 255 fuel pump (new), turbo xs utec (new). kit was installed on sunday and tuned on monday by forged performance(sharif). it ran ok on monday, but from tuesday i noticed car was spuddering time to time when i'm driving. today i took the car back to forged. sharif test drove my car and he said my car was running on 5 cylinder intermittently. that's why car car sounds like it's been camed. what i have found is, when the car is on 5 cylinder i would disconnect one of the injector and waited 2-3sec and reconnect will fix the issue, but it will happen again. problem got worst from this morning to now.

anyone had same issue or know what might be causing it? is it the injector, fuel pump, or utec? sharif thinks it's the utec and i think so too. i belive it's not the mechanical issue, cause it won't be intermitten. please help me out and thank you in advance.

 

at idle does it have the same symptoms? i had a problem with my haltech recently. i couldnt figure it out until i tried unplugging my haltech and plugging just the stock ecu in. surprisingly it fired right up and idled fine with 600cc's 255 and return system.

just a thought.

 

Yeah, this was a scarey test drive this morning. Out of the blue, drops a cylinder and then magically comes back to life about 3 mins later.

My bet is a bad injector driver in the UTEC.

 

quite possibly what happened to my haltech. currently its in australia getting fixed.
when its idling like crap, turn it off, plug the stock ecu back in. and then if it runs fine, theres your problem for certain. worth a shot.

 

you can run stock ecu with bigger injectors and fuel pump? u dont have check engine light? and dose it run with no issue?

 

yup, i will be calling turbo xs tomorrow to have them involved. sharif do you know a contact name at turbo xs? one more question do you think throttle body sensor might cause this issue? last time i had check engine light (around 4:40pm) i ran obd II test and i had p1120 and p1126 error codes. let me know what you think. thanks again.

 

my car fired right up with 600cc injectors, 255, and fuel return set up. i do not drive it however. this is how i figured out it was my haltech that had the problem. my car would idle and run like crap. so i unplugged the haltech and plugged my stock ecu back it. fired right up and held idle. i dont recommend driving it like that at all. but for identifying purposes, i suggest it. looks like thats the problem with the OP's set-up.

 

oh..ic. i will try your trouble shooting tactic, but my problem would happen when car has been droven a little.

 

ah ok. well thats why i was asking if it happens durring idle. hmm. crappy situation buddy!

 

thanks bro, for your input. at this point every info is great help.

 

Why not hook a scope up to the injector line and see if #5 looks different from the others. Could be the spark too...UTEC is known to have weak outputs.

 

well. the kicker is we don't know which injector is not firing. i disconnected the injectors and reconnected one by one while i was having the issue and thought that i found one of the injector was causing not to fire(one from under the plenum top left injector when you are looking down from front of the car). so i swapped the bad injector(so i thought) to different slot which i can get easier access to if it happened again. the problem did recur, so i disconnected the bad injector(so i thought) but it was not the injector. you said could be spark? means spark plugs? or not enogh outputs from utec to have poor spark? or just bad utec even tho it's new? i'm kind of noob at this. hope this all make sense. thanks

 

Weak coil pack???

 

do i need to replace the coil pack? can i do any troubleshoot to find out it is the coil pack? thanks

 

Maybe a coil pack? it could be... My buddy had a problem like that and it was one of the coils

 

+1. Basically bad UTEC. Bad injector or bad ignition driver. You can get another bad one or you can upgrade to something more reliable.

Alternatively, some folks manage just fine with their UTECs after adding a Ken Bell Boost-a-spark.

 

just dont over analyze the problem. take it one step at a time or you'll create a headache for yourself. thats the fun part about working on cars. to some people; its the most frustrating. I would try loading your map on another utec and see if that fixes your problem. if not, then get into the coil packs and scoping injectors. sorry i cant be of much other help. thats what i would try.....

 

with coil pack problem did your friend had intermitten issue or was it more consistent issue. my car wiil run fine and it will go into dump mode lose major power and car sounds very loopy, but it will fix it self and runs fine.

 

man, u have been very helpful. i thank everyones commons in here. turbo xs is sending an another utec for me to try out and sharif will load the map to see if i'm going to have same issue. if i do have same problem i belive it's going to be coil pack.

 

nice. good call, man. i hope that works for you.