Some help here guys. So after the twin charge setup my car ran great for the past month. I was running errands and was going into boost just fine. I stopped to fill gas, pulled out of the gas station, went to get on it, and thats when everything changed.

It will stutter badly once the turbo boost kicks in and will puff black smoke. The bov and the exhaust have a quick loud flutter and the car goes no where and my boost wont climb.

I can go into Supercharger boost at 4.5 lbs boost but as soon as i get on it hard (when the turbo would kick in) it acts up. I have done all the troubleshooting and everything seems solid. I have full fuel pressure at wot. The only think i thought was weird is i disconnected the map sensor from the utec and drove it and it acted the exact same. Bad sensor?

Could it be im drowning it with fuel? Is it wastegate related?

 

Check/clean your MAF... but also test the MAP sensor by looking at the dashboard on the UTEC with a PC. Back when I had a UTEC the MAP connector on the UTEC would have loose pins and sh!tty connection...be careful with this because it means you're basically untuned when this happens. My engine was pinging like a popcorn cooker in higher boost levels until I fixed it.

 

Yeah it looks tune related since utec takes over at WOT. If you have a map selector switch check if its still at the correct map, and if the utec is actually working.

Also like djamps mentioned check the map sensor. If you can make a data log of what's happening it would be much better info to try to figure it out

 

what is your A/F and what PSI does utec see? could be injector pumping to much fuel when on boost.. if you disconnected the map sensor or switch utec to the 0 map your car should lean because utec doesnt see the right boost.

 

I dont have the Utec software on my computer. Im trying to get ahold of my tuner so i can read what its doing so i dont know what PSI im getting at the utec. But, my wideband plunges below 10 when wot. I wish it would read lower to know just how low im going but when i mash it it drops to 10 right away.

My utec was tuned off of the 0 map. Thats what it was set at when i pulled it out anyway. I never ended up hooking up my map selector switch even though its installed.

 

There is no software for utec. It connects through hyper therminal. You can download it , winxp has it build in

 

so i you have the Map selector installed what is the value on that? Map 0 is ECU pass through, meaning Utec uses the ECU value. Maybe the selector got changed to a map that wasnt tuned. Best practice is that you want to populate all the 5 Map with a tune in case you accidentally switch the map.

 

There is a switch directly built into the utec. Its set at 0. It was tuned at that (im guessing). Unless somehow a gremlin got up under my dash and turned that **** to a different setting. The selector (installed by my VSA switch) was never connected to the utec.

Just now over lunch I tried to re-seat my map sensor in the utec harness and I got my wastegate to open for a short period of time, like 2 seconds and felt the boost. Then it started stuttering. I re-sat the harness again and this time it went back to instant stutter/flutter with no signs of boost coming on.

Im beginning to think thats the issue. I didnt know I could just hook up a laptop. Thats the first thing im doing when i get home.

 

Map switch 0 is utec bypass and oem ecu controllers the fuel ignition

 

You cant put a tune on Map 0. Only map 1-5 can hold a tune.

From utec manual

6. MAPs are selected using the rotary switch at the rear of the UTEC or with the remote
switch. If you are using the remote switch, you must have the UTEC rotary switch set to
position “0.”

GENERAL INFORMATION
1. Stock mode is selected with the rotary switch at the rear of the UTEC set to “0”. If the
remote switch is fitted this should also be set to “0”. You can not run stock mode if
you have upgraded your injectors!
2. Maps 1 through 5 are selected by turning the rotary switch at the rear of the UTEC to “1”
to “5”. If the remote switch is installed, ensure that the rotary switch at the rear of the
UTEC is set to “0” and select the map you want using the remote switch. Switching
between maps will take effect only when the engine is below 1600 rpm. Use
caution when switching maps.
The UTEC Dashboard will show both the number of the Map and the switch position that is
selected once the car is running. If the car is not running the UTEC may revert back to
stock mode. Valet mode is selected by turning the switch to Map 6. If your Z is
turbocharged and you are using the UTEC for boost control, this mode lowers maximum
boost to your wastegate setting, runs limited timing and uses your Map 1 fuel map (note
this is why we recommend placing your conservative street map in Map 1). The valet will
have no fun hotrodding in your Z!
3. Security mode is selected by turning the switch to Map 7. This only disables the engine
once the ECU and UTEC have been powered down. If activated, the security mode will
continuously flash the CEL. To exit the security mode select an alternative Map.
4. Switch position 8 = stock mode (repeated)
5. Switch position 9 = Map 1 (repeated)
6. The UTEC HOME MENU is shown in the following figure. From here you can access the
Edit Map functions for modifying Maps and Parameters, the Dashboard for real time data
viewing, the main Logger screen or the Data Logger screens.

 

Maybe the selector was actually connected and got disconnected. as the manual state, if you have a map selector the Utec must set to 0.

Edit: you could be running on stock mode where the ECU was able to do a correction in close loop but once you go WOT, the ecu wont be able to compensate for the much bigger injector hence running so rich and bogging...

 

This is weird. I never had the remote selector hooked up. I personally tied the cables up not hooked up. We tuned the car and put the ecu back up under the dash. It ran great for a month. I filled gas. It ran like hell. Took ecu out. Setting on utec was on 0.

Im confused!

 

Connect to the utec with your loptop and check what map # you actually have a map, atheng said the 0 position is oem map, basically utec turns off, you can only tune in map 1-5

 

Car has been running fine until he filled up the gas? So the Gas ruined his tune?

 

^ I think maybe the map selector was hooked up before and somehow it disconnected. Arvin you know how the car runs when its on OEM map or on a really bad tune. the transition alone from closed to open loop would be harsh

 

/\ I don't think its the tune.. My hunch is that the selector got disconnected so now ecu has control because he's on map 0 or the utec switch got flipped to map 0.. On ecu control the ecu will pump enough fuel for the extra air and because of the bigger injector, his a/f is dipping into the 9's.... If the OP just know how to access the utec interface then this should be easy to find out...

 

My tuner said he tuned to either 1 or 2 but def. not 0. I turned the utec from map 0 to 1 and it ran even worse. I put it to 2 and it runs great! Hooked up my laptop and it reads good. Seriously WTF!! Thats extremely strange. Unless somehow the utec has a safety built in to where it defaults itself back to 0 if it senses a problem like a short or something....but I seriously doubt it. ****** Effing Gremlins!

Im hoping to get back on the dyno this saturday. I have installed a Hallman RX pro boost controller and im going to turn the boost up on the turbo. Ill post my dyno sheet up if i get on.

Id still love to put that 8.5lb pulley back on since going to the 6 really hurt the low end power, but seems everyone, including myself, feels the heat would be an issue.

 

Like others have said, copy your tuned map to every position.