Texas_Ace

If the cat was clogged if anything it would decrease vacuum in the manifold since less air would be flowing though the engine.

The fuel kit could very well be what the problem is as well, that old style kit tends to have issues like that. Not much way to fix it other then retuning.

cpizzle42

If I have my battery disconnected for a day, will my tune be "lost" from the piggy back?

nothingbetter

I'm not framiliar with superchargers, do they have a wastegate like a turbo set up does?

Thats what causes my 7m to do that. The wastegate releases some air when the throttle is let off, releasing air with no fuel into the exhaust system, O2 reads it as super lean, dumps in fuel to compensate. If I'm under boost and close the throttle suddenly, sometimes the engine will stall from too much fuel. I can get around it if I buy a different downpipe, but I'm too cheap.

cpizzle42

No wastegate on this guy.

nothingbetter

well in that case I'm stumped...has this been happening since the SC install or just pop up recently?

cpizzle42

since engine rebuild and S/C install

vital22re

iTrader: (2)

No you will not.

nothingbetter

Sounds like it must be SC related then. Give the company a call/e-mail. They must have delbt with this before. I'm interested in knowing what it is!

cpizzle42

This is what URD had to say about my problem...

I am sorry to hear you are having trouble.

You will need to clean that up with a custom tune.

Gadget

Awesome customer service. Seems like he does not care I spent $1100 bucks on his parts.

UKrunner

Do you have the ability to look at injector duty cycles? An OBDII scanner will work, or even an oscilloscope?

Also, disconnect your O2 sensor and see if it drives differently.

nothingbetter

Customer service, definatly not, but hes headed in the right direction. We've been suggesting electrical components that have failed in assumption that something is broken. But I get the feeling nothing is broken (as it all worked before), it just has to be tuned to work with the forced air.

cpizzle42

The scanner I was able to borrow did not have the ability to moniter the injectors, just fuel trims. But I can go to the dealer where my buddy works and theirs will. What are you thinking with the injectors? Like what am I looking for?

And which 02 sensor? I assume front?

cpizzle42

I keep on thinking its the IAC, because I know those can get dirty and cause problems. When the truck is doing this running rich under no load thing, the RPM's hang around 1100. Is the raise in RPM's due to the extra fuel? Or not likely?

Texas_Ace

Ah, see you didn't specify before that this all started when you installed the supercharger and the fuel kit.

Sounds like gadget is spot on, you need a tune. The mail order tunes can not be made for every truck and will need adjusting to fit each truck perfectly. Some will need a complete retune like mine did.

I would stop looking for a problem outside of the tune for the time being. The massive negative fuel trims say that the tune is off a fair amount as well. They should be at around 0.

Do you not know how to tune? You will need to hook the piggyback to a laptop and get into it or find a tuner that can handle it. This is why the 7th injector is so much better, it is far simpler and won't cause problems like this unless the tune is really bad, it only effects the tune in boost.

cpizzle42

I have a laptop with software to tune. I just dont have a scanner that will show fuel trims. I wonder what the cheaper route is, dyno time or a scanner that shows the stuff I need

Texas_Ace

The cheaper route is to do it yourself. You can get a scanner for $25 that will work with the laptop.

cpizzle42

Like this? Looks ike it has everything I need.

http://www.scantool.net/obdlink-sx.html

Can you point me in the direction of one for 25 bucks?

EDIT: This one?
http://www.amazon.com/ElmScan-Compac...8335737&sr=8-1

Texas_Ace

Yeah like that only a lot cheaper. Check out Amazon/Ebay, lots of options, just read the reviews and pick the model you want.

cpizzle42

I was just reading URD's U-tune guide, and I realized something, my problem is not happening in open loop when the URD FTC box is modifying the signals. Its happening in closed loop. I agree that my truck needs some more tuning. But how is open loop tuning going to change the problem that is happening in closed loop?

Texas_Ace

If you had the 7th injector then you would be correct but you said you have the kit with 6 larger injectors. In which case the piggyback effects the tune ALL the time. This is why the 7th injector is far superior.

It sounds to me like you need to remove some fuel across the whole vacuum area of the map if I had to take a guess with the little real info given on the tune.