91ls1silverado

I have a LS1 rebuilt with cam and its in my 91 c1500. I put about 3 feet of piping after the headers so i won't mess up the o2 sensors. Well i drive it around and when i barely step on the gas it like stutters and it sounds weak until i lay the hammer down and it runs good, i thought it was misfiring but nope the scanner reads everything good..all the spark plug wires are on good and oil pressure is good....it does say that the fuel trim learn is disabled...idk what that means can anyone help its starting to be a pain in the butt...and it doesn't smoke neither...pleaae help....it has a mail order tune as well

ls1nova71

iTrader: (4)

Mail order tunes are good for stock applications, but when you start throwing cams and things in them, a live tune or even better a dyno tune will really help.

91ls1silverado

So you think it can be the tune??

bczee

iTrader: (12)

Yes, it can be tuned, but the more cam or mods you have, the better the tuner needs to be. Like LS1Nova said on the mail order tunes.. they will get you started and might be good for a mild cam.. but how much cam are you going with ? If you can collect data, you can forward that to the tuner and they can mail you back a modified tune for you to load if you have the software (HPT or EFILive, etc).

Question, where are the O2 located, how far from the exhaust ports or end of collector ?

91ls1silverado

The cam is 227/235 613/620 on a 110 lsa..and i gave the tuner all the info...I'm going to try and talk to him tomorrow...thanks guys...btw its running rich, like a lot.

81s

Its gonna seem to run rich because youre still in open loop. When you get it to go in closed loop you will seee the fuel trims get better and it will lean itself out.

Also check the tps sensor. If its worn out itll run bad where that spot is. Everything needs to hooked up to get closed loop.

Did you tell them to turn off evap,egr, and tq Management?

91ls1silverado

Well i talked to the guy who tuned my computer and he tuned it for 99-00 injectors which are 26.4lbs and my injectors are 98 injectors which are 28.6lbs...and now he doesn't reply to my emails...oh well now i need 99-00 injectors..

ls1nova71

iTrader: (4)

Might be better to just find someone local who can do a good live tune on it rather than trying to match parts to a mail order tune from someone who may or may not be any good. If he was a good tuner he would reflash it for you.

91ls1silverado

He replied back, i sent back the computer so he can put the tune for the injectors i really have

lsxRanger94

If the tune doesn't help, Check to see if you don't have a leaking injector. My mustang had the same symptoms. I use some injector cleaner and that helped for a while. Then I had to replace one injector.

91ls1silverado

Ok will do thanks! I might just buy some o rings just to he safe thanks!

91ls1silverado

I got the tune back and it stutters less than before but it still stutters....i just changed my injector o-rings as well...i do not know what to do....

91ls1silverado

Bump*

91ls1silverado

Ok so this is what it did. Last night i put the computer baxk on from getting it retuned. Started it up and sounded good, when i take off it sputters and it sputters when barely tapping gas. But when I haul *** or rev it, it sounds and feels great. So after driving it for 30min does sputtering stops even when I'm cruising. But after i turn it off for about 10 min and start it up it works great for the 1st 30 seconds and it starts to sputter...sometimes it wont keep idle as well..

91ls1silverado

Some guy told me that my fuel enrichment parameter is not right....

Joe Lluvia Avila

your mail tuner is not doing the proper tuning. its best to go with a live tune in which they can do a wideband tune. you are running too rich. the sputtering comes from flooding the piston with gas and not enough spark to burn it.

Joe Lluvia Avila

What spark plugs are you running?

91ls1silverado

So a dynotune would be my best option right? And ngk tr55 gapped at .50

Joe Lluvia Avila

Try re-gapping them to 0.60.

Joe Lluvia Avila

I've seen people gap those anywhere between 0.45 and up 0.60. I personally just left the gap it had when I purchased them.