TURBHOE

iTrader: (4)

ok i'm working on a 4.3l silverado. 96' reg cab short bed auto. when cold (bone cold) it will fire up and idle great and you can put it to the floor and it will rev to fuel cut. but after it warms all the way up to operating temp it will still idle ok. but when you stuff it to the floor it will just bog and sit at like 2500-3000 rpm. you can hear the intake howl through the k&n but it will not rev. if you slowly roll into it say up to 1/4 throttle or so it will rev to fuel cut. but you have to do it slow. if your in the middle of a slow rev up and stuff it it will bog to about 2500-3000 rpm and sit. you can hear it try to rev up a bit but then it goes back down a little and never goes over 3000 rpm. it started doing it out of no where. just driving along and the guy lost power. and is slowly getting worse. he can't drive it at all. sometimes when you go wot it will just die and will not crank back up until it cools to about 170ish.

what we checked: maf (replaced it), map, o2's, tps, coolant temp sensor, iat, spark comming off of coil (big spark), and spark at plug. we gutted the cat just to see and it didn't work either.
we replaced the fuel filter it was dirty as ****. got 5 psi of fuel pressure gain and its alot more steady fuel pressure.

so this thing has the spider injector harness thing. i'm wondering if the central box might be clogged after it warms up. or is there a sensor that is taking affect after warm up? he just got a check eng light for the first time which is a multiple miss fire code. so is it the rotor bug and cap or is it the fuel injector thing? could the rotor mess up when hot and not when cold causing the spark plugs to get blown out at wot?

al trouble shooting has been done in park. we can not drive the truck.

mcfarlnd

iTrader: (15)

damn i never had a single problem with that truck!!!! wtf did he do to it????? the way he explained it to me it sounded like a fueling issue. his fuel pressure was low too wasnt it????? tell him not to waste the time and get crackin with that ls1 didnt ron have a prob with the "spider"?????

TURBHOE

iTrader: (4)

i say its th "spider" too but he doesn't want to replace it just yet. he stuck on it going into close loop and thinks a close loop sensor is the problem. i need to find out what sensors it does and doesn't use in open and close loop. he took off the rotor cap and said it looked burnt. i told him to clean it and read it out with a meter and then heat it up in the oven to 200* and read it out again to check. he was going up and down alot of big hills last weekend to get the ls1 when he got back is when it started. maybe the 4.3 is just mad because it seen the ls1 lol.

litreddevil

iTrader: (4)

man you should have 50lbs of fuel pressure change your fuel pump

TURBHOE

iTrader: (4)

well, we are getting between 55 and 60 psi on the guage after the fuel filter replacement. funny thing is, about two or three weeks ago i guess it was he just replaced the pump.

mcfarlnd

iTrader: (15)

remove and replace the driver did you talk to him again yet to see how the cap test went????

TURBHOE

iTrader: (4)

nope i'll call him in a bit though.

mcfarlnd

iTrader: (15)

well.............................

2001si3rr@

iTrader: (1)

I was thinking fuel pump till you said he replaced it. That LS1 should fix the problem for sure.....

TURBHOE

iTrader: (4)

well he fixed it with: a new cam sensor that put out from too little voltage to too much voltage, a crank sensor that put out too little voltage, a new rotor cap it was shot from the shotty cam and crank sensor had black marks inbetween the contacts, a new maf (same one as at the beginning), a new egr valve it was slow to respond and or did not respond at wot, and finally a o2 sensor. now it runs like a champ lol.