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92 jimmy 4.3 vortex high idle/stalls when shifting/egr ok/iac ok/more


randolphtpr
11-05-2007, 06:57 AM
this 92 4.3 vortex "w" was ok until it sat a while and started up running rough and has ever since except now it stalls when i put it in gear and sometimes when i come to a stop...unless i keep rpm up to like 1500...runs good down the road...new fuel filter and pressure are ok....egr was clean when i checked it except for the remnants of an old screen...at least i think it was a screen....i lost it when i cleaned up and didn't get to look at it real close....doesn't matter....anyway..i also cleaned the intake air control iac but it seemed pretty clean also..i'm willing to take the vortex cover off and inspect through the center hole where that round thing iswith the two torx screws....i'm beyond where i have ever been but i've seen the plenum off this thing before so i'm not afraid to go in there....have i missed something before i go ahead and do that???....what can i see through the hole to identify washing in the plenum???....do i or should i replace the so called nut kit and the regulator /cpi thing????....i can always change only what leaks when i get in there.....am i on the right track????

maxwedge
11-05-2007, 08:15 AM
Egr bleed thru, vacuum leaks, inoperative iac, I don't think the reg/spider are at fault based on your symptoms, check fuel pressure see if it bleeds off quickly after shut down that points to the vortec unit.

randolphtpr
11-05-2007, 11:18 AM
thank you......i will have to locate an adaptor for the fuel pressure test valve fitting....i have gauges but can't hook up hard without that adaptor and use my gauge with the little release valve....in the mean time ....can i test the iac valve with a meter or how does one test that thing...????

maxwedge
11-05-2007, 02:34 PM
I don't see this being the iac based on what you say, it would idle low but it would unnecessary to keep it at 1500 even if the iac was dead. Check idle vacuum while you are in there also.

randolphtpr
11-06-2007, 09:37 PM
ok...i have a report.....fuel pressure checked out at a solid 58 pounds (60 when the pump was still on)...and held a solid 55 pounds for 5 minutes and after a half hour or so was at 40 pounds....weak but adequate i think.....i got codes too!!!!..i got a count the blink kind..on mine there was a 15....temp sensor high voltage...and 22 throttle position sensor....(tps)....i installed a new one(tps)....$31.....turned the key....no pedal action...and presto....started right up....ran at about a thousand which i thought was high but it was idling and responding to a little pedal action....while it was running and seemed good i hooked up the vacum gauge .....i did have a little crack right out of the vortec..i double checked and replaced all the short stuff....i even thought for a minute that could be it....but no.....any way.....idle vacum was a solid and steady 20 pounds....at a thousand but steady..i thought i had it licked .....i shifted a couple of times and it did not stall....i did what usually made it stall (shift and under load)..enough and of course...it stalled....usually i could hold the pedal to the floor and it would always start up again but right now it won't..the couple of times i did get it going again it was really struggling....black and pretty wet in the tailpipe too.....i'll wait a bit here and try to start it again....i reset the code by disconnecting the neg battery terminal and still have the 15...temp sensor high voltage ..this is not going to lick me....however....i'm confused and don't know what to do....i can change the temp sensor easy enough ...what do you think????....from old school it seems like it's loading up and dumping .....knowing what little i do about this i want to think that something is telling another what to do because of some defect in the system...otherwise it's a great vehicle ....i'm stuck....any suggestions would be appreciated

randolphtpr
11-06-2007, 10:26 PM
and just for a teaser.....the cruise control doesn't work and what about that vac line to the tranny...it shifts good though.......and the vac checked out ...just so you know i'm thinking.....is that you in the white pants or are you driving???

randolphtpr
11-07-2007, 10:10 AM
yes...well...the old man in the parts store....at first he gave me a blank stare....but he was thinking .....gotta go but i'll explain the solution later

maxwedge
11-07-2007, 02:37 PM
The code for the coolant temp sensor is the key here, it probably is staying in the cold position causing a rich mixture when warmed up. A full scan would help here.

randolphtpr
11-08-2007, 07:16 AM
funny thing....when i ran into the old man at the parts store he mentioned vacum booster and i thought ahaa....since i w2aqs after a vac leak because of the sytoms and i was checking vacum at the brake booster hose i thought that could be it...i plugged the hose and it started and ran....i guess only until it warmed up alittle cause it stalled again....i really needed a new cap and rotor and plugs ...stuff was growing in that cap....long story short....the code read 15...coolant temp sensor....i put in a new one and everything is good and normal...amazing....i put the sensor in before i changed plugs and it would not start so i have a question about that....for the computer to realize a new sensor is installed would it be necessary for the engine to cool completely or would it be necessary to reset the computer????????????....because right after i put the sensor in it would not start...when changing the cap and plugs i did disconnect the neg batt terminal....and you know that changing plugs would give it plenty of time to cool down.....could easily have the cap/rotor plug adding to the situation though....also if you could enlighten me as to the message the coolant temperature sensor sends and how it affects the fuel injection system....thank you maxwedge and automotive forum for the help....

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