94,c1500,low power,need help?

pumba · 06-07-2007, 08:16 PM

I am new here,,hope someone could help,I have a 94 c1500,2wd,5.7L,4L60,,I got it about 4 mo ago,I replaced the heads,plugs,wires,cap,,,it ran good about a month,,the T.mission went-out,,I replaced it,,run good 1-wk,,and it started missing,low power,uses more fuel,,I found the distributer was loose,,I re-set the time,changed cap,plugs,coil,air filter,fuel filter,pcv-v,distributer,ign.module,ecm,knock sensor,fuel looks clean,cat was removed,not running hot,the fuelpump was replaced 2MO b-4 I got it,and took it to the T.mission shop to be checked,T.mis,checked-OK,Truck runs but sluggish,some IGN.ping,in OD,under a load,,what can it be?

pbouffard · 06-08-2007, 06:24 PM

well noone wants to touch this question, but i gotta ask a few, is the check engine light on? does it flash or act stupid? the obd 1 computers will not tell on their selves, i had to replace mine in a similar situation. check for codes even if the light isnt on. u could also get a compression guage and check compression. did a shop time the engine, you cant time it like 87 and older truck, the plug by the distributor for the computer has to be unplugged to do this. if you dont unplug it wont work right. need a little more technical info to better help, replacing all this stuff is good for preventative but was it needed? how r your injectors spraying?. let me know

pumba · 06-08-2007, 07:44 PM

You are correct,no one wants to touch it,so I am attempting to do it my self,The check engine light does flash,when the engine mis-fires,and when it is running good it comes on for awhile and goes out,has an egr code 3-2,I replaced the EGR valve and controller valve,still does-it,so I removed the hose from valve,and plugged it,still comes-on?..I thought the ecm was telling the valve to open when it shouldn't,so I replaced the ecm,,injectors,spraying good,The parts replaced didn't fix it so,may-be ??I timed the engine,I pulled-up #1 tdc,the button points to #1 on cap,un-plugged the wire behind glovebox,set time to-0-,locked down distributer,plugged wire back-up,time,advanced to 11deg.???do not have a compression guage,,trk,not smokeing,runs rich but no smoke.The plugs I removed are clean-burn,text-book clean,,they are ac-delco cr45ts,a little hotter than stock.It does run better on 93oct,Thanks for the reply..

pbouffard · 06-10-2007, 07:19 PM

ok....... first off the wire behind the glovebox???, the wire im talking about comes off the distributor the wire is purple with black stripe on my truck, i have an 88. anyway you set the timing while running with that wire unplugged itll run like **** but thats how you set it. when you plug it back in it will advance about 11 degrees which is normal. i wish i could tell you at what degree it needs to be but i dont have a book and i kinda forgot. does the truck sounds like it has a miss? if so ground out each wire individually with a test light to see which one doesnt change the idle. your prob sounds like timing nothing more my truck has an egr light on also, ive been trying to fix for awhile. the only time i get spark knock is when i punch it, which makes the light go on. i havnt replaced the egr because i think i have the 80.00 one. there r 2 egr valves, expensive and not. here is a silly part though, the temp switch on the manifold, about 11 bucks. that controls fuel delivery, according to engine temp, if going bad or is off a little itll mess up you amount of fuel sprayed. the temp switch does not have a engine code and will not trigger it. im trying everything i can think i went through with mine. changing my switch did make it run a little better when cold. i really hate the computer **** im a carb person but i now own an 88, had a 82. hope this little more help

pumba · 06-12-2007, 11:04 AM

Well,on my year model the wireharn.is equip,with a wire just above the kick pannel in dash,on pass side,,it is to be un-plugged,when time is set,,you are correct,, it is actually one of the wires that is on the distributor,This is what everyone has told me and what i have read,,when un-plugged the engine runs badly until plugged back in.It is tan in color,with a black stripe.As for the temp sensor,,I un-plugged it,and the c-k eng,light came -on,verry quickly,,plugged back in went out,,it appears to B working.The engine is not missing it has a rough idle,I have heard this is common,It seems to idle a little hi,even when placed in a gear??It is when engine is at cruise speed with T.miss,in O/D,with full lock-up you attempt to accelerate at like 60,or 70,it rattles,IGN.ping,slow to -go??push a little harder on throttle,kicks down,and slow to climb up to speed,,ITS like the same way It would act iff it were takeing-off in the highest gear wile pulling 40,000lbs,,??My EGR valve is new,,it was like 70sumthin??I am going to change my plug wires again,see iff it helps??I cleaned my grounds,from motor to cab,and cab to frame,Do you know of any more?may-be from ECM to cab?Thanks 4 helping..

pumba · 06-12-2007, 11:22 AM

OOPS,,4-got ,It was missing sometimes going down road,I mean it would miss-fire,like thump,and cut the engine almost off ,and fall on its face,It would pick back-up and go 1/2 mile,and do it again,,I changed the cap,button,and pluggs,that took care of the miss,These parts changed had less than 1,300 mile on them???shouldn't be bad yet,,but it helped???now it is like I described above???

pumba · 06-13-2007, 08:42 AM

IT worked??? I changed my plugwires,used same brand,made them-up my-self,The power came back!,"no ping",even with low grade fuel??? IT does idle a little hi,and smells a little rich,still.The wires were not old,may-be 1300mi??? What could-have happened?

pbouffard · 06-14-2007, 05:21 PM

they could have burnt on the exhaust without you seeing it causing a misfire, or just a bad set, glad you got the prob fixed atleast now you have a big index of answers for several problems. thanks

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06-07-2007, 08:16 PM	#1
pumba Full Member Join Date: Jun 2007 Posts: 15	94,c1500,low power,need help? I am new here,,hope someone could help,I have a 94 c1500,2wd,5.7L,4L60,,I got it about 4 mo ago,I replaced the heads,plugs,wires,cap,,,it ran good about a month,,the T.mission went-out,,I replaced it,,run good 1-wk,,and it started missing,low power,uses more fuel,,I found the distributer was loose,,I re-set the time,changed cap,plugs,coil,air filter,fuel filter,pcv-v,distributer,ign.module,ecm,knock sensor,fuel looks clean,cat was removed,not running hot,the fuelpump was replaced 2MO b-4 I got it,and took it to the T.mission shop to be checked,T.mis,checked-OK,Truck runs but sluggish,some IGN.ping,in OD,under a load,,what can it be?

06-08-2007, 06:24 PM	#2
pbouffard Senior Member Join Date: Apr 2007 Posts: 100	well noone wants to touch this question, but i gotta ask a few, is the check engine light on? does it flash or act stupid? the obd 1 computers will not tell on their selves, i had to replace mine in a similar situation. check for codes even if the light isnt on. u could also get a compression guage and check compression. did a shop time the engine, you cant time it like 87 and older truck, the plug by the distributor for the computer has to be unplugged to do this. if you dont unplug it wont work right. need a little more technical info to better help, replacing all this stuff is good for preventative but was it needed? how r your injectors spraying?. let me know

06-08-2007, 07:44 PM	#3
pumba Full Member Join Date: Jun 2007 Posts: 15	You are correct,no one wants to touch it,so I am attempting to do it my self,The check engine light does flash,when the engine mis-fires,and when it is running good it comes on for awhile and goes out,has an egr code 3-2,I replaced the EGR valve and controller valve,still does-it,so I removed the hose from valve,and plugged it,still comes-on?..I thought the ecm was telling the valve to open when it shouldn't,so I replaced the ecm,,injectors,spraying good,The parts replaced didn't fix it so,may-be ??I timed the engine,I pulled-up #1 tdc,the button points to #1 on cap,un-plugged the wire behind glovebox,set time to-0-,locked down distributer,plugged wire back-up,time,advanced to 11deg.???do not have a compression guage,,trk,not smokeing,runs rich but no smoke.The plugs I removed are clean-burn,text-book clean,,they are ac-delco cr45ts,a little hotter than stock.It does run better on 93oct,Thanks for the reply..

06-10-2007, 07:19 PM	#4
pbouffard Senior Member Join Date: Apr 2007 Posts: 100	ok....... first off the wire behind the glovebox???, the wire im talking about comes off the distributor the wire is purple with black stripe on my truck, i have an 88. anyway you set the timing while running with that wire unplugged itll run like ** but thats how you set it. when you plug it back in it will advance about 11 degrees which is normal. i wish i could tell you at what degree it needs to be but i dont have a book and i kinda forgot. does the truck sounds like it has a miss? if so ground out each wire individually with a test light to see which one doesnt change the idle. your prob sounds like timing nothing more my truck has an egr light on also, ive been trying to fix for awhile. the only time i get spark knock is when i punch it, which makes the light go on. i havnt replaced the egr because i think i have the 80.00 one. there r 2 egr valves, expensive and not. here is a silly part though, the temp switch on the manifold, about 11 bucks. that controls fuel delivery, according to engine temp, if going bad or is off a little itll mess up you amount of fuel sprayed. the temp switch does not have a engine code and will not trigger it. im trying everything i can think i went through with mine. changing my switch did make it run a little better when cold. i really hate the computer ** im a carb person but i now own an 88, had a 82. hope this little more help

06-12-2007, 11:04 AM	#5
pumba Full Member Join Date: Jun 2007 Posts: 15	Well,on my year model the wireharn.is equip,with a wire just above the kick pannel in dash,on pass side,,it is to be un-plugged,when time is set,,you are correct,, it is actually one of the wires that is on the distributor,This is what everyone has told me and what i have read,,when un-plugged the engine runs badly until plugged back in.It is tan in color,with a black stripe.As for the temp sensor,,I un-plugged it,and the c-k eng,light came -on,verry quickly,,plugged back in went out,,it appears to B working.The engine is not missing it has a rough idle,I have heard this is common,It seems to idle a little hi,even when placed in a gear??It is when engine is at cruise speed with T.miss,in O/D,with full lock-up you attempt to accelerate at like 60,or 70,it rattles,IGN.ping,slow to -go??push a little harder on throttle,kicks down,and slow to climb up to speed,,ITS like the same way It would act iff it were takeing-off in the highest gear wile pulling 40,000lbs,,??My EGR valve is new,,it was like 70sumthin??I am going to change my plug wires again,see iff it helps??I cleaned my grounds,from motor to cab,and cab to frame,Do you know of any more?may-be from ECM to cab?Thanks 4 helping..

06-12-2007, 11:22 AM	#6
pumba Full Member Join Date: Jun 2007 Posts: 15	OOPS,,4-got ,It was missing sometimes going down road,I mean it would miss-fire,like thump,and cut the engine almost off ,and fall on its face,It would pick back-up and go 1/2 mile,and do it again,,I changed the cap,button,and pluggs,that took care of the miss,These parts changed had less than 1,300 mile on them???shouldn't be bad yet,,but it helped???now it is like I described above???

06-13-2007, 08:42 AM	#7
pumba Full Member Join Date: Jun 2007 Posts: 15	IT worked??? I changed my plugwires,used same brand,made them-up my-self,The power came back!,"no ping",even with low grade fuel??? IT does idle a little hi,and smells a little rich,still.The wires were not old,may-be 1300mi??? What could-have happened?

06-14-2007, 05:21 PM	#8
pbouffard Senior Member Join Date: Apr 2007 Posts: 100	they could have burnt on the exhaust without you seeing it causing a misfire, or just a bad set, glad you got the prob fixed atleast now you have a big index of answers for several problems. thanks