1995 C3500 (350 TBI) idles good but falls on its face when accelerating
January 14th, 2018, 8:13 PM
#1
CF Beginner
Thread Starter
Join Date: Jan 2018
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
1995 C3500 (350 TBI) idles good but falls on its face when accelerating
Hello, I have a 1995 C3500 with a 350 TBI, truck has only 80k on it. Was running great then the truck started to loose power and stumble when trying to accelerate to the point it wants to die completely. If I push the clutch in, or have it in neutral it runs fine again. Truck was throwing no codes until tonight. Things I have done and checked from reading on the forum. Seems to run better when first starting up and when its really cold out ( in Michigan right now around 15 degreees)
Replaced coolant temperature sensor ( the one that goes to the computer)
Check fuel pressure before the filter ( checked at 12 psi) and put a new filter on
Replaced Idle Air Control Valve.
Injectors seem to be spraying normally
Checked/Replaced Vacuum lines
Tonight I ran some seafoam through the vacuum system to clean it out for any blockage and the truck ran a tad bit better but not much. On my test drive down the road it was running like garbage barely got it up to 30 before it wanted to fall on its face then the truck finally threw a code and the truck drove perfect. Got back and checked it and it was Code 15 (low coolant temperature)
I let the truck cool down for an hour, started it back up and the check engine light was off and same thing...truck accelerated like garbage for a few minutes and then it threw a code and truck ran great.
Code is telling me it is the CST, but what? Replaced the sensor already.. Wiring? Bad computer? Anyone ran into this issue before?
Appreciate any help.
Replaced coolant temperature sensor ( the one that goes to the computer)
Check fuel pressure before the filter ( checked at 12 psi) and put a new filter on
Replaced Idle Air Control Valve.
Injectors seem to be spraying normally
Checked/Replaced Vacuum lines
Tonight I ran some seafoam through the vacuum system to clean it out for any blockage and the truck ran a tad bit better but not much. On my test drive down the road it was running like garbage barely got it up to 30 before it wanted to fall on its face then the truck finally threw a code and the truck drove perfect. Got back and checked it and it was Code 15 (low coolant temperature)
I let the truck cool down for an hour, started it back up and the check engine light was off and same thing...truck accelerated like garbage for a few minutes and then it threw a code and truck ran great.
Code is telling me it is the CST, but what? Replaced the sensor already.. Wiring? Bad computer? Anyone ran into this issue before?
Appreciate any help.
February 12th, 2018, 4:49 PM
#3
CF Beginner
Join Date: Feb 2018
Location: ft worth, tx
Posts: 15
Likes: 0
Received 0 Likes
on
0 Posts
ok,,, i had a 93 k1500 that would start when cold then stumble to the point of stalling. it seemed to be too rich, like being choked too long but the throttle body has no choke.
After weeks of trying to figure it out, my master mechanic friend could not find the problem i took it to the dealer and.....
it was the temp sensor for the computer not the temp switch for the gauge..
computer sensor should be on the coolant return line, some on the intake/engine block but right up front on the 350;s mine was on the gooseneck.!
ya really got to stay on the guys at the parts shop as many dont have any idea of what you need, gm should have made the threads different so there would not be that kind of confusion....they did use two different connector tho...
as soon as i changed the sensor the truck started running better as that sensor is for when the engine is cold and acts like a fuel enricher to the computer then backs off when it reaches the correct temp, i imagine if the therostat was changed to a cooler temp that sensor could be on a lot longer then necessary
JR
hope it helps by the way the sensor was only 16 bucks so really a cheap sensor compared to other parts...
After weeks of trying to figure it out, my master mechanic friend could not find the problem i took it to the dealer and.....
it was the temp sensor for the computer not the temp switch for the gauge..
computer sensor should be on the coolant return line, some on the intake/engine block but right up front on the 350;s mine was on the gooseneck.!
ya really got to stay on the guys at the parts shop as many dont have any idea of what you need, gm should have made the threads different so there would not be that kind of confusion....they did use two different connector tho...
as soon as i changed the sensor the truck started running better as that sensor is for when the engine is cold and acts like a fuel enricher to the computer then backs off when it reaches the correct temp, i imagine if the therostat was changed to a cooler temp that sensor could be on a lot longer then necessary
JR
hope it helps by the way the sensor was only 16 bucks so really a cheap sensor compared to other parts...
