I need help diagnosing 1987 chevy

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

sqaurebody

Junior Member
Joined
Feb 16, 2023
Posts
14
Reaction score
2
Location
Florida
First Name
Riley
Truck Year
1987
Truck Model
R20
Engine Size
350 sbc
I have a 1987 r20 and it has started stalling out while driving just fully losing all gas it seems like but still has power. Any help diagnosing that is appreciated
 

AZ Highlander

Full Access Member
Joined
Nov 15, 2022
Posts
303
Reaction score
845
Location
Prescott AZ
First Name
Frank
Truck Year
1987
Truck Model
K15 (aka V1500)
Engine Size
350 (5.7L)
Its gotta be a lack of fuel, air, or spark.
Is it the 87 original throttle body injection or carbureted?
Does it happen at a particular time/situation?
Has anything been fixed/done lately before this started happening?
 

Scott91370

Full Access Member
Joined
Apr 2, 2018
Posts
933
Reaction score
904
Location
Burleson, Tx
First Name
Scott
Truck Year
1985
Truck Model
Sierra1500
Engine Size
350
You're definately going to have to be more specific.
Does it happen under accelleration, at constant throttle, when letting off throttle or any time?
Have you check the fuel filter?

I'm confused by 'it still has power'. Do you mean electrical power?
 

mtbadbob

Full Access Member
Joined
May 9, 2021
Posts
629
Reaction score
948
Location
Montana
First Name
Bob
Truck Year
1987
Truck Model
V20
Engine Size
350
Start by replacing fuel filter on passenger side frame rail under the front of the bed.
 

sqaurebody

Junior Member
Joined
Feb 16, 2023
Posts
14
Reaction score
2
Location
Florida
First Name
Riley
Truck Year
1987
Truck Model
R20
Engine Size
350 sbc
Its gotta be a lack of fuel, air, or spark.
Is it the 87 original throttle body injection or carbureted?
Does it happen at a particular time/situation?
Has anything been fixed/done lately before this started happening?
Tbi it usually happens when I'm go9ng around 50 but it happened for the first time when I put it in reverse and went to back up, no I don't think I messed anything up
 

sqaurebody

Junior Member
Joined
Feb 16, 2023
Posts
14
Reaction score
2
Location
Florida
First Name
Riley
Truck Year
1987
Truck Model
R20
Engine Size
350 sbc
You're definately going to have to be more specific.
Does it happen under accelleration, at constant throttle, when letting off throttle or any time?
Have you check the fuel filter?

I'm confused by 'it still has power'. Do you mean electrical power?
Happens usually under acceleration and yes sir still has electrical power constantly thru the whole process of just completing dieing
 

squaredeal91

Full Access Member
Joined
Mar 10, 2023
Posts
1,814
Reaction score
3,193
Location
Cave junction Oregon
First Name
Greg bush
Truck Year
1991 SB
Truck Model
K30
Engine Size
5.9 Cummins 12 valve
Sounds kinda like symptoms of bad distributor components. When it dies does it usually restart? Does it happen more often when it's warm? Does it loose injector pulse?
 

sqaurebody

Junior Member
Joined
Feb 16, 2023
Posts
14
Reaction score
2
Location
Florida
First Name
Riley
Truck Year
1987
Truck Model
R20
Engine Size
350 sbc
Sounds kinda like symptoms of bad distributor components. When it dies does it usually restart? Does it happen more often when it's warm? Does it loose injector pulse?
I haven't checked the injector pulse but it will start right back up immediately after about 2 minutes
 

peats

Full Access Member
Joined
Dec 2, 2016
Posts
290
Reaction score
238
Location
Pennsylvania
First Name
john
Truck Year
72k5, 81c10 short step, 83k10 short fleet, 03 SSR. 25 chevy doodlebug
Truck Model
k5 c10 k10 SSR doodlebug
Engine Size
406 360 6.2 5.3 171
Fuel pickup sock? What did the filters that you replaced look like?
 

squaredeal91

Full Access Member
Joined
Mar 10, 2023
Posts
1,814
Reaction score
3,193
Location
Cave junction Oregon
First Name
Greg bush
Truck Year
1991 SB
Truck Model
K30
Engine Size
5.9 Cummins 12 valve
I just replaced both of them, it seemed like the injector were spraying good
I'm sorry meant to say check pulse while cranking to know if its losing spark and dying or losing fuel and dying. I understand the injectors are new. But there told when electronically. Sometimes the pulse will fade because of a bad pickup coil and give these symptoms.
 

Dale A

Junior Member
Joined
Feb 16, 2020
Posts
26
Reaction score
15
Location
Bremerton Wa
First Name
Dale
Truck Year
1991
Truck Model
R 3500
Engine Size
454
I had a similar a problem that turn into not even starting. The map sensor was bad. I would also check or replace other sensors in and around the TBI and engine, such as the TPS, Throttle Position Sensor. Maybe even the heat sensor in the block that fed the ECM.
 

Hugomartin

Banned
Joined
Jul 23, 2021
Posts
256
Reaction score
71
Location
Nc
First Name
Hugo
Truck Year
1987
Truck Model
V20 3/4 ton 5.7 350 suburban
Engine Size
350
Try gunning the gas from a dead stop if it shuts off it’s ignition module (sits on dizzy two screws)
 

Latest posts

Forum statistics

Threads
42,188
Posts
910,962
Members
33,683
Latest member
jturner
Top