I need help diagnosing 1987 chevy

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sqaurebody

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Feb 16, 2023
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Location
Florida
First Name
Riley
Truck Year
1987
Truck Model
R20
Engine Size
350 sbc
I did that and it bogged (cut out) really hard
 

gmbellew

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Location
Kansas city
First Name
glen
Truck Year
1990
Truck Model
suburban 1500
Engine Size
350
I'd suggest a visit to the reference library on this site, pull up the 1987 emissions and drivability manual, find the chart for "cranks but doesn't start," and see what you figure out.
 

sqaurebody

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Location
Florida
First Name
Riley
Truck Year
1987
Truck Model
R20
Engine Size
350 sbc
Try gunning the gas from a dead stop if it shuts off it’s ignition module (sits on dizzy two screws)
I just got done replacing the ignition module 30 min ago start it up go to gas and it still hesitate gots me confused
 

sqaurebody

Junior Member
Joined
Feb 16, 2023
Posts
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Location
Florida
First Name
Riley
Truck Year
1987
Truck Model
R20
Engine Size
350 sbc
I'd suggest a visit to the reference library on this site, pull up the 1987 emissions and drivability manual, find the chart for "cranks but doesn't start," and see what you figure out.
It starts and runs fine just from time to time it will stall out ot hesitate when you accerlate fast
 

sqaurebody

Junior Member
Joined
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Posts
14
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Location
Florida
First Name
Riley
Truck Year
1987
Truck Model
R20
Engine Size
350 sbc
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.
I've went thru almost every one besides the map even did every emissions hose
 

gmbellew

Full Access Member
Joined
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Posts
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Location
Kansas city
First Name
glen
Truck Year
1990
Truck Model
suburban 1500
Engine Size
350
if you replaced the EGR with the wrong part (or maybe if it is stuck partially open), it will hesitate just off idle. not sure where you are with the parts gun, but unhooking the EGR vac line that goes to the solenoid and plugging it will quickly let you know if that is the issue.
 

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