Engine Problems

[87sierra]

I have an 87 Sierra with a 350 tbi and while driving the truck it starts to sputter and bog down just recently it died and i had to wait 30 mins before it would even fire again
just replaced spark plugs
wires cap and rotor a year old

 

[crazy4offroad]

Vapor lock? Low fuel pressure? Stopped up fuel filter?

 

[87sierra]

i never thought of vapor lock i know i changed the fuel fiter about 6 months ago
also the check engine light came on a couple of times

 

[crazy4offroad]

If it has OBD I pull the codes, let's see what ya got. Vapor lock could judt be the gas cap isnt venting, and your charcoal canister is plugged not letting the gas tank vent right. Next time take the cap off and put it back on and see if it fires right up.

 

[87sierra]

okay just checked to see if there where any codes and the only code was 12 and that means the computer is working right and the truck fired right up and ran good

 

[Jims86]

Sputtering screams fuel filter.
No vapor lock, fuel moves too quickly through the system.
When you turn your key to the on position, does the fuel pump prime for 2 seconds, or 15 seconds?

 

[87sierra]

the fuel pump primes for 15 seconds

could it also be electronic spark control modual
or the Ignition control module which was replaced last year

 

[Jims86]

the fuel pump primes for 15 seconds

could it also be electronic spark control modual
or the Ignition control module which was replaced last year

Could also be the coil. Have you confirmed no spark when this happens?

 

[87sierra]

no but the coil was replaced last year but i know that doesnt mean it cant go bad again

 

[87sierra]

just today the check engine light came on and through code 42
i have already replaced the ignition control module a year ago and checked the wires that lead to it and they looked good

 

[Jims86]

just today the check engine light came on and through code 42
i have already replaced the ignition control module a year ago and checked the wires that lead to it and they looked good

check the timing connector, and make sure its snapped tight.

 

[87sierra]

where is the timming connection located not sure if its under dash my wiring diagrams are hard to follow

 

[Jims86]

where is the timming connection located not sure if its under dash my wiring diagrams are hard to follow

should be near the brake booster. its a single plug with a tan wire.

 

[87sierra]

the only wire i found was tan w/black stripe but ill check tomorrow
also after i disconnected the battery for a few mins and reconnected it the truck ran fine

 

[Jims86]

the only wire i found was tan w/black stripe but ill check tomorrow
also after i disconnected the battery for a few mins and reconnected it the truck ran fine

Thats the wire. When you disconnected the battery, did youlet it get to operating temp? If not, it will run fine on factory settings from the calpack, until it gets into closed loop mode, where it uses the readings from the sensors.