Long Q's about Jimmy

[rscamp1981]

Hello everyone. I joined hoping to find some extra support with the new truck. First, a little about it; It's an '84 full size sierra classic. Has the 305, too bad not a 350 ahhhh V8, four wheel, etc. When I bought the truck the kid said he thought the fuel pump was going out but changed the fuel filter. It ran good but when I got it on the highway going about 60 it started to decelerate on it's own even with pedal to floor dropping me down to about 25-30mph. A "friend" changed the fuel pump for me but ended up not really knowing what he was doing. The push rod was stuck and after beating and pulling he got it out ( I found out later) He didn't even grease it before replacing it! The next day it was making a ticking, rather than knocking, noise. Tried cleaning the carb, hoping it was simply carbon knock. Fired her up and she died when shifting into reverse and drive. I drove it one more time for less than a mile and it kept dying while I tried to back out and get out of a parking lot to turn around. Then as I was about two blocks from home it died. I was trying to accelerate over 25-30mph, the pedal was down and it tried, it was rev'd and then it just quit and I rolled to the side of the road. I have the time and money now to fix a lot of things so don't try to spare my feelings My first step, recommended by my mechanic friend is to check the fuel pump first. Any others? Hoping someone has a similar vehicle and experiance.

[screwballl]

my 91 burb had this happen... I replaced the distributor module and that fixed it... after replacing the intank fuel pump since that was my first thought as well.

[Shock_Me]

Screwball, is this the same module as the Electronic Spark Control module?

I had the same symptoms happen to my 85 a while back. I replaced the electronic spark control module. If I remember correctly, it's located up under the dash behind the glovebox?
It worked fine for a while but died again, (bought it at a junkyard).
Lesson learned, bought it new from GM and worked fine.

[rscamp1981]

Hey guys thanks for responding! So I read up on the Electronic Spark Control.. I see what you mean and will definatly give it a look see first. Now does that mean I have a problem with spark knock? Anything I need to think about concerning knock when getting it up and running again?

[AR15DEFENSE]

does it only do it only when hot? or does it do it all the time (hot or cold, in gear or not) ?

[rscamp1981]

The noise is constant, no matter what gear/idle..But it isn't a predictable sound, it varys with the speed I'm going, faster as I go faster etc. But at this time it doesn't run at all, it hasn't started since it died.
the battery tested fine.
Haven't checked spark plugs.
cables are brand new
rotor button looks pretty burnt
have not checked starter or solenoid

[tiggerstoy]

Originally Posted by rscamp1981

Hey guys thanks for responding! So I read up on the Electronic Spark Control.. I see what you mean and will definatly give it a look see first. Now does that mean I have a problem with spark knock? Anything I need to think about concerning knock when getting it up and running again?

i would pull the pump off again, inspect the push rod for scars, and especially warpage....that would explain the tick speeding up with the rpm's.and in short....is it the corect fuel pump?....i'v seen that lot's.

[rscamp1981]

Originally Posted by tiggerstoy

i would pull the pump off again, inspect the push rod for scars, and especially warpage....that would explain the tick speeding up with the rpm's.and in short....is it the corect fuel pump?....i'v seen that lot's.

Actually I took the old fuel pump down to the parts store to double check.. it was the correct part. Again, when the fuel pump was installed by my 'friend' he had a hell of a time getting it in. He didn't know to grease the push rod and ended up spending a lot of time trying to get it in. I really think that is the place to start.

[Blazer86]

Start at the fuel pump. The knock started after it was replaced, right?
As for the loss of power don't forget to check the catalytic converter.
A plugged coverter will cause the same power loss symptoms.

There is a bolt hole on the front of you engine It is the upper bolt on your A.I.R. pump bracket. If you use a long bolt you can hold the fuel pump rod up and out of your way while you install the pump.
Make sure that the cam lobe is rotated to the low side.
Just push the rod up and lightly screw the bolt in. Not tight, just touching.
Remember to put the correct length of bolt back in after the install or you will not have any fuel.