87 R10 305 bogging down

[gmhammes]

Maybe this will shed some light on the problem.

https://www.youtube.com/watch?v=UB_WBst38no

[68longhorn]

Do 87s have the ESC box off the distributor? If so that could be an issue

[gmhammes]

Can't see the ESM. Anyone else have thoughts on this?

[gmhammes]

Still trying to keep this one alive! (thread and truck)

[68longhorn]

Do you have four wires coming out of the back of your distributor? Have you blocked the egr vacuum?

[gmhammes]

I only have 2 wires coming from the distributor. I have not blocked the egr vacuum line. Should i try doing that?

[68longhorn]

Yea thats worth a shot. Take the line off the egr valve and put a little bolt in the line

[NastyBuzzard]

I will tell you exactly what it is. I have come across this issue twice.

I have a 1987 GMC V1500 350 tbi. What has happened is because of sitting so long the rubber hose between the fuel pump and the sending unit has "disintegrated" leaving hole or a slit in it. This has happened every time I let my truck sit too long, gas just eats through it.

Record fuel pressure while driving, it will be 11-14psi all day long while idling and revving in park, that is how it was for me, but when I tried to drive it, it would spit and sputter, and when I had a long hill for a driveway it would cut out and roll back down the drive way.

Give it a check!

[gmhammes]

i've read abou this a few times now and have only not checked it because i was too lazy to pull the tank down again. I will report back on these two things.

Thanks!

[gmhammes]

Okay. Pulled the tank. Replaced fuel lines going from sending unit to tank selector. Pulled the sending unit and checked the hose to the pump. The new pump or sending unit included a new hose from pump to sending unit however there is no hose clamp on the pump side however I don't think the factory had one either.
Haven't been able to check fuel pressure while driving yet.

[gmhammes]

more thoughts?

[NastyBuzzard]

What's your timing set at with the esc wire unplugged?

[gmhammes]

not sure how to tell that. Can you provied a way to detetmin that?

[pontgta]

The pump. Should have a clamp on both sides . Use fuel injection clamps

Like this

[NastyBuzzard]

Originally Posted by gmhammes

not sure how to tell that. Can you provied a way to detetmin that?

Unplug esc it's on ds firewall down near steering shaft. Sticks out of the loom with black/brown wire.

Put timing light on #1 cylinder and start truck and see where it's at on the timing mark on the cover.

[gmhammes]

Here is what the new pump and sending unit look like.

[NastyBuzzard]

Originally Posted by gmhammes

Here is what the new pump and sending unit look like.

Seems like you're missing a clamp. It needs one on both sides of the rubber hose. Factory where this plastic ones but if you replace use the smooth fuel injection clamps like listed earlier.

[gmhammes]

i will pull the tank back down this weekend and add the clamp.

[NastyBuzzard]

Originally Posted by gmhammes

i will pull the tank back down this weekend and add the clamp.

Make sure they are the smooth ones, not the ones that cut into the hose

[gmhammes]

Originally Posted by NastyBuzzard

Make sure they are the smooth ones, not the ones that cut into the hose

New clamp installed. No change in the bogging. Timing check will be next. Thanks for all the help!

[Mr.Chevy4x4]

The spray pattern from your injectors looks good to me. I doubt it's a timing issue if the truck was running fine when parked and the timing hasn't been messed with since. I've had a similar bogging problem before caused by a bad EGR valve. If you replace it make sure to get the right one. The 350 and 305 valves are different. The first one the parts store gave me was for a 350, and although it made the problem better there was still some bogging. Realized what happened, went back and got the right valve, problem cured. Not positive that's your problem, but possible.

[NastyBuzzard]

I can't remember, but have you checked your distributor? Sometimes they rust and start performing badly. If you pull the cap off and it looks like there is some minor surface rust in there go ahead and replace. There is a company on eBay selling brand new distributors for like $40-50 shipped. It comes with everything from cap to distributor gear. I got one and it works great.