'82 pickup question?

[dirtroad]

I have an '82 pickup that is causing me to lose my hair.

It starts up just great, has plenty of power, doesn't smoke, idles and runs smooth, and then after about 5-10 minutes...

It falls on its face. No power, Rough or No Idle, Can hold it to the floor and it won't rev up.

You can turn it off, wait a few minutes, it will crank back up and run just fine for about five minutes, then it will do it all over again.

Fuel tank has been removed and cleaned. Filter is clean. Fuel lines have been blown out, cleaned or changed.

Clean fuel can be seen in the fuel line entering the injection pump, which has been changed also.

I don't understand how it can run like a champ for a few minutes and then do the exact opposite.

Please Help!!!! Any Ideas?

[bscutt]

Still sounds like fuel starvation. You could try an electric fuel pump in line between the filter and the injection pump or even before the filter to see if it's lack of fuel to the pump. I used a small booster pump on my 79 due to a worn vane pump and it cured most of my problems - the other problem was the tank was hopelessly clogged and I had to replace it but it sounds like you're pretty sure the tank isn't a problem. Also a vacuum gauge on the fuel line will tell you if you have a restriction. Wired that it's intermittent and also difficult to troubleshoot while you are driving. If you have a tiny air leak it might not show up until you use enough fuel to start sucking substantial amounts of air.

[dirtroad]

Forgot to say that I already added a fuel pump near the tank to push the fuel to the front....Didn't Help.

I can visually see that the fuel line is full upon entering the injection pump. I don't think it's a fuel starvation issue at this point, but I guess anythings possible.

Could it be sucking air somewhere and cause this? If so, Where?

[TylerDurden]

Clear tubing on the return line can show if air is getting into the pump.

The banjo fitting on the inlet might leak in air after it gets warm. The copper washers are vulnerable to dings and scratches.

[82vdub]

Classic signs of fuel starvation. Rig up a bottle with diesel in it and an inline filter and connect that directly to the injector pump (IP). If the problem goes away, it's a problem somewhere between the IP and tank, if the problem persists, it may not be fuel related.

Check your return fuel line for restriction and also the fuel tank vent hose. If the vehicle runs without the fuel cap but won't run with a fuel cap on it, it's pulling a vacuum somewhere. A vacuum gauge on the IP will give an indication of when the filter or something is going on and the vacuum gets too high and could leave you stranded. Fatmobile has a writeup on adding these.

[dirtroad]

Thanks

Hopefully, I will have a chance to try those options this week sometime.

[dirtroad]

The fuel line between the IP and filter is clear. In this line I can see very tiny bubbles (imagine the size of the little bubbles in a bottle of Sprite) . Is the presence of these bubbles an indication of my problem or not enough to worry about?

[82vdub]

The little bubbles indicate that air is in the fuel system. Small little bubbles shouldn't cause the issue you're seeing though.

On the pusher pump, is it new, and what pressure and flow rates does it produce?

I had an aux electric pump installed on ole 82 years ago that started to fail (although I didn't know it), and it would create a fuel restriction in the fuel line and my incoming fuel would turn to foam and the car would die.

I would do a couple things. First, rig up a jar of fuel, an inline filter and connect that directly to the IP. Run it. If the problem doesn't happen when bottle fed, the problem is in the fuel system somewhere else. You're isolating components and using the divide and conquer method of troubleshooting. As of now, you're problem is the entire fuel system until you start to remove components from the list of potential causes. If the bottle method doesn't work, then you have an issue with the IP or return fuel system.

If the bottle trick works, then connect the bottle to another point in the system and troubleshoot from that point. Depending on the results, the problem will be either upstream of where you connected it, or downstream between where you last connected the line.

You may want to dig up fatmobile's thread on adding a pressure/vacuum gauge to your IP. If your electric fuel pump is operating correctly then the IP should have a little fuel pressure on the incoming line. If there's still a restriction somewhere, then the vacuum gauge will show a vacuum, and then you'll also have a better idea of what's going on.

[mogwopjr]

I had a problem with fuel starvation that mirrors the symptoms you've stated here. I took the opportunity to hook up the clear line and bottle feed a couple of cans of Diesel Purge straight into the IP. It drank both bottles and never stalled.

The problem was a clogged screen in the fuel tank.

Have you bottle fed the IP yet?

[dirtroad]

Diesel Bypass.jpg

Well I made a little progress today. I ran the lil' truck off of a bottle for about two hours and it never missed a beat. It ran excellent the entire time. So now I know my problem is between the tank and the IP. I think my next step will be to run a new fuel line from the tank to the IP and bypass everything inbetween.

82 VW truck.jpg

[TylerDurden]

Nice IV bottle.

You might want to keep a filter inline when using fuel from the tank.

[82vdub]

And nice truck!

[zman]

Just a though here but you need the hard plastic factory fuel line from the filter to the pump . It may work perfect with a short soft hose from an IV bottle but as soon as you try and draw fuel through 10 feet of 1/4 inch fuel line plus filters and screens it will collapse a lesser hose.

[dirtroad]

Well, I think I've gotten all the bugs worked out of it. Seems to be running just fine now. It will probably be after Christmas before I can drive it enough to know for sure, but I've got a good feeling about it.

Now I need to find a latch for the sliding back glass. Anybody got one that they would part with?

[Josh]

I'll try to keep an eye out for a latch for you. I can probably snag one cheap from a junker if it's still there.