Injector Return Line Pressureising ang Blowing off.

[Sorro71]

I'm having trouble with the injector return lines blowing off. I'm going to start at one end and see where the blockage is. My question is, if I have to. Can I bypass the small hockey stick shaped steel line that runs from the injector pump to the back of the engine on your drivers side, between the inlet manifold and the rocker cover. The one that has those dreaded olives that connect to the brass solenoid at the back of the engine. it then returns to the tanks via the selector valve. You can see the back part of it in the attached picture on the far right. its the brass fitting with a hose in that convoluted tubing, running from it then under the CDR can and over the injectors on the other side. I've hardly driven it in six months so I guess some things have become stuck / gummed up.

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[Sorro71]

Here's a better picture

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[towcat]

fuel switching valve is suspect. gasser/ diesel the same as long as they look the same externally.

 

[MTKirk]

You're on the right track, try to remove the fuel line down stream of the tee where the injector return connect with the tank return (up near the firewall, it's a treat!). Run a long piece of hose from here into a fuel can. Then fire it up & see what happens!

 

[IDIoit]

i delete this line on my engines.
replace the olive fitting with a barbed fitting,
run it to #2 cylinder return 2 way plastic nipple
get a 3 way T with barbed fittings in the rear, and delete this line all together.
makes it way easier to time also.

im with Calvin, suspect switch valve.
you cant clog this line by itself, filtered fuel runs through it.
if your fuel is alge'd up, you would be seeing it in the filter, IP and injectors.

only other thing i can think of is a kinked line.

impossible for shower head pieces to reverberate into the return line

 

[Sorro71]

Thanks guys, I'll be sure to take a jerry can, a few meters of fuel hose along with some barbed fittings, clamps, filters etc. Hope its not the selector valve but ,knowing my luck of late it will be that and more. I was worried about the solenoid at the back of that steel line near the fire wall and what affect it would have bypassing it. Thanks IDIot sounds like bypassing wont cause problems.
I only run it on diesel and always put an additive in it at each fill up. Never say never but, algae shouldn't be the problem.

 

[typ4]

Solenoid? Steel line goes to a tee then to tank valve.

 

[icanfixall]

I thought I saw a solenoid back there on the return line. Who installed that??? My best thing to say is get rid of it. You are the first engine I have seen a solenoid valve on the return lines. there is no need for this because the return fuel flows by gravity back to the tanks thru the tank switching valve. You set the valve to draw off the rear tank and the return goes to the rear tank thru the valve. You never did tell us where the return lines were "blowing off". Honestly I'm surprised the engine ran with no return flow back to tanks. When return flow becomes pressurized internally the injection pump becomes pressurized in all the wrong places. then the engine shuts down.

 

[Sorro71]

I'm in and out of reception at the moment. I'll post a picture of it when I get home in a couple hours

 

[Sorro71]

Guys, here's a couple of better pictures of the solenoid I've been referring to. These are from when I rebuilt the engine a while back. This solenoid was on it when I bought the truck a couple of years ago I think I've fixed the problem, my younger brother has had the truck for a couple of weeks, He lives about 2 hours drive hours south of me. When I got down there to pick the truck up we found the tank breathers with the rollover valves were both blocked with mud and the tanks had built up some pressure in them. So I cleaned the plastic rollover valves and put some new hose on them and reused the original caps, I renew the caps as soon as I get a chance. I then disconnected the return lines at the tank and checked to see if the fuel was flowing back to the tank. Both were working well. I drove the truck back home on Friday night and haven't had any more problems. I guess time will tell if I fixed it. Gary the return lines were blowing off the plastic caps on the injectors.

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Thanks for all the advice Guys It really makes tackling these issues a whole lot easier

 

[OLDBULL8]

That return steel line looks like a unique set up of some kind to me.

Doesn't that rubber line off the top of the IP go to #2 injector cap?

What is that thing that the steel line with the solenoid on the end is attached too?

 

[IDIoit]

if you have an issue again, may want to explore a single rear tank mod!

 

[icanfixall]

Thanks for the great update on the issues and how you fixed it. There is really no reason for the solenoid valve on the end of the steel line located near number 8 cylinder. As I posted.. The return flow is gravity flow back to tanks. No need for any valve in that line. Inside the tanks at the very end of the returns is what many call a duck bill valve. Fluid flows thru them by gravity. Many boats have this type of bilge drain valve.
Now about removing the steel return line running down the side of the intake manifold like you asked.. Yes that can be done and most later engines do not have this line. My 89 had it but I removed it when I changed ALL the return line fittings to the larger size. You appear to have the smaller lines. the green clamps are the small and the red clamps are the large. You can't run both types on the same return system either.. To remove the steel line you must direct the return flow from the top of the injection pump to the number 2 return line at the injector. I also noticed you are missing a injector hard line vibration damper on the drivers side. Best replace it because running without these clamps will cause the hard lines to crack and leak horribly. Has happened to me but only once. It made a huge mess everywhere. Fuel was squirting every place under the hood and engine.

 

[Sorro71]

That return steel line looks like a unique set up of some kind to me.

Doesn't that rubber line off the top of the IP go to #2 injector cap?

What is that thing that the steel line with the solenoid on the end is attached too?

If I remember correctly there's a brass fitting with two barbs where the returns from the injectors attach too. Then the solenoid and then a brass elbow that a rubber line attaches to and runs back to the selector valve. I went through my files this morning and found these pictures. All the rubber dampers are back on the injector lines, the PO must of taken it off. I found it in one of the door side pockets IDIot since mines a tray back I was looking at keeping two tanks but making them bigger. Once you get off the coast here, you really want to be able to get a 1000km between fill ups

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[franklin2]

I bet the solenoid was added to combat air intrusion in the system. It would keep the fuel from draining back to the tank as the air leaked into the system.