injector return line repair... HELP!

[brianblack138]

I've got a 1994 K1500 with a 6.5L TD and i've got a bit of a fuel leak. Seems to me that it is most likely an injector return line on the #6 or #8 cylinder that has popped off. I'm going to have to remove the turbo and possibly the manifold as well to get to this thing... does anybody know the part numbers (or where I can find them) of the gaskets i'll need to reattach everything? Any advice on an easier way of doing this? I'm really trying to fix this by saturday so I can haul a moving trailer, so i'm in a time crunch and wondering if I could find the gaskets at a local napa/autozone or if they are more exotic.

[ronniejoe]

Any turbo overhaul shop will have the metal gasket for the turbo flange and the paper gasket for the oil return. The manifold does not need a gasket against the head.

[Turbo Al]

If I remember correctly all you need to do is remove the inner fender, the turbo heat shield, pull the wiring harness off the fire wall. Then you should have enough room to see and work on the rubber return lines --- #8 is a real bitch to work on because it is almost touching the fire wall. There is a kit avaliable that has a complete set of the rubber return lines.
Al

[brianblack138]

Ok, I got the kit from kennedy and it's being shipped overnight. It should have the gaskets I need in it as well as the no-clamp return lines. I'm going to try and do this myself (theres a first for everything, right?). I know what the turbo heat shield is, but what do you mean by the fender? (or are you talking about the grey plastic turbo power thing, because I removed that a long time ago)

[tommac95]

You need unscrew a couple hex-head sheetmetal screws securing the (originally plated) steel sheet turbo radiation heat shield to the bracket on the psgr side valve cover [flex/unbend & lift off slots; wear gloves to avoid bloodletting].
That might do it, but probably also need (access #8 injector fr below) to:
Remove the rubber (neoprene?) composition sheet which covers/seals the fender-to-frame gap, preventing puddle-water and road trash from entering engine compartment . Access here is thru tire/wheel fender well ; plastic trim pins/studs need pulled from hole in sheets .

[Turbo Al]

Yes remove the inner fender well and you can get a good look at what you are up to and probabaly do #6 return line through there. #8 I did through the top and it was not easy. But hey I have BIG HANDS LOL
Best of luck
Al

[brianblack138]

Ok, I got the return lines from UPS waiting for me when I get home. I'll pull the fender off and see if I can tell for sure whether it is the #6 or #8 line (or the cap at the end!) that is leaking. I'll take off the turbo heat shield and make my girlfriend stick her hands in there and do it if mine won't fit :)

[ronniejoe]

I hope by "fender well" you are actually meaning the composite splash shield that is held to the metal fender well with plastic push retainers. There is no need to remove the metal fender well to do this job.

The turbo must come off, then the heat shields that have been mentioned before. That's it.

Good luck.

[brianblack138]

That is correct. I'll remove the splash guards and the turbo heat shield. I'm going to try to avoid removing the turbo or anything else if I don't have to. Right now i'm just focusing on locating and replacing the line that is leaking. When I have a bit more time i'll replace the lines on the other side of the engine as well. I need to truck up from DC to baltimore, pick up a 15x12 ft. trailer full of furniture and haul it up to a storage unit in west virginia. So if I can make it through that, then i'll have a lot more time to tinker with things. The leak seems to have gone away (or at least it is hard to distinguish because of the AC condensation) but I know that these things can vary depending on fuel pressure and temperature and whatnot. It's probably just a little split that sprays fuel right onto the hot downpipe of the exhaust and thats what is causing the smoke and the exhaust smell. I might try pinching the return hose that goes to the tank a bit to see if I can force more fuel to leak out at the hole so I can see it.

[ronniejoe]

I doubt that you will be able to remove the heat shields without removing the turbo. I tried once, and was unsuccessful.

[Bnave95]

I doubt that you will be able to remove the heat shields without removing the turbo. I tried once, and was unsuccessful.
Years ago I installed JK high flow inj. and line kit. Did not need to remove turbo and was able to remove heat shield. May have been EZ'er had I remove turbo. Still a doable job. (your hand's RJ were to big:D)

[brianblack138]

Looks like you're right Ronnie... I couldn't remove the heatshield (I must have big hands)

Basically the story is this... I added a second fuel tank and 2 3-way valves so that I can switch tanks/return lines with the flip of a switch. On the stock tank, my pressure at the ip is 4psi (from the lift pump) and I get no leaks. When I flip the switch, my pressure at the ip is still 4psi (from an electric lift pump I installed on the second tank system) and i get leaks that seem to be coming from the return lines at the #6 or #8 injector. (I say "seem to be coming from" because i still haven't been able to see them with my own eyes, all i can see is the dripping and hitting the hot exhaust and causing smoke).

I drove about 250 miles this weekend on the stock fuel system and it worked fine, switched over to the aux tank and i get leaks and air in the line...

I tried to remove the heat shield, but no luck. My questions are such...

1) do you guys think it really is likely the injector return lines leaking? (I'm thinking it is because of the air in the line and because I think I had a pinched return line to the tank that caused one of the hoses to pop off, but if thats the case, why isn't it leaking when i'm running on my stock tank?)

2) should I remove the turbo or the fender to get in there? which is an easier removal for a relative newbie?

3) anybody know of any good mechanics in the DC/VA/MD area in case I screw this thing up :)

The auxilliary tank was a custom job I put in myself to do a vegetable oil conversion, and everything ran fine until I had that build up of pressure due to the restricted return hose. Thats why i'm thinking i must have popped a split in the injector return hose. I'm just perplexed why it only leaks on the one fuel system and not from the stock tank.

[DmaxMaverick]

If you have a restricted/blocked return line to the aux. tank, that could explain a lot. Same as if you have a leak in your supply line from the aux. tank, but that shouldn't cause a leak near the engine. At what point do the two fuel tanks/lines merge to supply the IP with fuel, and provide a return to the correct tank? If you have a "popped off" return line or plug, it would leak with either fuel tank selected. It could be you have a crack, or sloppy connection in your return line, which would allow leak free operation with an open return, and a leak with a restricted/blocked return.

If one tank works fine, and the other has issues, the problem would have to be between the merger point and the respective tank. I don't see how a blocked return line could allow an air leak, so there may be more than one issue at work.

How is the fuel pump power switched? Are both pumps working at any one time? Another possibility could be back pressure from the "offline" fuel tank, overwhelming the fuel return line.

At least you have one working system to use until you get the issues worked out.

[brianblack138]

Dmax: The fuel systems never merge. I have a seperate filter/lift pump for each. They connect to a 3 port solenoid switch before the IP and then go through a glass sight tube/inline filter into the IP. I connected the return line to another 3 way solenoid switch so that flipping a switch powers both of them, this switches the tank to auxilliary, switches the lift pump and switches the return line to run from the stock tank to the aux tank.

I'll check the return hose to the aux tank and make sure that it isn't pinched or obstructed. This would make a lot of sense...

[john8662]

Small hands here too, got the heat shield off back in the days of the '95 burb w/o removing the turbo. It's not fun, but at least I didn't have to go to the dealer for another oil drain gasket or have a helper hold the downpipe up while I secured it to the turbo outlet.

Helpers are expensive these days, they always want something to eat :eek:

[Robyn]

The heat shield will come out without removing the turbo.
You should be able to access the return lines without removing the manifold.
Its a tad bit of a witch but doable. The work is all from the top not from the side as all the stuff you need to get to is between the valve cover and the turbo. Patience and time will get you through.
Robyn

[brianblack138]

So i'm beginning to think it might not be the injector return lines, because it only leaks when I switch to my auxilliary tank... now i'm thinking that maybe the return hose on that aux. tank is somehow plugged. I checked it for kinks last night but couldn't see any or feel any. I pulled the hose out of the tank and ran the truck on the main tank flipping over to the aux tank for a few seconds at a time (any longer than that and the truck stalls out) and no fuel came out of the return line, which boosts my theory that the return is somehow plugged. I still can't figure out how air would be getting in the line though (and why the air only gets in the line when i switch to my aux tank!)...

[DmaxMaverick]

So i'm beginning to think it might not be the injector return lines, because it only leaks when I switch to my auxilliary tank... now i'm thinking that maybe the return hose on that aux. tank is somehow plugged. I checked it for kinks last night but couldn't see any or feel any. I pulled the hose out of the tank and ran the truck on the main tank flipping over to the aux tank for a few seconds at a time (any longer than that and the truck stalls out) and no fuel came out of the return line, which boosts my theory that the return is somehow plugged. I still can't figure out how air would be getting in the line though (and why the air only gets in the line when i switch to my aux tank!)...

With that in mind, I'd first suspect your switching valve (aux) is either poorly connected, connected wrong, or isn't switching full throw. If the valves are identical or compatible, try swapping them, and try again. Like said before, a return line blockage shouldn't cause a suction air leak. A piece of you puzzle is missing.

[MTTwister]

It's the "Mud" Flap on the inside of the fender well, around the suspension A-ARm that you would need to remove - @ 6 plastic push pins. No unbolting required for that step. Edit - and obviously the front wheel for working room. OK - & use a Jack Stand ( safety disclaimer.:) )

Does sound like somethings flakey on the aux tank plumbing.

[brianblack138]

I figured the first thing I would do is disconnect the return line and verify that the 3 way valve is switching over and actually letting fuel come out the port (should be able to hook a 2 ft. length of hose to it and sit it in a bucket, switch over and see if fuel is returning to the bucket) if that fixes the leak, then i know there is an obstruction in the return hose somewhere under the truck on the way back to the tank. After that, I'll blow air through the return hose to make sure that there isn't any blockage. If the fuel isn't coming out of the valve properly, i'll recheck all of the electrical connections (although even if it doesn't switch, it would just default to the open port, which could cause veg oil to return to the main tank, but wouldn't cause a pressure build up or a leak)
The aux tank is vented through the cap, so there is no pressure there.

I'll see if I can try and fit my hand in again. Maybe i'll just have to jack it up higher to get some more clearance, I didn't lift it too high the first time I tried.

Before long i'll replace the glowplugs and injectors, so even if I don't do it all now, i'll get to it.

Thanks for all the advice, I agree that there has to be a missing piece of the puzzle. It's probably something really simple that will make me kick myself when I find it, but I know it's out there...

[DmaxMaverick]

....It's probably something really simple that will make me kick myself when I find it, but I know it's out there...

That's the answer 90% of the time. Unfortunately, the times we check that stuff first, leaves the remaining 10%.

[brianblack138]

Tonight I came home and disconnected the aux. return line from that 3 way valve and ran a hose to a bucket. Started up on my main tank (ran fine as expected) switched to my aux tank and lo and behold, nothing came through the 3 way valve into the bucket, so it looks like a problem with the 3 way valve is causing it to not switch all the way over and that causes a pressure build up and the related leaking. I'll pull that valve tomorrow and blow some air through it, apply 12v to see if it switches, etc. I bought them both from greasecar.com and they are pretty good with customer service so i'll shoot them an email. I'm wondering if the heat killed it. I have it mounted right on my manifold (bolted to one of the bolt holes where the "turbo power" engine cover used to screw down into. Shouldn't be THAT hot though... otherwise it would melt the plastic "turbo power" cover.

[brianblack138]

Pulled the return 3 way valve, blew air through it on "default" and it worked fine, but when i applied 12v to it, it didn't open the other port all the way, blew air through it, and it wouldn't go. This is obviously causing a pressure build up and leaking. A new 50 dollar part and i'll be good to go.

[tommac95]

Brian--
Not to be chronic pia, but someone here posted description of the electrically operated fuel 3-way valves as 'very unreliable' .... just as a very late warning!

[brianblack138]

Well, I know this is a potentially unreliable part, especially when pumping hot vegetable oil through it. Fortunately the greasecar folks had custom made these valves to handle hot fuel and will be replacing this one free of charge. Do you know of any alternatives to electric 3 way valves? I'm open to any suggestions. If these things start failing every few months i'm obviously not going to stick with them.