6.5 Turbo Fuel System Diagrams (and advice)needed

[CptTrog]

Hello, all. My Suburban's front end fuel system is in dire need of an overhaul. I was replacing the cooling system's thermostat and literally 'broke' the rubber fuel line connected to the small T-valve by simply moving it during the process! Quickly came to the realization that every rubber hose on top of the engine is dry-rotted beyond belief. Touch them and they break. I now have a pool of very expensive diesel under the intake and truck out of service.:mad2:
I've checked the site and found a number of schematics but nothing on the overall fuel line layout on top of the engine. [http://www.compnine.com/index.php?t...K&makecode=LG&grouptype=B&modelid=6934&uid=1]

It appears to be clear I'll need to remove the intake manifold to do the line replacements. Especially those two running to/from the fuel manager (filter) housing. There is just no easy way to get at them otherwise.
Any advice and or a pointer to a fuel line layout would be tremendously appreciated. I DO NOT want to get this wrong!
Thanks!

 

[ak diesel driver]

There is only 2 fuel lines under there one from the filter manager to the drain (which you broke) the other goes from filter manager to the IP. Assuming they aren't to brittle you can use the old lines to pull the new ones thru without pulling manifold. It would probably help to unbolt the filter manager to gain a little better access.

 

[CptTrog]

I've considered what you suggest about using the old lines to thread new one. Very good idea. And unbolting the FM was something I hadn't thought of. Thanks!
However, the line on the left of the fuel manager (on the left looking down on the housing) must be the one you state leads to the IP. Thing is, I've tried to trace it visually and can't see how it's routed. It disappears beneath the intake manifold. Does it run through any bends or kinks where I'm likely to get hung up? The lines are in such rotten shape, I'm certain it will break without only a minimum of pressure if I pull on them.
Thanks again!

 

[ak diesel driver]

IIRC there are a couple of clip under the manifold at the back. You should be able to feel them and disconnect it by feel

 

[JiFaire]

And there are no other fuel lines under there... if it breaks when you pull it (to snake the new one through), then you might have to pull the intake... but you shouldn't need to if it doesn't break.

Personally, I'd pill the intake just to check everything else out - it's a good chance to clean things up, to check on the status of other things (wiring harnesses, OPS, etc), a good opportunity to do the Feed-the-beast mod, and a great opportunity to pull the intake plenum off and clear out the restriction (lots of 94's had webbing in the plenum, even if they were an F engine - cleaning that out really helps with your airflow)

Just a few sort of random thoughts... we can help with all those ideas, and have pictures of most things, should you want to do more while you're in there.

Jim

 

[Woody35]

plus you can clean out the carbon buildup

 

[CptTrog]

Pulling the intake to check out the other items was the second reason I had for pulling it at all. With the condition the rubber lines are in, no telling what else I might find under there.
The 'Feed the Beast' mod looks like an easily doable thing. Got all the tools and even a drill press (and hopefully the skills) needed to make the changes.
Any links to pics on areas I should clean up as suggested by Jim and Woody would be appreciated.
Now, if I can get 'Maxine' pushed into the garage, I can get started! It's in the 20's outside right now! Shade tree is NOT the place to start this project!
Thanks for the advice so far, folks.

 

[buddy]

You might confuse some people calling your 6.5TD a Duramax Since the Duramax was GM's follow on Direct Injection common rail diesel engine.

You are on the right track, changing those is a great idea. Little air or fuel leaks can cause so many confusing diagnosing issues, when its just a brittle fuel line in death valley.

FTB is great idea too, HERE IS SOME INFO ON IT

Walking J Designs sell only steel fitting I could find for the IP.

 

[CptTrog]

You might confuse some people calling your 6.5TD a Duramax Since the Duramax was GM's follow on Direct Injection common rail diesel engine.

Reckon you're right about that, amigo. Calling it what a greasemonkey friend thought it was. I suppose 6.5TD [Turbo Diesel] would be more accurate, eh?

 

[JiFaire]

There ya go... your 6.5TD thanks you!

 

[buddy]

Reckon you're right about that, amigo. Calling it what a greasemonkey friend thought it was. I suppose 6.5TD [Turbo Diesel] would be more accurate, eh?

Yeah, the 6.5TD is Indirect Injection with mechanical nozzles (injectors) fed by the distrubtion Injection Pump.

The 94-2000 6.5TDs have a unique electronic injection pump, that helped raise injection pressures and meter fuel and timing better, but still nowhere near the potential of Direct Injection Common Rail with electric solenoid injectors.

 

[CptTrog]

Several discoveries tonight in the removal of the intake manifold and fuel filter/manager:
1. THANK GOD for 18 year old mechs in trade school! I lasted all of 10 minutes folded up on top of this beast!
2. I now know why it's called the valley of death. The designer(s) had to be an Italian masochist. Looks like a big bowl of spaghetti under there!
3. Speaking of noodles, there are two tiny lines that broke up just like noodles when we moved them. One runs over to the bottom of the turbo. The other to the vacuum pump(?) under the AC compressor. Literally crumbled in my hands.
4. Dry-rotted rubber hose will hang on to a metal line or barb better than JB Weld could ever do. Had to whittle everything off with a box cutter.
5. If I get this thing back together and it actually runs, I may have to head to church.
6. Jim said "...pull the intake plenum off and clear out the restriction (lots of 94's had webbing in the plenum." I don't see anything like that in the manifold. Looks wide open to me.
7. Missing bolts in the top of the intake, bad vacuum lines, leaking fuel hoses, it's a wonder Maxine cranked and ran at all.... and didn't go up in a ball of flame!! If she does run, I'm betting I'll at least double our mileage!

Wish me luck, fellas. I'm about 40% there! (wishful thinking)

 

[CptTrog]

Broke down tonite and got the proper Chilton's manual and found that the previous owner removed the EGR valve and MAP sensor plus their solenoids. This would of course explain at least two of the open bolt holes in the top of the upper intake. Got plenty of extra air flow there, eh?
Question 1: how critical are these items (valve, sensor and solenoids - not the bolts) to engine performance? (question may not apply in the state of CA.)
Question 2: the TINY vacuum lines coming from the turbo and vac pump are too brittle to reuse and finding lines that small are proving very difficult. Is there a problem with using larger diameter hose (3/16" I.D.)for this? I'm also considering routing away from heat sources.
Thanks, folks.

 

[buddy]

In your 94 Sub, you need both the boost sensor on the intake and an IAT sensor, then on the drivers side firewall there needs to be another "MAP" that is a barometer, that was hooked up to the vacuum lines for EGR as a vacuum sensor. If PCM programming is changed to remove EGR, the vacuum line can be pulled off the barometer, but its still used as a barometer, so it has to stay there electrically.

In a sub though very few were even eqiupped with EGR, most all had "F" engines. Does it even have the 2 EGR solenoids on drivers side valve cover, next to the boost solenoid?

The vac lines, use anything you can find, doesnt matter the size or routing, as long as vacuum goes into turbo solenioid and then from solenoid to wastegate actuator.

All of the sensors are important, the EGR can go.

 

[CptTrog]

If PCM programming is changed to remove EGR, the vacuum line can be pulled off the barometer, but its still used as a barometer, so it has to stay there electrically.

No way for me to know if any programming was changed. I'm inclined to believe it was at some point due to the custom straight pipes the exhaust now sports past the exhaust manifolds

In a sub though very few were even eqiupped with EGR, most all had "F" engines. Does it even have the 2 EGR solenoids on drivers side valve cover, next to the boost solenoid?

NOPE. Just the one with lines over to the Turbo and Vac pump.

The vac lines, use anything you can find, doesnt matter the size or routing, as long as vacuum goes into turbo solenioid and then from solenoid to wastegate actuator.

Looking at the solenoid with the ports facing me, can I tell which port is which? Right - Vac pump, Left - Turbo?

All of the sensors are important, the EGR can go.

The only sensor I've been able to identify with 100% confidence is the one sitting on top of the upper intake. Small black box about matchbox size held on with 2 1/4" screws. Plug with rubber skirt protudes down into the intake. It appears remaining sensors may be MIA.

 

[JMJNet]

You can eliminate the vacuum system that controls the turbo by putting mechanical waste gate actuator aka TurboMaster (TM). You can make it yourself or buy one from Heath Diesel.

Some people replace it with regular rubber vacuum line.

I crumpled my vacuum lines yesterday trying to fix the coolant crossover leak. Good thing I have put the TM 3 months ago so I would not worry about it.

 

[buddy]

looking at the ports left goes to turbo, right goes to pump. although it really doesnt matter there is no check valve that i know of.

you must be missing the IAT sesnor. the black box is the boost sensor. there should also be a similar black box on drivers side firewall that is barometer.

 

[CptTrog]

Looked up that TM from Heath (http://www.heathdiesel.com/T/Chevy-GM/Chevy-9495/Turbocharger-Boost-Controllers/) Is this the right one?
I'd happily get rid of the Vac Pump if I can.
BTW, cleaning up the heads last night, I found what appears to be a 3" long 3/4" wide line clip with "HASCO" inside a diamond stamped on it lodged inside the #1 cylinder intake port. The bolt hole end had been "chewed off" most likely by the valve. Had to work hard to pull it out of there. I'll need to do a compression check of that (and all) cylinders to see if I have any major damage. No noticable miss when it's running so I'm hopefull the valve is okay.
Not doing the 'Feed the Beast' mod at this time. Just want to get her back motoring. Got the intake back on and torqued down, fuel and vacuum lines replaced. Putting the top on tomorrow.
That missing sensor, Buddy. Would it have been connected to a 3 prong wire connector coming off the FI? Got an extra down there that has no female partner that I can locate. Maybe would have connected to the MIA EGR??

 

[buddy]

3 prong wire harness, did you mean down by the Injection Pump (IP)? That would be the Crank Position Sesnor (CPS), an important one. Its down on the side of the timing cover by the crankshaft.

Other 3 prong sensors are the boost sensor, baro sensor.

The Intake Air Temp (IAT) would be a two prong harness, just like the Coolant Temp Sensor (CTS) on the themostat housing crossover.

 

[CptTrog]

3 prong wire harness, did you mean down by the Injection Pump (IP)? That would be the Crank Position Sesnor (CPS), an important one. Its down on the side of the timing cover by the crankshaft.

Other 3 prong sensors are the boost sensor, baro sensor.

The Intake Air Temp (IAT) would be a two prong harness, just like the Coolant Temp Sensor (CTS) on the themostat housing crossover.

Yup. 3 prong coming up in the jumble of small looms by the IP. All 3 ends are busted to heck and I'm not finding the female partner for it. Gonna have to get into the Chilton's manual and find the complete diagram for all of this. Of course, it's never to scale and there are never purty pitchers to help me physically locate matching connectors, but it beats nothing!
Thanks, Buddy. Off to a paying gig with my lil' rock-n-roll band
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