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Discussion Starter · #1 ·
howdy Folks:

i am a new member to the board and to this truck - quick background -
85 Blazer 4x4 - dual tanks ( the waste oil is disconnected at present)

previous owner retro fitted a 6.2 or 6.5 ( that is what the sticker on drivers valve cover reads ) - the fuel filter is a square Stanadyne - just like the 6.2

I have read High Sierra's post - yet as a new one here - fotos would be of great help to me - also cause this has a conversion to waste oil so things are not quite stock or in place

truck just quit running - I figure I have a leak some where - air must be getting in as I had racing and sputtering about a month ago when I first purchased the truck - and its jacked up all to hell - practically have to high jump up to get in the cabin- by the way the waste oil system is not functioning right now

so I changed out the fuel filter to see if the problem was simple - as it bounces alot - I get no fuel to the injector line no.5 cyl- figure I would try the remove air from fuel system write up - but i'm lost


the return line to IP - the rubber line ( as you look down to injector pump centre , close to where IP mounts to IP timing chain housing - on top - is this the return line from the injectors that has a TEE - connects to hard lines that runs to injector no 1 ( drivers side cylinder front/ first ) ?

And outlet side of fuel filter - is this the line ( mine is soft fuel line / probably due to conversion) on passengers side of fuel filter almost top of filter housing

thanks for letting me start there and hopefully my expaination makes sense
 

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I ve got an 85 shortbed dual tank 4x4 6.2 Bought /ordered new.
I suggest you try to get a manual through helms for your truck.
You can try helms , the original GM supplier , or Ebay or Hemmings Magazine.
My truck and truck cover frozen in snow, so cann't go look to give much of an answer . Where you from ?
 

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Discussion Starter · #3 ·
howdy ctgmcduramax:

cheers thanks for the reply :

I am in the Phoenix valley - truck was purchased in Atlanta GA area - but the truck originally was petrol - so they guy I bought it from retro'd the oil motor - but like I said - says 6.5 on the valve cover but the filter is square - which i am pretty sure means it's a 6.2

I'll be running the motor i.d. no first thing tomorrow with the stealer( ship )
as soon as I figure out what motor I have I'll get a book
thanks for the offer

cheers
 

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Welcome to the forum! :welcome:

Since this is a retrofitted engine with a waste oil conversion there is no way of telling exactly what you've got. I am sure many of the little things on the truck are not stock.

You could have just about any kind of fuel filter on that truck... It sounds like you've probably got a filter off of a late '80s truck with a 6.2, but there are all kinds of different filters it might have. Since it has been converted to run on WVO it probably has at least one aftermarket filter on it.

I'm going to say what you've probably got in there is actually an early naturally aspirated 6.5. It doesn't make that much difference because the 6.2 and 6.5 are practically the same engine. There were minor differences, but they were pretty much the same.

If it would help I can take some pics of the engine in my truck (which is currently 99% stock) and label some of the important things, but it might actually be easier if you posted pictures of your setup... It may be vastly different from stock.

Hope this helps and welcome again! :)
 

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Discussion Starter · #5 ·
Howdy High Sierra:

Cheers thanks for the reply and for the post you wrote.

I did some checking up today and think perhaps I do have a factory rebuilt 6.5 NA - as they came with a 6.2 fuel system - never stop learning something new -

As for the Veggie oil system - I think the only thing really different with the fuel lines has been some hard lines ( The output line from the fuel filter perhaps ) were made soft lines to accomodate the fuel line switch valve
and the main fuel pump is electric

I'll take some fotos and post them tomorrow - and tomorrow I hope to know more about this engine from the dealer - though I think the No. I took off the engine may just be the i.d. no. for the intake manifold.

As for my original post here - am I correct on the soft line on top of the IP( close to the mounting housing / IP timing gear ) being what you know as the return line ?

And then also the outlet side of the fuel filter being passenger side top of filter housing - directly opposite vacuum line?

Cheers thanks again for your assist and welcoming

enjoy the week

Cheers
 

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Yes, the line on the injection pump is the return line. It should go onto a metal line about 8 inches after it comes out of the injection pump and then a few inches further down the return line should T and go down to the injectors.

I'm not sure what to say on the fuel filter... There shouldn't be a vacuum line to the filter (at least not with a stock filter). On the stock box-style filter setup there is an inlet line and an outlet line, both of which are on the upper driver's side of the filter if it is mounted in the same position as it was originally. There is a bleed valve which is on the upper passenger side and may or may not have a hose on it and there is a water drain valve which is on the lower driver's side of the fuel filter and also may or may not have a hose on it. Other than the electrical stuff (fuel heater, water in fuel warning light sensor, pressure sensor), that's all there is to it. I will take a picture of a stock filter setup as it was originally mounted and post it.

As for the Veggie oil system - I think the only thing really different with the fuel lines has been some hard lines ( The output line from the fuel filter perhaps ) were made soft lines to accomodate the fuel line switch valve
and the main fuel pump is electric
If those are the only modifications that have been made, the conversion isn't done. For a reliable, functional WVO setup you need to heat the WVO lines and tank. The problem I've found with running without line or tank heaters is the fuel will turn into grease at a pretty warm temperature and that doesn't do the fuel system any good. Others say the fuel needs to be plenty hot so it doesn't ruin the injection pump and I am inclined to believe this although I've never seen it happen myself. I ran WVO unheated for a little while and it worked fine but didn't work very well when it wasn't 80 degrees outside, but I didn't do it long enough to see if it would hurt the pump (didn't want to find out).

I'll take a few pics of a stock mid-'80s 6.2 and post them in a little bit. Some pics of your setup would really help... It is very difficult to tell what you've got without seeing it.

Hope this helps! :)
 

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Discussion Starter · #7 ·
howdy High Sierra:

here is what I took today - whilst looking for the i.d. no off the engine - which the parts counter guy at local dealer told me was of no use

I have more fotos - and will post them in the next message

Cheers
 

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Discussion Starter · #9 ·
Howdy Folks:

last one

Maybe these will help to tell what I am dealing with - I am thinking I have a DB2- 4911 IP as I dont see anything electronic
Dealer also told me the 6.5 was a turbo diesel - yet I dunno if I mentioned I found a web site that sells factory reman'd diesel engines - they offer a 6.5 for a " P" chassis - motor home or bread truck , that is 6.5 long block with 6.2 fuel system

to the foto of the fule filter - On top is a plastic screw - the convex cross pattern - Is this a bleed line - and the rubber line attached to that side - sure looks like a vacuum line

interesting to hear what y'all have to say about what I got

thanks in advance:

Cheers
 

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What you've got there appears to be a naturally aspirated 6.2 or 6.5 (probably a 6.5) out of a HD application. It appears to be a later model because of the location of the fuel filter. That is the same filter that was used on mid-'80s trucks, but they relocated it to mount on the back of the intake manifold somewhere around '90-'92. I can tell that whatever the engine came out of (or at least whatever the injection pump came off of) was equipped with a TH400 automatic because of the unused vacuum regulator valve mounted on the passenger side of the injection pump.

When they relocated the fuel filter assembly they turned it around. In other words, you are looking at the back of the filter when you look at the truck from the front. The hoses on the passenger side of the filter are indeed the inlet/outlet hoses. The vacuum hose on the driver's side isn't a vacuum hose at all... It's just a piece of vacuum hose somebody stuck on the air bleed valve. If you follow the line you will probably find that it doesn't go anywhere. Because the location of the fuel filter on the late model trucks makes access to the ordinary water drain valve at the bottom of the filter, they put a hose on there and relocated the water drain valve to the front right next to the injection pump. The drain valve is quite noticeable in the last picture you posted.

Come to think of it, I guess I didn't mention the fact that they relocated the filter on the late model trucks in my sticky. That would be confusing for anybody who had the fuel filter mounted on the intake... I guess I should add that information and maybe some pictures. The thread is locked already so I guess I will have to contact a mod and see if there is anything I can do about it...

The 6.5 did indeed come in a non-turbo version. Among other things it was commonly used in military Hummers, although it looks like yours is probably a civilian engine.

That could be any one of a whole bunch of injection pumps... Virtually any pump will fit that and there's a lot of different models of mechanical pump. On the side of the injection pump there should be a tag which has the number of the pump on it.

It looks to me like the previous owner did a pretty nice job with the WVO conversion. I'm not sure what's up with the colored fuel line, but it does look like it must have a fuel line heater of some sort, apparently a coolant heater. The way the heater hose splits shortly after exiting the crossover pipe tells me that it goes to more places than just the heater core...

Hope this helps! :)
 

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Discussion Starter · #11 ·
Howdy high Sierra:

thanks for the note :

I believe it has a coolant heater in the second tank /VO tank as well as a heated filter for the veg oil - and that one has already leaked

So basically since I have the 6.2 fuel system i should follow your " stickie " instructions but the outlet will be on the drivers side for me - yet all I see on the drivers side of that filter housing is the rubber line and the electric connections ( presume for that type heated fuel filter )

I did speak with the guy today who installed this engine - is a 2001 6.5 crate engine from GM - he just did not install the turbo- but the fuel system and all of the other components are from a 86 6.2 litre - fuel pump etc....

So I suppose I diagnosis this like I would a mid 8o's 6.2

if you have any other suggestions - please to let me know and i certainly will report back what i find tomorrow

Cheers
 

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you keep saying cheers so i would say an ausie or a euro

what stumped me is that you said phoenix if you are in phoenix az usa i can swing by and let you know what it is perty fast just have too pull one glow plug hook up my nifty lil air volume guage and we will give her a crank and see what she puts out in 1 rotation


git r dun yeee haw
 

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Wow. A crate engine from GM? That must have cost some serious $$$. Good engine, though... :cool2:

Yep, just follow the directions in the sticky. If you follow that piece of vacuum hose until it ends you will probably find that it doesn't go anywhere anyway... Just stick the end of the hose in a pop bottle while you are bleeding the system.
 

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Discussion Starter · #14 ·
Howdy folks:

i'll post what I find out - cheers thanks again for all your help

Howdy Goodtunes1978:

Cheers thanks for the offer - truck is in Lower Scottsdale/Tempe border - so I may take you up on your offer if you are close to the area
I am sure the engine is sound just a bit slopy in certain areas- mostly electrical - for right now I may just completely disconnect the Veggie system as its not operational right now and just deal with stock operations - at least to get the truck running

From speaking with the previous owner / installer - I wonder if it is as simple as the OPS or Lift Pump

Cheers - I lived cross the pond for a bit -
 

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sweet another hellizonan lmk when

yea i think i am about too go back over the pond lol i have about enough saved to live off the interest maybe another year too be on the safe side and get a nice weee lil engineering job over there in scottland or ireland we will see when that happens who knows maybe gb i miss it over there like nothing else but i was young when grandparents brought me too america ahhh oh well i will dream a bit more later

peace
 

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Discussion Starter · #16 ·
Howdy Folks:

was at it for a few hours today - cracked all hard lines to see what was up - as still not sure how to bleed this system - as the line on passanges side fuel filter is intake - anywho - nadda on the hard lines - checked the fuel cutoff solenoid / pink wire to IP - getting 11.4 volts and clicks when reattached
getting power to glow plugs

traced/ followed one red fuel line from switchover fuel valve down to lift pump - pulled to check stream pressure - nadda - so pretty sure that is problem - and from what i spoke with installer - this is mechanical lift pump - So I figure I will just replace with mechanical to be safe

High Sierra - what do you think on putting an electronic lift pump inplace - i would have to relay it and also get power to it - not sure this is worth the effort

also - just how does OPS switch effect the mechanical pump - or does it just effect the fuel cuttoff on IP

Howdy goodtunes1978: jump over the pond for you eh.... best to ya matey - for me there is little better on te eyes than English Countryside - could not live in London again - i'm farm raised and seek peace and quiet now - 'cept for the purr of a fine tuned diesel - love that sound

Cheers y'aal for your shared wisdom
 

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Howdy Folks:

was at it for a few hours today - cracked all hard lines to see what was up - as still not sure how to bleed this system - as the line on passanges side fuel filter is intake - anywho - nadda on the hard lines - checked the fuel cutoff solenoid / pink wire to IP - getting 11.4 volts and clicks when reattached
getting power to glow plugs

traced/ followed one red fuel line from switchover fuel valve down to lift pump - pulled to check stream pressure - nadda - so pretty sure that is problem - and from what i spoke with installer - this is mechanical lift pump - So I figure I will just replace with mechanical to be safe

High Sierra - what do you think on putting an electronic lift pump inplace - i would have to relay it and also get power to it - not sure this is worth the effort

also - just how does OPS switch effect the mechanical pump - or does it just effect the fuel cuttoff on IP
Here's how the standard section of the fuel system is set up. Yours should be about the same... Only the location of the components will vary unless you have an electric lift pump. I won't get into the return system.

From the pickup in the fuel tank the fuel line runs to the tank switch. From there a line should go to the lift pump. From the lift pump a line goes to the fuel filter. From the fuel filter a line goes to the injection pump. Simple, really...

Basically, what you need to do is make sure there is no air in any part of that system. The simplest way I know of to accomplish this is by pressurizing the fuel tank and opening the system somewhere close to the injection pump (as you probably know if you've read the sticky I wrote). This allows all the air to be pushed out of the lines by the pressurized fuel which fills the lines. Without pulling the intake you can't really bleed the system right to the injection pump, so the fuel filter is the logical place. That's what the bleed valve is for. You pressurize the fuel tank somehow and open the bleed valve until fuel comes out. Then you close the valve so that air can't enter the lines when you remove the pressure. Since you can't bleed the lines right up to the injection pump you have to use cranking alone to push the last bit of air out of the lines.

You don't need to crack the injector lines. Once you get fuel to the injection pump everything else is taken care of automatically.

Does that clear things up a bit on how to bleed the system out? If not, are there any specific questions you have about bleeding the system?


This may sound like a stupid question, but what is an OPS?

I wouldn't bother with the electric lift pump. To me it isn't worth the effort. Some people have done that and love it... Personally, I don't think it doesn't make much difference so it's just extra work as far as I am concerned.
 

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Discussion Starter · #18 ·
Howdy High Sierra/ Folks :

Ok - OPS - oil pressure sensor ( I think ) - perhaps I am a tad confused breathing in all this diesel and also working a 7.3 Navistar

Finally got it running today - after figuring out all the electrical bugs - no.3 glow plug gets no juice - now this has a manual glow plug switch - remember this is a 6.5/6.2 slip in engine

Did wire teh correct switch to the POLLAK switch over valve - toggle DTDP - dual throw , dual position

after cracking all the lines and cranking for a while - finally saw fuel coming thru the hard lines - put a clear line onto the " Tee" handle - the return line and opened - no bubbles - Say , what position is that tee to be in - mine is always closed tight - open just to bleed the line - am I correct ?

returned the rubber line ( black ) - hit the glow plug for 10 seconds - fired right up

thanks y'all for all the assistence / taking the time with me

Cheers
 

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Roy, "Sierra" is exactly right about the bleeder valve with the "vacuum hose" attached to it. I have a '87 military CUCV, which has two trays for some special-order military batteries, so there's room for a 750 ml rum bottle to sit in the after battery tray along with a group 27 battery. With the bleeder hose stuck into the rum bottle, it simplifies bleeding air out of the filter.
Which is necessary, because the bleeder screw is leaky. If you take the bleeder screw all the way out, you'll notice that the seal is a special little rubber plunger on the bottom of the screw, which must seat in an orifice down at the bottom. In any event, I think my plunger has gotten flattened out over the years, and doesn't seal so well anymore. I was at the GM dealer today, and the parts guy said that the bleeder screw and/or seal is not available. I'm hoping they're still available on the aftermarket.
 
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