help!! newbee

[wraith6.5]

ok i know you have heard it before but i have a knock it has been to 5 shops they all tell me 1500 to 3500 to fix it i have never worked on a diesel before.
but i can tear down gassers. its not fuel i went through changed (1) injector and replaced the fuel pump ill attch pic of old fuel pump later but it was duct and so 3/8 fuel line anyway i bought the tahoe with the knock i have been told its a piston (rod knock) and i have been told its not and to just pull the head and ill find the problem the knock is getting louder its coming from (#8) how hard is it to pull the pan and rering that one cylinder and put new berings if thats it i dont have the cash to pay someone to do this if any of you live in southern cal and feel like ya want to help me out feel free i have this weekend and the next to get it fixed. i have to move. its a 4x4 2dr tahoe.

 

[buddy]

Can you tell us more about your vehicle, its a Tahoe I gather. Is it an S or F engine any other modifications? Where is the PMD located?

Can you describe the knock, how loud, you can hear it in the cab when on the highway? Does it increase with RPM?

 

[wraith6.5]

the pmd is still in stock location(was replaced at 98k along with new IP i dont know weather it is an f or s code engine dont know where to look.as for the knock you can hear it in the cab, across the sreet its lound but it sounds more like a lifter to me but i just want more guidance.if i tear it down the motor has to stay in truck and i have one weekend maybe 2 to get it finished it wont fit in my garage and i live in a condo the hoa told me 2 weekends tops or they will tow it away as for mods i dont belive there is any but it does have a 3inch down pipe and 4inch straight pipe no muffler. turbo spools very well there is still lots of power even goining up hill .

 

[ak diesel driver]

If memory serves if its a rod bearing it will get quieter when you give it the gas and louder when you let off the gas. If its a main it will stay steady. I would change the injector first when one is sticking it sounds alot like a bearing going out.

 

[buddy]

Waht year is it? Does it have an EGR on top of the intake and did it have a catalytic converter before, which would be an S engine. The S or F is the 8th digit in the VIN. How many miles are on the truck now and were on it when you bought it? Any codes?

How do you know for sure it is cylinder 8?

 

[wraith6.5]

1996 its an (s) code no cat just straight pipe and it does have egr valve (obd2)as to the ? how do i know its #8 i started cracking all the fuel lines when i cracked eight the knocking stopped so i swaped out #1 injector with #8 knock seemed to follow to #1 so i bought a new injector knock came back i also replaced the gp in #8 as well knock is still there in #8 i have no smoke but i do have some blowby.i also have a sethiscope i really want it fixed but just cant aford to pay what shops want to charge me

 

[chevyinlinesix]

By the sounds of that description, injector. What kind (brand) of injector did you buy? I have read that "off brand" ones are known to fail, even if they are brand new.

Glad to hear it doesn't sound like a bottom end issue, in my opinion anyways.

 

[buddy]

Yes, the full story is good. When installing injector did you use the copper washer down first? Or remove the old one?

And we attribute just about every other ailment to the PMD if it still on the IP, so get that off of there ASAP. maybe its causing an imbalance. And you have no codes in it? No SES light?

Maybe the injector got fouled during install or something in the fuel line is fouling it, is the fuel line bent at all?

 

[Missy Good Wench]

If the knock goes away when you crack the injector line then its definately related to the firing on the particular cylinder.

If the noise returned to the same Hole #8 then I am suspect of a mechanical issue.

Ring are usually not suspect for "Knocking"

How is the oil pressure?? If the oil pressure is LOW as in 20 or less running at speed then I would suspect a rod.

If you have normal oil pressure then it couild be a piston with a broken skirt or a wrist pin bushing thats gone south.

Now with this sort of thing its probably not an issue to try and repair in the truck.

Personally at this point, if it were mine I would get the beast out of the truck, steam it off good and do a Post mortem on it (Carefully) and find out whats ailing it.

Getting the pan off one of these in the chassis is a nasty job and then getting it back on and sealed properly can be even more of a wretch.

If you can work on gassers, you can work on this little creature.

There is absolutely no difference mechanically.

IF you decide to remove the IP be sure and accurately scribe the pump and the timing housing so you can replace the pump exactly where you found it.

Mark the HP lines as to which cyl's the fed and keep them in the pairs that are in.
I usually use duct tape and write 2-4 or 1-3 depending on the locations

Cyls 1357 are LH side and 2468 are RH side

Cap the injectors and the IP ports to keep crap out.

Now with this said the rest is simple V8 engine tech.

A couple other areas to keep track of. All the pushrods have a marked end (Usually copper colored ball goes to rocker, look carefully as this is important due to hardness)

The head bolts are a throw away item once used (New ones are about $27 a set (1head)

The rods are not marked so stamp the cap and rod with the proper ### on the block side before removing the caps.

The little fire chamber (Ricardo Bowl) always goes to the lower side of the cylinder.

The engine has all metric fasteners and threads too (with a couple exceptions)
Some models reatained 3/8-16 for the bellhousing but yours should be metric 1996

Follow Listed torque procedures exactly when installing head bolts.
Be sure the new bolts have the dry sylicone sealer on them.
Dont use any other products on the bolts and the prefered gaskets are the Felpro ones with the reinforced area at the end cylinders (water passage at each end has extra metal piece)

Dont use any other goop on the head gaskets either.

The VC and the pan can be installed with black High temp sylicone or you can use the gaskets supplied by most Mfg.

I have done it both ways and am still not sure which I like best.

If you use a VC gasket though, glue the gasket to the VC with weatherstrip adheasive and then apply the sylicone to the mating surface before installing

One last thing. These engines can break cranks though this usually does not manifest iteself in the way you describe.

Once the engine is coming apart you can l;ook it over well.

Wrist pins bushings do go away and they will get very noisy.

Keep us posted and we can help if you get snagged.

Best

MGW

 

[buddy]

If issue moved with injector as thought, then I'd think it was an injector issue, like fouled. And it went away for a while after replacing injector.

 

[wraith6.5]

thanks for all your help ill know in a few days what really wrong with it even the shops are stumped so i took it to one more shop and they are taking it apart for me to see if all else fails i guess ill go and swap in a gasser

 

[JMJNet]

Most shop unless they are Diesel shop does not know much about 6.5 TD.

You have to provide the knowledge to them that you learn from this forum.

My suggestion is to DO the diagnostic list if you still have access before tearing it apart. Since we don't have access to the vehicle, so you have to be our ears and eyes. There are a lot of expertise in this forum to help you through the diagnosis before bringing it to the diesel shop. Then you just tell the diesel shop what to do or change, or any shop probably can do part replacement but not diagnostic.

That is what I would do if I were you.

 

[buddy]

You might find a shop with a good diesel mechanic, but that doesnt mean they know the 6.5. You have to find a diesel fuel injection specialty shop that deals with Stanadyne IP rebuilding and one of their mechanics drives one. Even here in CA I was able to find a shop like that, and still they werent as up on the know how as this forum.

Did you remove the copper washer when replacing the injectors? and put a new one in?