1994 6.5 turbo Diesel.

[Ghost]

I new to the Community.. I'm thankful we have things like this. I just picked a 1994 Extended cab, 2wd, Automatic truck with 154.000 miles on it. I got the truck running and drove it home for $800 dollars. I bought it taking a little bit of a chance. It had what sounded like a rocker arm that had jumped off it maybe really bad injector knock, But from owning a few IDIs in the past and learning on those.I was hoping I could work it out. From where I bought it was 55 miles from home. So with my Son following me, we took off with the thought in mind to avoid the highway and take all back roads. If the truck made it that would be great if not we would come back in the morning. About half way thru the truck downshifted, squatted and took off. Once I got control again. I realized the noise was completely gone and the truck was running really good. I even jumped on the highway and finished the trip. That was a week ago, now everytime I start it, she fires right up idles, runs great. All but the turbo I'm not making any boost at all. I am getting ready to order a turbo to put on it on. Before I do wanna ask first. Has anyone had that happen, to them? Even if not any ideals on what the noise was about? It was super loud and pretty bad. 2nd on a stock bottom end with lower miles what's the biggest turbo I can run or/and whats the biggest I should run? I'm new to the Turbo world. I would like to get all I can out of truck as far as pulling power. And Not so I can stay in it but so I'll have the power when I need it. Also thinking maybe a tuner or a chip. Looking for advice
Thanks in advance

 

[MrMarty51]

Read through all of the stickies on the front page of the forum. There is a lot of tips and hints on there.
Try pulling the codes with a paper clip, through the ALDL connector under the dash and just to the left of the steer column.
Check to see if the vacuum pump is still installed. If it is then hook a vacuum gauge to the suction hose/tube. If there is vacuum then hook the vacuum hose to the tube at the waste gate actuator, a T is helpful there, add enough hose to see the gauge when it is secured under the wind shield wiper, or long enough to get the gauge into the cab. Take the truck for a drive, see if the gauge fluctuates in vacuum. If not then, the solenoid is probably shot.
If so then check the WG arm with the vacuum hose disconnected from the actuator. Be sure that the arm mooves freely. If not, then, free up the arm so that it rotates smoothly. Retest.
If no vacuum at all, replace the vacuum pump.

 

[MrMarty51]

Oh yeah, welcome to the forum.

 

[Ghost]

Thank you, I will look at the sticky notes too. Like I said in my post I'm grateful to have a place to come to like this when I have questions. So thanks again. How about the knocking noise have you ever heard of or experienced anything like that?

 

[ak diesel driver]

Probably an injector sticking. They sound terrible, like a rod knock

 

[MrMarty51]

Probably an injector sticking. They sound terrible, like a rod knock

From too much fuel ?
Hope the pistons is okay.

 

[MrMarty51]

Thank you, I will look at the sticky notes too. Like I said in my post I'm grateful to have a place to come to like this when I have questions. So thanks again. How about the knocking noise have you ever heard of or experienced anything like that?

Be sure to check the harmonic balancer and the belt pulley thats hooked to the front of the crank shaft. You do mot want a busted crankshaft because of a faulty HB or pulley.
Check the rubber portions for cracks or any sign of slippage.
The pulley, can most likely grab it and see if the pulley portion will turn, with the engine shut off. If the pulley will move any at all, it is junk.

 

[Ghost]

Thanks yall, that thought did cross my mind. My 7.3 IDI had injector knock once. I'm guessing it was because of bad fuel and you are right it sounded horrible. Im just glad it cleared up.

 

[Will L.]

Welcome.
I agree description is like an injector.
There is several things to do on a “new to you” higher mileage 6.5.
Yes harmonic balancer and pulley in front of it - they can break a crankshaft.

Are you familiar with adding lube to fuel?
Do you have maintenance records?

@ 150k, probably due (better at 100k intervals) is new injectors and balancer/ pulley combo.

DONT BUY parts until you check what/where because there is a ton of junk parts out there and rip off places.

The biggest killer of 6.5 is heat. 195-200 normal, 210 watch the gauge more than the road, 220 pull over and let it idle back to normal. At 220 the cylinder walls are collapsing enough to pinch the rings and remove tempure from them and even scuff piston skirts.
The dash gauge is not trustworthy. Get a quality gauge installed.
Learn about balanced flow waterpump system.

Engine oil cooler lines often fail and ruin engine instantly. Inspect/ replace them immediately.

Lack of fuel lube, lack of fuel pressure to the ip (injection pump) from the LP (lift pump) and water are the damaging issues of the ip and injectors. My best suggestion is getting a pressure gauge that is reading at the ip and have gauge mounted where you can read it while driving. There are details to learn before buying parts for this and the other suggestions are more critical to do first.

 

[MrMarty51]

I had read about installing a temperature gauge in the rear of the right side cylinder head. That is the hot spot on these engines.
I removed the right side inner fender, pulled the plug from that port and installed a gauge sender unit into that port.
It seems that both gauges are accurate enough, within reason, except now, I have the ability to read exactly what is going on with that right side rear cylinder as far as temps goes.

 

[Ghost]

Welcome.
I agree description is like an injector.
There is several things to do on a “new to you” higher mileage 6.5.
Yes harmonic balancer and pulley in front of it - they can break a crankshaft.

Are you familiar with adding lube to fuel?
Do you have maintenance records?

@ 150k, probably due (better at 100k intervals) is new injectors and balancer/ pulley combo.

DONT BUY parts until you check what/where because there is a ton of junk parts out there and rip off places.

The biggest killer of 6.5 is heat. 195-200 normal, 210 watch the gauge more than the road, 220 pull over and let it idle back to normal. At 220 the cylinder walls are collapsing enough to pinch the rings and remove tempure from them and even scuff piston skirts.
The dash gauge is not trustworthy. Get a quality gauge installed.
Learn about balanced flow waterpump system.

Engine oil cooler lines often fail and ruin engine instantly. Inspect/ replace them immediately.

Lack of fuel lube, lack of fuel pressure to the ip (injection pump) from the LP (lift pump) and water are the damaging issues of the ip and injectors. My best suggestion is getting a pressure gauge that is reading at the ip and have gauge mounted where you can read it while driving. There are details to learn before buying parts for this and the other suggestions are more critical to do first.

I completly agree, I asked about the Turbo because mine is not making boost at all. I have owned several Diesels and my favorite being the IDI.. Yes I add Diesel Kleen or hotshot every time I get fuel, I also keep my coolant in check so I dont get cavitation in the cylinders. I have sent off oil samples for other trucks I've owned to get back readings. I have never owned a turbo for any type of performance all my cars have all been Nitrous cars. I do appreciate any opportunity to get educated on any topic especially this topic. Yes I do have all the service records for the truck I am the 3rd registered owner of the truck. It actually still has the original sticker in the glove box. It was bought with just about every up grade that was offered in 1994. So it can definitely be a nice truck with some love.

 

[DieselAmateur]

Welcome!

you've come to a good place for all things 6.5. Take the time to do some digging and read up on all the aftermarket fixes/ upgrades and the necessary maintenance already discussed like balancer & crank pulley etc

There are many better options for turbo, especially if you want to do any serious towing. Take the time to learn the engine and when it comes time for upgrades you'll have a lot of sound suggestions from all of us here

 

[dbrannon79]

Welcome aboard! Take Will’s advice, he’s blown up more 6.5 stuff than any of us can shake a stick at!

best thing to do starting off is fix everything that’s stock in the truck first before doing any upgrades so you’ll have a baseline and not question yourself later “was this doing that before”.
There’s lots of upgrades and options for the 6.5. And you’ve come the right place. Learn as much as you can. You’ll thank yourself later.

lol I’ve always thought if it as “be one with the truck”. Ive learnt lots from the guys here and still there’s lots for me to learn! There an awesome group of good people

 

[snarl95]

How do you know it's not making boost?

 

[WarWagon]

The biggest problem is the truck "ran away" on it's own. This can kill you and others if you don't have a plan to deal with it. Drop the damn thing in neutral: engine expendable and hope it don't blow hurting people on the sides of the vehicle. Key off may or may not stop a runaway, but, it can lock the steering wheel and loss of Power Brakes/Steering.

Some PMD's are known to fail and cause a runaway. Other sources of fuel like it's own engine oil from a bad turbo can cause a runaway. I would be inspecting the intake after the turbo and the turbo for excessive oil. Is the engine oil overfilled?

I am getting ready to order a turbo to put on it on.

Word: don't throw parts at it. I will be the first person to tell you what a POS Asthma Attack turbo Mediocre GM stuck us with. However you did not say what you expect to do with this pickup: DD, tow a RV, 1/4 track... Many turbo's to choose from today and a Pallet-O-Parts to go with it.

Regardless start with air filter condition and as mentioned if the Vac system is working. Hose connectors fail as well as the solenoid that controls the turbo Waste Gate. Check codes. Clean grounds: take apart and clean not just a visual "It looks ok. But it aint." The two or three grounds (ECM) by the trans dipstick and battery cable grounds are critical.

Remove the fan belt and spin each pulley by hand to see if they may have been the knock.

 

[MrMarty51]

Even a natural gas leak from someones house can cause a run away engine condition. Propane tank leak, anything that is a source of fuel that reaches the intake system can cause a run away condition.
Old detroit two stroke diesels, they have an emergency shut down handle that is hooked to a cable, hooked to an intake flapper. In case of a run away engine, pull that T handle and shut it down. On tje detroit two strokes though, usually that would destroy the oil seals on tje super charger so that would usually need to get resealed before firing it back up.
I am thinking a throttle body from a gas car or truck, without the injectors, placed between the turbo and the intake manifold would be an excellent emergency shut down valve.
Just needs a cable to control it.