Leaky fuel injectors?

[toddlnrd]

When I let off the accelerator, my engine makes a "girgling" noise and the RPM's fluctuate for a few seconds. Then it settles down to normal. I have 278,000 miles on the truck. I have put 100,000 on it myself. I don't know how many miles are on the injectors themselves. Could it be leaking fuel injectors leaking into the cylinders?

Thanks,
Todd

 

[Edzzed]

If you have put 100k on it yourself then it's probably a safe bet that the previous owner might never have changed them either. From what I have read 100k is about the limit for injectors. They can spray a stream of fuel rather than atomizing the fuel. If that happens it'll cut a hole in a piston. I don't know that new injectors will cure your problem but it'd be a good place to start, A new timing chain would also help. Ed

 

[Koots]

Sounds like it could be air in the coolant. I know my 98 gasser would make a similar wooshing sound when i had a bad intake gasket (different motors but same symptoms). The RPM fluctuations could be a possible headgasket issue, not sure how the computer controlled engines handle coolant bubbles.

 

[Acesneights1]

Your description is rather vague. Perhaps a youtube HD video ?

 

[great white]

Gurgling?

Like water gurgling?

If so, you've probably got air in the coolant. Most likely trapped in the heater core if you can hear it. All the GMT400 chassis I've owned have done it at one time or another. It eventually works it's way out, seems to be nature of the beast.

Now, if you're loosing coolant or there's bubbles in your overflow causing the "gurgling", that's a bad thing......

As to injectors, Bill Heath recommends replacement at 90,000.

Although, I've never been able to find a factory replacement schedule for them. I'm not saying one doesn't exist, but there's none I can find in my FSM or in TSB's.

Worn injectors can be as benign as causing excessive fuel consumption or as catastrohic as burning a hole in a piston.

Mine had around 300 000 kms on them when I replaced them.

Truck got smoother, quieter and MPG picked up a couple.

If you check ebay, you can probably still get a full set of 8 for around 200 bucks shipped form a seller named "moneyslave". That's where I got mine. Brand new in box, bosch injectors, proper part number and the orange ring for turbo applications.

Definately worth doing them if you're sitting at 275000 miles.

If you don't have an EGT guage, it's also a perfect time to install one. It's all apart anyways.

And do the glow plugs too. something like 80 bucks will get you a full set of bosch duraterms. Great plugs.

 

[WarWagon]

Cheap injectors only last about 30K miles. You need to spend around $550.00 to have new ones or them rebuilt with good German or India nozzles. They are only good for 100K before you risk the engine. New old stock may be a source...

 

[toddlnrd]

I am pretty sure that it is in the engine, not the cooling system. I hear the noise coming out of the exhaust. It sounds like it is trying to burn off fuel in the cylinders when I let off the accelerator. Maybe gurgle was not the most accurate description, more like a rumble.

Ok, opening up a big discussion here. Who has the best and most affordable injectors? I know those to criteria are probably mutually exclusive, but give me feedback. I know Heath has a great reputation.

Also, how much of a pain in the butt are these things to change out?

Thanks,
Todd

 

[WarWagon]

I am pretty sure that it is in the engine, not the cooling system. I hear the noise coming out of the exhaust. It sounds like it is trying to burn off fuel in the cylinders when I let off the accelerator. Maybe gurgle was not the most accurate description, more like a rumble.

Ok, opening up a big discussion here. Who has the best and most affordable injectors? I know those to criteria are probably mutually exclusive, but give me feedback. I know Heath has a great reputation.

Also, how much of a pain in the butt are these things to change out?

Thanks,
Todd

Local Stanadyne dealer/shop for local rebuilds. Benefit is they can test the old ones. Any cheaper and, well, read my long thread about burning up starters with smokey 30+ second cranking with sticky 'bad' injectors with 30K on them. One part you just don't want to go cheap on. I was lucky that they didn't burn up a piston.

Injectors don't make a funny noise when you cut fuel. So the injectors may need to be done, but, are not going to cure the symptom you are after.

The job looks harder than it is. Pull the turbo, get the proper injector socket or 30 MM socket and new return lines. Also plan on replacing the glow plugs at the same time as you are there. Pulling the turbo is the hardest part with the down pipe clamp...

A funny noise when you let off the throttle could be a muffler or kitty coming apart, engine mounts, turbo bearings letting the turbine hit the housing, bad fan clutch, etc.

 

[chefmike]

I went with the injectors from money slave off flea bay. I was very happy. Search his name here and you will find threads on people happy with him. Now I have my old set to be rebuilt at a local shop for next time. That same shop can pop test the fleabay injectors.

 

[Koots]

I spent $450 on a set of new Stanadyne injectors. I didn't have a place to have them pop tested but i liked the piece of mind of having a brand new set to rebuild as many times as i can, plus it's the company who makes our pumps so i figured they had to be good LOL

 

[toddlnrd]

Would it be possible that my injectors are allowing more fuel in the cyliners than they are supposed to when I let off the go pedal? (leaking into the cylinder)

Todd

 

[Crankme69]

278K...?

How does it start in the morning clean? What kind of power does the truck make? Is it getting descend 15+ mpg?

I'm not saying not to change the injectors but if there is something major in the making hate to see ya dump cash into something that is very unlikely to correct the issue that yr describing IMO.

Leaky injectors IMO will leak fuel into the cylinder after you shut the motor off, so when it starts it will likely smoke & knock for a sec or 2 until the fuel that leaked in dissipates.

 

[toddlnrd]

The truck starts and runs great. Just a little smoke at startup and no extra knocking. Seems to have decent power, although, I have not driven another 6.5 to compare.

Todd

 

[WarWagon]

Would it be possible that my injectors are allowing more fuel in the cyliners than they are supposed to when I let off the go pedal? (leaking into the cylinder)

Todd

Diesel engines are controlled by fuel. When you let off the throttle the computer or mechanical governor has the ability to completely shut off fuel and usually will until the engine slows down or throttle is applied. If you want to get cold, use compression braking down a long hill on a cold day. Your heater will go cold after a few miles of this....

Suppose the injector pump (Injection pump feeds the injectors as the injectors do not control how much fuel.) dumped fuel when you let off the throttle. As a diesel is controlled by fuel the engine would go balls to the wall and attempt to light up the tires while blowing black smoke in an attempt to burn the fuel.

Still sounds like coolant and perhaps a bad pressure cap blowing off when you let off the throttle. maybe a loose part or exhaust hitting something when the powertrain unwinds from power to de-accel.