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Injector discussion no fighting allowed!

Crankme69

Crankme69

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My motor has 209K miles on it. I think my injectors are original, but I'm not sure...:confused:

It starts good & smooth pronto, has great acceleration, 19mpg avg, almost no visible smoke at startup or otherwise. Noise, it sounds like a diesel to me, I love it. :smile5:

Here's my question, many times here I read that with all them miles you are playing with fire by not being proactive & changing them injectors...:eek:

Am I really? I mean the noise & mpg & visible smoke at startup & general smooth operation & also how it runs isn't going to provide me enough to prevent risking major issues? Help me please, because I have an ole diesel mechanic that lives next to me and he listened to my 6.5 & more or less told me, tear it apart if you want to waste some money or if ya feel the need, but that thing sounds like new & in his opinion I'd be nutz, so tell me please...

THX in Advance,
69
 
I did the same thing. I think I had 180-190k miles on the original injectors. A little smoky under acceleration (which now I think is due too the original IP). I was getting 19-20mpg, barely any smoke on cold startup but I swapped em out anyway. I didn't notice any difference. Amount of smoke is the same and the mileage is identical. Power is the same too. So, I think the 100k mile injector life might be a little overrated.

There was an article in Diesel Power Mag last year sometime with a 92 6.5 td with almost 600, k miles on it with all original parts including IP and injectors. Truck looked like crap but it was still running. It has a list of the parts that had been replaced...like 16 batteries, 12 starters lol
 
I changed mine at 300k kilometers, I don't know if they were original or not. It ran good before but seemed better with the rebuilt marines.

I pop tested the old ones about a year later and they tested bad. 400 psi difference on pop pressure and better than 1/2 pee'd.

I would pull and test them at least.
 
Per Bill Heath, the issue of concern is that older injectors do not cleanly close off, leaving a dribble or pooling of fuel that can create hot spots and burn pistons. It's a much greater issue if you are doing a lot of towing. Since I'm 80% towing boats, I changed them though I too was not seeing any degradation in performance.
 
I've seen the damage peeing injectors can do. They had eroded half way through the top of the piston on 4 of 8cylinders. The truck had 200,000 miles on it. I wouldn't risk a engine over less than $150 worth of nozzles[I have my own pop tester]
 
I just replaced mine 2months ago.
It was defiantly louder but "starting" smoked more and rolled worse at idle.

A month later replace the IP. It was failing after a hot soak.

What a difference. Smokeless starts, smooth idle and tons of power.

My son said why did you wait so long:toetap05:
 
I know it's the wrong vehicle but I recently had the injectors cleaned on my wife's CTS and it corrected a rough start condition that existed from delivery. My impression is that one or more injectors weren't popping properly from day one.
 
How does it do on start up, do you get a puff of fuel smoke, especially on cool morning mine were doing that at 160K ran great otherwise, but those were hi-pops and supposedly the higher pop pressure causes them to fail sooner, if you aren't towing with them and no smoke and EGTs are normal eh??? you may be fine, not that hard to pull them and pop test them,

Toward the end mpg was suffering, new ones 2 months ago made it all better
 
My BURB was still getting 18MPG with the old 6.5 that had origanal injectors in it. When I had good glow plugs it would start up decent too. When I tore it down though, I found that 5 pistons had burn damage on them from diesel being dribbled down out of the injectors, and 1 is almost down to the ring land. The old 6.5 still ran strong, and didn't smoke that much either. But the injectors were definately shot, and it was only a matter of time before the one piston self destructed from the burn damage.
 
It starts very well only a light puff in the am or after it sets for like 4~5hrs when I fire it up to go for lunch at work. No rough idle smooth right off even in the winter. My EGT's run at 70 mph around 550~600 DegF. If I can figure out how to run my camera to take a video I'll post one.

Thanks for all the replies & sharing, I really like this truck, so I will prolly make the investment just to be sure I'm not doing harm. I also am concerned about the balancer issues & I am keeping an eye on that also.

Had a recent oil sample done by the Geek, would any potential damage being done by injectors show up possibly on a 5K mile oil run sample results?
 
The towing types would be the ones to really hurt themselves by running poor injectors. Because poor atomization on sustained fueling will run EGTs and head temps up. But can be harmful nonetheless to any engine.

Poor injectors often run easier, smooth since they dont make the IP do much work before popping. If your factory engine runs real smooth with all factory parts, its probably because the injectors are shot.

The reason typical performance isnt an issue is the IP can pressurize the lines up to 10k psi while injecting and the turbo charger and amount of compression from it.
 
I'm just letting him know with the symptoms (no smoke on startup, good fuel economy, smooth running) not to expect any difference with new injectors.

Now the injection pump is another story - as mentioned, he'll probably see a huge difference in performance with a new IP.

I've never heard of a smooth running diesel being the symptom of shot injectors......my experience has always been the opposite..... Oh well, that's why I'm here - to learn something new anytime I can.
 
Most diesels I've been around run smoother with good injectors, mainly because the injection event is when it's supposed to be.
 
Yes sir I have gained a great deal of info from many here. The 6.5 has been a learning experience for me and a challenge that has been fun. Many folks here have forgotten more then I will prolly ever know.

Many of my experiences with other aftermarket replacement parts have not been so great and sometimes ya just can't win.

If I have gathered the info correctly from the replies to this, the risk I'm taking by not changing my injectors is somewhat minimized due to the fact that I use this truck for my daily driver & I rarely tow anything with it.

The other concern I may want to consider with changing my injectors is if the old ones are weak with lower pop press now from wear, the new injectors may push my IP back to the full required discharge pressure and from what I know my IP has over 130K on it. No issues presently with my IP but placing the additional load on that could push it to failure.

Hmmm decisions decisions ...

Have I correctly articulated the info or did I make a wrong assumption?
 
All I can add is that at 404 000 kms on the originals (sure look like the originals, right down to the bosch germany markings) I changed mine out rather than risk roaching an engine.

Not that expensive, I got away for less than 250 bucks.

PITA to do though...

Some personal experience notes:

Pull the freaking inner fender on the passenger side right away, you life will be much easier.

Pull the tire off the side you're working on so you can reach in through the wheel openings (you'll see what I mean when you start).

jack stands! Use 'em!

Plan to not have the truck a couple days. Can be done in a day, but plan for the worst.

I pulled the turbo. Pretty easy and makes life Sooooo much easier.

Get a proper sized socket for the injectors - 30MM. Injector socket is probably easier.

Universal joints and extensions will make your life sooooo much better

Get an injector install kit from someone. I used a non forum sponsor and was very pleased with what I got for the price.

Do the glow plugs while you're there. 10 mm deep socket. Cheap to do and easy since you've already got it apart.

If you've got the turbo off, it's a great time to install a thermocouple for an EGT gauge.

Get lots of rags, you will get black, sooty, greasy. Latex disposable gloves are great!

Clean around the injectors before pulling them off. Degreaser and a strong hose stream works good, follow up with a compressed air blast in the area. Dirt dropping into the cylinder is Baaaaddddd......wear safety glasses!

Wear safety glasses pulling the "hoses" off the injectors. Diesel in the eyes sucks.:rolleyes:

Do the drivers side, then start the truck. Then do the other and start the truck. Keeps you from cranking and cracking lines to bled air trying to get it to start.

The rest is pretty much plain ol' spinnin' wrenches and cursing...

That's about it, off the top of my head.
 
It can run smoother at a more retarded injection and combustion which is what happens when it pops early or doesnt atomize correctly. The less advanced the less force against the piston.

As far as the minimized risk, there is less noticeable issues when you dont stress the truck, however the main concern of pitting the pistons and scratching the cylinder walls still exists. Thats because if it dribbles when off or just doesnt combust and get pushed out or dribbles just a little after shutdown the fuel will clean the lubrication off the cylinder walls. This could lead to more blowby I suppose as a notibeable indication it has been happening.

Dont worry about overworking the IP, thats a myth. The IP is capable of pushing 4000psi at idle rpm if it had to. So popping off at 2200psi is nothing it would stress over. Additionally at higher RPM line pressure it squirts fuel at 10,000psi, so again 2200psi pop isnt hurting it. What I meant by the IP is working easier is you dont hear as much ticking/clatter from it popping as high. If you arent in the pursuit of power and dont use the truck for power then a low pop pressure could make it run quietter/smoother. Too low of pop might be how injectors are getting burned/scarred when we use these high fuel output PCMs and injection has to work against the pressure of the cylinder compression at high boost.

Definately something that should be common preventitive maintenance. IMO, 100,000 maybe if only a daily driver, 50,000 if you tow often or have performance PCM and have a heavy foot a lot.
 
buddy said:
It can run smoother at a more retarded injection and combustion which is what happens when it pops early or doesnt atomize correctly. The less advanced the less force against the piston.

As far as the minimized risk, there is less noticeable issues when you dont stress the truck, however the main concern of pitting the pistons and scratching the cylinder walls still exists. Thats because if it dribbles when off or just doesnt combust and get pushed out or dribbles just a little after shutdown the fuel will clean the lubrication off the cylinder walls. This could lead to more blowby I suppose as a notibeable indication it has been happening.

Dont worry about overworking the IP, thats a myth. The IP is capable of pushing 4000psi at idle rpm if it had to. So popping off at 2200psi is nothing it would stress over. Additionally at higher RPM line pressure it squirts fuel at 10,000psi, so again 2200psi pop isnt hurting it. What I meant by the IP is working easier is you dont hear as much ticking/clatter from it popping as high.

Definately something that should be common preventitive maintenance. IMO, 100,000 maybe if only a daily driver, 50,000 if you tow often or have performance PCM and have a heavy foot a lot.
Click to expand...

This raises and interesting question:

Where did the 100,000 mile change interval come from?

I can't find anything in the schedule in my 98's factory service manual about injector changes.

Is 100,000 just a number someone threw out one day, or is it documented somewhere from GM/Bosch/Stanadyne?
 
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