Injector replacement observations

[Turbine Doc]

Hi Ya'll,

I just installed a set of JK HP injectors this weekend definite seat of the pant attitudinal adjustment in the truck :D , I don't know if the old ones were so afflicted, or new ones are just that much better.

One thing I can't explain though is something that has been a mystery since I owned this truck has been fixed with the injector swap.

For those that have been around long enough to remember one of my earliest posts back in 2001 was to look for help with turbo surge/drift when I joined DP, I was having a problem with rapid boost swings on hard acceleration 3-5psi swings on boost gage., everything else normal IAT, manifold at MAP sensor, coolant, WG actuation, EGT steady

Through lengthy posts maybe 3 pages over 3 mos or so, we found a bad donut gasket between upper & lower intakes, EGR valve being unseated under load when running on L65 PCM unpowered EGR sol, vac leak across unpowered baro and EGR solenoids, so we single plumbed vac to WG only, & added boost controller.

And finally Intercooling all of which knocked the swing incrementally in stages progressively better to surges of .5 to 1.5, seen only on hardest accel demand. Say race demand :D or cruise control kicking in up long hill, let off the throttle and swing tamed out gradual throttle application no swings, stomp the pedal surged until at steady state speed or back off a bit.

New injectors has stopped this completely zero surge regardless how hard I stomp on it, go figure. I can only postulate that 1 or more of the injectors was weak and wasn't holding fuel delivery under high demand situation.

If I wasn't gauged and didn't have a Snap On scanner to view it all, probably would not know it was happening as you could not feel it only indication was at the boost gage.

You Diesel Swamis/Gurus out there care to weigh in on this one.

As for the injector install not too difficult on drivers side, pass side another story, I'm told it can be done without removing turbo, for life of me can't figure how.

Tip for turbo removal, soak nut/studs on exhaust manifold with good penetrant PB Blaster worked for me, then find "ALL" of your extensions and access the nuts from the bottom of the truck, you have just enough room to get around suspension to get on the nuts.

Use a 6pt wiggly socket, 12 pt will slip, have somebody keep the socket on the nut while you turn from underneath. I didn't have a somebody handy as per usual except for me.

I inserted the extensions up from below as close as I could then took a plastic zip strip around the extension shaft to the frame/torsion bar pulled tight for the 3rd hand; to tension while positioning socket to nut and hold it there until I could crawl under to turn the breaker bar & ratchet. That worked for 7 of 8, #8 cyl back right; under AC dryer no advise on that one, perserverance and holding your mouth right only thing I can say on that one.

Now that I have passed the initiation test of #8 injector, do I get to learn the secret handshake and password ;) for the been there done that society.

Final advise if you haven't done this before, plan to make a day of it, start with #8, make it through that one rest are easy.

[Jim P]

I replaced the injectors without removing the turbo. I just removed the heat shield on the turbo, The brace from the turbo to the engine and the heat shield between the turbo and injectors. I thought that getting this heat shield off and back on was the hardest part of the job. Actually I thought that #4 and #6 injectors are harder than the #8.

I have read that you can get to the injectors through the wheel well opening after you take off the front tire but I couldn't even see the injectors through there. The glow plugs yes but injectors, no.

[Turbine Doc]

Good job Jim,

The shield behind the turbo looked to be too much for me to want to fight which is why I didn't try harder at doing it with turbo installed.

#4 & #6 are a breeze without the turbo in the way, I wonder if you having a HD frame vs my K1500 LD makes access to #8 easier, it was a consideration in special routing I had to do when I installed the big Spearco IC, I'm with you on glows thru the wheel well I don't see injectors happening that way.

[Jim P]

I have to admit that I thought about taking the turbo off a few times but when I looked at those rusty bolts, I decided to try a little harder with it on.

[gmctd]

Very good, Tim - glad to know you've cleared up the boost surge. Seems like that SnapOn should have indicated something in the cylinder balance and\or timing areas, doesn't it? Good job.

Wanna see how I replaced all eight of my injectors without removing the turbo or shield, check out Photo Contest post in 6.2 Forum. :D

[Turbine Doc]

Funny you should mention cyl imbalance I never had a hard code set but every once in a while in the history log I would see cyl imbalance 1 or all cyls, logged in history but never a MIL lit, when I'd go to history review it always cleared in history section.

The L65 PCM is a 99 and my Snap On cartridge only goes to 98 but still reads codes and works the test functions, thought the codes were a fluke from having the 2 different years, maybe not. I'll have to plug it in next road trip and see if I get them again.

[patrick m.]

thanks for the warning, i am thinking about a set of inj's myself.
sounds like a good idea, doing the turbo side first.
this is the 3rd, or 4th post ive read about the injectors really giving a power improvement you could feel
nice explanation, thanks, and congrats!
Pat

[MikeC]

I replaced mine with only the removal of one of the shields :D

But, when the wrench slipped off of the hex on the socket, I ended up in the local Urgent Care getting 4 stitches :mad:

Overall my install went great, the hardest part was the numbing shots :eek:

Mike

[Barry Nave]

Loss of power, fuel not injecting as when new and injectors just getting week is hard to tell untill new ones are installed.
For the added cost of high flows my 2c tell's me that they are worth it.
Even though I changed my 3yrs. ago and now some 50K+ later the truck still runs as it did when injectors were replaced. Mileage has stayed the same and will run these injectors till mileage differ or Eng. prof. changes. ;)

[Scooby]

What are the best HIGH FLOWS to get ?? My '96 has 101000 on it, and injectors may need some attention. I thought about calling a local injection shop I have used for heavy diesel pump work, and seeing if they work on stuff for the 6.5. smile.gif

[gmctd]

Cylinder imbalance DTC's set only History codes when they occur, due to the varied causes, so as not to alarm Driver.
To a skilled hand on the Tech-II, they can be cause or no cause for concern., depending on what else has (is) happening.

[DieselDavy]

Tim,
Congrats on the new injector install! Nothing is easy when you stuff this much engine between the fenders!
Can you give me the G2 on the '99 PCM? Did the change give you a big kick? Any functions not work on your chassis? (96 I think) Costly? Fill me in if you can!
Thanks,
Dave

[Turbine Doc]

Dave,
Not so much a kick in the seat upgrade, but unleashed more of the inherent potential of the engine & gives more grunt ability. The L56 PCM that came with the 1/2 ton; is set up as a emissions engine, MAF, EGR, Baro and Cat and only 63mm/3 fuel delivery. I tried a reflash PCM and was going that route, but wanted to have ability to swap PCM's to make sure I did not have to fight voided warranty issues with "after market" program.

Looking for a exchange core I went to junk yard and found the 99 L65 PCM, unbeknownst to me at the time, it had GM's HD program 76mm fuel delivery 215 Hp?(99-2001)already in it, up from L56 stock 185 Hp.

What I noted between the 2, was that there wasn't that much difference between reflash and the Generals HD program so a no brainer $125 j.y. vs. $600; the reflash went back. Another side benefit here is that the L65 PCM I have is a stock GM program, no way can claim be denied because of program change issues I have same cut back curves for overtemp over fuel etc. Other than emissions hardware, I'm no different than any other factory delivered HD engine set up with my 6.5.

M/M act requires that a mod must be proven to be the root cause of a failure before a claim can be denied, they will try but it can be fought, easier battle though if you are closer to stock config, or the mods improve the engines durability, which is what these mods do. Now they also enhance your abilty to run harder but hey that is your call/story and also theirs to prove you have done so.

The L65 lets me run with out restrictive L56 emissions gear, L65 does not have them, so it doesn't look for them; "look Ma no codes when EGR is blocked off". Of course I only run this mode when off road operating.

I carry the L56 PCM with me and rest of the gear is left installed (electrically connected to keep ground loops active thru sensors/solenoids to reduce potential of stray "trons" getting back to the PCM, but mechanically bypassed). It's also a handy troubleshooting aid to know if I have a bad devcice or PCM issue, been running with it for 2 years no problem.

I have a blank off shim under the EGR with upgrades I found that engine can lift EGR off it's seat which is why I went blank off shim, converting back to L56 takes about 20 min. under hood, a little longer to reinstall cat. "now where did I put that thing" :D

[additive]

I replaced the injectors without removing the turbo. I just removed the heat shield on the turbo, The brace from the turbo to the engine and the heat shield between the turbo and injectors. I thought that getting this heat shield off and back on was the hardest part of the job. Actually I thought that #4 and #6 injectors are harder than the #8. Could you tell me if there are more bolts to remove other than the top two for the heat shield between the turbo and the injectors? I am working on the 2nd half of the injectors this week and having an absolute ball :( doing this job.

Thanks,
Additive

[MikeC]

Additive,

There are just the bolt(s) that are in plain site. The shield slips over a couple of tabs on the engine end. Wiggle it with some force but with TLC and it should come off. Once mine was off it made sense and went back on easily.

Mike

[tom.mcinerney]

Additive, the curved shield will be sprung between valve cover and turbo. After remove top 2 screws, lift, wiggle, and pull it toward center of engine--it will spring in that direction.

[marktara]

Which injectors do you members that have changed them reccomend, because I have see quite a price difference in high performance injectors from $55 a piece to $700 a set?

[additive]

Thanks guys for the help, I have the shield removed.
I took care of #8 first before I removed the shield. #6 is out and after I get the glow plug replaced, I will put it back in. However, when trying to remove the fuel line on #4, the injector turns instead of the nut on the fuel line breaking loose. I am a little stuck on that one. Don't know what I am going to do as I have not removed the turbo and don't want to.

On #2, my socket is hitting the solid line leading to under to the trubo. I am going to have find a shorter socket to get to it.

Like others have said, the driver's side injectors is a bit of a pain.

Additive

[JoeyD]

Mark, Bill Heath, Kennedy and Pennisular Diesel all sell the injectors. I believe they are all set to the same flow and pop pressure. I went with Bill as I got his Turbo master at the same time.

[additive]

Finally got the job all done. It feels good to start 2004 with new (rebuilt) high flow injectors from wickliff diesel and glow plugs (from Kennedy) all the way around.

A few things that helped me:

1. Read all the advice on the posts on injector replacement.
2. Purchased a stubby wrench set that had a 9/16 and 7/8. Also purchase a set of stubby ratchets.
3. I had the 30mm axle socket (or whatever it is). This worked fine for all except the #2 injector. I purchased a shorter 30mm deep well from AZ tools (just like harbor freight). This is an impact socket that was just short enough to get this injector off. All the rest were done with the longer socket.
4. I removed the heat shield off of the turbo for more room and also the heat sheild between the turbo and the motor. No need to remove the turbo.
5. I purchased the fuel injector kit from Kennedy so I wouldn't have to try and put the samll clamps on the fuel lines. This is a life saver.
6. I gave myself a couple of days to do the passenger side in that it is such a pain. This way when I got sick of working on it I could quit for the day or for an hour or two.
7. If I was to do it again, I would not worry about changing the #4 or #6 glow plug at the same time. There is no advantage to having the injector removed in that the exhaust covers the glow plugs. I would just focus on getting the passenger side injectors done and worry about the glow plugs another time.
8. #2 injector is not torqued, all the rest are. I was unable to get my torque wrench into the socket due to the angle of things.

The suburban presents a bit more hassle because of the hoses for the rear heater. Just more things in the way.

#8 cylinder is not as bad as #4 and #6. I hope I don't have to do this for a while as my hands are now a little sore, but fortunately no stitches or bad cuts. It is funny how you can almost remove the engine quicker than these injectors.

Once again, this site has saved me countless hours and $$$. This site is by far the best value out there.

Additive

[MikeC]

How can anyone do injectors without a cut or two, or is that a stitch or two? tongue.gif

[additive]

MikeC,
Where did you get the 30mm deep well socket with the hex on it? I found that would have been very handy for this job. I was unable to find one after searching a little on the internet and looking at Sears.
Thanks,
Additive

[rjschoolcraft]

From reading these posts and others in another thread, I think this job was a whole lot easier with the turbo off. It only took me about twenty minutes to remove the air box and turbo. After that, the injectors were readily accessible and easy to get the torque wrench on. At this point, I don't think I would ever do it any other way.

[additive]

When the turbo is removed, are you able to move the support bar(I think that is what it is) between the #2 and #4 injector? That support bar was the biggest pain for me. This bar is the one that the heat shield is shaped to fit over.

I could go either way on turbo removal. I am mechanically inclined to screw things up, so I was trying to limit any damage to other areas.

Additive

[TurboDiverArt]

Originally posted by Joey D:
Mark, Bill Heath, Kennedy and Pennisular Diesel all sell the injectors. I believe they are all set to the same flow and pop pressure. I went with Bill as I got his Turbo master at the same time. Hi All,

I believe JK has posted that he pops his injectors to 2400. I also remember other places popping them to 2200. Anyone know what pop pressure Heath Diesel and Pennisular Diesel pops them to? I believe there is also a different tip that is typically used. Do all 3 above use the same ones?

I too have been planning to replace them. With 120K on the clock I think it's time to replace the injectors. I'm pretty sure they are the original once.

Thanks,
Art.

[Bobbie Martin]

Where did you get the 30mm deep well socket with the hex on it? I found that would have been very handy for this job. I was unable to find one after searching a little on the internet and looking at Sears.
You can get it from Snap On (http://buy1.snapon.com/catalog/pro_det.asp?P65=&tool=all&item_ID=10720&group_ID=1326&store=snapon-store&dir=catalog). Like all Snap On stuff, its pricey but probably worth it.

[triggerman]

Additive;
I picked up a hex nut 1 3/16ths socket from JC Whitney as a sensor socket once for $8 bucks. It looks like they droped it from the catalog tho. The 1 3/16ths is only .005 thousandths larger than the 30mm so it will work just fine if the SAE is easyier to find. Oh, Whitney also listed a deep 6pnt 30mm impact socket for spindle nuts for $5.99 PN #81UC1087Y.
Hope this helps

[MikeC]

additive,

SORRY it took so long. John Kennedy loaned the socket with the High flow purchase.

Mike

[POINTERMAN]

I found whole set of 6 pt deep impact sockets at harbor freight for 20.00 bucks.

[cruzer]

I was able to remove the nuts for the turbo by
going thru the fender opening like doing glowplugs and using extensions to get to the nuts. This maybe easier the laying under the truck
and dealing w/the suspension & frame rails.

I think Kennedy has higher BAR values also.

[autocrosser]

I believe the 30mm socket can be found pretty easily. I have seen them in Walmart that's where I bought the one I have. It was sold as a hub socket for the 4wd trucks. Harbor freight or Northern Tool should have them cheap also.

[additive]

Guys,
Just to clarify for the 30mm socket with the hex on it. I have 2 30mm sockets - 1 axle one and one impact one. The axle is 1/2" or so longer than the impact socket. The feature I am looking for is the one shown in the snap-on (picture provided by clicking on the Snap-On link above) with the hex on top of the socket so you can get a wrench on it. The rachet head is a nuisance to get on the socket when it is placed over the injector.

Additive

[Bobbie Martin]

Hey Autocrosser,
Nice Super Seven. What kind is it? Hard to tell in the pic.

[S\W Off Road]

I picked up a socket at AutoZone for about $6.? It did the job great.