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Good day everyone,
I found this article helpful when replacing my lb7 injectors, I am in reassembly mode now but I have hit a snag; On the driverside, in a wire grouping with the baro sensor there is a 3/16 eyelet on what looks to be #8 stranded wire dose anyone know where that connects? thanks in advance cp:argh: |
Originally Posted by jchris60
(Post 1072632)
Good day everyone,
I found this article helpful when replacing my lb7 injectors, I am in reassembly mode now but I have hit a snag; On the driverside, in a wire grouping with the baro sensor there is a 3/16 eyelet on what looks to be #8 stranded wire dose anyone know where that connects? thanks in advance cp:argh: |
thanks for the reply, I found it; was the glow plug link for the passenger side,
trucks up and running now Praise the Lord for all his mercies :jump: man what an improvement Kudo's to Merchant Automotive for a real decent kit |
Just changed injectors
Just wanna say how helpful this write up was and would like to say thanks to 2500hd and merchant automotive
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Yeah I know its an 09 post , but thanks.
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dang i wrote this 5 years ago? D:
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What is the password to view your photobucket images?
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Originally Posted by Sokr915
(Post 1076611)
What is the password to view your photobucket images?
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2004 lb7
Ok here it is. I was getting fuel in the oil. Due to the economy too many kids whatever the budget was not enough for new injectors so I pulled the injectors. The front 2 on the drivers side had blown o rings. Got new o rings and seals. Cleaned injectors put a little silicone one threads reinstalled. Rebuilt fuel filter housing. Checked all fuses and wires. Primed over and over and cranked and cranked. It will try with gas on a rag but won't go on its own. I have built cummins cat and detoit motors for heavy equipment. But they were old school. This is driving me nuts.I have tried every trick I know but still nothing.
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Originally Posted by Caleb C
(Post 1080039)
Ok here it is. I was getting fuel in the oil. Due to the economy too many kids whatever the budget was not enough for new injectors so I pulled the injectors. The front 2 on the drivers side had blown o rings. Got new o rings and seals. Cleaned injectors put a little silicone one threads reinstalled. Rebuilt fuel filter housing. Checked all fuses and wires. Primed over and over and cranked and cranked. It will try with gas on a rag but won't go on its own. I have built cummins cat and detoit motors for heavy equipment. But they were old school. This is driving me nuts.I have tried every trick I know but still nothing.
Your injector bodies are more than likely cracked, and the only solution is to replace them. If you are on a tight budget and you want to replace only the 1-2 injectors that may be leaking you'll need to remove both valve covers, reconnetc the high pressure fuel lines and wiring, then start the engine without the valve covers, and visually inspect to see which injector(s) are leaking. While you're at it, disconnect the fuel pressure regulator, that way the fuel rail builds up maximum pressure, so you don't miss a leak. Wishing you the best! - Titus |
there is also a high probability that one or more injectors have a high return rate and that will drop your fuel pressure preventing it from starting. a bottle test should pin point which ones are the culprit. while you have the covers off and are testing them that would be the best time to do the bottle return test. otherwise it may be a shot in the dark to find out which ones are your problem
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Originally Posted by 2004LB7
(Post 1080145)
there is also a high probability that one or more injectors have a high return rate and that will drop your fuel pressure preventing it from starting. a bottle test should pin point which ones are the culprit. while you have the covers off and are testing them that would be the best time to do the bottle return test. otherwise it may be a shot in the dark to find out which ones are your problem
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true, true
what i was trying to get at was that if he was already in there to fix/diagnose/repair/replace the injectors and was on a tight budget then the bottle test would be the way to go for replacing only the bad ones. the problem with testing a whole bank is that two or more slightly higher return rate injectors can look like one really bad injector and vise versa. then once you get in to replace them you still have to figure out which one(s) to replace. do you replace all four? what if both banks are returning too much. that could be eight injectors vs just two. that is why i say bottle test with valve covers off. likely much cheaper that way |
Good advise guys,
It sounds complicated because it is :humm: The easiest way to fix it is to replace them all while your at it, if you can afford it. |
Of course it will be more complicated but for someone that cant afford all 8 then this is about as cheap as it can be and still do the job. Things are always easier if you can throw money at it. For someone who doesn't have the money i try and give other options
I have replaced the injectors in my LB7 several times. The first two times i replaced all 8. After that i decided it was getting too expensive and now only replace the ones i find bad. Thanks Jason |
Did you get better Mileage on your injectors with the new fuel filter?
Originally Posted by Back-in-Black
(Post 1028182)
Blake,
I bought my 2002 new. Drove it off the lot 11.5 years and 301,000 miles ago. My injectors go out about every 80,000 miles and have been replaced 4 times so far. Twice under warranty and twice by me. I do the work myself now that it's out of warranty. It's really not a bad job for a DIYer. I've kept this truck and am still keeping it because the alternatives are not all that much better from what I've seen. In the used department you could buy a Ford with the 6.0 and it's long, long list of problems. Or you could buy a Dodge/Cummins and have the truck fall apart around a pretty good motor. Maybe the Fords with the 6.4 are better? Not when it costs $7,000 to $9,000 to replace a blown fuel pump (recent quote posted on another forum). In the "new" department you're looking upwards of $50,000 for a truck from any of the big 3 and it even comes with all the EPA mandated CRAP, including the "potato in the tailpipe", poor fuel mileage, EGR valves, DPF fluid, catalytic converters and all the other wonderful things all that crap does to make repairs even more common and expensive. No thanks!!! As far as injectors go, your tune probably has nothing to do with your injector failures. From all I've read, it's a problem with tiny, tiny pieces of trash in the fuel. At 28,000 psi, it's a bit like sand blasting going on inside the injectors with any particles in your fuel. My truck was bone stock until this weekend when I converted over to a Donaldson filter/ separator that supposedly is much better than the Delco filters I've used since the truck was new. Everything I've read says that dirty fuel is where the problem comes from. Unfortunately, nothing I've read proves that better filtration actually makes the injectors last longer either. But, I will find out if it helps. Being the original owner, I know intimately the history associated with injectors on my truck and they are pretty predictable at around 80k miles. If I get more out of this set (that I changed last month), then I'll pretty much have to attribute it to the filter change. For your current injector problem I would suggest that you may want to try replacing them yourself. It's a heck of a lot cheaper and it's really not that bad a job. I've done mine twice. It cost me right at $1600 ($201.75/injector) for Bosch injectors from a GM dealer that sells online. I spent a few more dollars on gaskets and bolts but way less than $100. One thing I did this time that I really, really wish I had done last time is that I replaced the valve cover bolts. The factory valve cover bolts are socket-head (you have to use an Allen wrench to remove them). The Allen wrenches or sockets are too long to get into some of the tight spots near the firewall and it greatly increases the time and difficulty of the job dealing with that. Also, over time, the holes in the socket-head bolts also fill with dirt and gunk making it even more difficult. You can't get the Allen wrench down into the hole of the socket-head bolt w/o using hammer to drive the wrench in. It's so tight in some places (working space)that hammering on the Allen wrench is next to impossible. Like I said, makes it a lot harder than it should be. I replaced all my factory valve cover bolts with normal hex-head type bolts this time. It cost me $21 for 50 bolts and 50 flat washers. The new bolts have a 10 mm hex head. I use a Snap On, 1/4" drive, wiggler socket with them and it eliminates all the space problems you get using an Allen socket. Just putting it back together with the new bolts, I know I eliminated several hours worth of screwing with those socket-head bolts!!! The other thing I did this time that I wish I had done the first time was adjusting the valve lash. Over the years my truck has become pretty dang loud. After adjusting the valve lash, it's back to a quiet as it was when new. My lash was out pretty bad is some cases but it was out by at least 5-8 thousands in every case. Some were 10-15 out. Like I said, made a HUGE difference and it didn't require much to do it. I removed the upper half of the radiator fan shroud and bought a 36 mm, 12 point socket at Advance Auto for about $12. You need the socket to turn the crank using the harmonic balancer bolt. Took maybe an hour and a half extra. You'll also need a feeler gauge if you don't already have one. Anyway, I did the math and spending $1600 to replace the injectors every 80k miles works out to about 2 cents per mile. I can live with that over paying $50k+ for a new one!! (I don't buy used). |
Originally Posted by ems8535
(Post 1082450)
Have you put enough miles to decied if the new filter helps? If so whats thee pros and cons to the filter and which one did you go with and would you recommend something different?
I'm using Donaldson filters now and they're listed as 4 micron as opposed to the OEM at 7 micron. Not only do the Donaldsons appear to catch more trash, they are MUCH cheaper at about $17 each compared to ~$60 I was paying for the AC Delcos. You will need an adapter to use the Donaldsons though. The adapter kit was about $100. Bought it and 4 Donaldson filters here: Nicktane Not only do the Donaldsons seem to filter better and are cheaper, they are easier to change. They screw on a centered pipe nipple like an oil filter does and that's waaaaaay easier than trying to get that damn OEM filter started on those dumb outside, rubber threads. That's what the adapter is for. It has NOT given me better mpg, but I never expected it to. |
So I followed the instructions from here as well as multiple other posts. I got both sides torn down and back together. No when I try to crank it it acts like it is seiazed up it originally tried to turn over about one rotation and then just locked. I am new to the diesel world. I know in a gas motor I would tear it back down and look for something in the lifter rocker arm area. is there a possibility that air could lock it up like this I have not bled the injectors yet.
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Sounds like it is hydro locked. Did the old injectors leak or did you get any diesel or oil down the injector holes?
Diesel engines have much higher compression then gas engines so it doesn't take much hydro lock it. If it is it will leak past the rings eventually freeing it up. Was it a "quiet" lockup or did it make noise like a hard part fell in there? I have locked mine up before when playing around with water injection. Had it spraying before i cranked it over and it turned about 1 1/2 turns and then just stopped. Tryed again shortly later and it freed up and started. It didn't make any noise Jason |
GREAT POST!!! the write up and pictures are awesome hope I never have to do it but if I do this helps ALOT!!:argh:
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2004 duramax injectors
Thanks a ton for all the tips info and pics, that's awesome. I will be doing this job soon on a 2004. Can i put in larger injectors without any other adjustments being necessary, or are thier mor things i need to know before putting beefy injectors in this thing? Thanks.
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Originally Posted by Buck Shot
(Post 1090328)
Thanks a ton for all the tips info and pics, that's awesome. I will be doing this job soon on a 2004. Can i put in larger injectors without any other adjustments being necessary, or are thier mor things i need to know before putting beefy injectors in this thing? Thanks.
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Just got through installing the 4th set of injectors in my 2003. the third set came from Pensacola were crap and barely lasted 20,000 miles. bought dealer remans this time with refurbished fuel lines all new washers. have 218,000 on it and looking for 300,000 before I start shelling out a grand a month for a new one. Thank you so much for this thread the info was invaluable .
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Originally Posted by tootallsteve
(Post 1098078)
Just got through installing the 4th set of injectors in my 2003. the third set came from Pensacola were crap and barely lasted 20,000 miles. bought dealer remans this time with refurbished fuel lines all new washers. have 218,000 on it and looking for 300,000 before I start shelling out a grand a month for a new one. Thank you so much for this thread the info was invaluable .
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Originally Posted by 2004LB7
(Post 1080795)
Of course it will be more complicated but for someone that cant afford all 8 then this is about as cheap as it can be and still do the job. Things are always easier if you can throw money at it. For someone who doesn't have the money i try and give other options
I have replaced the injectors in my LB7 several times. The first two times i replaced all 8. After that i decided it was getting too expensive and now only replace the ones i find bad. Thanks Jason |
Originally Posted by slednecks1
(Post 1099593)
Have you ever put a lift pump in it to help eliminate the injectors from going bad?
Anyway, I now have 338,000 miles. My injectors have been pretty predictable and each set has gone out right at 80k miles. They've been changed 4 times so far - twice under warranty and twice by me (learned how on this thread- thanks 2500HD). About 38,000 miles ago, I changed from using the OEM Delco fuel filters since new to Donaldson filters. The OEM (made by Racor) is a ~7 micron filter. The Donaldson is a 3 micron filter. In all the reading I've done on this subject, it seems the consensus is that over the course of thousands of miles, the internals of the injectors are sand-blasted by tiny particles of trash in the fuel. This eventually causes them to start leaking or dribbling fuel as damage to the needle and seat becomes worse. So I always wondered... If trash in the fuel is causing the injectors to fail, why didn't GM put a 2 or 3 micron filter on when the problem was discovered in about 2003. Indeed, at that time, I got a "recall" letter from GM saying bring your truck in and we'll install a new, improved filter on it for free. Which I did. Apparently it wasn't all that "improved". Still a 7 micron filter. So why didn't GM put finer filters on? I think I found out why. Once I switched over to the Donaldsons, I started having problems keeping the filter full of fuel. I didn't change anything else and my truck is bone-stock. Many times my truck would not start and I would have to pop the hood and pump the primer pump on the fuel filter housing in order to refill the filter and get the truck started. This was especially true when towing (and using fuel at a faster rate). Stop at a fuel station to fill up and it was guaranteed to require a "primer pump" to get restarted. Forever, I thought I had an air leak in my fuel system. But my gut was telling me it was something else. So I did some more reading and asked some more questions on forums like this. Seems the CP3 is the only fuel pump in the system. Apparently, it's not strong enough to suck fuel out of the tank through a 3 micron filter at a fast enough rate to keep up with consumption... especially when towing. So I did some more reading and asking - I needed a lift pump. I ordered a lift pump and installed it. Just a single "factory performance" model. Not some super-duper hi perf dual pump, high volume gizmo. Just a simple pump that pulls fuel from the tank and keeps the filter full. Bingo -problem solved. Haven't had to pump that primer pump ever since (except when changing filters). Anyway, that's my theory of why GM never came out with an OEM 3 micron (or less) filter for these things. They knew the CP3 pump couldn't handle that w/o adding another pump. So anyway, I'm about halfway through with my experiment now. Since I KNOW that my injectors have failed like clockwork at about 80,000 miles, I also know that if these go farther, then I have extended the life of my injectors by installing a better filter and a lift pump to keep it full. BTW, the added benefit of the Donaldson filters is that they only cost $18 each compared to the $50-$60 each for the Delco ones. It'll probably take me another year and a half to hit the 80k mark on this set of injectors. Should be interesting. It's still possible that these injectors will still fail around 80k miles. For one thing, I didn't switch over to the Donaldsons till maybe 8k-9k miles after I installed these injectors. I'm also hoping that the problem with low fuel flow didn't damage these injectors. We'll see. Time will tell. |
Perfect, once you get there Id love to know if the injector life was extended.
That is the same info I had found out as well. I run a 2 micron CAT fuel filter and just did a full injector swap and fine tuned the fuel pressure on the lift pump last night so will take it for a drive tonight and hopefully all is well. I am second owner of 2003 LB7 223,000 . My buddy did a full injector replacement and added lift pump and has put over 80,000 on with no issues. I had found a great thread link on here about this vary issue and the lift pump instal was said to be the solution to injector failure problems since the design of the CP3 cannot keep up to the demand of the truck. I started it up to check PSI off pump and motor was surging like crazy and throwing FPR code (P0089). As soon as I trimmed the spring in the return line on the pump to adjust pressure and got it down to 7PSI and runs great in garage and no code, hopefully just as well on road. We'll find out tonight fingers crossed. |
So just took her for drive and still starts rough, runs rough at idle and motor runs louder than before and not seem to have the power it had. Ive installed injectors before on this and havent had an issue. Lift pump is the only new addition. So thinking I should uninstal that and than see how she runs? Any suggestions? And there is a slight tick in the motor bot not throwing any codes...:argh:
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Great write-up and pics, thanks for taking the time.
On post #2 you refer to a link regarding injector service (Duramax Diesel Fuel System - Fuel Injector Service). The link works but not much info there, I realize it's not your thread but curious if you know what happened to it. I'm a newb here and sometimes long time posters have updated info. Thanks again Phil |
Great thread, great pics and commentary.
Howeverrrrrrrrrrrrrrrrr,,,,, Not to be a wise acre, but I have a couple of comments to add from my own experience of having just done this; 1) Do NOT use ball ended Allen keys. They have six very short lines of contact in the bolt heads and (given that all LB7s are now at least 12 years old) you are likely to run across a few tight ones if it has never been taken apart before and the ball end hex key will "burr out" the bolt head. Sure, it is a PITA to use a 5mm 1/4 inch drive bit on the ones against the firewall, but that is NOTHING compared to the difficulty of getting one out with a wrecked head. I was particularly paranoid about getting my allen key all the way down to the bottom of the cavities to get max contact. I flushed each one out with a blast of brake cleaner using the tiny plastic straw. Be careful if you do this, it can spray right back at Ya. 2) I disagree with the suggested tightening sequence for both upper and lower valve covers, it jumps from one end to other end, then to the middle and out to the ends again. I prefer middle to ends, i.e. start at the one that is labeled 3 and continue in sequence, finishing on what are labeled in the original post as 1, 2. 3) Oh yeah, do NOT drop anything. The front end on these trucks is a maze of traps for small parts. There is a corollary of Murphy's Law, the smaller the part the less likely it is to get all the way to the ground. Something like that. In any case have a garden rake handy in case you have to rake out parts or tools. |
Originally Posted by ArrBee
(Post 1124074)
Great thread, great pics and commentary.
Howeverrrrrrrrrrrrrrrrr,,,,, Not to be a wise acre, but I have a couple of comments to add from my own experience of having just done this; 1) Do NOT use ball ended Allen keys. They have six very short lines of contact in the bolt heads and (given that all LB7s are now at least 12 years old) you are likely to run across a few tight ones if it has never been taken apart before and the ball end hex key will "burr out" the bolt head. Sure, it is a PITA to use a 5mm 1/4 inch drive bit on the ones against the firewall, but that is NOTHING compared to the difficulty of getting one out with a wrecked head. I was particularly paranoid about getting my allen key all the way down to the bottom of the cavities to get max contact. I flushed each one out with a blast of brake cleaner using the tiny plastic straw. Be careful if you do this, it can spray right back at Ya. 2) I disagree with the suggested tightening sequence for both upper and lower valve covers, it jumps from one end to other end, then to the middle and out to the ends again. I prefer middle to ends, i.e. start at the one that is labeled 3 and continue in sequence, finishing on what are labeled in the original post as 1, 2. 3) Oh yeah, do NOT drop anything. The front end on these trucks is a maze of traps for small parts. There is a corollary of Murphy's Law, the smaller the part the less likely it is to get all the way to the ground. Something like that. In any case have a garden rake handy in case you have to rake out parts or tools. #2 is the actual tightening sequence from the OEM :humm: #3 the fun spot is when you drop something and it ends up inside the cross member that the front plastic splash guard bolts up to, took me about 30 minutes to even locate there the fucking bolt went :argh: |
Originally Posted by stagerguy
(Post 1101900)
Great write-up and pics, thanks for taking the time.
On post #2 you refer to a link regarding injector service (Duramax Diesel Fuel System - Fuel Injector Service). The link works but not much info there, I realize it's not your thread but curious if you know what happened to it. I'm a newb here and sometimes long time posters have updated info. Thanks again Phil |
Agree on that "Special place" inside the cross member where parts and tools go to.
Every vehicle seems to have one. Here's the thing on ball end allen keys; {back in the day} We were "instructed" in the early 60s that our jobs wold be on the line if we were caught with one within 20 ft of a Decca tape deck in one of those large gymnasium size computer rooms. L-keys were all we were allowed, they worked fine then and I used one last month for the bolts up against the firewall. If your hands get sore from the end biting you at the same spot for all 46 bolts just slip a deep socket over it - but ONLY for the initial loosening. The snap on 5 mm alternative with a U joint is rumored to be over $40 - - a LOT compared to a whole set of L keys and with my luck it would disappear into that cross member on bolt #2. I agree with the sequence ONLY for putting the bolts IN. The end ones are the farthest apart and will align the cover. The (largely hypothetical) possibility is that the head or valve cover faces are not flat and parallel. Assuming you don't know whether they are like this () or like this )( the best way to get them together like this || is to start in the middle and work toward the ends. {Yeah; picky, picky} PLEASE don't take any of this the wrong way. As others have said, this is a GREAT post and if I hadn't found it I would probably have unloaded the truck - $5K being too large a % of its current value. Then what ? I would have shopped for a truck and probably bought what someone ELSE was unloading for undisclosed reasons. Hey, thanks again. |
Since doing mine a couple of weeks ago I have been scrounging around for a way to measure balance rates.
After MUCH messing around with a trial version of Torque Pro I followed a lead that got me to using my old Scan Gauge II. Not "elegant" but it does the job and I have about 13years of use from it anyway, cost me $150 at the time IIRC. Go to the Scan Gauge page, open the support page, go to manual, look up X-Gauges, follow ODB codes for GM, select LB7-LLY Duramax, punch 'em in. OK, so you can only see 4 of them at a time, but it isn't in the same price bracket as EFILive. Pleased to say mine are all WELL within spec. |
Originally Posted by ArrBee
(Post 1124289)
Since doing mine a couple of weeks ago I have been scrounging around for a way to measure balance rates.
After MUCH messing around with a trial version of Torque Pro I followed a lead that got me to using my old Scan Gauge II. Not "elegant" but it does the job and I have about 13years of use from it anyway, cost me $150 at the time IIRC. Go to the Scan Gauge page, open the support page, go to manual, look up X-Gauges, follow ODB codes for GM, select LB7-LLY Duramax, punch 'em in. OK, so you can only see 4 of them at a time, but it isn't in the same price bracket as EFILive. Pleased to say mine are all WELL within spec. four is better than none :tu: i have out out of spec right now... it only shows out of spec when engine is cold and only when the rail pressure exceeds 12k psi at idle. the balance rate for that one injector is within "oem specs" its ok because it only tells you to check at idle and at gear when the engine is at operating temp. the engine does have a slight hiccup and the miss its noticeable in the exh tone untill it finally warms up. dont you just love diagnosing shit :s: luckily i have a LLY now so replacing one injector is a breeze now :jump: |
Originally Posted by 2500HeavyDuty
(Post 1124653)
four is better than none :tu:
i have out out of spec right now... it only shows out of spec when engine is cold and only when the rail pressure exceeds 12k psi at idle. the balance rate for that one injector is within "oem specs" its ok because it only tells you to check at idle and at gear when the engine is at operating temp. the engine does have a slight hiccup and the miss its noticeable in the exh tone untill it finally warms up. dont you just love diagnosing shit :s: luckily i have a LLY now so replacing one injector is a breeze now :jump: Not sure that 12K psi at idle is right, I think mine is around 5K (memory, I saw it but didn't pay much attention). Also, not sure that X-gauges work on the LLY (or LML) I think they are only programed for LB7. It would be worth a try if you have a scan gauge, but probably not a good idea to buy a scan gauge for an LLY without checking into FIRST. EDIT: I just checked the scan gauge web site and YES INDEED the x-Gauge codes DO support LLY. https://www.scangauge.com/x-gauge-co...7-lly-duramax/ :END EDIT |
yeah 5k is the norm for idle. mine jumped up as soon as i put on my FASS so i had to modify some fueling tables on EFI live
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vale cover bolts
the Dealer did the last install and the valve cover bolts were gorilla tight. I ruined 4. I found if you hammer a 16 point 9mm socket over the bolt they come out no problem...
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thinking of buying a 2002 duramax with 45k... excellent condition... am I a foul???? I'm reading about this injector issue and have a buddy who got over 200k on his 2001 with the dual filter system and lifter pump...
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