Diesel Place banner

New injectors, now has a miss

7K views 70 replies 13 participants last post by  SickSpeedMonte 
#1 · (Edited)
1993 K3500 auto, 135k miles. Original mechanical IP, to my knowledge.

The truck was having a rough time starting with a lot of smoke but it would clear up and run fine after 15 seconds or so. The injectors had probably never been changed with 135k miles on the truck, so I bought some rebuilt ones from Badger.

While tearing it down, I noticed a good bit of oil in the intake and on both ends of the turbo compressor. I put new bushings in the turbo, cleaned out the intake, and bought new injector lines from a Hummer off of Ebay because mine were pretty rusty. The new lines required me to remove a little fitting on the #1 injector line at the IP. The fitting just looks like an extension. There's no check valve or anything when you look inside it. I can't find any info online for it.

I got it all back together on Thursday night. I bled the driver side while my wife cranked it and then tightened the lines back up and it fired without much trouble. It has a bit of a lope though, sounding like it had a miss and it's smoking a lot too. I let it run for about 5 minutes to see if it needed to work some more air out, but it never got any better. If you rev it, it sounds like there's some kind of knock, but it sounded like that before when it had rough starts. I bled the other side while it was idling and no improvement there either.

I cracked each line while running, and the engine stumbles with each one cracked. This morning, I pulled the intake back off and double checked the firing order. Going back over everything, I did manage to pull one of the terminals apart on the temp sensor in the coolant crossover/thermostat housing. I pushed it back together, maybe that's open. Otherwise, I'm starting to run out of ideas.
 
See less See more
#3 · (Edited)
It's not just the knock though, it misses and smokes. If you rev it up, it runs really rough.

I cant find a replacement for this temp sensor anywhere either. All I can find is the one in the head for the gauge...
 
#4 ·
Black smoke?
 
#7 ·
White. Looks just like it did on start up. It still starts rough as hell too. $400 into this project, 3 weekends, and all I've managed to do is break stuff and make it run worse.

Start suspecting a tired IP, with the newer injectors the pump is working harder to push the fuel...
I really hope not... It just never ends with this damn thing. Did I mention the passenger side GP's are stuck in there so hard that I broke the hex off of the body on the first one I tried? I have no idea what to do about that...

Is it common to only get 135k miles before having to replace the entire fuel system? The IP is the only thing fuel touches from the sender to the injectors that I haven't replaced at this point.
 
#8 ·
Thanks Freddy. I bought one and had to replace the pigtail because my old one had two male terminals sticking out rather than the shrouded terminals for the weatherpack connector. It made no difference unfortunately.
 
#9 ·
Sorry for the rant guys. I'm just really frustrated.
 
#11 ·
The one on the crossover is the one that was broken. I replaced it with the one with the weatherpak. I can't find the other one on any of the parts sites that I use. Could the smoking and missing has something to do with the cold advance? I could try jumping the terminals on the connector to the sensor on the crossover.
 
#15 ·
Your looking for AcDelco # 10154649 for that sensor. The one you have in there doesn't work the same. If you jumper the plug it will mimic a cold engine and you'll see the cam roll on the IP and the high idle solenoid will activate when you press the throttle to the floor waiting for the GP light to go out.
 
#12 ·
Did your Badger injectors come wet, dripping with diesel?
 
#13 ·
Not dripping but there was residue on them. Did you ever talk to him on the phone?
 
#14 ·
My Badger remans came with red plastic caps, and were dripping with diesel.

Residue? Dry? Wet? Were they remans?

I never needed to talk with them on the phone.
 
#16 ·
Mine came with the red caps too and were wet, but not dripping wet. They were remans.
 
#19 ·
It's a switch right? So I can test it's effect by either opening or shorting the connector? I know it needs to be replaced, but if I'm going to try other things too, I might want to bundle shipping on parts.
 
#20 ·
You use a piece of wire and short the plug. It mimics a cold engine. If your high idle solenoid is in good shape it will function again with the plug shorted and the IP will advance as well.
 
#21 ·
I jumped the connector and it didn't make a difference. I'll have to jump the high-idle solenoid and see if that's working.


I used an automotive stethoscope on each injector and each line while it was idling. They all sound the same. Bear in mind that the engine responds by slowing/stumbling when you crack any one of the 8 injector lines.


I'm thinking I might pull the injectors one at a time and spray them into a jar by cranking the engine to see if they have a decent pattern. At this point, I think the problem is one of the following:


1.) I got some dirt into the system and clogged/stuck an injector
2.) One or more of the injectors wasn't rebuilt right
3.) The IP isn't up to the task of popping the rebuilt injectors


I found a local shop that can dyno my pump to test out #3. I think patterning the injectors would address #1 and #2. I know it's dangerous because of the pressure so I'll use an abundance of caution.
 
#22 · (Edited)
Its Normal to rebuild entire fuel system on 20 year old diesel truck yes even at 130,000 miles or whatever. So You have no cold advance try applying 12v + to the green wire (s) on the ip and see if it advances it will give much more rattle and bump idle a tad. The reman injectors are fine Id bet because the guy rebuilds them all the time and has a good rep. Anyways mine from him knocked like crazy for like 2,000 miles at least. When I say they knocked I mean very loud on cold starts and would diminish more once warmed up good. Now after a few months they are still a bit noisy on cold start but after a good few hours of driving if I pull in somewhere and idle the truck it sure sounds good just that 6.5 diesel sound almost quiet actually. Far as your rough run or miss I cant be much help but obviously if you have glow plugs snapping off you have some issues there. IP? I don't know Id start with checking all sorts of other things out first...
 
#23 ·
Will do with the advance wire. Thanks for the advice.


I let it run for a while the first night and it got up to operating temperature (the coolant at least) and it was still smoking and running rough. The GP's need to be addressed, but I can't see how they are the cause of the miss/smoke if the engine can warm up and still run that way. The truck ran fine before I did this work. It's also still really hard to start it. I know it's getting pressure from the LP as I'm getting 8-10 psi on the gauge.
 
#24 · (Edited)
If you want to feel better about your truck, then check out mine. About 120k miles on my 6.2L diesel, and I am on my 2nd set of injectors, and 3rd injection pump. And it is due for another set of injectors from what I can tell. Time wrecks havoc on these systems (on everything, really).

I just had to replace my injectors in my Duramax after less than 10k miles. Just the parts was $2,900. That's why I don't break a sweat when my 6.2 needs a part. A new IP is a drop in the bucket compared to the LB7.

So just be glad you don't own a LB7 Duramax, and enjoy your cheap 6.2/6.5 parts!

I think you are on the right track with testing the cold advance and injection pump. If the pump tests good, you might have got a bad set of injectors. Though that seems pretty rare on the 6.2/6.5, as the injectors are fairly easy to rebuild with modern equipment. Let us know what happens with the cold advance (though that wouldn't cause it to run rough when warm), and how the pump tests out.
 
  • Like
Reactions: JCDiesel
#26 ·
I like this:thumb: Not too many Duramax guys post here or list 6.2 / 6.5 in their signature.
 
#29 ·
lol yeah we can still get them in quite a few stores around here. It's hard to beat a warm krispy kreme donut!
 
#30 ·
I found a company nearby that rebuilds IP's and called them. He said that he has seen this situation before and recommended changing the IP. He said that the service life of an IP is right around 100k too and that it's best to change injectors and the IP together. He said worn injectors tend to advance the timing and a worn IP tends to retard the timing, so when they age together they offset each other.


I guess I'm going to remove the intake and turbo again, pull the IP, and take it up to him. I'm also going to pull the passenger fender again and work on those GP's. I might even get ambitious and pull the exhaust manifolds and restore them. They are pretty rusty and I'd like to get rid of as much rust as possible so it doesn't spread.
 
#31 ·
I found a company nearby that rebuilds IP's and called them. He said that he has seen this situation before and recommended changing the IP. He said that the service life of an IP is right around 100k too and that it's best to change injectors and the IP together. He said worn injectors tend to advance the timing and a worn IP tends to retard the timing, so when they age together they offset each other.
A Stanadyne IP will last you 250,000+ miles when properly cared for.....
That guy is full of S***Censored..
He is telling you that with the hopes of a sale and your the SUCKER!
He will rebuild that IP and cut corners to save money and leave you stranded!
Now he is correct in telling you about the Injectors replacement.
Rule of thumb is 100,000 miles then replace!
 
  • Like
Reactions: HeavyChevy95
#33 ·
Continued.​

Fuel Supply System Checks​

1. Check the output volume of the lift pump in the following steps:
A. Remove the electrical connector for the fuel shut-off solenoid at the injection pump.
B. Remove the pipe at the lift pump outlet fitting.
C. Install a hose at the lift pump outlet fitting and place a 1 -liter (0.946-quart) container at the hose to collect fuel.
D. Crank the engine and measure the fuel volume (see Figure 7-62):
• If the volume is more than 0.24 liter (1/2 pint) in 15 seconds, check lift pump output pressure (part 3).
• If the volume is less than 0.24 liter (1/2 pint) in 15 seconds, check the lift pump suction line (part 2).

2. Check the suction line of the lift pump in the following steps:
A. Remove the fuel tank cap and repeat the lift pump output volume check (step 1):
• If the volume is more than 0.24 liter (1/2 pint) in 15 seconds, replace the defective fuel tank cap and go to part 3.​
• If the volume is less than 0.24 liter (1/2 pint) in 15 seconds, go to step B.
B. Separate the lift pump suction line from the fuel pick-up/sending unit.
C. Connect the suction line to a source of clean fuel, using an additional hose.
D. Repeat the lift pump output volume check (see Figure 7-63):
• If the volume is more than 0.24 liter (1/2 pint) in 15 seconds, remove the fuel pick-up/sending unit and check it for restriction.
• If the volume is less than 0.24 liter (1/2 pint) in 15 seconds, go to step E.
Note: If the fuel pick-up filter is restricted with waxed fuel, bring the fuel to operating temperature before performing further tests.
E. Check the lift pump suction line for restriction:
• If restriction exists, repair it and re-check lift pump output volume.
• If no restriction exists, replace the lift pump and re-check lift pump output volume.
F. Attach the lift pump suction line to the fuel pick-up/sending unit and check lift pump output pressure (part 4).

3. Check the output pressure of the lift pump in the following steps:
A. Install a tee adaptor between the lift pump outlet fitting and pressure line.
B. Connect a pressure gauge with a dial indication of 0 to 103 kPa (0 to 15 psi) to the tee adaptor.
C. Run the engine and measure the fuel pressure (see Figure 7-64):
• If the pressure is between 40 and 60 kPa (5.8 and 8.7 psi), go to step D.
• If the pressure is less than 40 kPa (5.8 psi), replace the lift pump and re-check output pressure.
D. Remove the pressure gauge and tee adaptor.
E. Install the pressure line at the lift pump outlet fitting.
F. Clean any fuel spillage.
G. Run the engine to check for fuel leakage​
H. Check the lift pump pressure line (part 4).

4. Check the lift pump pressure line in the following steps:
A. Separate the hose of the lift pump pressure line from the fuel filter inlet fitting.
B. Install an extension hose at the lift pump pressure line and place a 1-liter (0.946-quart) container at the
hose to collect fuel.
C. Repeat the lift pump output volume check (see Figure 7-65):
• If the volume is more than 0.24 liter (1/2 pint) in 15 seconds, check the fuel filter.
• If the volume is less than 0.24 liter (1/2 pint) in 15 seconds, go to step D.
D. Check the lift pump pressure line for restriction:
• If restriction exists, repair it and re-check lift pump output volume.
• If no restriction exists, replace the lift pump and re-check lift pump output volume.
E. Attach the hose of the lift pump pressure line to the fuel filter.
F. Clean any fuel spillage.
G. Run the engine to check for fuel leakage.​
H. Check the fuel filter (part 5).

5. Check the fuel filter in the following steps:
A. Remove the electrical connector for the fuel shut-off solenoid at the injection pump.
B. Separate the hose of the filter outlet to the injection pump inlet fitting.
C. Install an extension hose at the filter outlet and place a 1 -liter (0.946-quart) container at the hose to collect fuel.
D. Repeat the lift pump output volume check (see Figure 7-66):
• If the volume is more than 0.24 liter (1 /2 pint) in 15 seconds, go to step E.
• If the volume is less than 0.24 liter (1/2 pint) in 15 seconds, replace the fuel filter element and re-check lift pump output volume.
Note: If the fuel filter element is restricted with waxed fuel, bring the fuel to operating temperature before performing further tests. Also check the operation of the fuel heater (see page 7-21).​
E. Install a tee adaptor between the lift pump outlet fitting and pressure line.
F. Connect a pressure gauge with a dial indication of 0 to 103 kPa (0 to 15 psi) to the tee adaptor.
G. Install the electrical connector for the fuel shut-off solenoid at the injection pump, then start and run the engine.
H. Repeat the lift pump output pressure check (see Figure 7-67):
• If the pressure is between 40 and 60 kPa (5.8 and 8.7 psi), go to step I.
• If the pressure is less than 40 kPa (5.8 psi), replace the fuel filter element and re-check lift pump output pressure.
I. Remove the pressure gauge and tee adaptor.​
J. Check the fuel supply for air leaks (part 6).

6. Check the fuel supply for air leaks, following these steps:
A. Install a transparent hose between the filter outlet and injection pump inlet.
B. Start and run the engine, observing the fuel for air bubbles (see Figure 7-68):
• If air bubbles are not present, stop the engine and go to step F.
• If air bubbles are present, stop the engine and go to step C.
C. Check the lift pump suction line for air leakage:
• Separate the suction line hose from the fuel pick-up/sending unit and plug it.
• Separate the suction line pipe from the lift pump, and connect a vacuum pump/gauge to it.
• Apply a vacuum to the suction line, and observe the gauge reading:
- If vacuum does not drop, attach the suction line pipe and go to step D.​
- If vacuum drops, repair the air leak in the suction line and attach the suction line pipe and hose.
D. Check the fuel pick-up/sending unit for air leakage:
• Remove the fuel tank.
• Remove the fuel pick-up/sending unit from the fuel tank, remove the filter and plug the bottom end of the pick-up tube.
• Apply a vacuum to the upper end of the pick-up tube, and observe the gauge reading (see Figure 7-69):
- If vacuum does not drop, install the fuel pick-up sending unit and fuel tank.
- If vacuum drops, replace the fuel pick-up/sending unit, install the fuel tank, attach the suction line hose and go to step E.
E. Start and run the engine, observing the fuel for air bubbles:
• If air bubbles are present, stop the engine and re-check steps C and D.
• If air bubbles are not present, stop the engine and go to step F.
F. Remove the transparent hose and attach the hose of the filter outlet to the injection pump inlet fitting.
G. Clean any fuel spillage.​
H. Run the engine to check for fuel leakage.


Fuel Return System Checks​

1. Check injection pump housing pressure in the following steps:
A. Remove the housing pressure regulator from the injection pump governor cover.
B. Install a tee adaptor between the governor cover and the housing pressure regulator.
C. Connect a pressure gauge with a dial indication of 0 to 103 kPa (0 to 15 psi) to the tee adaptor.
D. Start and run the engine, observing the gauge reading (see Figure 7-70):
• If the pressure is between 55 and 83 kPa (8 and 12 psi), go to step F.
• If the pressure is more than 83 kPa (12 psi), go to step E.
E. Replace the housing pressure regulator and re-check housing pressure:
• If the pressure is between 55 and 83 kPa (8 and 12 psi), go to step F.
• If the pressure is more than 83 kPa (12 psi), check the fuel return system.
F. Remove the pressure gauge and tee adaptor.
G. Clean any fuel spillage.​
H. Run the engine to check for fuel leakage.

2. Check the fuel return system for restriction in the following steps:
A. Separate the hose of the fuel return line at the fuel pick-up/sending unit.
B. Separate the hose of the fuel return line at the housing pressure regulator on the injection pump, and connect a vacuum pump/gauge to the hose.
C. Apply vacuum to the return line and observe the gauge reading (see Figure 7-71):
• If vacuum does not build, go to step D.
• If vacuum builds, repair the return line restriction and re-check housing pressure.
D. Attach the hoses of the fuel return line at the injection pump and fuel pick-up/sending unit.
E. Clean any fuel spillage.​
F. Run the engine to check for fuel leakage.

3. Check the fuel return system for air leaks, following these steps:
A. Separate the return hose at the injection pump housing pressure regulator.
B. Install a transparent hose between the housing pressure regulator and the hose of the return line.
C. Start and run the engine, observing the fuel for air bubbles (see Figure 7-72):
• If air bubbles are not present, go to step D.
• If air bubbles are present, check the fuel supply system for air leaks (if the fuel supply system checks good, replace the injection pump and re-check the fuel return system).
D. Stop the engine.
E. Remove the transparent hose and attach the fuel return hose at the injection pump.
F. Clean any fuel spillage.​
G. Run the engine to check for fuel leakage.



'Fuel Injection Pump Transfer Pressure Check' pg 221
'Fuel Injection Pump Advance Mechanism Check' pg 223








 
#34 ·
Thanks for the wisdom fellows.


I know that the truck ran fine before. No smoke, plenty of power at any RPM, loaded, towing, etc. I replaced the injectors and all of a sudden it has an obvious problem. I didn't touch anything upstream of the IP and I know it at least has plenty of pressure to the fuel manager, just as it did before. If there was a fuel supply problem, wouldn't it have caused problems before now?


I can check the return for bubbles easily enough. There are no bubbles at the fuel manager when bleeding there. I'll check the housing pressure too.


I wish I still had my old injectors to try.
 
#36 ·
You may need to clean the Screen manager down inside of the FFM and also the last ditch screen on the IP inlet..
 
#35 ·
Not a fan of the raptor LP or the use of pre-filters.. Often cause more problems than they were intended to eliminate.


Your Glow Plug System operates different than the DS4 models.
Your glow plugs are controlled by the glow plug relay and controller.
If the glow plug controller malfunctions, it can damage the OEM plugs.
IF most of the glowplugs are found damaged, it is reccommended that the controller be replaced also..
The Glow Plug System begins on pg 244. See Glow Plug System Diagnosis pg 252.
 
#39 ·
Badger diesel rebuilt stock injectors.
 
#40 · (Edited)
Ok, I would suggest to follow the fuel supply check list that HeavyChevy95 posted and go from there..
 
#41 ·
I'm having a hard time finding info on how to test the IP housing pressure and IP transfer pump pressure (Figure 7-48). Any chance I can get a screenshot of that figure?
 
#42 ·
Cant help ya with screenshots, is that like snapchat.. :hehe:

Seriously.. For pictures, illustrations, and many more detailed diagnostic checks, download the DB2 student handbook in my signature. Its the next best thing when the factory authorized pubs and/or competent subs are nowhere to be found. DIY, and get your diesel on..

Good Luck
 
#43 ·
When it comes to fuel injection replacement parts, injection pumps, injectors and PMDs. Cost point aside, given the degree of difficulty to R&R said expensive s'it. I wont compromise on quality for walmart pricing.. Go OEM, GM, Stanadyne, ACDelco, or stay home.. All Im sayin'

Really why go anywhere else... Central Plains Diesel... 'nough said.

I would suggest you thoroughly test the liftpumps modified electrical system. Frankly, I'd remove the filtered and coddled raptor pumpsless and install an unfiltered OEM ACDelco EP158 liftpump on there, just for diagnostics.. You can put all that s'it back on when your done.

Sort of ironic that I bought my ACDelco EP158 at Walmart, $65.00 on-line, shipped (free) and picked up at the local store the following day or two. No bulls'it, no hassle, and no waiting in the checkout lines.. Now I check for availability at Walmart 'fore I go to local autoparts micro-warehoused outlets.

My recently fully restored fuel supply system now produces 12psi static pressure, maintains 9-11psi at idle, 5-7psi at 75mph, occassionally dropping to 4-5 when the DS4 goes to binge drinking. Try as I might, foot deep in 'er ass, cant get fuel pressure to dip to the 3psi minimum yet, but I suspect that will change as the FFM element becomes ever more dirtier with age.

Point being.. If the rotary vane type Raptor lift pump isnt receiving full voltage, it reacts just like the OEM solenoid type liftpump and slows down 'production' accordingly BUT unlike the OEM lift pump, the raptor doesnt have an inherent fail by-pass and becomes an unwanted restriction when the IP gets thirsty, causes momentary bouts of fuel starvation...
Dont even get me started on the pre-filter, any less than triple digit micron rating amounts to a pre-restriction for the IP and yet, folks spend a small fortune if not add on a rolling refinery to further protect a $100.00 electric pump that takes all of 15 minutes to R&R when they need to concern themselves more with just making sure the $800+ IP is receiving proper fuel pressure and sufficient flow..
 
#44 · (Edited)
I put a nylon line on the return and didn't see a single bubble. My LP pressure stays at 8-10 psi, so the pressure and volume flow rate are not the cause of my problem. If it couldn't supply the needed volume, the pressure would drop. I tried bleeding the injectors again, and #1 and #7 keep spitting out bubbles. The return was free of bubbles during that process. The other lines will spray fuel out. 1 and 7 will only do that on the initial opening but not again after. Bubbles form between the line and tube nut. I'm going to swap #1 with #3 injectors and see if the behavior follows. Unfortunately, I don't have a whole lot of time to play with it during the week.

Next step will be to test them. I might be able to take them to the local tractor dealer and have them do it... friend of a friend situation. Otherwise I'm stuck either buying the tester or paying someone to do it.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top