How to check injector return rates

[fj40mon]

I just typed a long post on my situation. Tried to post it and it was lost. I have a 2001 2500hd 4x4. Can anybody tell me how to check my injector return rates so that I can verify which injector or injectors are failing me so that i can replace them. I lnow this is a little vague but I dont want to type it all again until I know this is going to work.
Shaun

[Inspector]

You will need a Tech II diagnostic tool that hooks up to the OBD port to read the return rates. Some of the folks here on the page have them but you will probably have to go to the dealer to have them read.
Denny

[fj40mon]

I was aware that the TECH 2 could check flow rates. I was not aware that it could check fuel return rates.
I'll try this again. I have a 01 duramax with 204775 miles on it. I have had all eight injectors and the pump replaced under warranty at different intervals. Not at the same time. They were replaced as they went bad.
I have been having problems lately with it going into limp mode just pulling a hill. It started once in a while when towing. Now I just have to go up a hill. Boom it will go into limp and not go over 1800 rpm's. Check engine light comes on. I know you guys have heard that a million times on here! Any way I checked codes and got 0093 and 0094. Small and large fuel leak detected. Sooooooo I was very busy at the time and sent it to Oregon Fuel Injection of Eugene, Oregon. These guys are supposed to be on top of the desiel market. My thoughts were I'd bring it to them and get it fixed the first time. I explained to them what it was doing and what kind of codes I found. I told them I believe I had a bad injector and would they check the return rates on the injectors. Well they checked it out and found that at start up, the fuel pressure was low. They commanded it to go higher but it would not go. They replaced the fuel pressure regulator. Tried it again and pressure was good. They had it three days to do this and called me late friday to come and pick it up. I asked them if they checked the return rates and they said no. They said they checked the flow rates and everything checked out ok. So I began the long drive home(180 miles). I got about 20 miles and it went into limp mode. By then it was after 5 pm and I had to go to work the next day. I noticed when I got home letting it sit there idling I heard a pronounced nock and the idle was blubbery. I checked the oil and there is no fuel in it. After work I checked codes again (with my buddies snap-on scan tool). I got a 0094 large fuel leak. I called Oregon Fuel Injection and talked to the service tech. Needless to say I was dissapointed they didnt check the injector return rates and told him so. He said bring it back. I have already payed them $550 to change the fuel pressure regulator. I'm afraid they will ding me again and not fix the problem. I have done all my own maintenace on this rig until know and believe I can do this to. I have a automotive back ground. 2 years general repair and 6 years transmission repair. I believe if I had the procedures in front of me I could diagnos this problem and repair it myself. I have read a old post here that explained how a repair facility had checked the injector return rates by disconnecting the return line and hooking up a hose first to each bank and then to the individual injectors. Turning the engine over for a given time and measuring the amount of fuel that came out. Comparing this to specs. Process of elimination to find the culprit or culprits. Has anybody done this? If so do you have specific insrtuctions on how to do it? Id rather fix this myself if I can. Everything I know about this engine I have learned from here. Awesome site!
Anyway please help!
Shaun

[fj40mon]

OKKKKKKKKKK, Does anybody know of a reputable shop to do this repair near me. I'm in kelso, washington. Not far from Vancouver, Washington. Also close to Portland, Oregon.
Shaun

[Bornready6.5]

Does anyone know if an updated Snap-on MT2500 scanner has the ability to show the rates? If so, what are the parimeters the injectors should be in?

[Jimomatic]

fj40mom.

I too have a 2001 2500hd D/A. During the first year or two I had issues with driveline launch shudder and unstable Idle. Both of these problems were fixed to my satisfaction at Curt Warner Chevrolet. I'm not sure how they are now but back then they had a pretty good diesel tech. Take I-205 south to the Mill Plain exit in Vancouver. Good luck.
PS I would'nt let the oil and lube guys touch anything unless you want a huge mess to clean up.

Jim

[mark45678]

I would do a simple vacume test on the fuel filter houseing, my 2001 pop a code , Cant recall what numbers but it would limp mode on hills towing or any time I got on it for more then 5 ~10 seconds.

[fj40mon]

Mark45678
I'm not sure what you mean by doing a vaccum test on the fuel filter housing. If you are thinking the fuel filter is clogged I just changed it. I can get this thing to go into limp mode now just driving down the freeway at a steady throttle opening.

Jimomatic, I have been dealing with the driveline launch for a very long time. I just havnt got around to having a new one piece driveline built for it. Do you know the name of the tech you delt with at Curt Warner Cheverolet? Thanks for the help man.

[fj40mon]

I dropped it off at the dealership yesterday. Asked them to put the tech2 on it and check the balance rates and injector return. They told me the balance rate was all over the place and they CAN'T check injector returns with the tech2. They said they need to replace all 8 injectors. They think I might also have a faulty injector pump, but they wont know that until they replace the injectors and check the balance rates again. They said they have no way off diagnosing individual faulty injectors in the vehicle. They need to remove them and put them on a machine to check the spray. SO I asked, you think that the injectors are leaking into the cylinders? He said yes. I said my mileage hasnt changed and I have no indication of fuel in the oil. I think they just want to throw 8 injectors and it and be done with it. $800 a piece. I'm out of warranty.

Denny (Inspector) says they can check return rates with the tech2. Am I getting jerked around by the dealership or what? Is there a accurate way to diagnos the injectors individually?

Oh yeah, before I took it in to the dealer we talked on the phone. They said it would take a hour to diagnos and a hour to replace a injector. We are at day three now.
Shaun

[LanduytG]

Balance rate is checked with a Tech 2, but return rate is checked by pulling a return line off and measuring the rate of return while cranking the motor. I forget what the max return rate can be before its deamed bad.

Greg

[fj40mon]

LanduytG,
Can the return lines be disconnected on each side first to determine which or if both banks have excessive return? If so were do I do this? Were do I disconnect the lines?

If that can be done can I check each injector in the same manner? If so how would this be done? Were would I hook a hose to the injectors?

Thanks, fj40mon

[DmaxMaverick]

I'd say the dealer is jerking you around, in one way or another. They obviously don't know what an injector replacement involves. 1 hour on an LLY, maybe. The LB7 requires about 6 hours for one bank, and 9 hours for both, with a WELL experienced tech.

[fj40mon]

I got a estimate from them. They recommend replaceing all eight injectors and the pump. To keep the costs down they qouted with rebuilt parts. The cost with labor was $6045. I had them print out three live data feeds from the tech 2. The first is at cold, second at 45 min. running, and third after sitting for a hour (not running). Not exactly sure how to read it, but they highlighted the consistently low injector pressures. I wish I had a scanner so that I could post them. I'll try this:

Engine speed 687 RPM Injector 6 command 0.41 ms
APP indicated angle 0 % Injector 7 command 0.31 ms
calculated fuel rate 8 mm3 Injector 8 command 0.43 ms
fuel temp. sensor 26 C Balancing Rate Cyl. 1 1.1 ms3
actual fuel rail pressure 40.1 MPa Balancing Rate Cyl. 2 -0.0 mm3
Desired Fuel Rail Press. 41.0 MPa Balancing Rate Cyl. 3 -3.3 mm3
FRP Regulator Command 35 % Balancing Rate Cyl. 4 0.0 mm3
main inj. timing 3.0 deg. Balancing Rate Cyl. 5 1.1 mm3
Injector 1 command 0.38 ms Balancing Rate Cyl. 6 1.7 mm3
Injector 2 command 0.35 ms Balancing Rate Cyl. 7 -2.3 mm3
Injector 3 command 0.27 ms Balancing Rate Cyl. 8 2.2 mm3
Injector 4 command 0.35 ms Engine run tim 5:06
Injector 6 command 0.40 ms

Engine speed 632 RPM Injector 6 command 0.43 ms
APP indicated angle 0 % Injector 7 command 0.34 ms
calculated fuel rate 6 mm3 Injector 8 command 0.40 ms
fuel temp. sensor 47 C Balancing Rate Cyl. 1 0.1 ms3
actual fuel rail pressure 35.0 MPa Balancing Rate Cyl. 2 1.0 mm3
Desired Fuel Rail Press. 34.0 MPa Balancing Rate Cyl. 3 -2.6 mm3
FRP Regulator Command 37 % Balancing Rate Cyl. 4 2.4 mm3
main inj. timing 0.0 deg. Balancing Rate Cyl. 5 -1.5 mm3
Injector 1 command 0.38 ms Balancing Rate Cyl. 6 1.8 mm3
Injector 2 command 0.41 ms Balancing Rate Cyl. 7 -1.8 mm3
Injector 3 command 0.31 ms Balancing Rate Cyl. 8 0.6 mm3
Injector 4 command 0.46 ms Engine run time 42:56
Injector 6 command 0.34 ms

Engine speed 665 RPM Injector 6 command 0.49 ms
APP indicated angle 0 % Injector 7 command 0.29 ms
calculated fuel rate 7 mm3 Injector 8 command 0.43 ms
fuel temp. sensor 53 C Balancing Rate Cyl. 1 0.3 ms3
actual fuel rail pressure 37.7 MPa Balancing Rate Cyl. 2 0.2 mm3
Desired Fuel Rail Press. 38.0 MPa Balancing Rate Cyl. 3 -2.3 mm3
FRP Regulator Command 38 % Balancing Rate Cyl. 4 0.8 mm3
main inj. timing 2.0 deg. Balancing Rate Cyl. 5 -0.7 mm3
Injector 1 command 0.37 ms Balancing Rate Cyl. 6 2.8 mm3
Injector 2 command 0.37 ms Balancing Rate Cyl. 7 -3.4 mm3
Injector 3 command 0.32 ms Balancing Rate Cyl. 8 1.6 mm3
Injector 4 command 0.40 ms Engine run time 1:17
Injector 6 command 0.35 ms

What do you guys think?
Shaun

[fj40mon]

Crap Thats not how I had it typed out. Its all bunched together. I hope you guys can make something out of that.
Shaun

[DmaxMaverick]

Are you aware your truck qualified for an extended warranty on the injectors? The warranty covers the injectors for 7 years/200K miles. From the sound of it, the dealer didn't cover your previous repairs under this warranty. It specifically requires all 8 injectors be replaced at the same time with certain failures, like what you are experiencing now, and possibly before. You are over the mileage a little, but your history may prove a need for the dealer to cover it. If nothing else, it is possible to get GM to cover half or more of a repair like this, so soon out of the extended warranty. If you had a previous complaint for the same issue that wasn't satisfied, and you were under 200K at the time, they are liable for the repair. Sounds like that dealer didn't comply with the campaign bulletin.

[fj40mon]

I tryed getting something done under warranty first. They didnt want to touch it because I had 203,000 miles on it. I know now has 205,000 miles.
Shaun

[More Power]

The first thing I'd do is measure the fuel supply restriction at the test port at the front of the engine, with the engine idling. Sure, you might have just changed the fuel filter (always a good idea as a first step in troubleshooting), but there could be some other problem that's restricting fuel flow.

As an example, I was testing Lil Red a while back with less than 1/4 tank of fuel. It apparently sucked a little air during a brisk acceleration, and the engine went into limp mode and set P0093. This code is set whenever the commanded and actual fuel-rail pressure isn't within a preset value.

Always eliminate the easy/less costly possibilities before throwing money at the problem.

Jim

[fj40mon]

Thats a excellent idea. I'll see if I can locate a guage. I've been wanting to purchase one for a while but havn't found a good source.

[jbplock]

I'll see if I can locate a guage .... havn't found a good source.

Best deal on the gauge is at Kennedy Diesel ..

http://www.kennedydiesel.com/detail.cfm?ID=289

another option is the J-44638 GM gauge from Kent-Moore but it's more $$$ ...

[fj40mon]

Looks like a good deal. Thanks for the info.
I got a # and called GM customer assistance today. Explained my situation. They are going to let me know if they can help me out by thursday. They really want me to fix it first and then discuss it with them afterword. I threw a fit. We will see thursday.
Shaun