Fuel injector knock
- Thread starter Trgglynn
- Start date
Here’s an update, checked cold compression again:
1 - 345#
2 - 340#
3 - 340#
4 - 340#
5 - 340#
6 - 340#
7 - 350#
8 - 350#
Codes present:
P0090: FPR Reg 1 control circuit
P0101: MAF Range/performance
P0102: MAF circuit low
P0193: FPR circuit high
P0299: Turbocharger underboost
P0401: EGR insufficient flow
P0402: EGR Control range/performance
P0405: EGR Sensor A low
P1404: EGR closed position/performance
Still have a slight miss at idle and low MPG.
Considering two things: FPR is bad. I found rust on the body of one of the glow plugs which indicates to me fuel may have had water in it. Which could result in the FPR being bad. Would the FPR cause bad mileage? Pressures seem normal while driving. P0090 is a new code.
P0101 and P0102 are new.
I did a bottle test on the FPRV and it is not leaking. I drove it lightly, and then drove it hard, and then continued to drive it hard for 10 miles and nothing came out of the rail relief port.
Also, the EGR seems to have additional codes than normal. P0401, P0404, and P0299 have been coming and going before the mileage issue, however the P0402, P0405, and P1404 are new.
1 - 345#
2 - 340#
3 - 340#
4 - 340#
5 - 340#
6 - 340#
7 - 350#
8 - 350#
Codes present:
P0090: FPR Reg 1 control circuit
P0101: MAF Range/performance
P0102: MAF circuit low
P0193: FPR circuit high
P0299: Turbocharger underboost
P0401: EGR insufficient flow
P0402: EGR Control range/performance
P0405: EGR Sensor A low
P1404: EGR closed position/performance
Still have a slight miss at idle and low MPG.
Considering two things: FPR is bad. I found rust on the body of one of the glow plugs which indicates to me fuel may have had water in it. Which could result in the FPR being bad. Would the FPR cause bad mileage? Pressures seem normal while driving. P0090 is a new code.
P0101 and P0102 are new.
I did a bottle test on the FPRV and it is not leaking. I drove it lightly, and then drove it hard, and then continued to drive it hard for 10 miles and nothing came out of the rail relief port.
Also, the EGR seems to have additional codes than normal. P0401, P0404, and P0299 have been coming and going before the mileage issue, however the P0402, P0405, and P1404 are new.
MAP is showing 14.5 PSI at idle,
33 PSI at WOT
MAF 42 gr/s cold,
MAF 40 gr/s cold (EGR closed?)
MAF 422 gr/s WOT hot
5300 PSI fuel pressure cold
4300 PSI fuel pressure hot
I don’t have the ability to check balance rates on this scanner, but should be getting a Flashscan this week. Also for whatever reason my scanner doesn’t read BARO. I have an older scanner (MT2500) that says the BARO is 14.5 but I’m not totally sure that’s a reliable number. I did replace the BARO recently because it was fluttering around at 3 PSI.
33 PSI at WOT
MAF 42 gr/s cold,
MAF 40 gr/s cold (EGR closed?)
MAF 422 gr/s WOT hot
5300 PSI fuel pressure cold
4300 PSI fuel pressure hot
I don’t have the ability to check balance rates on this scanner, but should be getting a Flashscan this week. Also for whatever reason my scanner doesn’t read BARO. I have an older scanner (MT2500) that says the BARO is 14.5 but I’m not totally sure that’s a reliable number. I did replace the BARO recently because it was fluttering around at 3 PSI.
14.5PSI is likely correct. The BARO sensor reads absolute (psia) not gauge pressure (psig). Absolute pressure at sea level on a "standard" day is 14.69psi (1 atmosphere), being that Portland is ~160ft elevation I bet that's correct. That also means at WOT you're seeing 18.5psig which isn't unreasonable on a stock truck with stock programming.
Thanks for the info, very helpful. It sounds like I am back to a fuel related issue. What gets me is if it was a contamination issue, how contaminates would get past a Airdog and factor filter. Mind you the WIF sensor is deleted, so that doesn’t help. I suppose it is possible that I don’t often use additives the FPR is crapping again.
Also as far as a slight lope at idle I have read some LLY FPRs can tend to create a lope, where as installing a LBZ regulator fixes that issue for some, unknown to me, reason.
To be honest they seem like the actual gold contact itself is melted. Would you happen know where I could find some diagrams to diagnose those pin outs?
So I am going to make an informed guess, it looks like there is a common ground on each harness. Then there is a command and a control for each injector. My FICM seems to be effected on three or more control circuits. I am guessing the command circuits supply the voltage to the injectors, while the control circuits would be switching ground…
Any idea on a way to diagnose the FICM output? Also any reputable sources for FICM repair?
Any idea on a way to diagnose the FICM output? Also any reputable sources for FICM repair?
There is two banks of injectors. Bank 1 = injectors 1, 4, 6, 7 & bank 2 = injectors 2, 3, 5,:8
There is a 96 volt supply for each bank. Then there is individual mosfets for each injector that switch the power through the injector coil to ground. These are labeled as "command"
Then there is 8 individual "control" pins for the signals from the ECM to tell the FICM to "command" the injector
There are two ignition supply that are tied together internally and two grounds that are also tied together internally.
When the FICM finds a faulty injector, either through over current or under current it, really has only one strategy. That is to cut power to the bank that has the faulty injector or harness. This will trigger a CEL and put the vehicle into limp mode
If the control side is faulty or has a bad connection then the FICM main not receive the signal and thus not fire the injector. But depending on the number of controls that are missing it may not trigger a code. I forget how many it was but I think it was two more more at the same time would do it. So of they are intermittent then it may continue to try and run without codes
There is a 96 volt supply for each bank. Then there is individual mosfets for each injector that switch the power through the injector coil to ground. These are labeled as "command"
Then there is 8 individual "control" pins for the signals from the ECM to tell the FICM to "command" the injector
There are two ignition supply that are tied together internally and two grounds that are also tied together internally.
When the FICM finds a faulty injector, either through over current or under current it, really has only one strategy. That is to cut power to the bank that has the faulty injector or harness. This will trigger a CEL and put the vehicle into limp mode
If the control side is faulty or has a bad connection then the FICM main not receive the signal and thus not fire the injector. But depending on the number of controls that are missing it may not trigger a code. I forget how many it was but I think it was two more more at the same time would do it. So of they are intermittent then it may continue to try and run without codes
Awesome, thank you for all the info. It seems that I need to see what it’s doing on the electrical side. I should be getting EFI in the next day or two. Would it be able to show me FICM voltage, or is this a multimeter type of task? What are the possibilities of trying to clean up the pins or do you think the issue goes into the FICM?
I’ll admit, I’m terrible at electrical diagnosis.
I’ll admit, I’m terrible at electrical diagnosis.
EfiLive won't give you any voltage or health information that can help you diagnose the FICM. What you need is an oscilloscope. A regular meter is a skilled user can do a lot but it won't show you the pulses and signals that are happening at the FICM pins.
I'd try cleaning up the pins and if possible even the female pins in the harness side. Then give it a try. You might as well open the case of the FICM and have a look inside to see if there is anything burned up.
Luckily LB7 FICM's aren't that difficult to find and they aren't as expensive as the LLY ones. So you might be better off replacing it rather then having it repaired if it's burned or you can't get it working properly.
But do make sure you inspect the harness connector pins carefully so you don't cause issues with the replacement or your current one if you get it working
I'd try cleaning up the pins and if possible even the female pins in the harness side. Then give it a try. You might as well open the case of the FICM and have a look inside to see if there is anything burned up.
Luckily LB7 FICM's aren't that difficult to find and they aren't as expensive as the LLY ones. So you might be better off replacing it rather then having it repaired if it's burned or you can't get it working properly.
But do make sure you inspect the harness connector pins carefully so you don't cause issues with the replacement or your current one if you get it working
