Woes with a 2004.5 LLY Dmax repeated P0089 Fuel pressure regulator codes.

Pretty much all I can grab for freeze frame.
It errors out when I try to save the data.


 
Buddy of mine has same truck but a GMC, I am going to hook the Solus up to his and see what it shows on his truck,
Main thing I want to look at is the if the actual FPR is jumping around like mine is.
 
Don't need graphs, and I need all the data, not just the fuel related parameters.
 
Buds truck shows same fluctuations on the actual side. But his shows correct actual and desired.
355k miles on it and it runs perfect, mother fucker.


 
Checked the resistance on the 3 wires going from the big connector to the FPR.
All checked good no resistance.
 
If you aren't backprobing it under load, you aren't confirming anything. A single strand of copper wire will show zero resistance, but you aren't going to carry much current through it, and will have a massive voltage loss under load.
 
SRGN said:
If you aren't backprobing it under load, you aren't confirming anything. A single strand of copper wire will show zero resistance, but you aren't going to carry much current through it, and will have a massive voltage loss under load.
Click to expand...

I hear ya, wanted to make sure ground was good. In the harness there are 2 wires that go to ground on the block.
 
Verify zero volts on the grounds going to the ECM by back probing the ground pins on the ECM connectors, with the engine running.
 
Correct me if I am wrong here, I don't see a ground in this list and yet I had the black wire on the FPR connection show no resistance
on one of these pins.

c107-connector.png
 
Low reference is basically ECM filtered ground for our purposes.
 
From your diagram above does C1,C2 and C3 mean the connectors?
There are 3 that go to the ECM
 
Here is something the des fpr (mA) 1513 actual 3
Compared to buddys truck in the above post I did yesterday it should be same. 1358 give or take on both act and des.

 
So I ripped apart one of these FPRs.
I think this one was actually good, it is the only one that moves, all the others I can't get to move.


 
Buddies truck threw a code tonight, and he can't check to see what it is, why?
Cause I have his scanner, whoops :ROFLMAO:
Told him I sold it for crack.
 
If it's reading current, and the current is below what's expected, it's usually indicative of an open circuit. Check the ECM grounds under load. If something is back feeding through the FPR circuit to find ground, it will burn up the FPR. Check the resistance of a new FPR and compare it to a bad one to confirm.
 
SRGN said:
If it's reading current, and the current is below what's expected, it's usually indicative of an open circuit. Check the ECM grounds under load. If something is back feeding through the FPR circuit to find ground, it will burn up the FPR. Check the resistance of a new FPR and compare it to a bad one to confirm.
Click to expand...

Do grounds go to one point or are there various ground locations.
I know I need to check each ground right at the ECM and then go from there.

The 2 grounds that are on the engine side harness are located down by the r/s engine mount and the drivers side battery grounds to drivers side
of engine down by the mount. Can't remember off hand where passenger side battery ground goes.(might be same place as the where engine harness grounds are.

I will do more digging this weekend.

One other thing I noticed in my emails to S&S Diesel the fuel pressure was stuck at 12k and now this time it's stuck at 8k
These FPRs are seizing up and I think the ones that make noise are physically broken inside( I can't get them apart though for some reason, I think
these might be the Ebay fake ones)
 
Check the grounds, by back probing the pins and measuring voltage at the ECM with the engine running. With the ground lead of the meter on the battery, you should read zero volts with the positive lead on this ground pins at the ECM. I'm pretty confident at this point, that the FPR failures are a symptom and not the root cause.
 
Lowrider said:
Grounds to ECM is showing .07 volts
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That's not good. Verify that the meter doesn't have an offset. 70 millivolts may not sound like much, but it's huge in electronics.
 
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