I,m getting codes 251 & 370 what to do??

[wlrdlr49]

I have been having drivability problems lately. Running rough at idle at stop lights. Today after exiting the highway it died at the end of the ramp. Got it refired,drove home w/check engine light on. It is pulling codes 251 & 370. Running very rough but running. #251-Injection pump metering control A, #370-Timing reference high resolution signal A malfunction. What needs to be replaced or ??? Thanx for your help in advance.

 

[JiFaire]

When did you relocate your PMD? Give some details about that... was it a new one? Where did you put it? Did you make or buy the harness, and who from?

Also, are you using any additive in your fuel? (just curious on that one)

PO 251 is an IP code, but seen together with PO370, it may indicate a possible electrical issue rather than a mechanical transient.

 

[wlrdlr49]

I made my ext. cable & moved the PMD to the opening in the front bumper about 6 mos. ago.It was a used PMD. I just put some Lucas fuel treatment in it 2 days ago. I filled out the checklist a month or so ago. How do I include it?

 

[JMJNet]

Well, if I were you, try to get a new PMD. Moving it outside does not mean that you reverse the damage or cooking of the electronics inside the PMD.

Have you tested the LP?

On another note, Lucas may be good for gasser but according to the lubricity study at DieselPlace, it does not do well in Diesel fuel. If you want to increase lubricity, add biodiesel or 2 stroke/cycle oil.

 

[wlrdlr49]

Just put a new fuel pump on 2 weeks ago. I am going to order a new PMD & cable tomorrow. Hopefully that will do the job. Thnx

 

[thedole]

I have had those codes going for an embarrassing long time, combined with hard starting and driveability issues. Fixed it yesterday by replacing the optic sensor and boy what a difference a day makes. I got a new truck again, I didn't even remember how well she was supposed to run. I think maybe I had issues even before I first realised I had a problem..

 

[Brooklyn Tow]

Dump a qt of sae 30 nondetergent motor oil (new) and clear the codes.....see if they come back.

 

[wlrdlr49]

I replaced the optic sensor around a year ago. Do they fail often? Are you wanting me to put the oil in the fuel tank? What will that do?

 

[matuva]

That will restore lubricity in fuel, if you're using ULSD which is too dry. Sometimes it's enough to get rid of these IP codes, sometimes not, but it's really worth a try.

 

[wlrdlr49]

It cleared the 370 code but not the 251. My cruise control quit at the same time.

 

[JiFaire]

It cleared the 370 code but not the 251. My cruise control quit at the same time.

<sniff, sniff> I smell baked PMD.

 

[Brooklyn Tow]

Bingo!

 

[JMJNet]

The cruise gives a hint that PMD may be the culprit.

Check all your grounds and also the battery cables.

 

[wlrdlr49]

THANX for the help !!!!! I will get a NEW pmd tomorrow.

 

[thedole]

My cruise went out (and came back) with the optic also... I so enjoy having it back!

 

[iamdave0887]

When i had those two codes i had a bad lift pump. it put out 0 psi at WOT and maybe 4-5 at idle. Changed the LP with one from a 93 K3500 and had 10 psi w/ truck off(key in run), 8 psi idle and 4-5 psi WOT. P0370 never came back.

later on i found out that the P0251 was from a bad optic sensor filter harness as it kept kicking up that code after the LP change. It was also accompanied by a random misfire. The engine would cough violently once and then be fine for hours. After i removed the Os filter harness and hooked the truck's harness back up directly to the Optic sensor, the P0251 was gone as was the random misfire.

 

[wlrdlr49]

Can you explain the optical sensor filter harness? Where it is etc. Thanx I just put a new pump on.

 

[BigArt]

Check this short thread. http://www.dieseltowingresource.com/showthread.php?t=13188

Art