Hi all,

It's been a while without incedence, so I have not been keeping up on the reading here. Which reminds me I still have a PMD cooler for someone. Anyway, I got nailed by that "great" fuel level gauge in my '95 Tahoe the other day. The gauge said 1/4 tank which is where I usually would have about 5 gallons left and fill up. What it actually had was absolutely nothing. Long story short... I ran out of fuel. So I got a can and put 5 gallons in it, bled the fuel filter, drained the water seperator, and re-bled the filter housing. Started it up after three tries... ran rough, then smoothed out. Drove it to the gas station, then to the park and shut it down. Two hours later, no start. One out of three times it would start and run for about 5 seconds and shut down. The other two times it wouldn't even fire. When it did start it smoked really heavy, black smoke. I got a handful of codes... I would imagine most were from running out of fuel. The one that scares me is the 35 or 36. I don't remeber which it was, I know i didn't get both. Could running it empty have set either of these? The truck has sat for about three weeks now. Should bleeding at the injectors still be done with this IP? Anyone else have any similar experiences with running out of fuel?

Thanks
Sean

Almost sounds like there is still air in there with black smoke... just a guess.

Well,

I had a chance to do some diagnostics this past weekend. I found that the passenger side battery cable bushing was about shot. That explained and solved the low voltmeter issue. I checked out the air bleed on top of the filter housing and there was fuel coming out. I put about six hours worth of run time on it on Friday with no problems. I would assume this eliminates the idea of entrapped air. Finally feeling comfortable with things agains, and wham... it shuts down. It wasn't like it slowed and lost power, it just plain shut off in mid cruise. Pulled off to the side of the road and I was geting the same business I had with it before. It would crank and fire... run for two seconds and shut off. Every once in a while it would fire up and run for 15 or 20 seconds... but very rough idle, and lots of smoke. I hate to say it, but I think I have finally pushed the last bit of life out of the old IP. I have not yet pulled codes, I don't even know that any were set... although I would imagine there were. So, next big question... is it possible to change the IP yourself, or do you need the tech2 to set timing? Also, do I go for a rebuild of the current pump or spring for a new one?

Thanks Again,
Sean

Fuel cap good too, eh?

Pump can be done yourself. It's not "technicially" difficult, just time consuming. You can get a new/rebuilt pump, and then exchange it for yours as a core. I'm hoping that yours is not the original. I take it your beyond the 120,000 mile 11 year warranty now huh?

No, not the original. Was replaced as a warranty job for the original owner at 70,000 miles, I think. I have the paper work on it. What should I be looking for in a rebuild? There is a local place here that can do it. What questions should I be asking them? I also have this knock... but that has been there since I bought the truck. I believe it to be an injector... they are original wit 170,000 on them.

Thanks Again,
Sean

Running out of fuel can damage the IP due to lack of lubrication under certain circumstances. I think that's what happened with yours.

You can replace the IP yourself, but it is a project. If you do it yourself, you need to find someone or a dealer with a computer tuning tool to set the timing right. I think the timing needs to be properly set with readings from the computer.

Just pulled codes and the winning numbers are 18, 19, and 81... Never mind the "81", my heavy foot causes that sometimes.
DTC 18 - Pump Cam Reference Pulse Error
DTC 19 - Crankshaft Position Reference Error
So... does this mean I have a problem with the IP as whole, the optic sensor, or the timing chain and gears? I just checked my lift pump and it has good pressure. Still bugs me... what the hell is going on here? I have had an ocassional "miss" at cruising speeds since I bought the truck. I think someone else described it as a "hiccup". Could this all be related?

Thanks Again,
Sean

Optic sensor will stall it if there is a conflict with the CPS.
To test unplug the optic and crank for 20 seconds+ then repeat it with the CPS unplugged only. The sensor the truck will run without is the failed one.

So,
would the truck run even with bad one hoooked up? And just crap out at random when the two disagree? Could that explain the "hiccup"? I just talked to the local fuel shop today and they quoted me $500-600 for an IP rebuild. I would sure love for it to be so simple.

no, the truck will not run with one bad one, it will stall, but as I wrote, it will run with one good one.

You can buy a DS-4 core from ebay for ~$20, chances are if you buy two of them you will have enough spare parts for your IP. Just switch lids(with optic) and your done (if it is determined to be the optic that is).

Sorry I should have phrased that as... "the truck would run with both sensors hooked up, even if one of them was bad?"
edit- although it would stall intermittently?

Same dealy-o.
but yes, it would run but then stall.
Figure the optic, but make sure it won't run on only the optic before spending money.

Going to check it right now

Ok,

I unhooked the three-wire connector running down toward the harmonic... I cranked it for about 20 seconds and got nothing.
I then re-connected the three wire connector and disconnected the five or wire (kind of dark and hard to tell how many wires) optic sensor connector... I cranked for about 20 seconds and it fired... ran real rough and a lot more diesel clatter than I have ever heard from that thing.
I thought I had better recheck the three wire just in case it did run on both...
I hooked up the optic and unhooked the CPS... cranked for 45 seconds (not continous cranking)... nothing.
So, based upon your judgement QM, which I respect and hold in very high regard, I need an Optic Sensor?
Next question, where can I get one those rather quickly? How much should it cost? And, can I change it without having a scanner?

That's my thinking, yes.
you can change it without a scanner and bump it at the same time. Have you seen canadian riggers optical bump pics?

Also a new optic cost~$260 but I've read that fuel injection shops may have old ones with broken clips they won't reuse.

Ouch... $260, really?

If you were a diesel injection shop it would probably cost less :)

Just called Eau Claire Diesel... $304.40. I have to find something cheaper. I will start a new thread on availability of IP parts, as I am sure others will find themselves in similar situations.
Thanks Again For Your Help QM,
Sean

My thinking on this is that an EFI 6.5L owner should have spare DS-4 pumps on hand for these situations and as a learning/reference aid.

It's kinda fun to take them apart and watch all the tiny pieces fall out and realize you're in the dark as to how it goes back in. I'd suggest pulling the head off and looking at the infamous Fuel solenoid armature that the PMD operates.

I remembered the clencher. Start it with the optic unplugged and then as it idles plug it back in. If it stalls the optic is bad.

If you had a scanner you see interesing numbers from timing , generally just erratic numbers that the ECm can't follow.

It's too cold out tonight to play around with wires. Maybe I'll get it in the garage tomorrow and have a look. What you are saying makes sense though...

It runs until the the computer sees that a timing change is "needed" when you plug th optic back in... It then over compensates and advances/retards it to death. Is this the thought process you are going with?

ok, next rediculous question... could a worn timing chain and/or gears cause of any of this?

Had the same code pattern as you did easyest thing was to change the crankand cam sensers made biggg difference no stalling or erratic jumping was gone