still need help

[dgrund61]

I posted a thread about stumbling on my 98 chevy 6.5td and I still need help. I have checked: Lift pump 3-4 psi at 2000 rpm,replaced fuel filter, bled several times . when running, good stream at fuel filter,cleaned all terminals battery and grounds, clean speedo sensor, helped a little, purchased used pmd and remote mounted it, with ground still on ip although I lengthened the ground, soldered the connections. Stumbles @ 1700 - 2300, rising up and down then holding then erratically, go back up. Questions: could be a bad injector(s), could it be optical sensor? Around 50000 on ip and pmd. Checked fuel cap left it loose, still didn't help. Running out of money and patience. Please help

[quickv6]

I posted a thread about stumbling on my 98 chevy 6.5td and I still need help. I have checked: Lift pump 3-4 psi at 2000 rpm,replaced fuel filter, bled several times . when running, good stream at fuel filter,cleaned all terminals battery and grounds, clean speedo sensor, helped a little, purchased used pmd and remote mounted it, with ground still on ip although I lengthened the ground, soldered the connections. Stumbles @ 1700 - 2300, rising up and down then holding then erratically, go back up. Questions: could be a bad injector(s), could it be optical sensor? Around 50000 on ip and pmd. Checked fuel cap left it loose, still didn't help. Running out of money and patience. Please help

MY truck in now doing the same thing but at all RPMs intermittent. Just stumbles and occasionally will die when comes back to idle. PMD?

[93GMCSierra]

I was speaking with a diesel tech about my truck stalling when coming to a stop, from high idle it just stalls when I push in the clutch, he mentioned a sticking valve in the injection pump as the most likely culprit, an recommended a fuel additive in the Ultra Low Sulfur that is sold now, as the valve is probably not getting lubricated enough.
And after adding some Standyne it went away.

[gmctd]

Any SES or DTC's?

Lonnie, at 450kmi, has the IP ever been close to a wrench? That's typical IP failure if you've verified the fuel supply system - if that's original injectors, they ain't helping matters, any.

What about injector mileage, dgrund? And what's total vehicle mileage?

[quickv6]

Any SES or DTC's?

Lonnie, at 450kmi, has the IP ever been close to a wrench? That's typical IP failure if you've verified the fuel supply system - if that's original injectors, they ain't helping matters, any.

What about injector mileage, dgrund? And what's total vehicle mileage?

The Injection pump and PMD (stock location) has about 170,000 miles on them. Injectors are oem 467,000 miles as of today. The truck ran fine most of the day today smooth as silk. Then later in the day when I would come to a stoplight it would die. I checked fuel pressure is 4.5-5 psi. The fuel pump is hot wired (runs with key on). Changed fuel filter last week. This problem just started yesterday. I was hoping to keep this thing running till I got the pistons cut down 18.1 for the new engine. No ses light of any kind. No codes.

[JohnC]

The two biggest causes of stalling with no codes are fuel starvation to the IP and the PMD. The PMD shouldn't care if you're stopping or whatever.

Mileage-wise you're WAY overdue...

That said, it could be a bad connection somewhere.

[gmctd]

Also a fresh load of bad fuel - 'bout the time of year it starts happening - when was your most recent date with the pump?

[dgrund61]

in response to your question, I assumed that the injectors were changed at same time as the pump, but could be original (160,000). Also just put cetane booster and lubricant in the fuel tank. The guy I bought it from ran it near empty for awhile,so don't know if that is causing any problems. Also noticed that it is worse for the first miles of driving.When it's parked and you raise the rpms, it tends to run smoother above 2300 rpm. It's just that area between 1800 & 2300 it may run smooth and then suddenly it will drop a few rpms like it's just had the fuel shut off or not hitting on all cylinders.

[quickv6]

I dont know if this is your problem but I has similar issues as you describe. The OS filter was the problem. The truck had the problem for a week no ses light no codes. Last night for the first time I got a code 18-19. Searched for problem here and found the optical sensor filter might be an issue. I bypassed and truck now runs great. Good luck

[Kenneth]

I had an oil pressure switch that went bad and had some of the same symptoms as a pmd failure. The truck would idle for a minute or so at startup and then die. It would turn over for about 10 sec and then start. While driving if I tried to floor it, the truck would run great up until around 2000 rpms, and above that it would miss and run really rough, there was a whole lot of black smoke. Although going the freeway at 75 mph the truck would sparadically miss. Heath Diesel told me to check the oil pressure swtich by letting the truck idle. Then go and open the fuel drain valve at the front of the motor. If the truck dies and no fuel comes out of the drain tube the pressure switch is bad. But if the truck dies and fuel comes out the pressure switch is not bad. I know it sounds pretty lame, but it only takes 5 min. to check. And the pressure switch is only like $25 and takes 20 min to change. It may not be the pressure switch but it won't hurt to check.

[gmctd]

With no SES amongst either of you guys, it's likely either fuel supply or electrical, in the grounding and engine harnesses, maybe a dash of PMD\FSD - may be a dead bulb in the SES indicator, maybe the STS, also - do you ever see SES illuminated?

VHM - very hi mileage - is also very scary on original injectors - 160-170kmi is vhm for any IP - the '94 has the problematical OS Filter, likely also has IGN switch issues - the '98 may have IGN switch symptoms

You can't just look at the grounds and bless them - remove the fastener, separate the individual terminals, wire brush each to a high lustre, reassemble the stack, bolt'em in and cinch'em down - eliminates myriad of intermittent-type complaints - same with the dual-connected passenger-side battery cables.

Separate each wiring connector, inspect for oxidation\corrosion, reconnect each - that action serves to burnish the contacts, also known to eliminate intermittents.

[quickv6]

I personally replaced Battery cables both battery's including cross over wire. Checked every wire I could remove cleaned and reinstalled. Replaced the PMD with new remote mount unit. Replaced the Lift pump with new and made 25 amp relay hot wire that keeps pump on with key. Installed fuel gauge to check fuel pressure while I was driving the truck. Checked voltage with Datalog multimeter to see if had a voltage drop. None of these items fixed anything. They needed to be done but got me no where. After 7 days of this the SES light came on for about 1 minute then went out. I checked for codes and there was stored codes 18-19. I looked up the info on this sight and decided to try the OS filter. It worked truck runs great. I reinstalled the OS filter and truck ran like crap again. Still no SES light but did have the codes. The light illuminates every time I turn on ignition. After 3 days truck still runs sweet.

[gmctd]

Good - see if it'll run, minus the OS Filter, without missing\skipping - if not, getta new one from Bill Heath - other stuff still applies at vhm

[Kenneth]

I didn't even think of the o/s filter. I actually had that replaced with one from Heath Diesel (they use a genuine GM filter) before I found that the actual problem was my pressure switch. Good luck.

As far as IP. I have 152,000 miles on my truck. The injector pump was replaced under warranty at i think about 30 or 40K miles (my grandpa bought this truck new). I replaced the injectors this may and they were the original oem injectors and were spotlessly clean! No soot, no buildup of carbon, nothing. They were clean! I started using Lucas injector cleaner in every tank of diesel since last October until I replaced the injectors. I was shocked and in fact almost put the original injectors back into the motor. But decided it was the right time to replace the injectors. They lived a long healthy life! twice the life what GM tells you to run them. My pump is still running strong. In fact I still get a healthy bit of black smoke under heavy acceleration, which tells me I am getting enough fuel to my motor. Although, I better not jynx myself. Who knows, my pump could go out at anytime.

[quickv6]

Good - see if it'll run, minus the OS Filter, without missing\skipping - if not, getta new one from Bill Heath - other stuff still applies at vhm

It does run good without but was going to install new anyway

[Kenneth]

I noticed in your vehicle listing you have a holset HX 35 turbo. Did you have to get any modifications for it to bolt on your existing setup? How high are you able to run the boost? I noticed in the holset webpage this turbo is meant for 100-280 hp. How does this turbo run? And how much did it cost you to install it?

[quickv6]

I noticed in your vehicle listing you have a holset HX 35 turbo. Did you have to get any modifications for it to bolt on your existing setup? How high are you able to run the boost? I noticed in the holset webpage this turbo is meant for 100-280 hp. How does this turbo run? And how much did it cost you to install it?

The HX35W bolted right on. The turbo drain was close the oil feed the same. Downpipe was a challenge to make the turn before the a/c dryer. I have not finished the intake for the air filter yet. The HX35 is 4" inlet with ported shroud housing. The new engine is not in the truck yet so I only had the turbo on the old engine for 1 day to get it up and running for the new engine. The truck ran like a raped ape night and day difference. The boost started at 22psi I had to work on the waste gate to get it down to 15. Then I pulled it off and the GM8 went back on. Like someone cut the balls off the truck. Much more back pressure with the GM8. The HX35 has less engine braking like the truck was coasting. With a stainless down pipe and cost of turbo I am at about $400 right now. I am going to say when complete around $500 including the cost of the turbo. Just be careful when you buy an HX35 there are many configurations of that turbo and some are not even close. Mine is the W.

[quickv6]

http://cgi.ebay.com/ebaymotors/Dodge-Cummins-Diesel-Stock-Turbo-12v-or-24v-HX35_W0QQitemZ170154810507QQihZ007QQcategoryZ33742 QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Exact turbo I have with flat plate bolted to exhaust housing that I mounted a V-band on to for down pipe