Okay - I have a hard start when warm and sitting.

Truck is a 1997.5 Hummer H1, 6.5LTD w/DB4 IP. Remoted PMD outside of the engine bay with 2006 date code and a new #5 resistor. Boost fooler shut off.

I'm experiencing the hard start only when the truck was run for a while, then shut down for at least 30 minutes. I've redirected the windshield washer stream output to the IP and the remoted PMD.

30wt oil added to the ULSD at 1qt per 10 gallons made no difference.

I plugged up the remoted PMD washer stream to see if it was the IP or PMD, and when the IP gets sprayed with warm water, it starts.

So - can a DB4 that's been rebuilt to 5521 specs have a worn rotor?

Here's the checklist...
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1. Does the engine Turn over? [yes]
1a. Does the engine start? [yes, but when cold or recent start]
1b. Do you have a Wait To Start Light & duration lit. [yes]
1c. Ambient Condition (temperature outside) [100*F plus]
1d. Engine Cranking speed (if you have an accurate tachometer). [250rpm via Scangauge]
1e. Are you experiencing stalling? [no]
1f. If Stalling, describe (upon startup only, down the road, hit a bump etc) [n/a]
1g. If Stalling, do you notice loss of dash or instruments? [n/a]
-note if experiencing stalling,you must indicate PMD location in #24.1.1Lift pump test (http://dieselplace.com/forum/showthread.php?t=39350)- describe results [Pass - fills a 1 liter soda bottle very quickly. Replaced 7 months ago]

2.Service Engine Light - on/off/intermittent [off]
3.Model year [1997]
3a. Odometer reading [79000mi]
3b. Miles on major engine components if been replaced (example Injection pump) [IP at 50,000 with rebuilt DS4]
3c. Indicate the model number on the Injection pump (starts DS4 or DB2......)[DS4831-5288]
4. Have you scanned for engine codes? (varies by pre/post 96) yes/no [Yes, with a Scangauge and a AutoEnginuity scanner]
5. List exact results on engine codes: [No codes found, none stored]
6.Air Filter condition (visual check) [Replaced and new]
7.Fuel filter condition (freshly changed or condition unknown) [Replaced and new]
8.Condition of Battery terminal connections (removed, cleaned and tightened) [Cleaned 20 days ago]
8A.Known condition and age of the batteries. [New, 20 days old]
8B.Are batteries of differing age or are they a matched set? [Matched Set]
8C.Condition of Major Grounds (http://www.dieselplace.com/forum/showthread.php?t=157085). (same drill as batt - removed, cleaned, retightened) [Cleaned and checked 20 days ago]
9.Upon cold start, does the radiator hose get hard quickly? Yes/no [No]
10.Upon cold start, do you have excessive white smoke? Yes/no [No]
11.Do you have excessive cranking time before the engine starts? [Yes, only when warm]
12.Have you used the block heater, and does this effect engine starting?(only try for starting problems) [Yes, normal startup]
13.During hard acceleration, do you have excessive black smoke? Yes/no [No]
14.Do you have any unusual exhaust smoke issues? [No]
15.Turbo check out (http://dieselplace.com/forum/showthread.php?t=39368)- pass/fail [Pass]
16.Do you have an EGR on the engine? (An F or an S engine code) [Yes, replaced at 76,000 miles]
17.Indicate if you know if it’s a 1500, 2500, 2500HD, 3500, 3500HD. [n/a]
18.Indicate fuel that you are using: Bio-diesel, #2 Diesel, #1Diesel, SVO/WVO, other [ULSD #2]
18a. If running a VO setup, indicate details of your conversion (homemade, or packaged system)[n/a]
19.Are you using any fuel additives? If so, please list. [Stanadyne PF or Power Service Diesel Kleen Gray bottle]
20.Please indicate geographic region you are in: (example: Texas or Canada) [Phoenix]
21.Do you have any service history available that might pertain to the problem you are having? [no]
22.Please indicate any modifications to the vehicle that might help us diagnose better. [Boost fooler, shut off. Windshield wiper fluid output redirected to spray the IP and the remoted PMD]
23.Upon unscrewing the fuel cap (http://dieselplace.com/forum/showthread.php?t=42338), do you have a large vacuum formed in the tank? yes/no [no]
24.Location of PMD/FSD (http://www.dieselplace.com/forum/showthread.php?t=39436)? On the pump/remoted over intake/remoted out of engine bay (please specify specifically) [Remoted out of the engine bay]
25.Are ALL glow plugs in proper working order as per this thread (http://www.dieselplace.com/forum/showthread.php?t=39182)?
[Yes - fully tested]

Pump is bad. Don't direct any water on it while it's running or it could seize up.

Wow. After nearly 30k it's bad again? Ouch.

-Steve

Pump is bad. Don't direct any water on it while it's running or it could seize up.

If your truck starts cold OK and runs warm OK -- but has hot start problems, it might not be the IP. Try replacing the OPS. As the FAQs for Lift Pump / OPS state, the OPS is a known trouble spot, a crummy $30 part that can fail early and often. I had a lot of trouble with the OPS / Lift pump combination with stalls and hot start problems. Finally upgraded (see sig.) and the problems went away.

Pump is bad. Don't direct any water on it while it's running or it could seize up.

ditto on this, the clearances in the pump are already very tight. Heat expands, cold contracts, if you try to cool the exterior of the pump while the inside remains hot it will sieze.

Well, the starter blew today. Quite spectacular too - when the starter seized, it blew half of my fuses too.So, its the starter, despite the fact it was cranking pretty good.

Update - replaced the starter, fixed the fuses, starts fine with a warm sitting start.

So - even if the starter is putting out what appears to be good RPM's, it might be on it's way out......nice....

Nice, I am having the very same problem, hot start drains the batteries nearly immediately. If I restart it within 15 minutes or so it is fine, or if I wait a couple hours it is fine, but that 1/2 hour to 1 hour window is a no-go. I have new batteries and new battery terminals. I was thinking it might be a starter issue before I stubmled on this thread. I had been thinking of the guys with headers on muscle cars that seize up the starter due to the heat. Time to get dirty I guess. :(

Well, changing out the stock starter on an H1 is a royal pain in the rear. The stock starter is 70lbs (it's a sealed marine starter), uses 0/1 Welding wire to the batteries, and you have to remove all sorts of undercarriage protection for this.

Replacing it with the standard 6.5L TD starter (which is 18lbs) is really nice. The gear reduction unit spins like a mother and it's faster starting than the marine unit.

I've got some header reflective wrap that will be protecting the starter and it's associated cables, since the positive wire runs really close (too close for my comfort) to the passenger side exhaust header.

-Steve

I put in a new Bosch starter for the 6.5l turbo diesel and it spins about 10x as fast as whatever was in there. It starts instantly hot or cold. :D