hmmwv has issue starting when warm

Hello I am a newbie to posting, first time doing this. I have a 1998 m998 had it for 3 years now, I'm starting to have an issue with it when it is warm. vehicle starts fine when cold or first start up. when warm it will crank and eventually start bunch of grayish smoke.
check the wait to start light when cold it turns on about 7-10 seconds vehicle start fine after it is warm wait to start light flashes monentary. I found out that if I cool the sensor (kds yellow band) pour water on it the wait to start light stays on 7-10 seconds and vehicle starts fine. I have a smart start natron box. tested gp with ohmmeter and are good. I replaced the temp sensor with a new kds yellow band and have the same issue . vehicle will start fine If it cools on its own or if I shut it down and start it in 10 min. any suggestion on what to do or check. thank you.

Have you changed the fuel filter lately?




Sent from my iPhone using Tapatalk

Hello , I changed it when I bought it about 3 years ago. Vehicle has approximately 4000 miles on that filter.

Do these vehicles have anything that functions close to a choke. Is it possible something is functioning like a choke that is cold?

Thinking along the lines of a gasoline engine, so sorry if I’m wrong.

tdad11,
this may help.

MODEL: HMMWV FOV

SUBJECT: HOT ENGINE RESTART COMPLAINTS

COMMENTS: Based on input from the field and information from the manufacturer of the Fuel Injection Pumps, it is possible your vehicle may experience a hot engine restart problem. If your engine is hot and you are getting a no start condition, the following information should help:

First, make sure you have run through your Top Level Engine Test and the Fuel System Test in the Troubleshooting Guide of TM9-2320-280-20-1, dated Jan 96. If all efforts have been exhausted, through the troubleshooting procedures and you still find that your vehicle is experiencing a hot no restart condition, identify the fuel injection pump model number and serial number.

It seems that some pre-1994 GM 6.2L and 6.5L DB2 Fuel Injection Pumps may experience a hot engine restart condition. To address the issue, Stanadyne implemented a design change to the hydraulic head and rotor assembly. The hydraulic head and rotor assemblies originally used on these applications have been superseded as outlined in the table below.

Head and Rotor Assy
Model Pump PN/NSN Serial Number Break Original PN New PN/NSN

DB2829-4523/2910-01-199-2355 7539307 23122 or 28396 31816/4320-01-317-0692

DB2829-4879/2910-01-326-9221 8064583 23122 or 28396 31816/4320-01-317-0692

DB2831-5149/2910-01-414-1272 7768648 29124 31506/2910-01-414-5382

DB2831-5079/2910-01-434-8597 7768648 29124 31506/2910-01-414-5382

NOTE: All Fuel Injection Pumps with PN DB2831-5209, NSN 2910-01-467-9029 incorporate the improved head and rotor assembly, PN 31506.

If your serial number is less than shown for the serial number break below, we recommend the fuel injection pump be replaced, tagged as a hot no restart condition and forwarded for rebuild. Replacing just the Head and Rotor Assembly alone may NOT completely resolve the problem. Depending on the pumps prior usage, it may be in a worn condition and other internal components may have to be replaced also to make the pump operate in manner that will allow the engine to run properly. We have no testing data available that will fault isolate the problem to the head and rotor assembly and/or worn components.

These tagged fuel injection pumps will need to be rebuilt in accordance with TM9-2815-237-34, dated Jan 96, paragraph 2-32, making sure all worn components are replaced with new and the old head and rotor assembly replaced with the new improved head and rotor assembly, per the chart above. These pumps will not need to go through a pretest analysis because they will more than likely not shows signs of the problem.
We have ensured that these new Head and Rotor Assembly part numbers are incorporated into the next change to TM9-2815-237-24P. However, the current engine RPSTL, dated Jan 96, Figure 19, Item 25, still shows PN 28396 as the correct head and rotor assembly for DB2829-4523 and 4879 model pumps. We recommend a pen and ink change be made until the new updated TMs are published and available through Pin Point Distribution.

PUBLICATION AFFECTED: TM9-2815-237-34
TM9-2815-237-34P

LEVEL OF MAINTENANCE: Direct Support/General Support
















]778302[/ATTACH]

As stated, worn out pump...this was more of an issue in m1009 and m1008’s early on...but It’s time for a new pump.

Thank you for the information, sorry it took so long to reply. I was informed that the timming could be an issue. I checked the timming and the lines were straight up. i was informed to adusted for altitude and possible wear. i advanced it 1/8 from the mark and that seems to do the trick. vehicle has more power and starts faster. thank you all for the help.