DS4 pump and Hot weather

[Robyn]

Well it seems that the heat (106F) got to the Burb today.

Since I have owned the thing its always been a tad anemic in the Hot weather.

This is the hottest weather I have seen here in a long time and way hotter than anything the Burb has been through sice I have owned it.

This afternoon I rolled in and shut it down and a few minutes later went to do a restart, it wound up but run very slow and sounded extremely shy on fuel (very little rattle) within a short time (3-4 seconds) things came right up to par. I shut it down and waited about 5 minutes and did another restart, same thing again. No codes showed up.

I am thinking that with only 1/2 tank of fuel and the extreme heat that the fuel was very thin and probably the IP is getting some serious time on it now, leading to the plungers not being able to deliver the fuel pressure needed to make things go.

This rig has the 5068 IP and it was rebuilt or ??? has a green tag I believe.

Will check the fuel filter as soon as I can but I doubt that there is anything amiss there, never know though.

Now I am begining to think that the IP is getting tired as the thing runs sweet in the colder weather, starts great at 15 F but hates the heat.

Any input here is welcome.


Missy

[ToddMeister]

Is the PMD still on the pump or remote mounted?

On my 95, the IP will act goofy in the heat with the USLD fuel. I add some 2-stroke oil to every fill up now, seems to cure that problem. My PMD is remote mounted in front of LH battery.

Fortunately, our summer has been cool, only one day so far over 90 degrees.

Crops are few weeks behind, wheat crop is normally harvested by now, this year harvest is just beginning this week.

Seem to be alternating between cold and dry, and cold and wet spells.

Oh well, the power bill will be very low this summer. :)

[Hubert]

Stanadyne was suppose to have accounted for the location of the IP being in the valley of the engine and compensated for elevated fuel temperature.

It does measure fuel temp and I thought it compensated for it but never have seen how. Only thing I have seen written about it was Jim saying it will code if over something like 257F ? There is a thread ? on it from me and a post on it from Jim.

I originally thought feeding the beast's performance gains were to better fuel circulation and reduced fuel temps. But now think it could be a combination of better fuel fill of plungers at high fuel rates with the less recirculation pressure in the IP when all the fuel is injected by the fuel solenoid AND maybe cooler fuel. But am leaning less on the cooler fuel since now I don't think more recirculates back to the tank with feeding the beast mod and better fuel lift pump.

HOT heat soaked fuel will have lower viscosity and will "leak" past plungers etc and not be as crisp injection. It will also have reduced lubricity.

This is a reason some like the 180F theromstats with the DS pumps & PMD in warm climates.

[Robyn]

The PMD is remote mounted down under the radiator on the inside of the skid pan that folds down. (Bolted to a large finned heat sink too)

I had a similar situation with a NO start on Sunday and assumed it was the PMD going away.

The other possibility of the funny start with the engine barely running could be a shut off solenoid that is not opening properly.

The sluggish running in the heat though is got to be a IP issue. Has done it every summer since we got the thing.

Took it out this morning and all was fine. Ran just as it normally does with all stock turbo/vacuum controls and factory original exhaust at 270K miles.

Not gonna set the road on fire but it just gets me here and there.


Once this heat goes away, I dont expect to see any issues again.

Missy