7.3L diesel stalling

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Aug 31, 2000 | 09:12 PM

goody

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7.3L diesel stalling

For all you diesel folks. I have a 91 F-250/ 7.3L with 68K miles. Just recently the engine tends to stall out particularly when coming to a stop where the clutch is in and other foot on the brake. The idle speed will sometimes drop below 500 rpm and the engine will halt. Normal idle is around 600-650. However the engine runs fine as long as the fuel pedal is used. I have a new fuel filter and have also tried some marvel mystery oil in the filter to no avail. Anybody out there run into this problem and find a fix? It is though something is sticking inside the roosamaster injection pump.

Thanks for any info---Goody

Sep 1, 2000 | 07:26 PM

deleontow

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From: Banning CA

7.3L diesel stalling

[font size="1" color="#FF0000"]LAST EDITED ON 01-Sep-00 AT 08:28 PM (EST)[/font][p]If your stalling is just an idle problem, then just readjust your idle screw. IF the problem is something else, please give more info. You may also have an air leak, if it is an air leak, then the truck will surge before it stalls. Suggest you advise. Other than that, you may have the injector pump starting to go bad.

Dave

http://a2ztowing.homestead.com/a2ztowing.html

Sep 1, 2000 | 08:56 PM

goody

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7.3L diesel stalling

Thanks for responding Dave.
I have already tried the idle adjust screw. When engine is cold the solenoid kicks in and brings idle up to about 800-850. After warm up the speed drops to about 650-700. That is fine when just sitting still without foot on accererator pedal. However, when for example I'm in 3rd gear and I come up to a stop light, I take my foot off the accelerator pedal and hit brake and clutch. As I take my foot off of fuel the engine speed wants to dip down low (500 or less rpm) just momentarily before it settles at 650. Sometimes it stalls. Not all the time. It is unpredictable when it will happen. It does not apppear to surge (air leak). It seems like a rate thing. If I could always take my foot of the fuel pedal slowly I don't think there would be a problem. I can't always do that though.
Do you think it is the injection pump? Can they be repaired at home with a rebuild kit of any kind? ( I know it is clean room conditions only)
Thanks for any inputs---Goody

Sep 1, 2000 | 09:58 PM

buckwheat

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7.3L diesel stalling

Sounds like the metering valve in the injection pump is sticking. This could be caused by water in the fuel, or possibly deposits on the valve. A new valve is about $20.00 to $25.00 if I remember right. The valve is not that hard to get to, but you really should have somebody that knows pumps do it. It is under the top cover. I don't think you need a total rebuild if this is your only problem. The Stanadyne pump is the easiest one to work on, look for a fuel shop in the phone book, they should be able to do this in an hour or less.