Common problem, 6.9L will not stay running.

[Sixnineliter]

Ive seen this question and this problem posted countless times but i havent seen any exactly like what is going on with mine. I have an 85 F250 with the 6.9L and 4 speed standard. It has 77k on it and has sat a majority of its life. So, the problem. I FINALLY got it to start, it starts and smokes alot but instantly shuts off. It will not run for more than 5 seconds, unless i pump the throttle a bit but it runs very rough and is unresponsive. It starts easily but just wont stay running. So at this point this is what ive replaced: Both batterys, starter, starter solenoid, terminals, fuel filter, mechanical lift pump, new solenoid on the injection pump, and ive gone through all the fuel lines which look like new. Cant figure it out!! So at this point im thinking maybe the injection pump its self. Any ideas would be appreciated

 

[Kevin 007]

Sounds to me like air intrusion for sure. After sitting all those years, rubber lines and seals dry up and start leaking. I would replace ALL the rubber lines between the injectors and the two o-rings under the injector cap and all the caps. You can get all of this in a kit for pretty cheap $50 or so. Contact Russ who is a user on here who goes by the name Type4.
Also replace the rubber line just ahead of the lift pump.

When cranking the engine, are you getting a steady stream of fuel at the filter? You can check this by pressing the little "tire stem" valve on the filter header while the engine is cranking.

As for the IP, just put that on the back burner for now until you are certain its getting all the fuel it needs with NO air.



And welcome to the forum!!!!!

 

[icanfixall]

Welcome to the forum. I did not read if you have replaced the fuel filter yet. Checking for fuel flow from the filter is a good idea. Are there any wet places on any of the fuel lines or at an injecter. For the engine to run for only a few seconds tells me there is a fuel delievery problem. Finding the reason can be easy or tuff What kind of fuel filter system are you running. In 1985 the fuel filter system was less than useable. They often leaked if you drained the bowl when checking for water in fuel. Some just replace them with what the 7.3 engines use or go aftermarket. Being an 85 truck the engine could have been upgraded to any form of an idi unless you know this truck well.

 

[Sixnineliter]

Thanks for the fast reply Kevin. Im deffinetly going to look into the fuel line kit. Yes the filter gets PLENTY of fuel, ive had my friend press the screw while turning over and there doesnt seem to be any air bubbles which I have seen before. I didnt mention it but the fuel filter was of course the first thing i replaced. One of the injectors has a couple of clamps around the line, maybe was leaking? The filter system works well. Its drivers side mounted right up front, but i have seen 6.9s with a filter that mounts passenger side towards the back.

 

[IDIBRONCO]

I haven't seen the filter locations that you're describing. Most Ford applications have the filter at the front on the passenger's side. International and vans have the filter on the driver's side toward the middle of the engine. Those filters have a mount that bolts to the top of the intake manifold. Russ is known as Typ4, not Type4.

 

[Sixnineliter]

Thats my poor wording. Right up front as the middle of engine drivers side.

 

[OLDBULL8]

One of the injectors has a couple of clamps around the line, maybe was leaking?

A good place to start, replace with the spring type clamps. Those screw clamps crush the hose and allow air intrusion, un less they are the kind that encircles the hose.

 

[idiabuse]

once all the lines are tight diesel fuel will flow but the tiniest leak and she is a pissed off machine.

Using thicker WMO makes that pesky intolerant beast a more enjoyable machine, just loves
to drink the thick stuff...


Javier

 

[Wyreth]

The problematic piece in the 6.9's fuel filtering system is the Stanadyne water separator. That's what Gary was refering to. It sits on the firewall next to your brake booster.

http://www.oilburners.net/forums/showthread.php?18212-The-Stanadyne-Water-Seperator-Exposed and there is the tech article writeup on it.

as a test, I would try bypassing it and seeing if that helps your air intrusion.


Also, if only one of your return lines has clamps on it, then that could be a big part of your problem.