I'm having a starting issue that is intermittent. For example, I fired up the truck for the first time (of the day) yesterday. Seemed to fire right up, kicked on the high idle and waited for it to warm up. Took my kids to football (about a 15 minute drive) and let it sit for a solid hour and 20 mins. When we went to leave, the engine would turn and turn and turn (with good power). I did this twice without the slightest indication of it wanting to fire. I even hit the Schrader valve on the fuel filter to check for fuel and nothing but diesel came out instantly (filter has 15K on it BTW). I remembered the heat soak topic and just happened to have a bottle of luke warm water. Poured it over the IP and tried it again. Same result. Let it sit for a couple of minutes and tried again...BOOM, it started. A little chunky at first but, it cleared out and ran like a top all the way home. I tried to recreate the experience 2 more times that day (letting it sit for an hour and re-starting) and it would fire right up every time.

I've experienced more of these symptoms lately. Usually after sitting at work all day. I won't pour any water on it and it will eventually go (often with some help from the accelerator pedal). It even died on me at random on my way to work the other day. Again, able to re-start with the pedal and cranking. Took 2 minutes though.

Other days, it starts and runs all day with no issues in similar environments. So, is this IP or something else? Could it be filter related? One more thing...While in park, if I bring the revs up to around 2 grand, it sounds like it's stumbling or missing (won't do this at speed). Runs like a champ otherwise.

Thanks for your time,
Dan

 

I've got to play stupid here. I've been working on pumps for 40 years and never head the term "heat soak" until I came to this forum. Maybe a regional term? I worked in a pump-shop in the northeast (New York). I am going to assume you mean the situation where a truck starts fine cold, runs fine cold or hot, but will not restart when hot. This a common problem that only happens with rotary-distributor pumps like the DB2s used on GMs (up to 1993) and Fords (up to mid 1994). It is a problem caused not by the high pressure pump itself. It is in the distributor section and happens when it is worn. When hot - it expands enough that once the engine is turned off - the starter motor cannot crank the engine fast enough to overcome the internal leakage and let the engine start. Once it cools and contracts - it works again. If this is the problem - it is NOT intermittent. No fix either except for a new head & rotor assembly. Sometimes a work-around is too turn up the fuel delivery and get the engine cranking faster with more battery power.

 

I'm relatively new to the forum and new to diesels as well. Just throwing around terminology I've heard. So, yeah, what you're describing is what I'm asking about. Doesn't sound like my issue. It will do it after an hour and the engine is hot...sometimes. it will do it after sitting at work for 9 hours...sometimes. It will have an issue starting (starts, but runs chunky and pedal is needed to clean it out) when cold...sometimes.

So, where should I start in my troubleshooting process? Should I put a new fuel filter in just for fun? It's been 15,000 miles and don't know much of its history aside from it not being used alot for a couple years. Maybe me using it as a daily is flushing some **** out of the bowels of the truck?

 

Probably one of the best tests is what someone else already mentioned. Hook up a gravity feed fuel tank directly to the inlet of the filter. I've done it with a 5 gallon outboard motor tank but anything that is clean and holds fuel will work. If all works well when hooked to that tank - then you know you've got air-in-fuel issues. From all the ones I've had to deal with - when air intrusion is the problem - it's pretty consistent. If you've got an air-leak before the fuel pump - it's always going to have air in it and rarely run correctly. I'd stick a new fuel pump on it and visibly inspect the fuel line all the way back to the tank. A new fuel pump is less then $30. So even if it does not correct the problem - it is still good preventative maintenance. That fuel pump is key to the system working right.

 

<p>if it does not start, pop the hood and wiggle the fuel shutoff switch power feed. then try to start and see if it fires up.</p><p>you may just have a dirty connection. not very common, but i have seen it 3-4 times over the years.</p>

 

Sounds easy enough to start with. Where can I locate FSS and said connection? Is it on the IP or fuel filter area? Thanks to all for your replies! I'll start experimenting.

 

<p>top of the injector pump there are two electrical connectors. the front is the fuel shutoff switch, the rear is the timing advance.</p><p>with key in run position, you should hear a click when taking the connector off the FSS and putting it back on like in this video:</p><p><a href="http://i41.photobucket.com/albums/e261/tjctransport/88/DSCF0322.mp4" target="_blank"><img alt="" src="http://i41.photobucket.com/albums/e261/tjctransport/88/th_DSCF0322.mp4" /></a></p>

 

Copy that!

 

Does it still do this,and does it do it worse when cold? If so, that is usually an indicator that the injection-timing is not advancing when you rev the engine.

 

Yes, it still does it. Haven't tried it cold.

 

I'm not saying this is your problem (or one of them). But the automatic timing advance is one of the first things that tends to wear out on these DB2 injection pumps. When it does not advance like it ought to - the engine will skip and break up when you rev the engine in neutral but seem to smooth out when you are actually driving it. The advance works by fuel pressure. The higher the RPMs, the higher the fuel PSI. Advance starts at around 10 PSI and can run up to 60 PSI. That until that part of the injection pump wears out and leaks internally.

One work-around if that IS your problem and you do not want to remove the pump for a rebuild - is this. Just loosen up the mount and rotate it a bit. NOT with the engine running. This is to advance the static timing. If you advance it - let's say 4 degrees - it will make the engine 4 degrees more advanced then it ought to be when the engine is at idle speed (you won't notice a difference). But it will also add 4 degrees advance to the top end. This sometimes will make the engine run smooth again. Not a perfect fix but sometimes good enough if you don't want to spend a lot of money on the pump. You can also turn up the fuel pressure and see if it helps - but that requires a special fitting that you likely do not have.

The automatic advance is something that usually dies slowly. NOT all at once. It uses a rotary blade pump to power it and has a piston that rides in an aluminum bore. That piston is what advances the timing. That aluminum bore gets scored and worn and leaks internally. Then the timing advance gets worse and worse.

 

Great info, thanks! Is the tool to adjust the fuel pressure something I can make or buy? If I do choose to advance the timing on the pump, how can I tell how many degrees I'm moving it? Get myself a li'l compass and make some marks?

 

Just revved it up cold. There is a slight stumble in that range but, if anything...its smoother. Not worse by any means.

 

No special tool needed to turn up the fuel pressure. The special tool is needed to hook up a pressure gauge to the back of the pump so you can tell what you are doing. In the back of the pump is a tiny bolt that holds a little lock-wedge to the pump inlet housing. The hole that that little bolt threads into is also a pressure test port. You'd need a Stanadyne part # 21900 to adapt that small hole to a 1/8" pipe thread to use a standard gauge.

If you decide to try to mechanically advance the pump by rotating it - just mark a scribe line between it and the engine. Then try moving it around 1/16th at a time. Keep in mind that the pump only runs at 1/2 engine speed so a 1 degree change at the pump will equal 2 degrees of engine timing change.

 

If your pump timing is going out, you might find this useful:
https://www.ford-trucks.com/forums/1...l#post15529487
I've been experimenting with changing the timing curves through this method, which should work equally well to compensate for other pump effects.

Just remember that the end goal when messing with the timing is:
1. At idle, a bit of clatter, no stumbling. It should /not/ sound like a gasser.
2. Part throttle/mid RPMs should be responsive. No smoke noticable. Should have a little bit of clatter, and hopefully it doesn't get louder or go away completely as you get higher in the range.
3. At full throttle under heavy load, it may sound like a gasser(no clatter). On a turbo engine, you want more retard; on a NA engine you may want a little clatter - Just watch how it feels.

That's just my 2C. Take it or leave it.