Help!! Diesel Gurus...

[Worldangler]

2001 7.3PSD Ford Excursion EB 4x4 - about 180,000 miles and regularly maintained. Occaisionally re-program with PowerChips (tow safe only).

OK, here's the situation. Cold start the truck, purrs like a kitten. Drive to work - 22-25 miles, no issues. On the drive home, after about 15-20 miles, the truck starts missing, losing power, running awful - and eventually dies. If I try to restart immediately - can't keep her running. Wait 25-30 minutes, she starts up and purrs like a kitten for 20-30 minutes, then dies off again.

After 1st time, ran the battery down trying to get her started and out of traffic - no luck. Had to have it towed to the dealership. Dealer has it two days and can't find anything wrong - no codes, nothing. Problem does not occur when they run it 30 minutes or so.

Pick up truck and it does the same thing two days later. Same deal, wait a little while and it starts up and runs fine for 20-30 minutes. After several restarts/die cycles - it won't start at all.

This has happened 5 times now. Seems to happen when the truck heats up (it's been 104+ here). The hotter it gets, the longer "recovery" period.

No codes ever thrown. Dealership is starting to think I'm a raving lunatic because they cannot find a problem and no diagnostic codes - even when it has come in dead on the wrecker.

Dealership keeps saying "they can't fix what ain't broke". Getting tired of breakdowns, tows, or waiting overnight. Getting tired of unreliability and I need the truck in 2 weeks for a long trip with some towing. Scared to leave town in the vehicle.

When dying/running bad/missing - no smoke. Turn key and the tach jumps, so don't think it's CPS (but heck, I don't know).

Unless someone has some ideas, going to have to start throwing parts at it - which is going to get expensive quick and still leave me with a reliability issue.

Some folks are telling me IPR valve would be a good thing to replace first "just for the heck of it", along with the CPS "just in case".

Anyone have ideas or diagnostic tests to run? Dealership seems clueness (but has a VERY good reputation and I've been happy with them for years).

Help in Dallas/Plano!

[Worldangler]

... don't know if this has any bearing but I'll mention it. Two years ago the alternator goes out. Replace it and it goes "bad" again 90 days later (just out of replacement warranty). Replace it again and still have the battery light intermittantly coming on. Replace it again and same deal. All this was done at a different repair shop I tried (where a friend was working).

Had enough and took it back to dealership - they couldn't find a problem and the light has stayed off for 6 months now with no issues.

[dhanna6powerstroke]

Personally I would go buy a new CPS and keep it and the tools with you to replace it. Drive vehicle until it acts up and dies, jump out and replace the CPS and immediately try to start. If she starts, then BINGO, you fixed your issue.

[guzzle]

When the o-rings on the IPR get worn the oil gets thinner as it warms up. The oil will then begin to leak past the o-ring seals and if it is bad enough, the truck will die.

I agree that you should look at the IPR but you may be able to get by with just replacing the o-rings with a reseal kit rather than having to purchase a complete new IPR.

[Worldangler]

Originally Posted by guzzle

When the o-rings on the IPR get worn the oil gets thinner as it warms up. The oil will then begin to leak past the o-ring seals and if it is bad enough, the truck will die.

I agree that you should look at the IPR but you may be able to get by with just replacing the o-rings with a reseal kit rather than having to purchase a complete new IPR.

That could explain the minor oil leak I have! Good info.

Passing all this along to the diesel mech at the dealership.

[guzzle]

Leak-by on the internal o-rings will not cause an external leak. An external leak on the HPOP is more commonly one of the discharge hose fittings or the small plug on the rear just above the IPR.

[OKANE1]

I have also found this problem on the 7.3s.
There was a recall on the cam sensor from ford so check if you vehicle meets the recall criteria.Usuall goes between 100k upwards.
I also found that the wiring harness on both valve cover gaskets because with the constant heating and cooling tend to lead to interminate no start or driving and die problem that you have experienced.This is common from 98 through 01 models as the harness inside the valve covers tends to become very brittle cause its plastic.
An aftermarket valve cover gasket internal injector harness and pigtail harness are avaibile.Be carful if you diy as normally the pigtail harness color code are not the same as original ford so you have eight wires on each side so don't mix them up.
Hope this was helpful.

[Worldangler]

Originally Posted by OKANE1

I have also found this problem on the 7.3s.
There was a recall on the cam sensor from ford so check if you vehicle meets the recall criteria.Usuall goes between 100k upwards.
I also found that the wiring harness on both valve cover gaskets because with the constant heating and cooling tend to lead to interminate no start or driving and die problem that you have experienced.This is common from 98 through 01 models as the harness inside the valve covers tends to become very brittle cause its plastic.
An aftermarket valve cover gasket internal injector harness and pigtail harness are avaibile.Be carful if you diy as normally the pigtail harness color code are not the same as original ford so you have eight wires on each side so don't mix them up.
Hope this was helpful.

Thanks for your suggestions. They are very helpful. I don't think it's the CPS - I already had it replaced once under the recall. I've been told a diagnostic for the CPS is when it gets into a no-run condition, to look at the tach when you try to start it. If the tach registers and goes up, then it's not the CPS. If the tach stay flat during cranking, it's DEFINITELY the CPS. My tach moves and registers normally. I dunno, that's just what I've been told.

I have heard about the harness issue - seem to be fairly common. Hope it's not that, because it is a more expensive repair - but hey, I gotta get it fixed. If the boys at the shop can't definitely find something, I'm gonna start instructing them to start doing some repairs. First would be fuel filter, next would be CPS (maybe), next would be IPR - and if it is STILL not taken care of, then next would be the wiring harness.

I have been told that they could check the harness by doing something called a "buzz test" - but that buzz test often points to bad injectors that aren't really bad. Scary.

Really getting frustrated. The dealer told me today - again - "We drove it for about 10-15 minutes and couldn't find a problem". I explained to them that you'd have to drive it 45 minutes or so before the problem surfaces - and they seem reluctant to do that. ("That requires us to have 2 guys - one in a follow car and a lot of time"). No sh-t Sherlock. What do they think? Spend a few minutes on it and give up?

[Worldangler]

Dealership called me back today and said they THINK it might be air in the oil - the oil is getting over-aerated. This would cause flucuating oil pressure to the injectors, and the symptoms we are seeing.

It's quite an expensive repair: replacing high pressure pump, IPR, a few sensors and labor - running from $1500-$2000 total.

Or it could be bad oil.

I am thinking of trying an oil change first (I did switch oil brand/type last change) then biting the bullet for the major repair.

I've never heard of "air in the oil" being a problem (and couldn't find any discussion on this board) - so I am bit skeptical.

Anyone have any comments on this?

[OKANE1]

I have heard that story before.In theory yes it would cause flucuating oil pressure but in my experience totally impossibile to diagnose unless you actually could take off the high pressure pump tank top cover and run the engine and look fro air bubbles.DO not attempt to do this as that would be highly dangerous to yourself!
If i were you, check with engine off, the oil level in the high pressure tank.
If you have been regemental in your oil changes with a good quality oil then i would tend to lead more to the harness under the valve covers.If the high pressure pump fails it usually goes all of a shot not interminate.The valve cover parts and labor are alot cheaper than replacing high pressure oil pump.Why not try unplugging the harness and look at the terminals to see if there is any corroision present?When it happens again when you have a no start wiggle the connector and make sure it has a good contact.