Diesel hot start issue

Hi All, I need help. 

I've got a 97 f250hd 7.3 116,000 miles

In the last week, since my last full fill up actually- I've developed an issue.  I've had this truck for a few months now and since 112k miles.  It's been trouble free.  After I first filled the tank and drove around a bit, it started stumbling.  I figured it must be some bad diesel and it didn't die...just acted like it was going to a few times.  Well, I've only burned about half of the front tank and now it will not hardly start after it's gotten good and hot.  Day before yesterday it stranded me.  I had driven it about an hour away, it sat for about 4 hours and then I drove the hour back.  I went to get something to eat, was only in about 20 minutes and tried to start it.  The motor will turn over fine but it won't catch.  No smoke. 

The next morning it started right up.  I changed out the CPS just in case. 

Today it did the same thing after I ran it for about 45 minutes, then went into a meeting.  I turned it off and then it started right back up.   I was out of the truck for about 2 hours and when I went to start it, the first try of 10 seconds of cranking didn't work.  The second try of about 15 finally finally caught.  

I installed a new fuel bowl when I first bought the truck, and changed the oil.  I added a quart today because it wasn't at the top line.  The fuel filter basket looks ok.  I've read about o rings and all that, but this truck doesn't smoke at all and once running, it runs perfect.  I'm stumped.  It does have batteries that are two years old and probably a little undersized, but I don't think that is part of the problem because it started right back up at the office after driving there and while hot.  

It feels like a problem that something might be leaking down over time when hot causing this, but I don't know enough about diesels to know what that might be.  Please help. 

IPR o'ring failure seems to be the common winner for this issue. 

That said, I'd be making sure your glow plugs are kicking in when warm. Could be a bad relay, dry solder joint or similar. Glow plugs working when cold but not when warm would fit the symptoms. It'd also explain why you can restart it immediately after shutdown. 

I'm gonna say it's not the glow plugs.  When somewhat warm, it should start without them.  Plus, if it just wasn't firing because it couldn't get the fuel to light off, it would be blowing white smoke (raw fuel) out the exhaust while cranking after a few seconds. 

I had exactly the same symptoms one my '96 a little while back. Check the HPOP pressure sensor (basically by disconnecting it) to see if you have a HPOP pressure issue.

In the case of my truck it was the HPOP pressure regulator that was playing up with the engine hot.

In reply to BoxheadTim :

I’ll look that up  thanks  

AIn reply to daeman :

It does start immediately after, just not after sitting for a bit. 

In reply to daeman :

I’ve seen a lot of those comments- that’s on the list. 

Ok, I replaced the IPR with a Ford part two days ago. It ran perfect that day as well as yesterday and then wouldn’t start this morning. I’m annoyed. 

I did check the batteries and he passenger one is reading 11.5 and the drivers is over 12. They are dated 7/16. They are value something and only 750 cca instead of the 850 prescribed. It would be easy to throw in two batteries but that’s also $250. Why would I replace batteries? Well, apparently it will still turn over but not turn on injectors unless the computer sees the correct voltage. 

Thoughts? 

I’ve had mine run with batteries down in the 10.5-10.8v range, so I’d think it’s not the batteries unless the voltage drops even further when cranking. I’d check that first. 

In reply to BoxheadTim :

ok. will do.  looks like I have a buddy with a ford scan tool coming over to help sometime soon as well. Hopefully, that will provide some answers.  

The International diesels with the HEUI injectors are all about oil pressure. On my 6.Ohberkmyheadgaskets, the injectors will not fire until they see 500psi of oil pressure. If the batteries are weak-ish, the engine turns slower and the HPOP takes a bit a build the pressure.

I would guess something in the HPOP system and it sounds like you are on the right track.

Also, check out FORScan; it's free and it emulates the Ford IDS software pretty well. It's pretty handy on Ford diesels.

Batteries should be ~12.6v when resting and preferably not drop below 10.0v while cranking. Diesels are pretty sensitive to cranking speed so I would check the voltage while cranking and if it's not good, replace the batteries. 

I get 9.7v on the drivers side battery when cranking. Icp was bine dry and HPOP reservoir  is full to the top. So...batteries? 

In reply to stanger_missle :

I’ll have to grab that. Thanks. 

I flipped the batteries and it started right up.   looks like i'm off to buy batteries. 

put some motorcraft batteries in her.  We'll see how it goes.  

With two batteries, you'd think that they would discharge at the same rate but it seems that what ever battery is directly connected to the starter dies first.

Some people run heavier gauge wires between the two batteries or swap them around every few months. That seems to help but one will still die before the other.

You did the right thing by buying two new batteries. Even if your wallet doesn't think so 

In reply to stanger_missle : 

It was painful! I have read the thing about switching them back and forth, I might employ that. I really want some of those battery terminal crimpers from project binky. 

Hopefully this has it fixed for a while other than that small diesel leak  

In reply to grover :

I feel like I'll have to face that same scenario soon on my new to me 07 F250. The batteries are a little over 3 years old but diesels are notoriously rough on batteries.

This winter is going to the real test.

I spoke too soon. I’ve been traveling a ton for work and haven’t been driving the truck much, but I still have an issue. When the truck is hot it will often take 10+ seconds of cranking for it to start. It will then stumble for a couple of seconds and then run perfectly. I replaced battery terminals today and that didn’t help. I’m considering taking off the valve covers to look for injector o ring leaks...but I’m headed out of town for work again tomorrow till Sunday. 

Does the injector o ring thing sound reasonable? 

stanger_missle said:

Also, check out FORScan; it's free and it emulates the Ford IDS software pretty well. It's pretty handy on Ford diesels.

"FORScan"?  What dick named that program?

I'm sorry. 

Long crank and then starts but runs crappy for a couple seconds sounds like fuel pressure taking too long to come up. I don't know exactly what the line setup is between the mechanical fuel pump and the filter housing but i'm wondering if the filter housing is draining down and taking time to refill? Maybe pop the top off and see if it's not full the next time it doesn't start in a couple seconds. You need oil pressure and fuel pressure to start. If you have a way of accessing the high pressure oil pressure reading (im sure there's a specific term for that) you could narrow the problem down by 50% by watching that. If your oil pressure comes up quickly but the engine doesn't start, it's a fuel pressure issue.

In reply to grover :

Yep, the orings leaking can definitely cause hot start issues on the 7.3L. They get hard and split.

If you have a scantool, watch the ICP sensor.  I've had to replace a few, and the connector.  I've also received bad ICP sensors out of the box.  The sensor is key to how the fuel system works.

I'm trying to think of a way to insert an Insane Clown Posse reference/joke but failing.

It's been a while since I had to berk with one of these, but when running, if the sensor starts going wiggy, the computer can't accurately control the fuel pressure and it will stumble and lose power at random.  When cranking, the computer will not even try to open the injectors until the ICP sensor reads over a certain threshold, leading to a very long crank/no-start with no white smoke when it finally fires up.  This is definitely not a part to just throw in without watching on a scantool, because I have gotten bad parts out of the box and if you don't have a scantool you don't know if the new part you got was bad, and you will chase your tail, ESPECIALLY if the old one wasn't bad.  Although if you unplug the old one and the inside of the connector is swimming with fuel, you know it's bad.

In reply to Vigo :

That's what I was thinking as well, but I've got a basically brand new fuel filter housing and filter.  Also, I just checked all the hoses.