Another No Start... with a twist.

[machine.doc]

So I first want to say thanks to all the folks on this forum for the wealth of information that has saved me hundreds of $$$. You all are truly the reason I still have hair... 👍

So to begin I have a 1997 truck now with a 1994 6.5 turbo in it. The engine swap last winter was smooth as butter thanks to y'all. The engine now has about 20,000 km (12500 mi).
The pcm as been programmed and I have a 15lb spring on the turbo with 4in exhaust.

So the problem is on hot and sunny days the truck won't start after sitting in the sun for a couple of hours. I never have a problem starting in the morning as it is cool enough. If I am already driving in the sun it runs fine till I stop for fuel or something then it won't start again. If I use the a/c on hot and sunny days it will quit while driving, like the key was shut off. If I pull a heavy trailer on said days it will quit while driving as well. Basically it doesn't like hot and sunny (yes the two together) days. 😧

It started doing this late last summer (with the last engine). Of course I never did anything about it for various excuses, the number one being it didn't happen all the time and I couldn't find the problem myself or anyone on this forum with the same symptoms. All winter the truck has worked flawlessly. So now I am stuck in a Home Depot parking lot sitting in the baking sun... And I thought it had fixed itself!

In all cases if I let the truck cool it works just fine. So the problem is definitely heat related but not engine block heat related. On hot days if I don't use the a/c and park with the hood facing away from the sun it works fine.


Things I have done:
relocate the pmd to behind the bumper with a bigger heat sink (it was behind the front grill with a small ass home made heat sink).
Redid ground connection for pmd.
Sent truck to local diesel mechanic - he said "it's the pwd". Bought a new one with no luck.
New lift pump when I changed the engine. Yes it is still working with good flow.
Checked all relays and fuses. Seems fine.

I'm thinking it must be a sensor on top of the engine or a relay or something.

Any thoughts?

[machine.doc]

so I have been sitting here for 2hrs now and IT STARTED.....

go figure.

[DieselDavy]

Hi Doc,
I am still going with the PMD area. If not the PMD itself, could it be the wiring from the PMD to the Engine harness? I heard you say you checked/added grounding to the PMD, but maybe there is a high resistance connection in one of the connectors. I think the 94 MY on had flacky engine wiring harness issues. I think I'd go through all of those connections and look for corrosion. But, hey, I don't know...., except that it can be very frustrating waiting for things to cool down while sitting by the side of the road!
Dave

[machine.doc]

I did check the pmd extention connections and they seem to be fine. They are soldered and shrink tubed. I didn't want to cut the seal on the shrink tube or I would have to re-solder it with new shrink tube. I suppose I'll just do it anyway.
I checked all the electrical connections when I changed the engine and nothing seemed amiss. Is there a connection in particular I should be looking for?

I should take it back to the mechanic and tell him he owes me $300 in diagnostic time...

[strykerAKAmack]

Might be a shot in the dark but how is your fuel cap ?
If the pressure release isn't functioning properly that could be causing a fuel problem up front .

[DmaxMaverick]

Might be a shot in the dark but how is your fuel cap ?
If the pressure release isn't functioning properly that could be causing a fuel problem up front .

This.

If you are using a gas cap (as opposed to a fuel cap), it won't vent properly, and allow too much vacuum to accumulate. A dysfunctional fuel cap may do the same. Always check/replace this first.

That said, I don't think this is your problem. If it's shutting off while driving, and sometimes not starting (with new PMD/harness), then it's electrical as suggested, or the ECM itself.

[Robyn]

Scare up another ECM (Stock one is fine to test with)

Plug it in and see wassssup.

Read farther down. Check the Fuel shut off first.

Performance will be off from the programmed one, but you can isolate the ECM as the cause of the issue or not.

PMD is always in the cross hairs as an issue when there are stalling or no start issues.

Having a new one helps.

How many miles on the IP itself ???

One other possibility is the ignition switch.

These little devils have driven many a tech crazy.

When was the fuel shutoff solenoid replaced ???

These can fail to open, and or close when they should not. (tall round unit on top of IP with wire coming out)


The solenoid has a magnetic coil that pulls the valve open when the key is switched on, and if the coil gets weak, no go.

A test can be as follows.

When the engine will not start, have a helper turn the key on and off while you hold your hand on the solenoid.

You should feel and hear a click as the valve operates open and shut.

Another test is to use a computer duster bomb can upside down and spray the solenoid to get it cold.

If the little beasty fires off, then there is your issue.

What happens is the spring inside the solenoid gets hot (expands) and then if the coil is losing it's power there is not enough ooooomph to open the valve.


Starter solenoids have been known to do this same thing.

If the solenoid is a tad weak, and the voltage is a bit low to the solenoid, it can cause the failure.

Do the bomb can thing and see what shakes.

Missy

[Robyn]

Sitting here sucking coffee and warming up my brain.

Check the voltage at the main power input lug on the relay/fuse box under the hood.

There is a large wire (#2 or so) that feeds the battery power to the box at a lug near the back, check it there with the engine running and all accessories on.

You should see 14 volts maybe 14.5 volts

If you are not seeing these numbers then there is likely an issue with the battery cables.

The cables are notorious for issues.

Next check the voltage to the fuel solenoid with the key on.

The wiring through the engine harness is very small, and any shortcomings anywhere can cause sufficient voltage loss to result in a failure.

Check these things and let us know.

Missy

[machine.doc]

Thanks for your replies. Had a chance to look at the truck today as it died in the heat again.

With the truck unable to start I changed to the new pmd and swapped out the ECM with one from a friends daily driver truck. No joy!

I looked at what wiring I could see in under the hood, No cracks or bad looking wire anywhere.

The voltage at the lug with the engine not running is normal 12.7v. I haven't tested yet with it running as I had to abandon its sorry ass for tonight. Will check in the morning when it finally starts again.

I have never replaced the fuel shutoff valve, but a month ago when I was stranded in a parking lot I removed the solenoid, tested it directly to the battery with spring pressure and it worked flawlessly. I let it cool and tested again with no issues. Truck still wouldn't start.

I have no idea how many miles are on the pump , but I doubt it is original. Its prob been rebuilt before. Though I don't remember seeing a stamp on it when I changed the engine. Basically I have no idea...

Is there something on the ignition switch that I can test, or is it just a replace the part thing. I hate just throwing parts at it.

The gas cap seems to work fine as I never get any pressure/vacuum build up.

I also had the mechanic look at it again. Waist of time cause he just said to change the IP with no explanation so I think he is just fishing also (at my expense).

Thanks for all your help guys. I'm starting to want to sell the truck. Any offers :)

Ill try the rest of your suggestions tomorrow and let you know the outcome.

[Robyn]

Does the fuel solenoid click when the key is switched on and off ???

With it working off the IP is good, but we need to know if it works on the IP.

This sounds like an electrical issue, as in no power ???

Knowing it's not the ECM IS A GOOD THING.

Does anything else quit when the shut down/no start happens ???

The ignition switch certainly comes into the cross hairs

A bad contact on the switch, or a burned terminal in the plug can certainly do it.

I had a van that would lose the electronic dash and the tranny would not shift.

Bad switch/plug melted plug.

Might be a worthwhile place to look see.

Not too bad of a job to drop the column down and snake the switch out.

Be sure to unhook the batteries first, ;)

Keep us posted

[machine.doc]

FINALLY 🙌🙌🙌

Some good news, I think... I hope...

So I stopped at the chiropractor on the way home from work today and of course being hot it would not start after I got out (about 30min). This happened on Mon as well and it would not start then for another hour and a half.

So I'm twitting my thumbs for a few minutes when I notice a Parts Source across the street. I ran over and grabbed one of those super cold bolt removing spray cans. Tried to start the truck again just to be sure it was still to hot. And proceeded to spray the fuel shut off solenoid for about 10 seconds.

Now I'm always amazed at how much you can think about in 10 seconds of time. I realised that I should be doing this very systematic in order to find the problem component. So I thought let's try something different since I've already had the solenoid out and tested once before.

I randomly picked a component on the passenger side of the IP near the bottom. It's about a 1in round thing facing up with a electrical plug going in the top. 3 wires I think. I sprayed this for 30 seconds (yes I counted) and tried to start the truck. And what do you know... It didn't start... Though it did cough some, which is more than it was doing before. Sprayed the same component for exactly 30 more seconds and it started!!!!! I must admit being a little giddy with such success caused me to turn on the a/c for 5 min to cool down. Honestly, it was only for 5 min so I wouldn't tempt fate to much...

So this could have been a fluke. Probably was. But it's something different, and different is good. Either way I'm ready to try it again tomorrow.

[machine.doc]

So this is a timing stepper motor...

I'll do a little more research on testing the sucker.

Tomorrow's job...

[Dvldog8793]

Save a little cash and buy air-in-a-can of some sort, like the air duster ect.... and then all you do is hold the can upsaide down when you are spraying and it is a super cold spray. Neet trick....don't tell anyone:D
IMHO- you probably cooled off some other component in the IP that was hot. 30 seconds of cold spray is ALLOT.

Good luck.

[Robyn]

Glad to see there is some progress.

A couple choices.

Mark your IP to the case location and send it in for a rebuild, or get a fresh one.

Either way it sounds like the IP has given its all.

If you have a good diesel pump shop in the area that's Stanadyne certified, I would say have yours gone through.

Letting the tech know the details of the issue is important.

I'm going to suggest you try something.

Add about 2-3 quarts of motor oil to the fuel tank and then add some fuel.

Goal here is to thicken the fuel mix a bit.

This will also add some lubricity to the fuel as well as get the viscosity up.

It sounds like the pump may not be able to maintain injection pressure high enough to pop the injectors.

When was the last time either the injectors or the IP were serviced ??

How many miles on them ???


Give it a go.

Missy

[Dvldog8793]

IMHO- I use tcW3 two stroke motor oil instead of engine or trans oil as it has some great detergents and is designed as a combustible lubricant.

[Robyn]

On a regular basis I would agree.

For the test at hand, nearly any oil will work to get the fuel a tad thicker and see if this helps with the no start.

The startup after spraying the cold stuff on the IP may well indicate a "loose" IP that can't make pop pressure at cranking speed.