[Silver7.3]

Morning my truck has been giving me some issues lately. 2000 F350 7.3 4wd automatic.

In mornings when I do not plug my truck in it dosent idle correctly. Almost sounds like it's missing. Start driving it and there's little power. Once it hits 3rd it shakes violently until all of the sudden it clears up and runs smooth as ever. This also happens in the afternoon after the truck sits for 8 - 10 hours. But if I plug my truck in then none of the above mentioned happens.

The weather is maybe 60 in the AM. Not. Very cold.
I replaced the GPR since it's very easy to get at.

Thoughts... help LOL

Andrew

 

[olddieseldude]

I'm going to say glowplugs. You have a few that don't work and your truck isn't firing on enough cylinders to support 3rd gear until warmer.

 

[ArcticDriver]

Your description could be the normal behavior of a 7.3 that is not given a chance to warm-up before being driven hard.
When it shakes violently in 3rd, are you accelerating hard?

Do you have a gauge for your EOT? If you know your EOT when your truck shakes and when it clears up and runs smooth as ever, then you can determine if its an issue or if its acting like its designed.

The fact this does not occur when you plug it in suggests it is related to your GP system and whether that is a faulty GPR and/or burned out GPs can be narrowed down by a few tests with a multi-meter.

When it is 60* in the morning at start-up, it is even more important to know what the overnight temperature was because that temp will be what your EOT is.

 

[Silver7.3]

I'm going to say glowplugs. You have a few that don't work and your truck isn't firing on enough cylinders to support 3rd gear until warmer.

I was afraid of that answer. Pulling the covers us just a pain in the butt... LOL

 

[olddieseldude]

Start simple. I would test to see if they are all on one side first. Then see if its the valve cover gasket wiring connector first. or something leading up to that connector.

 

[Silver7.3]

Your description could be the normal behavior of a 7.3 that is not given a chance to warm-up before being driven hard.
When it shakes violently in 3rd, are you accelerating hard?

Do you have a gauge for your EOT? If you know your EOT when your truck shakes and when it clears up and runs smooth as ever, then you can determine if its an issue or if its acting like its designed.

The fact this does not occur when you plug it in suggests it is related to your GP system and whether that is a faulty GPR and/or burned out GPs can be narrowed down by a few tests with a multi-meter.

When it is 60* in the morning at start-up, it is even more important to know what the overnight temperature was because that temp will be what your EOT is.

Thank you for the response. I typically start the truck and it idles for 5 or so minutes while I load my truck.

After that I get on the road and drive normal. Definitely not hard since it's not exactly a race car. As far as the EOT I only have the factory gauge set and the pillar boost/pyro/trans

I do not believe its acting as designed as this is a newer issue. Started doing this a couple weeks ago. Only way to avoid it is to plug the truck in. There is no CEL or SES lights coming on either

Thank you
Andrew

 

[Greg687]

You can check the glow plug resistance through the IDM harness connection. Look up GB Tech bulletin 103. It's on here somewhere and is there to check the wiring before you go replace an IDM.

 

[ArcticDriver]

I wasn’t sure how long you had owned your truck to know what was normal.
At 60* cold soaked and after a 5-minute warm-up, 2-3 failed GPs should not result in your issues.

The longest they cycle is 120-seconds even in sub-0 temps.

It is possible your new GPR is faulty.
Both the new GPR and the eight GPs can be tested with a multi-meter (and a stepladder) while the engine is cold before you spend time & money to replace anything.

Does your thermostat work correctly, maybe it is remaining open and resulting in slow engine warm-up?

I have a ScanGauge-2 and watch it each morning at start-up. It provides a voltage reading, EOT, ICP, IPR and several other real-time metrics. They are about $140 at Advanced Auto and cheaper with on-line discounts.

This morning, ambient temp about 60* and EOT at 53*, I started truck and idled it 5 minutes. After 5-minutes, the EOT was 110* and the idle was at 1050-rpm and the EBPV was still closed. It continued to act sluggish until EOT was around 154* which happens to be around when the EBPV fully opens.

 

[klhansen]

You can check the glow plug resistance through the IDM harness connection. Look up GB Tech bulletin 103. It's on here somewhere and is there to check the wiring before you go replace an IDM.

A much easier place to check glow plugs is at the valve cover gaskets. Click on the Hard or No-Start link in my signature (you may have to expand it to see the link) for how to do that.
Checking the IDM with the GB Tech bulletin is the next step, but don't dig that deep until you confirm that your glow plugs are OK.

 

[Silver7.3]

Great suggestions. Super helpful. Will get the meter out Sunday AM when I'm off work and have a cold truck.

However its 85 or so out right now and o just started my truck and the idle/lope is back. The truck has been in the parking lot since 8am. It's now 5pm.

Something to take note of... this morning at about 5am while it's in the 50's the truck idled fine and had normal acceleration with no shakes. Also just so it's out there. The truck dosent hesitate starting mo matter the current temperatures

Andrew

 

[Silver7.3]

So this morning without plugging in the lope and shakes returned. I stopped at my buddies shop and had him do a code scan. It returned nothing. He did not have his big scanner with him. So he wasnt able to dig deeper for stuff like ICP IPR etc... said that scanner will be back from repair next week.

There is oil in the ICP connector. Said I should replace it. I disconnected it the other day and it started fine when I left work from home

Andrew

 

[ArcticDriver]

There is oil in the ICP connector. Said I should replace it. I disconnected it the other day and it started fine when I left work from home.

Its great you identified the failing ICP.
Motorcraft for all these sensors.

I have not had to replace the ICP pigtail when I get leaking ICPs but I think it is a function of how long the oil has been in there and how saturated the wiring has become. I have been fortunate to just blast the connector with electronic cleaner and after it evaporates, just a dab of dielectric grease on the little gasket.

I know many guys coat the conductive connectors without problems since the grease is mostly scraped off when the connection is made but I do not do that. I had an issue with the di-electric grease, which is non-conductive, creating an impedance in a sensor that functioned in micro-voltage range and it broke me of the habit of gobbing on the di-electric.

Let us know the results!