7.3 Misses when cold

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Sep 24, 2021 | 05:43 PM

bigridge

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7.3 Misses when cold

Hey everyone. The issue is absolutely driving me nuts. The truck cranks and starts fine every time. It will idle good when cold about 80-90% of the time but will have a couple rough strokes here and there. If I don’t let it idle for ATLEAST 15-20 minutes as soon as I get out on the road it will miss pretty hard until the temp gauge gets within the normal range and then it won’t miss a beat. It only white smokes a little wee bit when I first get on the road and pull the hill out of my driveway. Is it injectors, pistons, or suggestions on something completely different??

Sep 24, 2021 | 06:31 PM

96 OBS

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From: Fowler Colorado

Could be injectors. How many miles? Have they been changed before to your knowledge? Does it throw any codes when it misses?

Sep 24, 2021 | 07:43 PM

bigridge

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Quote:

Originally Posted by 96 OBS

Could be injectors. How many miles? Have they been changed before to your knowledge? Does it throw any codes when it misses?

The truck has 192,000 on it. I just got it last October and I don’t know if they’ve been changed. It does not throw any codes when it misses

Sep 24, 2021 | 07:45 PM

96 OBS

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From: Fowler Colorado

Try running a good amount of diesel Kleen or hot shot secret in your next tank and run it for a good hour or so on it see if it helps with the next start up

Sep 24, 2021 | 07:49 PM

bigridge

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Will do, could that be a somewhat long term fix to clean the injectors out or just prolong the inevitable?

Sep 24, 2021 | 07:51 PM

96 OBS

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From: Fowler Colorado

Just prolonging if they’re ready to go. Take a good look at the valve cover harnesses too see how they look. Make sure there’s no worn spots or bad connections

Sep 24, 2021 | 08:14 PM

Jimmy's Pilot Service

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Joined: Nov 2020

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From: Republic of Texas

How are you pulling codes???
FORScan/ FORScan Lite or the local china parts store? Most off the shelf and parts store readers will not tell you what you need to know.

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Sep 24, 2021 | 08:28 PM

bigridge

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Quote:

Originally Posted by Jimmy's Pilot Service

How are you pulling codes???
FORScan/ FORScan Lite or the local china parts store? Most off the shelf and parts store readers will not tell you what you need to know.

96 OBS is correct there is no check engine light. I have not hooked a reader up to the port and pulled the codes that way.

Sep 24, 2021 | 10:05 PM

#10

97-psd

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From: knoxville, tn

What oil are you using and how many miles on it?

Sep 24, 2021 | 11:30 PM

#11

Bitterroot Diesel

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Joined: Sep 2020

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From: Florence, MT

Injectors could be a cause, but you'll want to check all wiring/connections first.

Sep 25, 2021 | 05:53 AM

#12

bigridge

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Quote:

Originally Posted by 97-psd

What oil are you using and how many miles on it?

15-40w rotella. I changed it last at 190,000 and it has 192,000 on it now

Sep 25, 2021 | 07:49 AM

#13

Oldfrogdiving

Cross-Country

Joined: Jan 2018

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From: Melbourne Ar/Melbourne Fl

Save yourself alot of hassle and pull the trigger on some sort of OBD reader. I use forscan and had ordered a dongle cable on amazon. Unfortunately its at my Florida place and my now non mission capable 96 F350 is in Arkansas. waiting on the cable delivery as we speak.

Sep 25, 2021 | 10:23 AM

#14

bigridge

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Quote:

Originally Posted by Jimmy's Pilot Service

How are you pulling codes???
FORScan/ FORScan Lite or the local china parts store? Most off the shelf and parts store readers will not tell you what you need to know.

It’s a 95 with the OBD2 under the dash on the passenger side. Could I download ForScan lite onto a computer and order an OBD2 to USB connection off Amazon to read them?

Sep 25, 2021 | 04:39 PM

#15

Sous

FTE Leadership Emeritus

Joined: May 2014

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From: Lake Hartwell, GA

Quote:

Originally Posted by bigridge

It’s a 95 with the OBD2 under the dash on the passenger side. Could I download ForScan lite onto a computer and order an OBD2 to USB connection off Amazon to read them?

My links and details are for the SD trucks, but a lot of the information is cross-generational and applies to your truck as well.

Over in the SD forum we have a 7.3L PSD Tech Folder.

Within that folder, we have a "FORScan" section.

FORScan

The last link above titled "Class Tutorial Q&A" is by an FTE'r that goes by the name of @BWST . He has taken hours, days and weeks out of his own time in order to help this community out. He has laid out exactly what you may need and how to get there in the Q&A post.

This information should get you pointed in the right direction at the very least and I hope it helps you out a bit. We all have to learn sometime, so feel free to post any questions, concerns or comments you have regarding anything OBS or 7.3L related.

Keep us updated!