Bad lope on cold start up

[gnxtc2]

Working on a friend's truck, 1996 7.3, auto trans over two days. Unknown mileage as the he bought the truck with a bad mileage odometer. Straightened out a lot of issues but has a bad lope on start up. This is what I replaced with Ford/Motorcraft parts.

Truck is all stock, no tuner; just intake and exhaust.

- Both valvecover gaskets (2) and (4) injector harnesses
- Glow plugs
- Glow plug relay
- (1) Broken rocker
- Fuel line hoses by the fuel bowl
- Resealed fuel bowl
- Replaced vacuum pump
- Fuel filter
- Oil/filter change (15w-40 Motorcraft oil)

When I had the valve covers off, there were four different injector solenoids which relay don't mean anything to a normal person. I myself wounldn't accept that but anyway.....

The bottom of the fuel bowl was loaded with crap. Yanked the fuel bowl and cleaned everything. The screen was loaded up, that was cleaned.

Started the truck after doing the fuel bowl, it loped but I contributed that to empty bowl. Today I start the truck, it fired right up but loped bad and smoothed right out. It sounded exactly like this video I found on YouTube. https://www.youtube.com/watch?v=nxdT-dso-cI

I'm gonna try to start the truck in neutral tomorrow to rule out the transmission range sensor.

Went for a road test; truck feels lazy. Maybe I'm just used to my truck.

Anything else I can check? No CELs set. I haven't put a scanner on the truck yet nor checked fuel pressure, got late.

Billy T.
[email protected]

 

[TyCorr]

It could be any number of things. Overcoming a lpo side issue. Like a pickup tube that is sucking air to a lpop that isnt staying primed or it could be hpo related also. If the ipr is tight/good it rules that out.

Only time I had that issue it was about 4 deg outside and it wound up being an injector.

 

[TyCorr]

Working on a friend's truck, 1996 7.3, auto trans over two days. Unknown mileage as the he bought the truck with a bad mileage odometer. Straightened out a lot of issues but has a bad lope on start up. This is what I replaced with Ford/Motorcraft parts.

Truck is all stock, no tuner; just intake and exhaust.

- Both valvecover gaskets (2) and (4) injector harnesses
- Glow plugs
- Glow plug relay
- (1) Broken rocker
- Fuel line hoses by the fuel bowl
- Resealed fuel bowl
- Replaced vacuum pump
- Fuel filter
- Oil/filter change (15w-40 Motorcraft oil)

When I had the valve covers off, there were four different injector solenoids which relay don't mean anything to a normal person. I myself wounldn't accept that but anyway.....

The bottom of the fuel bowl was loaded with crap. Yanked the fuel bowl and cleaned everything. The screen was loaded up, that was cleaned.

Started the truck after doing the fuel bowl, it loped but I contributed that to empty bowl. Today I start the truck, it fired right up but loped bad and smoothed right out. It sounded exactly like this video I found on YouTube. https://www.youtube.com/watch?v=nxdT-dso-cI

I'm gonna try to start the truck in neutral tomorrow to rule out the transmission range sensor.

Went for a road test; truck feels lazy. Maybe I'm just used to my truck.

Anything else I can check? No CELs set. I haven't put a scanner on the truck yet nor checked fuel pressure, got late.

Billy T.
[email protected]

If the truck is lazy as well check fuel pressure and hpo output.

 

[DEEZUZ]

Sounds like the injectors are just worn. On the oil side. A cold buzz test will usually tell you what injectors are the issue.

 

[78f100]

Maybe I missed it but did you check the icp sensor? It will cause it can cause a lope or romp.

 

[gnxtc2]

Checked the ICP, no oil inside. Unplugged the ICP sensor, it loped and died. Plugged it back in and it slight loped.

When the motor started and was loping, the slightest press of the throttle it smoothed out.

Haven't put a scanner on it yet.

Billy T.
[email protected]

 

[Dmstrucks02]

Checked the ICP, no oil inside. Unplugged the ICP sensor, it loped and died. Plugged it back in and it slight loped.

When the motor started and was loping, the slightest press of the throttle it smoothed out.

Haven't put a scanner on it yet.

Billy T.
[email protected]

I was going to suggest touching the throttle while it's loping. Mine used to do the same thing cold until I put the adrenaline on. I have since done injectors as well but the adrenaline seemed to help me when I had stock injectors

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[TyCorr]

I was going to suggest touching the throttle while it's loping. Mine used to do the same thing cold until I put the adrenaline on. I have since done injectors as well but the adrenaline seemed to help me when I had stock injectors

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These trucks...i swear... some of these issues are interconnected.

 

[PsdPullerJr]

Does it lope when it's hot or after it's been warmed up and has sat for a few hours or just when it's cold? Any time I've had lope issues it was oil related.

 

[97f350stroker]

My truck actually just started doing this once this colder weather came in. Once it fires it'll lope 3-4 times and smooth right out. She's been a little cold hearted so I got some new glo plugs into planned on throwing in. Seems like that's not gonna take care of the lope though goin by this thread.

 

[Arisley]

I was going to suggest touching the throttle while it's loping. Mine used to do the same thing cold until I put the adrenaline on. I have since done injectors as well but the adrenaline seemed to that help me when I had stock injectors
touched
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Same here. When I installed my Adrenaline pump, my lope on start went away. I bet a new stocker would have made it go away also. I think loping until the throttle is touched is a sign of a tired HPOP.

 

[psduser1]

My excursion will lope 3-4 times on cold start, below 20*. It has an adrenaline, also.
Funny thing is, it used to lope at idle after a good run down the freeway. Since I swapped the complete drive train from the black ex to the new ex, the hot lope disappeared. Same chip, same engine/modded parts, etc. New gpr and resealed the engine. Weird.

 

[Dmstrucks02]

Same here. When I installed my Adrenaline pump, my lope on start went away. I bet a new stocker would have made it go away also. I think loping until the throttle is touched is a sign of a tired HPOP.

Yea it seems to be HPO related. Its weird that touching the throttle made it quit- just enough for it to see a signal input on the pedal

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[gnxtc2]

Fuel pressure was at 60.

At first start up after sitting overnight or a long time, the motor lopes. The slightest pressure on the throttle pedal, the loping stops.

Billy T.
[email protected]

 

[dsberman94]

Mine has done this in the cold sinceI bought it. Not sure what it could be because I've replaced the hpop and injectors twice. Fuel pressure at idle is good. Also smokes a chit ton for 10 seconds. I'm just adding it up to abuse before I bought it and it's getting a new motor sooner than later.

 

[DEEZUZ]

Sticking IPR?

 

[79jasper]

Seems real common on the 7.3's.
Mine has done it in the past. I guess doesn't get cold enough where I'm at now. But I'm going home soon, so we'll see in a few months. Lol
I know mine wouldn't do it if plugged in. So I guess I would say injectors or something within the hpo system. Ipr would be a good place to start.

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[seabee15]

Would doing a hpop rebuild be worth it? I mean pay the $50 at international for a rebuild kit or pay the $450+ for a stock hpop.




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[dsberman94]

Sticking IPR?

Mine is brand new this past spring As is the Icp sensor. With no oil in the pigtail and reads as it should.

I used to change from 15-40 to 5-40 for the winter and it would still do it but the temp would be 10-20 degrees colder for it to romp than it would be for the 15-40.

 

[dmd]

Same here. When I installed my Adrenaline pump, my lope on start went away. I bet a new stocker would have made it go away also. I think loping until the throttle is touched is a sign of a tired HPOP.

+2. No problems since install. Used to be real bad.