Ford Power Stroke Nation banner

1 - 20 of 24 Posts

·
Registered
Joined
·
17 Posts
Discussion Starter #1
Hey everyone I’m new here but have been looking to these forums for a while now and reading everything you guys have to say it’s its great.. so thank you first off. Anyway I have a

1997 OBS 7.3 f350 crew cab automatic I have a few questions but mainly why under low rpm mainly in OD does my truck kind of “sputter”? It runs very very healthy fires up even in very cold weather right away and when you get into it or normal driving runs just perfect I am a mechanic and have watched scanner members closely but am seeeing no issues would really love some input thanks.. sorry for long post my mods are..

Ts6 position chip K&n intake Ccv delete 35” muds Straight pipe Fuel bowl fuel flow mod And for some reason my 97 has all 8 AB injectors?
 

·
Registered
Joined
·
2,861 Posts
Sounds like your 97 may be a California model. Cali 97s have splitshot injectors, a fuel pulse damper on the top of the fuel pump banjo assembly, and a shunt on the Glow Plug Relay (along with GP monitoring circuit wiring). It will use a DPC-312 PCM with MME series code. The DPC-312 PCMs are very hard to find and pinned out completely different than the DPC-202 PCM used in the 49-state (Federal) trucks. I am unfamiliar with your Fuel Bowl fuel flow mod nomenclature, so what exactly is that? What's your fuel pressure look like at idle? You might need to physically remove the chip and see if the stutter remains. Cheers!
 

·
Registered
Joined
·
3,351 Posts
Welcome to PSN,
So when you say stutter/sputter in OD, can you provide a little more information like what RPM range? Does it do it in all your chip settings? To better understand the stutter/sputter, is this a sound or the engine actually lurching,missing? Reason I’m asking, is with straight piped trucks I’ve owned over the years when under say 1700 rpm noise coming out the exhaust would not be smooth, would be kind of a staccato exhaust note. Would be pronounced when driving beside no post concrete guardrail as the exhaust note would reflect back at you. Truck would run fine was just exhaust pulses not being dampened. I usually leave on the cat, (or run a resonator) just have it gutted to act as a resonator, this softens the exhaust note. Hope that makes sense.

Fuel bowl flow mod meaning you’ve increased fuel pressure by modding the fuel regulator spring?

Thinking your truck is a California emissions truck, as ABs are split shot injectors as I recall.
j
 

·
Registered
Joined
·
17 Posts
Discussion Starter #4
Thanks for the replies guys.. so first I don’t actually think it is a Cali model I’m all the. Way on the east coast and I’m thinking someone just put them in as number 8 is not a different injector code and yes the bb in the regulator at idle I have 600 psi and wot about 2500 2600 the thing is it does it only when truck is warmed up which is still only about 1/4 maybe a little more it never gets to half on the temp gauge.. it does it wether the chip is on or off just more prevalent with the chip on I think bc it’s getting more fuel I’ve been chasing it forever and can’t figure it out. If the truck is cold it runs so much better I’ve actual had the pcm replaced bc of this issue it only happen between about 1500 and 1700 rpm it’s the actual engine stuttering if I push threw it it goes away also if I make it downshift it runs smooth.. I’ve tried oil and fuel additives as I thought it was a oil issue (cold oil is thincker hence the running perfect when cold) still no results
 

·
Registered
Joined
·
17 Posts
Discussion Starter #5
Sorry also I have replaced 3 injectors because I thought they might be the weak link.. (watching the poppett valve) done the rear diff speed sensor.. throttle position sensor, the crank sensor, of course, the icp basically anything that could cause an issue I’ve replaced and have still never been able to pin point it
 

·
Registered
Joined
·
1,281 Posts
How many miles on it?
I'm in no way an expert so this is more of a question/random thought, is the ebp sensor tube clogged? Could the manifold pressure sensor (map?) be acting up?

Sent from my E6810 using Tapatalk
 

·
Registered
Joined
·
17 Posts
Discussion Starter #8
How many miles on it?
I'm in no way an expert so this is more of a question/random thought, is the ebp sensor tube clogged? Could the manifold pressure sensor (map?) be acting up?

Sent from my E6810 using Tapatalk

290,000 and the map sensor is working just fine all parameters are good the ebp sensor tube I’m sure is clogged again but had cleaned it and the sensor and still have the issue like I said for some reason it will only do it once truck is warmed up it’s very strange if the teuck is cold it runs 100% better



The map sensor is working fine and I’m sure the ebpv
 

·
Registered
Joined
·
3,351 Posts
What I’d do is figure out if it’s a 49 state truck or a Cali truck first. Refer to what Patrick noted in second post regarding IDing Cali truck. When you say turning chip off does this mean pulling it right out? I’d remove it totally and see how it runs.

As I recall split shots will run on a 49 state PCM truck, but not the other way round. If for noted is the case this could be the problem with stutter at given rpm. Solution then would be to swap in some single shot injectors.
j
 

·
Registered
Joined
·
17 Posts
Discussion Starter #10
What I’d do is figure out if it’s a 49 state truck or a Cali truck first. Refer to what Patrick noted in second post regarding IDing Cali truck. When you say turning chip off does this mean pulling it right out? I’d remove it totally and see how it runs.

As I recall split shots will run on a 49 state PCM truck, but not the other way round. If for noted is the case this could be the problem with stutter at given rpm. Solution then would be to swap in some single shot injectors.
j
Just looked right now as I’m cleaning my ebp sensor tube and It definitely is not a Cali truck no blue sticker on valve cover and my fuel pump does not have the pulsing dampener.. I’m very confused as my truck had this sense I bought but how is it even running good beside slight stutter??
 

·
Registered
Joined
·
17 Posts
Discussion Starter #11
But I will be getting some full force 1.5 I don’t know I guess I’ll just send them a set of single shots?? I have 3 OBS 7.3 and one is parts so I’ll use those to keep my truck while I wait
 

·
Registered
Joined
·
3,351 Posts
My rough and dirty understanding how the splitshots work: A small amount of Fuel is injected as piston reaches TDC, (or perhaps just prior to), with the remainder injected after, so a two stage event. As you can see Cali trucks have to account for this splitshot sequence via PCM software, fuel delivery (dampener) and of course injectors (and not sure what else). The notion was to meet CARB emissions I think, back in the day.

So your Cali injectors in a 49 state truck will run, just with some hitches. Full Forece 1.5s will most definitely wake up your ride, just make sure you have supporting mods. Just as a heads up, way back in the mid-late 90s I ran K&N filters on my powerstroke trucks.... as a suggestion when you go to service the filter, take a clean white cloth and run it through the intake into the turbo inlet and have a look. Your results maybe different then mine, as I’m often in dusty conditions. K&N are a good filter (MO) and I run them on non forced induction engines. On my 7.3s not any more, Donaldson large paper element, like a Tymar system, is all I use now and change ever 2-3 oil change.

Cheers,
j
 

·
Registered
Joined
·
17 Posts
Discussion Starter #13
My rough and dirty understanding how the splitshots work: A small amount of Fuel is injected as piston reaches TDC, (or perhaps just prior to), with the remainder injected after, so a two stage event. As you can see Cali trucks have to account for this splitshot sequence via PCM software, fuel delivery (dampener) and of course injectors (and not sure what else). The notion was to meet CARB emissions I think, back in the day.

So your Cali injectors in a 49 state truck will run, just with some hitches. Full Forece 1.5s will most definitely wake up your ride, just make sure you have supporting mods. Just as a heads up, way back in the mid-late 90s I ran K&N filters on my powerstroke trucks.... as a suggestion when you go to service the filter, take a clean white cloth and run it through the intake into the turbo inlet and have a look. Your results maybe different then mine, as I’m often in dusty conditions. K&N are a good filter (MO) and I run them on non forced induction engines. On my 7.3s not any more, Donaldson large paper element, like a Tymar system, is all I use now and change ever 2-3 oil change.

Cheers,
j
Thanks for the heads up it runs just absolutely perfect plenty of power and everything hit crushing and try to go a little under load and low rpm is stutters bad especially up a hill just wanted to make sure that it wasn’t the torque converter or anything I keep up the truck very well and am really hoping the new injectors will solve the issue
 

·
Registered
Joined
·
17 Posts
Discussion Starter #14
My rough and dirty understanding how the splitshots work: A small amount of Fuel is injected as piston reaches TDC, (or perhaps just prior to), with the remainder injected after, so a two stage event. As you can see Cali trucks have to account for this splitshot sequence via PCM software, fuel delivery (dampener) and of course injectors (and not sure what else). The notion was to meet CARB emissions I think, back in the day.

So your Cali injectors in a 49 state truck will run, just with some hitches. Full Forece 1.5s will most definitely wake up your ride, just make sure you have supporting mods. Just as a heads up, way back in the mid-late 90s I ran K&N filters on my powerstroke trucks.... as a suggestion when you go to service the filter, take a clean white cloth and run it through the intake into the turbo inlet and have a look. Your results maybe different then mine, as I’m often in dusty conditions. K&N are a good filter (MO) and I run them on non forced induction engines. On my 7.3s not any more, Donaldson large paper element, like a Tymar system, is all I use now and change ever 2-3 oil change.

Cheers,
j

Also if this was the case why does it only do it after the truck warms up??? It runs soooo much better when first starting the truck
 

·
Registered
Joined
·
3,351 Posts
Not sure what would be the cause of stutter when warm.... the only thing that comes to mind is when 7.3s have a noticeable difference in starts ups between cold (it’s fine) and poor or not start (when hot), it can be the Injection Pressure Regulator. There is a kit that replaces the square cut and o-rings on the end of the IPR. Comes with new tin nut and spacer thrust washer too as I recall. I usually clean up the armature on the IPR too if cruddy, and put a light coat of dialectric grease on the armature. Albeit what you are experiencing doesn’t seem to fit the usual IPR rebuild kit situation, just throwing it out there as not sure what else to suggest, aside from trying 49er jectors.

I’m sure the guys at Swamps Diesel or Full Force or rep jector manufacturer can explain why (stutter) is due to splits in 49er.
Cheers,
j
 

·
Project Shamu
Joined
·
2,417 Posts
I have the EXACT same problem as you, word for word same. Replaced all the same parts, several ICP's, CPS's, IPR's, new HPOP, new throttle positioning sensor, several speed sensors, new fuel pumps, new IDM's, different tunes, and the ONLY thing I can find, is what Dave Armstrong said in this:

https://swampsmotorsports.com/files/7.3LInjectorDiagnostic.pdf

I'll quote the section he mentions,

The fuel side of the 7.3L fuel injector contains many more components, which are not normally
considered ‘wear’ items. With proper fuel filtration, good, clean diesel fuel, and adequate fuel
pressure, the fuel side of the injector can go well in excess of 400,000 miles without issue.
However, ONE bad tank of diesel fuel (water, gasoline, poor filtration, etc) can immediately and
permanently damage the fuel side. Particularly, the ‘plunger & barrel’ assembly, which relies on
the diesel fuel to lubricate these very tight tolerance components. (Think of a piston in a cylinder
bore..without piston rings…with a “gap” of only 0.0001”) Since the injector is “fired” by high
pressure engine oil…any lack of lubrication inside the plunger and barrel will almost instantly
cause metal transfer between these two components (galling).
Once/if the fuel side of the injector is damaged, the symptoms are usually much more consistent.
As in..IF “a” plunger and barrel assembly is damaged…it may be so severely galled, that any
fuel that is trying to be pushed out of the nozzle, simply escapes up/past the plunger…and is not
injected at all. Any time a truck has a “dead miss”…hot or cold, part throttle, or full throttle this
is almost certainly a problem with the fuel side of the injector. A slightly damaged P&B
assembly can, occasionally cause a rough running when HOT…since the thinner/hotter diesel
fuel is thin enough to escape up past the scored/galled plunger & barrel assembly
So, I chalked mine up to being old/damaged AB injectors (which are the same ones you have as well), and am waiting until they die completely to replace with some 238/80% injectors.

If i still have the problem after that, I'm gonna lose it.
 

·
Registered
Joined
·
3 Posts
I’ve got the same issue, 96 f350 zf5 with an 01 7.3 with ab splitshots. Mine will usually only do it at about 2k rpm or higher, but it will do it wether it’s warm or cold and wether I’m going down the road empty loaded or sitting in the driveway with my foot on the pedal holding it there. I’ve got a hood stack and a video of what it shoots out of the exhaust when it skips I’ll try to upload. I’ve only had my truck for a few months but it’s seemed underpowered and I’ve been able to smell an unburnt fuel smell from the exhaust. I’m down to it being a single shot tuned pcm trying to run splitshot Injectors so I’ve got a hydra with custom tunes on its way and hopefully it will fix it.
 

·
Registered
Joined
·
471 Posts
Just because the solenoid says AB on it does not mean the injector is an AB code. I can put a BC code stamped solenoid on a AA and it's still an AA code. Do you have another IPR to try?
 

·
Registered
Joined
·
3 Posts
The chip and custom tunes made a night and day difference in the way it runs. There’s still a stutter but it’s gone from jolting the whole truck to if you weren’t looking for you wouldn’t notice it. The previous owner had China made valve cover gaskets and uvch so I’ve got the oem stuff to go back on today and hopefully that’ll fix the rest of it.
 
1 - 20 of 24 Posts
Top