Engine/Transmission (1994 - 1998) engine misses under fast acceleration

[MBradway]

i have a 96 12 valve 5 speed 4x4 with 93,000 miles all stock but for straight pipe and fuel filter relocation kit. in cold weather at first start up n after oil pressure is up, fast acceleration in first and second the truck starts to miss and falls on its face in the rest of the gears it is fine and after the truck completely warms up u can accelerate as fast as u want n no missing, on a warm day it will do it a little also. my 91 has never had a problem like that n my buddies 06 doesnt either. i have changed fuel filter many times n the valves just recently adjusted. my concern is that every one says its not rite but they dont have answers.

 

[RStankevitz]

no idea but my dads 95 is doing something like this he says it seems to stumble or defuel in second but the top 3 gears she will blow slight black smoke and haul *****? havent tried it myself but will follow this thread with interes

 

[The patriot]

Have you done the fuel return line?

 

[WPeschel]

i have a 96 12 valve 5 speed 4x4 with 93,000 miles all stock but for straight pipe and fuel filter relocation kit. in cold weather at first start up n after oil pressure is up, fast acceleration in first and second the truck starts to miss and falls on its face in the rest of the gears it is fine and after the truck completely warms up u can accelerate as fast as u want n no missing, on a warm day it will do it a little also. my 91 has never had a problem like that n my buddies 06 doesnt either. i have changed fuel filter many times n the valves just recently adjusted. my concern is that every one says its not rite but they dont have answers.

I would never run the truck hard while cold... Most diesel trucks dont run properly until warmed up...

 

[WDimig]

i agree with Wpeschel, but if it still is doing it even while warm, i would check the fuel system throughly, check both the supply, and return rubber lines, if they are stock, i can garuntee you that the 12 year old rubber is bad. i would highly reccomend replacing the lines with new high grade marine fuel line, check the fuel pre heater element, sometimes they melt, and allow air into the fuel system. also if you can, check your fuel pressure at high idle, should see above 25 psi. hope this helps.



wes

 

[Vaughn MacKenzie]

MBradway, I would do as WDiming & The Patriot suggest. What I think could really be causing it is timing that is too retarded. I would have your timing adjusted to 15. 5- 15. 8 degrees, that'll make a big difference.

WPeschel made a good point though, drive gently and don't "get on it" until you've driven a few minutes and the temperature is coming up.

 

[The patriot]

I had my supply pump go bad right around the same time the fuel heater went.

Drove me crazy for a while there.

At any rate, sounds like air in the system. If it hasnt been done yet, you'll need to do the return line anyway. Get SAE J30R9 spec hose. IIRC a foot should do it.

 

[MBradway]

i dont like running it hard cold either but when i m at work, i let the oil pressure build n let it run for a few minutes, i also dont max the rpms its just accelerating fast,( i read in this mag that its is not the best to let them run at an idle forever to just drive them and easy) so when i leave work there is too much traffic to pull out easy so when i do pull out and accelerate the truck falls on its face n i get no where with idiots flying around me and almost into me, when i leave home i drive easy n its fine, though its not good i have seen many other trucks start cold and be fine. i bought the truck at 86,000 in jan of this year, so i havent replaced any fuel lines yet but that is my next move when i get free time, thanks for all the info i plan to look into all of your suggestions

 

[dieselman24]

Fixed mine with a Airdog I had the same issue.

 

[MBradway]

this might be stupid but what is an airdog and what does it do. i have never heard of that

 

[dieselman24]

Airdog

Airdog is a Fuel System sort of like the FASS Fuel System and basicly the same thing one is not better than the other just availability. It replaces the factory Lift pump on the engine and is able to provide enough fuel to the Injection Pump also does away with the hard starts some even claim that they give better fuel mileage but I have yet too see a difference in either one I have them both and I run a HPFP from FASS on my Freightliner FL60 Rollback with a 5. 9 VP44 and I have put like 50k miles on it without any issues or fuel pressure problems at all either. They Both make very good Products and work very well.

 

[MBradway]

o okay, n thats good if it stops the truck from cranking for so long on start up, thanks

 

[The patriot]

I dont know what year your truck is. Mine is a 98 12 valve and within one engine revolution it's running.

 

[MBradway]

mine is a 96 and i m not sure how many revolutions it takes but is definately more than one, so i guess it is a fuel problem... I know someone else that has a 98 12 valve and it will not start with out pressing the accelerator to give it fuel and it the sun visor of the truck even has directions telling u that u have to do that, and i experienced the same thing when i tried to start it, and its bin that way from the dealership new, have u ever heard of that?

 

[Missouri Mule]

I have heard member having to depress the go-pedal to get the ctd to fire-up.

What is your rpm at idle in gear with a/c on. It should be 750 t0 800. Some members have set it higher for better starts.



Long start problems can be cause by air getting to fuel system. Have you replaced your rubber fuel line lately if not marine grade hose for diesel is the way to go.



Also a weak starter can cause long cranking.



Missing when cold mite be the p7100.

 

[dieselman24]

That is not right on a 12 valve truck my racing truck has been sitting all winter and it just started right up maybe 2 revos at the most I would really look into getting the timing looked at by a good diesel shop my race truck is set about 33 degrees but that is way too much for a street truck. You need too have it set at around 16 degrees and it will get really good fuel mileage too and start right up. TJ