Engine/Transmission (1994 - 1998) 370 Idle lope when cold - theory

[T. Baker]

I guess other people have notice a slight lope at idle possibly more pronounced with 370s.

Mine does it when it is cold and idling slowly - about 6 or 700 rpm. My guess is it is the pressure spikes of the lift pump causing one cyl to get slightly more fuel. It seems to go along with the throbing of my return line.

I have been thinking of putting in an accumulator to stop all that presure spiking and to save the overflow vavle spring and even out the fuel presure. I think it will make the lift pump last longer too.

 

[DMC]

I guess you upgraded the delivery valves. If not,that could possibly be the problem. Or its just cold and going to do that until more complete combustion occurs, after it warms up some. I was kind of thinking about this kind of thing today. And wondering how much larger size injector a guy can go to without changing the delivery valves.



Don

 

[T. Baker]

I have 181s and they work fine. There is no lope when it is warm and idling at 600 or so RPM.

It's not a problem - I was just theroizing.

 

[Forrest Nearing]

I just hold my foot on the throttle and hold it at 800-1000ish for a bit untill I start driving... I don't idle while cold for long at all... oil pressure is up and I start driving to get some heat in the motor ASAP.



Forrest

 

[T. Baker]

I don't let mine idle cold for long either. I think it promotes carbon and coke build up. It is better to just start driving it - gently.

 

[Woodenhead]

Yeah mine loped too. So I put in a high idler (manual throttle cable). Now when it's cold I just idle it up to 1000RPM, no lope and good oil pressure



Mike

 

[Forrest Nearing]

Originally posted by T. Baker

I don't let mine idle cold for long either. I think it promotes carbon and coke build up. It is better to just start driving it - gently.

man, w/ the extra fuel and the big ol' turbine side, I can't drive it anything BUT gently when it's cold or it'll sputter and pour un-burnt diesel smoke out the pipe!



Forrest

 

[SEmerson]

Mine will lope if you put it in gear right away. If I let it warm up for 20-30 secounds it will idel fine. It drives me crazy. I only have 181s too. I would love to find a fix. :{

 

[bmoeller]

TTT

 

[pwknapp]

Mine lopes big time in the winter. (-15 to -40 deg) Rocks the whole truck for about a half a minute or so. I turned the idle up to 975 and for now it has stopped. We'll see this fall. I always thought it was not having my 3K GSK tuned dead on?

 

[CATCRACKER]

i have the lope after the 370 injectors when it is cold after it has been driven for 1min down the road its fine but when it lopes its bad. i up my idle that helped keeping the truck from dieing but its still not good i think this is the nature of these 370's which throw lots of fuel and can even put the fire out when the truck is cold. goosing my truck real quick really just bliping the throttle will kill it. oh well. i can live with it it just sounds like a ford's romp romp when cold.

 

[HoleshotHolset]

Here I was thinking that Dad's truck was the only one to sound like a mud drag racer first thing in the morning when he slaps it into gear... My '94 sorta sounds like a 2-stroke Detroit with a 'properly' adjusted governor. :-laf



Anyone here with the lope have a pump that has been balanced? I wonder if from the OEM - these P7100's aren't exactly balanced very well... the 370's (or any bigger injector for that matter... ) tend to exaggerate everything...



Matt

 

[biggy238]

Is there any way to identify the injectors without pulling them? Or any sign that I could look for to see if they've been replaced?

 

[JoshPeters]

Mine does it a bit cold... in gear. I have found if I don't have the A/C on... . it isn't as apt to do it... but still will. I think if I bump my idle up... it'll go away... if I manually bump the idle up it's fine.



Josh

 

[bmoeller]

Originally posted by HoleshotHolset



Anyone here with the lope have a pump that has been balanced? I wonder if from the OEM - these P7100's aren't exactly balanced very well... the 370's (or any bigger injector for that matter... ) tend to exaggerate everything...



Matt

Good question. Mine has never has run as smooth as I think it should, like I may need to have the pump on a test stand. The 370s made it more noticeable. Need to bring my idle speed back up also.

 

[HoleshotHolset]

I'd LOVE to put a pump on a test stand... I think the injection pump tech would throw me out of there, though. I'd be asking too many questions and getting in the way...



Dad emailed me - he said that his popping/spitting on the first fire in the morning has been reduced with the "022" DV's... He didn't say whether or not it still lopes like a mud drag racer in gear, though...



Once it's warmed up just a little bit - it always ran fine.



Matt

 

[HEMI®Dart]

It's gotta be the 370 injectors. I have DD III's and 191 DV's w/ NO lope anytime. Warm or ice cold.

 

[HoleshotHolset]

It's that darn spray pattern that's made for them marine pistons...



Even still - you can't beat 370's for the 'bang for the buck' factor...



Matt

 

[pwknapp]

My new motor has the marine pistons and the 370's still lope, no different from the old motor with stock pistons. Go figure.

 

[HoleshotHolset]

You'd think that the Scheid pump would be balanced... BUT with all the extral fuel - it might still lope... no matter what.



I'd like to see someone run a balanced pump putting out OEM cc's and a set of 370's...



Matt