Lope on cold start

[rammertide07]

Hey guys, got nother one for ya'll. Whenever it gets cold outside (this morning OHD read 33*) and I start up the engine, without having it plugged in, it has a bad lope...like the lope tune. It loped probably 5 times this morning. But back around Christmas...about 20* outside....it loped for about a minute before it cleared up. Fluid levels are good. Also my usual start-up it twice as long as my uncles 99 F250. I've read on some other forums that it could be caused by a bad/weak low pressure oil pump never heard of that on our engines. Could the 2 be related??

 

[thompson238]

Rammertide how many miles are on your truck and are you still running the original injectors? My truck has 230k on it and it done this very thing last winter and it would shake like crazy if i tried to drive before it warmed up really good. I replaced the injectors this summer and I have not had any issues since.

 

[commanderjjones]

Mine occasionally does that too, but only at much colder temps.......like down in the teens and colder. It typically goes away in a few seconds, and I always let it idle for at least 2 minutes or longer when it's that cold (just to make sure everything is well oiled), so I haven't been overly concerned about it. If my blockheater was plugged in, it never happens.....so I try to remember to plug it up on cold nights. But even with the occasional loping issue, it always starts right up.....no prolonged cranking.

 

[Red Monkey]

Thats normal for 7.3's when it's cold. I started using Rotella synthetic oil and now I have no more 'lope'. I told a buddy that also has a 7.3, he changed to synthetic and it cured his 'lope'. You may want to try synthetic oil or just learn to live with the 'lope' when it's cold.

 

[BIG JOE]

Cold soaked Engine..Cold Oil ?

The GP's provide enough heat for detonation. The heads start to heat up. The oil rails are connected to the heads. The rails heat up. The Oil in the rails heats up (doesn't take much heat). The injectors now "pop", more evenly.. Like they should..Lope goes away.

Simply put but, make any sence ?

Always been my take on it anywayz.

Joe

Not To Worry.. it's the nature of a Diesel to do that: also my take on it.

 

[Stroked68]

I'd say its weak glowplugs or weak GPR. Injectors would cause that too I've read. Mine does the same thing when its very cold. If I cycle my GP's 2 or 3 times doesnt do it very bad or not at all. If its plugged in usually doesnt do it. Mine has over 258k on it and I dont think my injectors have ever been replaced. Im due but it still runs great. I run 2stroke supertech all the time. I wouldnt worry bout it till it starts running like crap on the road or somethin. I had the same concerns with mine and i've come to the conclusions by hearin what all these awesome guys say on here its nothin to really worry about. When I save up enough I will do a total fuel system upgrade. Sucks our injectors are so expensive.

 

[Tail_Gunner]

The cold start lope is usually an oil related thing. When the standard summer (15w40) weight oil is cold, it gets rather thick and doesn't like to flow very well. FWIU, when the oil is real cold/thick, a oil pressure imbalance occurs between the right & left HP oil passages that feed the fuel injectors. But there is an HPOP oil pressure sensor only on one side. Because of that, when cold, the HPOP pressure is not modulated real well, it's either high or low. As the HPOP oil pressure bounces back & forth between too much and too little, the injectors are not operating in a constant modulated fashion or even in sync with the injectors on the other side. They are going back & forth between on or off with the oscillating HPOP oil pressure.

There are a few things you can do to cure or treat the cold start lope.
1) Plug your truck in. The block heater will warm the oil enough to help prevent lope.

2) Use a lighter weight, winter oil as specified in the owners manual. Its viscosity, or resistance to flow will not be as great as summer weight oil in cold weather. Again. the thinner oil will help prevent lope.

3) Install a H/X mod. It is basically a balance hose or tube that connects the oil passage in one head to the oil passage in the other head across the valley. I've tried a few of these mods. The hose types always started leaking after a while. I did finally installed a KCM HPX Line which has been working leak free for about 8 or 9 years now.

There has been a lot of discussion about whether HX mods are worth it. I guess it depends on your definition of "worth". For me, HX has worked good preventing cold start lope for about 10 years now. IMO, the truck runs smoother & quieter. But most importantly, it hasn't loped since I installed my first HX line.

 

[BIG JOE]

Thanks TG.. for the fully explained version of.. Lope

Joe

 

[commanderjjones]

Thanks TG.. for the fully explained version of.. Lope

Joe

Ditto.

 

[rammertide07]

Wow, thanks guys. Odometer says 186,000...but I figure its closer to 200,000. It didn't do it last winter....guess the wear-n-tear is getting to it. How hard is it to install the H/X line? My dad's 96 7.3 has 640,000 miles on the original injectors. It would usually "clack" on a cold start but never lope like my truck Always ran Valvoline 10-30/40. I feal better now that I know it's normal. Thanks guys