hard start after injector change
 

Hey guys I put in some jammer 5 injectors (they ROCK!!) The install went great but after a few starts, I still have to crank it for 10 seconds or so to get it to fire. f/p is 15psi, and even if i crack #1 and get fuel, it still takes a while. my friends 12v with the afc gutted will not start unless you blip the throttle, could this be similar with the larger injectors?? I thought it was maybe just more fuel and needed to build more compression or somthing but it cranks fine within around 15 minutes. Anything much more than that it takes awhile to fire and runs rough. maybe cross over tubes? can those 3/4 nuts be too tight? orings somewhere?? please help! Thanks
TNutcher

There are orings on the crossover tubes.

There are copper washers on the injectors.

Did you replace any of those?

the copper washers were new on the injectors but not the orings. is that a very likely possibility??
TNutcher

The 12V with a p-pump starts better when you blip the pedal. It has to do with the internals of the govenor. On the 24 vp it won't do anything.

BigBlue went through this with his, here's the thread,

https://www.dieseltruckresource.com/...&highlight=155

thanks. I checked one of the crossovers and the o ring wasnt deteriorating but did have some type of build up on it, i'll try changing those out and see what happens. is it very common for the tubes to get some stain lookin things on them??
TNutcher

Is there anything I should do to clean up the gunk build up on it???
TNutcher

well sh*t i took out all the crossovers, cleaned the gunk off them with an emory type cloth and put new orings on them, put them back in, bled it, and started it up. These bigger injectors seem to make it run a little rougher at idle... but idk maybe its just me. but ran it, runs fine still, no leaks at the 3/4 nuts or anywhere else i could find, and shut it down. 30 minutes later i cranked it and it wouldnt start untill maybe 15 seconds on the thing. SOB!! [verymad]

any other ideas? i dont really wanna pull the injectors unless i ABSOLUTELY have to again... 3 hrs but still it sucks reachin back there and all...

how tight should those 3/4 or 19mm nuts be??

Thanks
TNutcher

Welcome to my world. Been living with it for months now. I have no idea where it's coming from. I even went and replaced all of my fuel lines and changed to a different set of injectors and I still haven't tracked it down. I'm thinking it's somewhere in the return system but I don't know where. I gave up. Member Big Smoky has the same problem and we can't figure it out on his truck either.

My truck had uphill and level ground starting problems and all of them were fixed when i bought a new overflow valve. It it the left front banjo bolt on the VP 44 and has a small ball bearing and spring that is set at 15 psi. If it leaks, fuel can drain from the VP's small reservoir down the return line to the tank. Then at start up, even if you cycle the lp twice, all of the air does not come out of the reservoir and you push air into the high pressure system. Part is only available at Dodge, costs 40 bucks but well worth it.

Bigblue, haha dang... not quite what i was lookin foreward to hear but thanks anyways! jk did yours start after changing injectors too??

I might give that overflow a shot but kind of leery not really being injector related... is there a way to test it by clamping some lines or something??? Thanks though.

lol today i parked at my grandma's in town and was leaving and cranking bliped the throttle to try to get it to start and it does, revs up and leaves a large cloud in grandma's yard.... WHOOPS =D sorry grandma!!!

TNutcher

The way I figured out it was the ball spring overflow on mine was that some times my Fuel Pressure would drop to 6 psi or so on the highway and only come up to 10 when I would let off and push in the clutch. That little valve was sticking open and allowing fuel to bypass at less than 15 psi. I just changed my injectors a month ago and I thought that it was the injectors or cross over tubes.

I'm still not following how the o-rings have anything to do with the fuel system. At nearly 17,000 psi, no oring is stout enough to do anything. All of those o-rings are there to keep dirt out of the engine "little one", and oil out of the injector cavity "big one". All of the high pressure seal is made with the flared tip of the cross over tube and the depression cone on the injector body. And the flared connection between injector line and crossover tube.

Most trucks will start on just three cylinders so I think that even if you had one leaky connection, your truck would start faster than 10 seconds. It sounds to me like air is getting into the staging reservoir of the VP and getting pushed into the injector lines. "Overflow valve problem" You might try pinching off the overflow line, but I have no firsthand experience with that.

One more thought, park your truck with nose down hill tonight and see if she starts better. If she starts, head down to dodge and get the part, it only takes one minute to replace with a 3/4 wrench or socket.

thanks Big Blue I'll give that a shot... it does kind of make sense... lol yeah true about those little o rings...

I'll give that a shot with my fingers crossed and get back to you tomorrow. thanks again
TNutcher

***watching closely***



I'll be slingimg jammer 5s into mine in the next week or 2.................