Need help

[mountaindan]

My truck has started missing again replaced the injectors thought it was fixed. Now has a miss between 1100 and1200 RPM no load. Hàve checked the Ac noise, cleaned the grounds, removed the vanaken tuner. Have a cam sensor haven't installed it yet.  Don't know where to go from here, this has been going on for a while now. No codes, any help would be appreciated. It is a 1998.5 basically stock fass DDRP 15 to 17 lbs constant

[Hawkez]

It was missing before and then you replaced the injectors, correct?  After installing the new injectors how long was it running fine before the miss came back?  Your signature says that you have replaced the IP twice?  Was it changed trying to resolve this miss?  How long ago were the changed?

[mountaindan]

Miss came back about 3000 miles after new injectors. The pump was changed about 3 years now first one was bad from new sent it back they tested it said it was good same problem no power a lot of smoke.  Needed The truck got one from a different builder been working fine. Miss started last fall.

[Hawkez]

Where did you get the IP that is in the truck now?  Have you suspected the camshaft position sensor in the past?  Is that why you have a replacement or are there other problems that motivated you to purchase that?

 

Just some thoughts, when you replaced your injectors, did you replace the o rings on the crossover tubes and make sure that the copper washers were installed?  Is your fuel filter good?

Edited May 30, 2018 by Hawkez

[mountaindan]

The injectors and crossover tubes had new o rings and washers.  I got the camshaft sensor from Geno's when it was mißing before.  Thought the injectors solved the problem. The pump that is on it now I think came from industrial injection,

[Dieselfuture]

I would have to say if miss went away after changing injectors it's still injector related

[mountaindan]

Would a injector cause a miss at only 1000 to 1200 RPM?  How would be the best way to find it?

[Mopar1973Man]

7 minutes ago, mountaindan said:

How would be the best way to find it?

 

Personally, pull all 6 injectors and have them pop tested.

 

8 minutes ago, mountaindan said:

Would a injector cause a miss at only 1000 to 1200 RPM?

 

As far as I know... I would say no. Basically an injector is waiting for pressure from the VP44. As the VP44 pushes pressure into the injector it has the power to over come the spring and lift the pintle firing several pulses of fuel in one stroke. As an injector wears it just fires sooner and lower pressure so the droplets get larger and more like a squirt gun. 

 

As you apply throttle you just raising the pressure to the injector. So at idle its right around 4,500 PSI so as you apply throttle you increasing the line pressure.

 

So I doubt it's an injector but to rule it out I would have the pop tested. 

[mountaindan]

Just had the injectors pop tested when the shop installed the new tips.

[Mopar1973Man]

1 hour ago, mountaindan said:

Just had the injectors pop tested when the shop installed the new tips.

 

What pop pressure was the injectors set for? Were the injectors flow matched? 

[mountaindan]

It was a diesel shop I think he said 230 I don't know about the flow match.

 

I did notice while checking if you rev it to above 1500 when you let off it will miss Everytime it gets to1000 down to idle then clears up and idles great,

[Mopar1973Man]

230 bar is junk.

 

293 to 327 bar is stock range. Stock set is 310 bar. Might explain poor running.

 

[mountaindan]

I have given up on this thing, taking truck to shop in the morning. I need a truck for a trip we have planned. Hope they can find the problem.  Ford is looking better every day I want to get it fixed before I do anything stupid. Thanks for your help.

[Mopar1973Man]

Sorry to hear that. All I can say is you might pay more money for taking to a shop and have some shop monkey wildly guessing at the problem charging you large amounts of money. There are things on these truck that is considered maintenance items like injectors. They are supposed to be replaced every 100k to 150k miles for the optimal performance. I know many people will say they ran their injectors over 400k miles and never changed them. Might be true but the fuel economy typically is much lower.  Sorry to say 230 bar is junk its way too low and will not atomize the fuel well at all. It will create misfire conditions. 

 

This is why some of us are experimenting with high pop pressure about the 330 bar realm to find out if there is anything to gain. Like myself as soon as I can get money ahead I'm planning on pulling my +75HP injectors out and going for (7x0.010) with pop pressure of 330 bar. As the pop pressure goes down the injection event happens early and and not sprayed in fine mist but a squirt.

 

Remember two things are needed for diesel to run well. 

1. Compression - Valve lash in good adjustment, cylinder health (good piston rings and no blowby), boost pressure.

2. Fuel - Sprayed in the cylinder in a fine mist at the right time. 

[mountaindan]

Thanks Mopar1973man, hopefully this guy won't take advantage of men. I need the truck and after a recent stroke I just can't do the work anymore

[Mopar1973Man]

You could look at the 911 listing and see if there are other members near you that might be willing to help.

https://mopar1973man.com/cummins/911-support.html

 

You could ask other members here in the forum to help you. Most guys here are really good at being helpful and helping with doing repairs on trucks. I'd love to help but I'm on the wrong side of the island from you. 

Edited June 3, 2018 by Mopar1973Man

[mountaindan]

Thanks that is what makes this forem so awesome

[dripley]

That is way to pretty a truck to swap for a Ford. From your description I assume you just had the old ones rebuilt with new nozzles? Who built them and were did the nozzles come from? 

 While I have never had a stroke 2 close relatives of mine have and i have seen the challenges they have faced. Me, just being 65 has it challenges. I hope the shop you have found will be of service. I have one here at home that seems to know what they doing but still like to do all that I can. 

[Guest 04Mach1]

5 hours ago, mountaindan said:

I have given up on this thing, taking truck to shop in the morning. I need a truck for a trip we have planned. Hope they can find the problem.  Ford is looking better every day I want to get it fixed before I do anything stupid. Thanks for your help.

I would stay away from Ford especially if you go diesel. Power Strokes are nothing but problems from the 6.0 all the way to the current 6.7. At least with Ford you could look at the emblem and say they circled the problem for you when it breaks down.

[Mopar1973Man]

I made it a point to contact @mountaindan on the phone today and try to help him out. Anyone near Dan would be a service to help him out.