Just installed a new CPS, now truck will not start. with the old cps it would start but run really ruff. Any ideas?

 

well I got it to start, but it runs rough. could the timing have jumped?

 

Probably one or more injectors not firing. Have the codes pulled. If that does not tell you the problem, pull off one of the valve cover gasket electrical connectors and then start the truck. If it runs bad, turn off the truck, plug that one back in and pull off another one and start it again. When you pull one and it does not change the way the truck runs, thats you bad set or wiring or injector/s. Also remove the oil fill cap and smell inside the valve cover, if it smells like burnt plastic, you have bad UVC (under Valve Cover) wiring.
Or you can have a buzz test and cylinder contribution test run. Let us know what you find out. I'm sure others will be along to offer more info.

 

plowhand has good advice.
Also which CPS did you buy? The blue or the black? Is the plug on tight? Is the fuel filter clean? Fresh oil and filter? Are you using fuel additive?

 

blue cps, plug is on tight, just change fuel filter & oil & filter. not using any additive.

 

From what I understand the blue CPS will change the timing. It was made for another engine. It should give you more low end, but since I didn't use one it is all hear say. Do a search, there have been other threads about it.

Edit: I just saw a thread about the blue one down the page a bit. Have a look.

 

I would put the old CPS back in and return the blue one and exchange it for the black one or a store credit. I think the blue one is for the DT466.Go with Plowhand's advice and check all your wiring. Takes less than a half hour. How many miles since you changed the oil? Fuel filter? Check the screen in the FPR. Takes 10 minutes.

 

the old 1 was doing the same thing the new 1 is. I broke the old 1 when I was tryint to get it out. When I checked the codes it said the cps.

Oil was changed about 500 miles ago. changed fuel filter when it started running ruff. so thats new.

what is the FPR?

 

Fuel pressure regulator.

 

I replaced my CPS a few months ago. I found an IH outfit. I asked the guru's behind the counter what the difference is.

He said the blue CPS is for the 6-cylinder and the black one is for the 7.3 8-cylinder. I went with the black CPS (1825899C93). No problems since.

In fact, I replaced the VSS in the rear diff today. My old one returned a reading of 809 Ohms. The book says if it reads 195 - 250 Ohms it should be good. I guess mine was really getting bad.

 

I did what plowhand said, I unpluged the wires. Passenger rear when unplugged ran smoother. The other 3 made it run ruffer. Now what? I'm no machinac!

 

Look inside the black plastic clip on the suspect wiring lead with a flashlight and reading glasses and see if all 5 pins are visible and clean and straight. If you're not sure what a good, unburnt one is supposed to look like then look at one of the other ones and compare. It is a subtle difference but once you see one and recognize it they will all stand out like a sore thumb in the future. Make sure you clean up all your wiring connections and hook them back up really good to eliminate poor connections which results in increased resistance which means additional heat which leads to more burnt connectors and future wiring problems.

That side has your oil fill cap. Take it off and see if it smells like burnt wiring inside the valve cover. If the outside wiring connection is fine but it smells inside then your problem is a little wiring lead that goes to the two injectors and two glowplugs from the inside of the clip. Most likely it is just a wiring problem you can remedy quite easily yourself. You don't have to be a master mechanic to fix it. You just have to have help finding out what the problem is and then you'll discover that the fix is fun and relatively easy and oh so rewarding. If it is a bad injector the repair is more involved but still something you can do yourself. If and when you get to that point we'll simply explain how to determine which one is bad and also how to fix it.

 

I checked the rear passenger wire, 1 pc was broken off, checked the front 1 and 1 spot looked to be melted. both on drivers side looked fine. what next?

By the way I want to thank all of you for helping me with this.

Scott

 

Was the broken piece on the VC (Vlave Cover) gasket or on the end of the engine wiring harness that plugs into the VC gasket?

If it was on the VC gasket You will need a new VC gasket: (Ford) F4TZ-6584-A / (International) 1818350C2.

If it was on the engine wiring harness you will need some or all of the following: Valve Cover Harness Repair Kits (contains 4 hard shells w/seals, w/o terminals): (Ford) F7TZ-14489-BA (94-96) (Ford) F7TZ-14489-AA (97); removal tool and Shells w/o pins: (International) 1830829C91; Pins: (International) 1661875C1; Pins with 6" wire: (International) 2501055C1.

You will also need to pull the valve cover and check the UVC (Under Vavle Cover) wiring harness. If one or more is bad you will need: Valve Cover Harness, "under valve cover": (Ford) F4TZ-9D930-K (94-97) / (International) 1815923C92 (94-97).
Remember that International is cheaper than Ford. Keep us posted.

 

plowhand, thanks for all the info.

any idea how much i will be looking to spend for all of the above?