towhungerford

Hey guys sorry for the slow response things have been very busy at the shop and home. Anyway the sound i was hearing was most noticable cold and would hardly be audible fully warmed up. Truck came in for a no start issue and was diagnosed as high returns in the injectors. So we put a set in from Diesel Pump & Injector Service in Houston, Tx. I never noticed a knock after i installed the injectors, so customer picks the truck up and calls a few days later saying the truck had a knocking sound. So he brings the truck back and sure enough i heard a knocking sound when the motor was cold. I could put it 3rd and come off the clutch kinda fast and it would kinda sound like a fuel knock or a slight pinging sound. Also taking off hard throttle i could hear it too. I ran the overhead just for sh--s and giggles but no difference. I checked exhaust temps with an IR gun and all clys where even. So I called the place where we got the injectors from a he told me about another customer that had the same issue, he put clear lines to and from the cp3 and found aeration in the return from the pump. He replaced the lift pump on the back of the cp3 and fixed his issue. so I did the same test and got the same results. Replaced the lift pump on the back of the cp3 and the noise is almost completly gone. On a side note something thats still in the back of my mind is that the engine is an HO model and not sure if non HO injectors would cause the noise I was hearing. Thanks for all input and ideas on this issue.

I had a motorhome with an 8.3 that I worked on a while back with a liftpump issue that bit me in the butt. The lift pump was not comming on so I unpluged the connector and put my DMM on to verify voltage and I had good power and gnd, or so I thought. So I put a new liftpump on it, hooked it up and ... nothing:banghead: So I put my meter back across it but this time I left the pump plugged in, no voltage, unplug the pump and I would get voltage. So I had to also replace the ecm. I learned a valuable lesson that day, now I issolate and load test EVERYTHING. Just because you get voltage on the meter does not mean the circut can handle the load.I even bought a fancy circut load tester (which I've never used, prefer the headlight)

Need to know if you have a in-tank pump or a engine mounted. If it is an engine mounted pump locate the two wire connector at the pump and backpin into it with a DMM and watch the voltage whenever you see the pressure drop. If the voltage drops when the pressure drops you"ll either have a wiring or pcm issue. If it is a in-tank pump the test is the same you"ll just need to backpin directly at the connector on the top of the tank module.Hope this helps.

Start with the basics. First check ur fuse and your power and ground conections, after that check your relay trigger feed from the ecm and verifiy voltage with a DMM, also load test with a headlight. To test the pump unplug the connector at the pump and supply power and ground directly to it, If it runs then you need to check the circut. Pin into the harness with a DMM and read the voltage, if ur getting system voltage then load test the circut by putting a headlight across the terminals along with the DMM and read the voltage. If the voltage drops out or you have no voltage at all then you could have a bad relay, bad power or ground connection, broke wire or a loose terminal at the relay or pump plug. Look at all the terminals closely for arcing, burning, or corrosion. Hope this helps.Ps. When you supply power and ground to the pump if it does not run I would still check the circut to make sure it was not the cause of the failure.

Yea somebody has this thing about WIRES!!! Lol

Great video Ryan, Can u tell us what the differences are between the 160,175,180,215 pumps?I know the 215 has the notches but what about the others?

I threatened to show up on Mike's doorstep a couple of times and he told me the first thing he would show me was a good a** kickin for all the s**t I give him, then show me around. lol

Must be nice to be able to up and get away like that.lucky bastard