Rebuilt IP and still problem

[cur.bill]

I have a rebuilt IP on my rebuilt 7.3 UDI and it starts up great. When I put in gear it will stumble for the 1st mile as if it is starving. It is beng fed with a walbro electric. New gas tank, new filter. new hose, double clamped, clear hose no air bubbles. Is there something on the IP which is causing this problem. I have had it to a mechanic and he had it overnite and was able to produce the same problem but has no idea what is wrong. He double checked all my fittings but basically said I dunno no. Any help will be appreciated.

 

[CDX825]

Is it smoking at all when its doing this and if so what color is the smoke?

 

[icanfixall]

What is the fuel pressure at the filter... Who did the rebuild is important....

 

[Exekiel69]

That was My first question too, what fuel pressure do You have at the filter?

 

[cur.bill]

No smoke at startup and the entire engine was rebuilt at a very reliable shop. The IP was done at a Bosch repair facility. They want me to take the IP off and drop it off to them so that they cxan test it. It has less than 20 hours of use. The engine has 3,500 miles on it. The electric pump is brand new. Like I said the engine starts right up and runs fine once it is warm. I have to drive it to warm it up because so long as I let it sit to warm up it will stumble. I can let it sit for 5 min and it will still stumble. After driving for about a mile it is ok.

 

[Exekiel69]

I'd still like to know how much pressure You are running.

 

[gonecrazyi]

Are you sure that the motors even broken in? From what Ive heard these motors need to be worked hard in order to fully seat the rings after a rebuild.

Try hooking onto a heavy trailer and head out to the nearest highway and let her open up a bit. Then see what she acts like.

 

[THECACKLER]

Are you depressing the Accelerator Pedal half-way to the floor on the cold start? It is necessary to allow the Cold Start Solenoid to raise the idle to about 950 RPM's. It is the external solenoid on the Front Right (pass) side of the I/P, There is also a a Cold Advance solenoid internal to the I/P. It is the smaller of the two terminals on the Left (driver) side of the I/P. It can be powered with a jumper to the battery to see if it's working. The control circuit is Ignition 12v to a 2 prong temp switch down behind your Thermostat Housing on the Right Front side of the block. The switch should be ON until the cool.ant reaches about 165* F then it kills power to the FSS & Advance Solenoids. So you can turn your key on when cold and just make and break the connection at the FSS to see if the circuit is good.
You might also have an injector sticking. Try to un-stick it by filling your Fuel Filter with a Diesel Additive and running it through. Do check your Fuel Pressure at the filter header to rule that out. Should be about 6 psi.
Post more info about your Truck in your Signature.

 

[cur.bill]

Its a 93 7.3IDI. I had a total rebuild on the engine to include nedw sleeves new pistons, new cam, new lifters, new rings if it neede it I had it put in. Rebuilt heads from Clearwater FL, injectors, glowplugs etc etc. The fuel pump puts out 12PSI at the filterhead and then it shuts down. New filter and just about everthing else. New tanks and you name it the only thing not new was the the IP. That was rebuilt like I said. If this was a gas engine I could describe the problem as a choke stuck. I will try the cold start problem and see if that helps.,