Ford Powerstroke Diesel Forum banner

1996 help with loss of power

6368 Views 36 Replies 7 Participants Last post by  BigFuel
Well boy's im in need of some help again.My truck has been (running off) kinda stumbling when i am driving. Got a buzz test done and good news is all past the test. Did the cylinder contribution test and not good news. Cyliners 3,4,and 7 are not helping the motor run (failed the test). The truck has 360,ooo mi on her but does not burn oil and does not smoke out tail pipe. Any help? I hope it is not rings,could the injectors be bad but pass the buzz test?

Thank you
1 - 12 of 37 Posts
All on the same side and next to each other huh? Check the pigtail going to the that side of the head looking for damage/melting.
DOH! My dyslexia fouled my hypothesis.
Is the Air intake sensor clean and not hidden or buried away under something?

Buzz test just sees IF the injectors pulse, CC Test tests the quality of the injector's pulse (I.E. the injector opens but only moves half the volume of fuel resulting in a less then balanced total injection pulse that includes all the cylinders or simply rough idle/cruising/accel). With the engine running do the "oil cap test".

CPS: dark blue original Ford (had issues), replaced by light blue or grey (still had issues but Ford concidered it "within spec"), black is the one from International not Ford (IMO the best there is). I buy International parts before Ford parts.
Right, if the cap stays on then there is not likely sufficient blow-by on three cylinders and it's the flow of the questionable injectors at stake. When was the last fuel filter change? What does the fuel filter look like? Clean and white? Run a fuel stabilizer/cleaner through the system for a couple weeks and retest.
Welllll, the filter and the fuel bowl screen (you are cleaning this too right?) should have caught any solid crap coming through the lines. IMO doing the fuel filter every oil change is excessive. Maybe twice a year unless you dont trust your filling station to buy quality fuel. These are stock injectors or semi-fresh?
I get the fuel filters free from work so I say why not you know. I got this truck in Nov. but I do think they are very old maybe even stock! I have no idea. Do they just go bad over time?........o sorry yes I did the screen clean two months agao and it was plugged solid. I should prolly do it again huh. If it might be the injectors is there any way to test fuel flow with out sending them in? If they are bad do you know where to get a good price on some?
Yeah they do go bad. Think of them as 8 little hearts, one for each cylinder. Your heart mathematically only has so many beats in its lifetime before it gives up. Same with the fuel injectors. Like in our personal lives things will change how many times they beat. Air and water going through them, silt, bad oil, too much heat. I'd doubt there was a way of doing it at home. Injector builders use all kinds of fancy machines to test theirs before sending them out to the public. NAPA wants $560 for 1 rebuilt injector. F-that Beans Diesel sells one at a time for $125ea. (+ a $100 refundable core so there is no down time on the truck waiting for the injectors to come). Most would do just the three, I'd do them all to keep the mileage the same on all the parts and have all of them under warranty at the same time.

Which fuel filter screen are you reffering to? I've only changed my FF when it comes to fuel
The fuel filter cartridge and the Fuel Pressure Regulator Pre-Screen (Ford PN 9150)

See less See more
^it's the '95 version of the fpr screen
No worries, sorry about the link. Easier then describing it and the pictures are better then reading.
^^not likely the warm up valve. Normally if it was you would be having problems right from a stand still. Feels like your towing a anchor because its acting like an exhaust brake. Could be a clogging FPR screen easy to check and make sure to add it to your bi-yearly truck inspection. Could also be map sensor, boost leak, weak HPOP and/or IPR valve, weak/clogging injector/s, and slight chance CPS.
Almost scary that a little screen that you'd find in your sink faucet is responsible for so much in the performance of the truck.
Thank you, but I am one of many on here that do their best to lend idea's and information to those that ask. Sometimes I'm on the ball other times I'm not so great. I'm happy that you are happy with your truck.
1 - 12 of 37 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.