FUSES being pulled for Comp. Check

[DFickel]

Hey guys, the book is saying for a comp. check I should pull the PCM BATT fuse located in the instrument panel fuse block, and the IGNITION fuse from the under hood fuse block. Only ones I could find were both in the underhood fuse panel and they were PCM BAT and IGN SYS. Are these one in the same? Or should I be looking somewere else. I opened the fuse panel where the DRL and Cig lighter and such were and nothing there Thanks

[Azrael]

Those sound like the right ones. To be extra safe, pull the fuel pump fuse too.

[DFickel]

well wouldnt the pcm batt take care of that? it should cut power to the whole system? u know what the symbol is for the fuel pump fuse is by chance?

[DefEddie]

Not sure what your working on,but alot of newer fuel injected vehicles have a type of "flood mode" you can default them to.
I use it on Ford's daily.
Turn the key to on,press throttle all the way to the floor/hold and attempt to start.
Pressing the throttle all the way to the floor triggers the pcm to shut off the injectors.

Not sure if it'll work in your instance or not.
If I can't do that with a vehicle,I just pull the fuel pump relay and all's gravy.
My computer has a nifty function I can use that does a relative compression test through the pcm by measuring cranking rpm utilizing the cam/crank correlation similar to how the misfire monitor functions.
Does the same thing using pulsewidth and pressure drop for a relative injector flow test,fun tools.

[DFickel]

nice, the book does say to have the throttle wide open by just holdin the gas down when u do this comp check though, wish this would be as simple as pluggin in a computer, i've messed with pulsewidth some in hyd classes at osu when we were into servo valves, pretty neat stuff

[DefEddie]

nice, the book does say to have the throttle wide open by just holdin the gas down when u do this comp check though, wish this would be as simple as pluggin in a computer, i've messed with pulsewidth some in hyd classes at osu when we were into servo valves, pretty neat stuff

Regardless of the way you do it,you will always hold the throttle open/down on a compression test. This is done to get the most possible airflow into the engine.
Pulsewidth in the sense I was speaking of is simply a measured opening of the injector.
OSU=Oklahoma State University?
I live in eastern oklahoma in sallisaw,few hours from stillwater.

[DFickel]

ya, when you mentioned it my mind instantly went to hydraulics though ha, and no sorry i'm referring to The Ohio State University, I always forget there is another osu out there. Any trick to moving the engine farther ahead? I took those brackets from the front apart and used a crow bar to rotate it, but it only goes like 3-4 inches ahead.

[pocket-rocket]

Ratchet straps? 3-4 inches is a good bit though. You might want to undo mounts on the bottom if you need to get more than that to avoid busting one.

[DFickel]

ya ill prob tie a strap to the bar when i get it moved forward, where are the bottom brackets located backside by the oil pan?

[DefEddie]

No tips there,i've got a fiero and I just reach around the back pretty easily for the most part.

[DFickel]

ha damn, who at gm decided lets make the back plugs impossible to get to ha

[DefEddie]

Better than the DOHC Fords I look at.
Have to pull the intake to even pull the coils off the rear plugs to check them.
Only takes 30 minutes to remove/replace not counting diagnostic time,but costs customer more still.
And most people think you don't need torque wrenches,so I get alot of easy check engine lean codes because of overtorqued manifolds from changing plugs at home.
Got one in yesterday,easy money.

[DFickel]

ha who at gm was thinking, lets make those back plugs impossible to get at on 3.1s, i wanna know, these eng. guys are like oh everythin works great it runs and such, but they never have to work on it and realize how stupid their design is. I did an intern at Bobcat once and they were the same way

[pocket-rocket]

The bottom mounts would be at the passenger and drivers side of the tranny most likely. You should try rear plugs on my DOHC, or on the 15 passenger Ford van I did with a 5.4l. To pull the coil-on-plug coils I had to pull the fuel rail first, but at least the intake stayed on.

[DefEddie]

The bottom mounts would be at the passenger and drivers side of the tranny most likely. You should try rear plugs on my DOHC, or on the 15 passenger Ford van I did with a 5.4l. To pull the coil-on-plug coils I had to pull the fuel rail first, but at least the intake stayed on.

You don't have to pull the fuel rail on a 5.4 E-series to get to any coils.
The #7/8 cylinders just require finesse,and you have to have a very shallow 7mm wobble.
The wobble get's out the coil bolt that can be impossible under the regulator,and the coil should come right out with a bend and a twist.
Actually easier in a van than a truck because you can pull the doghouse and it's right there.
We don't even pull the fuel rails to remove broken plugs on the 3 valves.

If your interested I'll give you the part number for the 7mm wobble you need.
It isn't a regular 7mm,it has an extremely shallow head and made to fit almost.
Most ford techs will have one,it's a must to get to those under the regulator.