what do i unhook to compression test a F.I.

[sharkskinman]

just want to know what to disconnect so the injectors Dont fire
when i do a compression test

[Lars S]

Just disconnect the plug at each injector.


/Lars S

[sharkskinman]

didnt think about that

other than disconnecting at the fuel pump
what wire off the fuse box goes to that so it wont run

its a 90 ford ranger pump
but i dont want it running every time i turn the key

it doesnt show which wire on the diagram

[wildthings]

Just pull the wire off the negative side of the coil that sends a signal to the FI. Once that is removed the injectors will not fire. You can also remove the green wire to the points from the coil and you will get no spark.

Not familiar with D-jet as I trashed mine years ago in favor of L-jet, but I wouldn't think your fuel pump should be running just because the key is on.

[raygreenwood]

As wildthings noted....pull either the positive or negative wire from the coil (no ignition) and simply pull the three prong plug out of the side of the distributor trigger points (no injection). Ray

[albert]

SHARKS,, for the best test,, take the compression beefore the valve adjustment,, and readjuste the valves and take again the compression,, for to see if you have an différence,, plus make shure if your ,,tdc,, with the piston ,,no.1 is correct with the rotor for to make safe,,and crank the startor for 4 rotation on the main crank,, appx. 30 sec. and the reading on your gadge can change with an différent oil,grade,like ,,grade 40,,or grade 10-30,,normal randge is 100 to 150,, my motor is an 1.7 with d,jet injection and i have 90 k,mills on my original motor and my compression is 150 on 2 cilynder and 140 for my oder 2 cilynders, and you can take the compression wend the motor is cold and see the différence wend the motor is hot,, afther 10 minutes of running,, for to see if you have a big différence,,