Coil Problem

[mike100]

You might have to get fancy and scope out the injector current with a current probe and an oscilloscope to see if any of your injectors might not be working right...even if they are new and you have a pintle sticking. Outside of replacing them all, this is a good way to check them.

like this, except you are not looking for shorted injectors per se... all C4's are the same- put a wire into the fuse panel. https://www.youtube.com/watch?v=RkKfoA7LSR8


I'm assuming you are not on the original multecs...

[BlackZR1]

Originally Posted by Locobob

So I decided to do some testing on the fuel side:

Doing the FSM chart A7 fuel pressure test with FP2 removed resulted in 45psi - about 4psi below the minimum okay range for the test.

I also used the fuel pump test circuit with a multimeter, I saw just over 4 amps draw on each pump and about 8.5 amps with both pumps running.

Activating each pump through the fuel pump test circuit and checking fuel pressure I got the following:

FP1 fuse removed resulted in 51psi

FP2 fuse removed resulted in 42psi

Shouldn't both pumps be the same PSI when activated individually through the fuel pump test circuit?

Yes, I got the same on both. Here are my numbers:

[Locobob]

Originally Posted by BlackZR1

Yes, I got the same on both. Here are my numbers:

Thanks for the info, that is what I suspected, looks like one of my pumps is a little weak.

[Locobob]

Originally Posted by mike100

You might have to get fancy and scope out the injector current with a current probe and an oscilloscope to see if any of your injectors might not be working right...even if they are new and you have a pintle sticking. Outside of replacing them all, this is a good way to check them.

like this, except you are not looking for shorted injectors per se... all C4's are the same- put a wire into the fuse panel. https://www.youtube.com/watch?v=RkKfoA7LSR8


I'm assuming you are not on the original multecs...

I'm running RC's, interesting testing set-up.

[Locobob]

So my worst drivability issues have gone away. I'm starting to think those were related to water. I went on an extended road trip a couple of weeks ago where the car was parked outside and it rained non-stop the whole time. I noticed quite a bit of water standing in the fuel filler area, and looking at it yesterday I noticed that I have a pretty good tear in my filler neck boot. Perhaps some water found it's way into the gas tank and it's mostly cleared out now? I checked the filler boot drain and it seems functional but somehow a lot of water was sitting in there. And with the torn boot and the filler neck gasket may not be all that great I could see where water may have leaked into the top of the gas tank. Think I'll just replace the fuel pumps for good measure and install a new filler gasket and boot in the process.
My new plug wires arrived so I'll probably be back under the plenum today to see if I can't get cyl #5 fixed up solidly this time.

[Locobob]

So new plugs and wires are on and #5 should be firing solidly again. The wire on #5 was super loose at the coil, I think the wire terminal itself was actually broken as squeezing it with pliers had little effect. Block learn on the left side is still high indicating fuel being added so apparently the ignition problem is not the cause of that issue. I seem to recall that the left side rail is more susceptible to issues when fuel pressure is low so we'll see what happens when I get the new pumps and filter installed.