As soon as I got my fuel pump check valve fixed another problem showed up. Now my battery drains overnight. When I try to start it the next day either it barely cranks, or I just get a click. I took it to the parts store today to have them load test the battery, and it's fine. In fact, it was supposed to have 850 cold cranking amps but it tested out at 897.

So now I need to track down whatever is draining my battery. I'm going to use the ammeter/fuse pulling method. This might take a while.

 

As Roseanne Rosanadana said: "It's always Somethin"

 

What other things did you do to the car other than pulling the tank? If I recall you had a problem pulling that tank out, do you think a wire could have been pinched? I found this tool to be useful 30 Amp Automotive Fuse Circuit Tester I hope it helps!

Also in 20A http://www.harborfreight.com/catalog...Circuit+Tester

 

I already looked. There are no wires in the area that I could have pinched. I think it's just a weird coincidence. With all of the cranking I had been doing to start the car I assumed I had just damaged the battery, but the load test today says otherwise.

 

Sorry to hear that Sam, especially after all the work you did on the tank AND the video too.....thanks for that

Trying to look on the bright side.......No doubt you'll track the problem and then make a video of the diagnosis and fix to be uploaded to the site.......All good ....lol

 

Howdy Rev:
I could not tell if you were going to check every fuse or not.
What I did was to disconnect the 12v cable from one fuse block(EDIT:take care as to not let this live cable touch any metal since welding / arching could occur) , and then check the total battery drain current at full sleep. If the total battery drain read more than ~35ma I would reconnect the cable and go to the next fuse block and check it in similar fashion. Otherwise reconnect that block and pull each fuse one at a time, checking total sleep current, then replace that fuse before going to the next one till the culprit circuit is found. (I saved the passenger fascia (LHD) block for last since I could not easily diconnect that 12v cable and did have to go one fuse at a time.)
My drain turned out to be fuse #15 on pass fascia box. As of lately, it seems to have fixed itself on its own. I used a cheap digital multimeter set on the 10 amp scale.(lower scales required care as to not wake up the sleep mode which in turn would blow the 300ma fuse in my tester)
Since we are looking for a target current ~25ma, I am not seeing the Harbor Freight fuse tester to be benefical if it has a resolution of 100ma.
If your findings do appear to be a module circuit, I have since read, (but have not checked mine yet) to compare the B+ voltage at the module to the voltage at the battery terminals as a small voltage drop could prevent the module from going into full sleep mode.

 

could it have something to do with your"fix" before you removed the tank?

 

You were doing the gas tank - perhaps the trunk light switch or wiring were impacted, and now the lights are staying on all the time?

 

Just a wild stab in the dark...but did you remove your 'custom' fuel pump trigger device completely, or just disconnect the trigger? Some electronic devices draw excessive current with their inputs 'floating'.

 

When looking for a current drain, use binary search.

If there are 128 fuses, the circuit of interest can be found in 7 rounds. 256 fuses would take 8 rounds.

 

HI Sam Sorry you have troubles.Could the fuel flap release module be the cause connector might not be fully home.
Good luck Al

 

Sam,

Not much I can think of beyond what's been suggested.

Maybe, given the coincidence part, it would be a good first test to pull whatever fuse feeds the fuel pump and see if that makes any difference over night. [edit: On second thought, not very likely.]

Otherwise, when you've gotten a measurement of the current drain, it may(?) help us narrow down the search by ruling some things in or out.

 

Plums - this sounds interesting, can you elaborate? In databases, binary search works like this:

Tables hold data. Each table has an index to show the precise location of each record.

The index is like a Dewey card catalog in a library.

In a Dewey, the cards are divided into drawers: A-C, D-F, etc. An index has a "master drawer" with A-J on the left side, and K-Z on the right.

These master cards point to a second index drawer. If looking for "Charles", the second drawer would contain cards for C on the left and D on the right.

So, by looking in the first drawer, the database eliminates all of the drawers but one, making the search much faster.

Similar?

 

My God, this forum is definitely different than the RX7 and MR2 forums I used to haunt when I owned those cars, with all the little kids sniping at each other and asking what they could bolt on to get 1,000 horsepower.

B

 

Noblesse oblige

Rev, I hope you get to the bottom of this latest problem. If I didn't have 3 other vehicles to keep me mobile, I would never have dared buy a Jaguar!

 

I'm afraid the "binary search" idea isn't so easy to apply here. If there were, say, 128 independent fuses, then the drill would be to pull half of them (64) and see if the problem went away. Whether it did or dd not, we would have narrowed the search to 64 fuses. On it would go: 32, 16, 8, 4, 2, 1.

But it doesn't seem to me practical to apply such a method here.

 

As Dr. D suggested, you can disconnect the power feeds to each fuse block, and then narrow your search to a single fuse block fairly quickly. That is probably the quickest brute-force approach.

 

The other thing is, if this leak pulls the battery down in the course of a single night, then we're looking for something on the order of amps, rather than hundreds of milliamps or less.

Maybe that can be of some value in the process of elimination.

 

Or, possibly disconnect half, and leave half each night?

How would one do this? Are there plugs into each block?

(My knowledge of automobile electronics is evolving. And BROTHER is there a lot of evolutionary potential here.)

 

Each fusebox has a heavy B+ lead with a lug terminal that can be disconnected (very carefully...it is not something you want to accidently short to the chassis unless you want to weld it there!)