Fuel Pump & Battery Drain Issues

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RobHannett

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Hello all,
can anyone tell me where to locate the relay for the fuel pump on a 73 CSL? The pump itself is situated behind the rear axle, but the only two relays I can find are beside the battery. Neither of these seems to relate to the fuel pump

Had the RAC out on the M4 after the fuel cut out on the way to Spa last week. To say it was gutting not to be able to take it is a bit of an understatement.

On a second issue, the battery drains very quickly. It's less than 12 months old, and have replaced the alternator, but still loses charge. Any ideas?

Thanks

Rob
 
Hello all,
can anyone tell me where to locate the relay for the fuel pump on a 73 CSL? The pump itself is situated behind the rear axle, but the only two relays I can find are beside the battery. Neither of these seems to relate to the fuel pump

Had the RAC out on the M4 after the fuel cut out on the way to Spa last week. To say it was gutting not to be able to take it is a bit of an understatement.

On a second issue, the battery drains very quickly. It's less than 12 months old, and have replaced the alternator, but still loses charge. Any ideas?

Thanks

Rob
 
Hi Rob, I think the relay is under the seat next to the brain if it isnt either of the two next to the pressure sensor.

Sorry to hear of your breakdown.

Not sure on the battery drain.

Regards,

Rohan
 
Hi Rob, I think the relay is under the seat next to the brain if it isnt either of the two next to the pressure sensor.

Sorry to hear of your breakdown.

Not sure on the battery drain.

Regards,

Rohan
 
when you say battery drain - how quickly does it drain?

My coupe had an issue with the rear luggage compartment light staying on. That drained the battery within hours.

I also have a manual clock in the instrument cluster that will sap the battery if I don't drive the car every few weeks. Of course my battery is old, but these are the two sources of trouble for me.

I had to chase down the power drain at the fuse panel by using a volt meter on every terminal. Very tedious. THere are so many places to look in terms of battery drain, but the two I mentioned seemed to be pretty common along with hood light switch and relay failure.

BTW - my car is not injected but I do remember the shop manual indicating that the fuel pump relay was up front near the fuses. I can't say I remember certaintly, but I have upgraded to an electric fuel pump and that is where I connected (under fuse panel) after studying the shop manual.
 
when you say battery drain - how quickly does it drain?

My coupe had an issue with the rear luggage compartment light staying on. That drained the battery within hours.

I also have a manual clock in the instrument cluster that will sap the battery if I don't drive the car every few weeks. Of course my battery is old, but these are the two sources of trouble for me.

I had to chase down the power drain at the fuse panel by using a volt meter on every terminal. Very tedious. THere are so many places to look in terms of battery drain, but the two I mentioned seemed to be pretty common along with hood light switch and relay failure.

BTW - my car is not injected but I do remember the shop manual indicating that the fuel pump relay was up front near the fuses. I can't say I remember certaintly, but I have upgraded to an electric fuel pump and that is where I connected (under fuse panel) after studying the shop manual.
 
Thanks guys. Think I've located it. It's a 12v 10A lump, connector pins are marked 85, 86, 87 & 30. Pretty sure that's the fella.

acat, in answer to the drain - it's usually within a couple of days parked up. My suspicions are the dashboard clock, it's just a question of how I can fix it.
 
Thanks guys. Think I've located it. It's a 12v 10A lump, connector pins are marked 85, 86, 87 & 30. Pretty sure that's the fella.

acat, in answer to the drain - it's usually within a couple of days parked up. My suspicions are the dashboard clock, it's just a question of how I can fix it.
 
Rob,

The clock is actually not a significant source of battery drain if it is working normally. It fires about one time every 7 minutes and draws about 0.25A for 0.2 seconds; this is equivalent of a steady drain of 0.1mA. Over the course of a day this would be about 0.0024Amp-hours and the battery should be at least 50Amp-hours or more, basically able to run the clock for a decade. Do you hear the clock solenoid firing (sort of a ker-chunk sound) and if so what is the approximate interval? Another note on the clock is that the most likely failure mode is for the contacts to corrode / pit and basically it will stop firing and thus stop drawing current.

If you do have a battery drain I also suspect that it is a light or a short. In addition to the trunk light suggestion there is a glove box light that can do the same thing. A small light can draw well over 0.2 amps continuously; this will drain the battery of 10 amp-hours each day or more.

On the battery how do you know it is drained? If starter is sluggish or not turning over well it could be a bad battery cable or starter connection (or even the starter/solenoid). If these seem fine I would recommend a battery load test to see if it has failed or was defective, many part stores will do this gratis. Also, if you have a volt meter you should look at the voltage when the car is running - it should be between 13.5v and 14.5v. If not, the alternator may not be working properly or the battery has a shorted cell.

If the battery and alternator appear good, my recommendation would be to pull the positive battery terminal. The first thing to do (with the ignition off) would be to touch the positive cable terminal to the positive battery post and look for a spark spark (make sure you are in a well vented area and no fuel fumes or battery vapor is present). If you see a spark the first time it could be the clock firing but if you do it again after a few seconds there should be no spark. Ideally you would then connect the cable to the terminal through an amp meter and look at the current; it should be zero or certainly not more than a milliamp. If you see current, start pulling fuses until it goes to zero and you will find the offending circuit (there are also a few circuits from the battery which are not fused to consider). From there we can go through the wiring diagram and look for possible causes.
 
Rob,

The clock is actually not a significant source of battery drain if it is working normally. It fires about one time every 7 minutes and draws about 0.25A for 0.2 seconds; this is equivalent of a steady drain of 0.1mA. Over the course of a day this would be about 0.0024Amp-hours and the battery should be at least 50Amp-hours or more, basically able to run the clock for a decade. Do you hear the clock solenoid firing (sort of a ker-chunk sound) and if so what is the approximate interval? Another note on the clock is that the most likely failure mode is for the contacts to corrode / pit and basically it will stop firing and thus stop drawing current.

If you do have a battery drain I also suspect that it is a light or a short. In addition to the trunk light suggestion there is a glove box light that can do the same thing. A small light can draw well over 0.2 amps continuously; this will drain the battery of 10 amp-hours each day or more.

On the battery how do you know it is drained? If starter is sluggish or not turning over well it could be a bad battery cable or starter connection (or even the starter/solenoid). If these seem fine I would recommend a battery load test to see if it has failed or was defective, many part stores will do this gratis. Also, if you have a volt meter you should look at the voltage when the car is running - it should be between 13.5v and 14.5v. If not, the alternator may not be working properly or the battery has a shorted cell.

If the battery and alternator appear good, my recommendation would be to pull the positive battery terminal. The first thing to do (with the ignition off) would be to touch the positive cable terminal to the positive battery post and look for a spark spark (make sure you are in a well vented area and no fuel fumes or battery vapor is present). If you see a spark the first time it could be the clock firing but if you do it again after a few seconds there should be no spark. Ideally you would then connect the cable to the terminal through an amp meter and look at the current; it should be zero or certainly not more than a milliamp. If you see current, start pulling fuses until it goes to zero and you will find the offending circuit (there are also a few circuits from the battery which are not fused to consider). From there we can go through the wiring diagram and look for possible causes.
 
Battery Drain

The clock shouldn't have that much of an impact. My car can sit for 3 weeks and still start right up and the battery is 2 years old. I would look at the trunk light and the alternator/regulator.
 
Battery Drain

The clock shouldn't have that much of an impact. My car can sit for 3 weeks and still start right up and the battery is 2 years old. I would look at the trunk light and the alternator/regulator.
 
Thanks for the advice JJ.
Regarding the drain, when left standing for a couple of days there is no power out from the battery - no ignition, no lights, electrics or anything. After a quick charge, it's all fine, which is why I thought it was the alternator and replaced it.

The boot light and glovebox lights both appear fine - they're off when closed. The one thing I do have is the bonnet inspection light only comes on when the lid is up with headlights on. I can't imagine that should be the case, so I'm wondering if there's something wired incorrectly there causing a drain.

Once I get the relay installed I can get her out of the garage again, have a closer inspect and try your suggestions.

Thanks
Rob
 
Thanks for the advice JJ.
Regarding the drain, when left standing for a couple of days there is no power out from the battery - no ignition, no lights, electrics or anything. After a quick charge, it's all fine, which is why I thought it was the alternator and replaced it.

The boot light and glovebox lights both appear fine - they're off when closed. The one thing I do have is the bonnet inspection light only comes on when the lid is up with headlights on. I can't imagine that should be the case, so I'm wondering if there's something wired incorrectly there causing a drain.

Once I get the relay installed I can get her out of the garage again, have a closer inspect and try your suggestions.

Thanks
Rob
 
Miscellaneous ramblings

RobHannett said:
the battery drains very quickly. It's less than 12 months old, and have replaced the alternator, but still loses charge. Any ideas?
Click to expand...

Reiterating others' advice, you might want to look here: http://www.popularmechanics.com/blogs/automotive_clinic/4283670.html and http://www.ehow.com/how_2249402_find-parasitic-battery-drain.html

Next, even thought you replaced the alternator, are you certain it is performing as expected? Assuming everything is A-ok, does your alternator have solid mounts or does it have rubber or urethane bushings? If the latter, are you certain the alternator is properly grounded? A weak ground or whimpy ground wire may cause the alternator to charge, but not particularly well.

Not knowing anything about your specific local environment and the condition of your vehicle, it is unlikely but possible something else is going on. I do not mean to suggest you park directly above the Chunnel, but humidity, exposed cables and a pinch of oil and dirt can be an interesting recipe for no lights. There is a reason why many marine battery applications include disconnect switches and insulated battery boxes/containers.

Have you absolutely eliminated the battery or the installation as part of the voltage drain? You might consider literally disconnecting the battery when you park and see how long the battery holds a charge just standing by its lonesome.

Backtracking just a bit, are you using an alarm?

If all else fails: http://batterybuddy.com/
 
Miscellaneous ramblings

RobHannett said:
the battery drains very quickly. It's less than 12 months old, and have replaced the alternator, but still loses charge. Any ideas?
Click to expand...

Reiterating others' advice, you might want to look here: http://www.popularmechanics.com/blogs/automotive_clinic/4283670.html and http://www.ehow.com/how_2249402_find-parasitic-battery-drain.html

Next, even thought you replaced the alternator, are you certain it is performing as expected? Assuming everything is A-ok, does your alternator have solid mounts or does it have rubber or urethane bushings? If the latter, are you certain the alternator is properly grounded? A weak ground or whimpy ground wire may cause the alternator to charge, but not particularly well.

Not knowing anything about your specific local environment and the condition of your vehicle, it is unlikely but possible something else is going on. I do not mean to suggest you park directly above the Chunnel, but humidity, exposed cables and a pinch of oil and dirt can be an interesting recipe for no lights. There is a reason why many marine battery applications include disconnect switches and insulated battery boxes/containers.

Have you absolutely eliminated the battery or the installation as part of the voltage drain? You might consider literally disconnecting the battery when you park and see how long the battery holds a charge just standing by its lonesome.

Backtracking just a bit, are you using an alarm?

If all else fails: http://batterybuddy.com/
 
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