Hello,

I have a 1999 24v what developed several problems.

1.  batteries get drained overnight

2. takes it several minutes to get it to charge 14 volts.

3. lift pump will not come on with key switch

4. lift pump will not come on with bump of starter.

 

Replaced alternator----same problem.

disconnected batteries for 1 hr.

 

Now lift pump will come on but it takes 5 to 7 seconds to come on after key is turned on.

Still takes several minutes for charging to get to 14 volts.

lift pump is not making enough pressure when running.

 

Batteries are less than 1 yr old and they are interstates.

lift pump is a fass that replaces the factory lift pump. its 2 yrs old.

I have a quadzilla programmer set to level 3.  level 0 does the same thing,  level 0 is factory setting.

quadzilla was installed 2 yrs ago.  also new vp was installed 2 yrs ago.

 

 

I am guessing its the pcm, but any ideas would be helpful

 

thanks

 

Does your   light come on as soon as you turn the key? If not the ECM may be having a hard time booting up. Something to try is to make sure the plugs on the ECM and PCM are still plugged in tight.

I would be looking to what is drawing your power down. Low batteries cause weird stuff. So, look up how to look for battery draw using a test light. Dont look into it too far until you fix the obvious things first

While you are at it, you might have both batteries load tested. Make sure they are both disconnected from the truck though. Last winter I had a battery that shorted internally. It would drag the good battery down overnight. They both even showed a good 12.5 volts. The shorted one dropped straight to 1.5 volts during the load test.

 

Note: This happened with both batteries less than a month old.

Bingo. I had one on my 01 that was bad and would draw the other one down. I forgot about that

update on issues:

 

I had charged both batteries up and load tested them.  both passed load test.  load tested them 3 hours later and still passed.

I decided to unhook the intake heater leads (the leads that hook to the battery on the drivers side.

I then unhooked both batteries (positives and negatives)  and left them unhooked for over 2 hours.

 

Note--when hooking up batteries, my lift pump came on and ran for about 10 seconds!

 

When to start truck

turned key on and waited for the lift pump to come on.  It took over 10 seconds for it to come on and it ran for 8-10 seconds.  

I cranked it over and it started right off.

Charging got to 14 volts in 3 seconds and stayed there.

I have shut it off and restarted it 5 or 6 times this afternoon and evening.

Charging seems to be fine now.

However, the lift pump still takes about 10 seconds after turning the key to ignition before it does the 10 second prime.

 

I went and talked to the local Dodge Dealership this afternoon.

They said that it the PCM and they would  be glad to get me one.

I asked if the were 100% sure it was the PCM,  they said no!  But that is how they would attack the problem.

 

needless to say I am not taking it there anytime soon.

 

Thanks for all the ideas.

 

I just want to figure out this delay in the lift pump coming on. 

I think I am going to rig up a way to detect when power gets to the lift pump to determine if my FASS is not starting correctly and to determine how many amps it is drawing.

 

I will update on my findings.

a thought on these FASS and Airdog pumps. do they draw power form the PCM directly or does one run that wire to a solenoid that then gives the pump power?

 

as per the OP problems. i would check grounds. bad ground bad electrical system.

For one thing, the lift pump gets its power/signal from the ECM. Not the PCM. If it is using an aftermarket harness with the FASS pump it only uses the signal from the ECM to trigger a relay. There could be a problem with the signal coming from the ECM or the relay not switching right away. You might try changing out the relay and seeing what happens.

 

If it is still using the stock lift pump harness, the pump is still getting all of its power from the ECM directly. Does your wait to start light come on right away or does it not come on until the lift pump primes?