Hey guys, I got a pretty unique problem going on with my f250. Its a '83 f250 xlt and I have swapped out the original 460 that needed a rebuild with a low mile EFI 460 from a wrecked '90 f250 with only 60k original miles. The problem that is happening is that after driving more than about 5 minutes and getting the engine warmed up, if I shut off the engine (or the engine dies - it sometimes happens at low idle), and I try to start it up within the next 30 minutes or so the battery's (yes I have a twin battery setup for those really cold mornings) don't have enough power to crank the engine over. However if I sit and wait about an hour after shutting it off/dieing to try to start it again it will start up without a problem, or if I jump start it, it will start fine. The battery's are big NAPA deep cycle, and about five years old, and I tested they read 13.5 to 14 volts when the engine is cold, and 11.5 volts after the engine is warm, and 5.8 as I try to start the warm engine. The engine doesn't appear to be over heating at all, has the proper amount of oil, was running when I pulled it out of the '90, but will occasionally sputter out and die when at low idle.

I have never encountered a problem quite like this one, and it has had me stumped for a while. Any suggestions or idea's????

 

Does it still have the OE ignition system ?

 

It has the OE distributor cab and rotor from the '90, the coil from the '90, OE PCM & ICM from the '90, and alternator is from the '90. The starter is from the '83, but is exactly the same as the '90, and it has the starter relay from the '83.

 

The previous poster is questioning the ignition system because advanced timing can cause that same problem. I am going to assume you transferred the whole efi system over from the other truck, and everything is timed correctly. There is a procedure to follow when setting the timing on a efi engine. Check that first.

2nd, I do not like your batteries. Deep cycle batteries are not starting batteries. The cannot supply huge amounts of current for a short period of time like a starting battery can. A deep cycle has large thick plates inside to withstand deep discharge and re-charge cycles without warping. A starting battery has a delicate honeycomb like structure inside to expose more lead to the acid, which gives more cranking power. You need to get rid of those batteries. Probably one normal starting battery will out perform both of your deep cycle batteries.

 

Thanks Franklin, I should have been more specific as to why I asked my question. Also, I do agree about deep cycle batteries as they give a false sense of initial start security. The PO of my truck had DC batteries in it and when the first winter hit, well.....

 

As a side note....regardless of the "type" of battery, given mass production, I wouldn't trust any battery past 3 years from heat stamp. Manufacturer's heat brand the case lid like rancher's branded cattle. (they use ear tags now...it's more humane).
(Not the date sticker on the lid of the case). And who knows how long it sat on a shelf from inventory purchase, then shelf time, to sale. Labels mean nothing.

 

Yes, I did transfer the whole EFI system as a unit with the engine, so the timing SHOULD be fine. How would I double check that it is timed properly? It runs nice and smooth the vast majority of the time, except for the few instances where it will stall at a low idle.

As far as the batteries being older, I do agree that their age could be part of the problem or the entire problem, and I have been wanting to replace them, but good quality batteries are a little expensive and I just haven't been in to town with enough cash yet to get some.

The reason I am running deep cycle batteries is because at times I'm running a big warn winch and two off road spotlights on the custom front bumper and four other off road spotlights on the headache rack, and I've always been told by all the old timers in the area that you want to use a deep cycle type of battery to run that many accessories at once.

And then if it is a problem with using deep cycle batteries instead of the standard type, why would they have plenty of charge to cold start, but not enough to restart when the engine is warm, but after the engine is cooler they have enough charge to start again without the charging system running? The engine is not overheating at all, but would/could the regular operating temperature in the engine bay compromise the capacity of the batteries?

This pickup is not my daily driver, I have this pickup mostly for going on fun off road trips up in the mountains out of cell phone range, so I have to trust it to be reliable and not leave me stranded out there.


As an off topic conversation to WhatsAChevy about batteries being branded like cattle; all of the several dozen commercial cattle ranchers that I know use both traditional hot iron branding as well as ear tags because its pretty easy for rustlers to change a ear tag, but a lot harder to cover up or change a brand, or to sell a animal with a tampered brand.

 

Find the wires leaving the distributor. You should have a group leaving the dist, and one of them will be suspiciously by itself. Follow this one by itself and you should run across something in the wire like a plug or a jumper/plug. This plug/jumper thing is called the "spout connector". To check the timing, you unplug this jumper/connector. This takes the timing control away from the computer and lets you set the timing with a light and by twisting the dist around like the old days. Once you get it where it's supposed to be, lock the dist bolt down, put the jumper/plug back in, and the computer takes back over.

I will warn you if it's way off, the engine may stall. The computer will try and pull the timing around where it's supposed to be of it's way off, and when you take control away from it by unplugging the spout the engine may not run. In this case you need to turn the dist slightly till you can get the engine to run enough to put the light on it and get it right.

Hopefully you know the specs on your engine, the timing info would have been on the sticker on the other donor truck where the engine came from.

 

You may very well know your cattle.... I concede, without contest, aside your self contested battery knowledge Given that, I know much,much better.

 

I'll back out at this point. Hopefully the OP figured it out or knows much more than I or FTE.
Obviously....the accessories are powered by the alternator(s)....not the batteries. Unless one would choose to operate those without the engine running.

 

+1 on the previous comments about deep cycle batteries. They can kinda maybe sorta handle the massive current flow required to spin the starter, but not reliably. They might work okay some of the time, but they have little reserve capacity. Exceed that reserve and the voltage drops way off, just like you experienced.

Why do your deep cycle batteries work generally work okay on a cold engine but not on a hot restart? I think two overlapping factors are at play.

1) A cold engine has lower compression than a warm engine. Lower compression means less effort is required for the starter to spin the engine. This means less current flow from the battery. Conversely, with a warm engine and better compression, more effort is required. This can exceed the battery's capacity, and slow or no cranking is the result.

2) Deep cycle batteries are only designed to put out low to medium current flow. This also means they can only recharge at a slower rate compared to a conventional starting batteries. After just a few minutes of charging, a deep cycle battery (already severely taxed) hasn't recovered enough for another start. After driving for a while, yes, a deep cycle battery would get sufficiently recharged, but not after just a few minutes.
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If you intend to run a winch or that much auxiliary lighting I'm going to suggest you fit a 130A 3G alternator from a '93 (or so) 3.8l Taurus/Sable/Lincoln.
You're severely taxing the already problematic 2G charging plug and harness.
Doing this upgrade eliminates the fire prone wiring and has more charge potential at idle than your current 2G does at redline.

As Dave already said, deep cycle batteries are okay for a 'house' battery but their slow charge/discharge rates make it hard for them to supply the current needed to crank the engine.

 

Greetings from Cherry City Willamette guy.

First question is, are both batteries charging? When the engine is running what voltage do you get on each of them? Should be around 13.5 14.5 volts. If you're under 12.5 you're not charging.

I run dual batteries, one for starting (the chassis battery) and the other for the "house".

What you want for the starting battery is cranking amps and they are often rated for cold cranking amps or "CCA". The more the better! This battery is attached directly to the starter solenoid and is the one (and only) that feeds the stater all those cranking amps.

Over on the house side I use a deep cycle to run all the camper stuff. Very important to note this battery is only connected to the electrical system via small wires (through an isolating solenoid that closes only when the key is on) and the full amperage potential of this battery is NOT available to the starter in any way. The wires attached to this battery are too small and don't go over to the starter.

Take a look at your set up. Do you have full size battery cables running from the auxiliary battery over to the starter? If you don't you're only starting off the one battery

However, if you're in a pinch you can always jump the house battery over to the chassis battery with jumper cables to get a jump start. You might give that a try and see what happens.

Idea. Run your winch and lights off the auxiliary battery. If your set up is like mine the auxiliary battery is isolated from the chassis battery when the key is off. Then you can sit there motor off and drain the deep cycle auxiliary battery flat but your chassis battery is still nice and fresh and ready to start the vehicle.

If you can jump start the hot vehicle every time the Single deep cycle battery that's trying to start the motor is inadequate...to overcome some of the heat related variables discussed below and still start the vehicle.

Heat realated issues may include corroded old original battery cables which should really be replaced by now or the classic starter heat soak.

460 starters get heat soaked living next to hot exhaust manifolds and pipes. They get hot, bind up, and won't work until the truck has sat for a while and cooled down. Maybe somebody missed a heat shield in the swap and the starter is exposed to abnormal heat? Maybe you can add a heat shield?

In summary; proper battery amps, heavy new battery cables and clamps. Check your starter for exposure to heat and potential for shielding. Check to see if you're charging and look at how the two batteries are tied into the overall system.

And if all that checks out your starter could just be tired and in need of replacement.