A few months ago Tommy (abear) asked me if I knew of “a 12v fixed or adjustable timer that could be paralleled with our lift pump oil pressure switch which would provide say 5 secs or so of run time when cranking the engine then would fall out of service allowing the oil press switch to take over.” This would allow the LP to fully prime and slightly pressurize the fuel system prior to the oil pressure switch (OPS) kicking in once the engine is running. I suggested the ELK-960 timer (http://www.elkproducts.com/products/elk-960.htm) (found during the early TDP Lift Pump work). Tommy subsequently purchased and installed an ELK-960 timer on his truck. Of course once I heard that his was working I had to have one too…http://www.dieselplace.com/forum/smileys/Embarrased.gif So, if anyone is interested here is a summary of the install. (This mod isn’t totally necessary … just cool… http://www.dieselplace.com/forum/smileys/Cool.gif )

The ELK-960 (available from Farifax Electronics (http://www.at-fairfax.com/ConstructionElectronics/Info/ELK960.htm)) has several modes. I used it as a simple one-shot timer. When power is applied it will run one cycle and turn on a built in relay for a preset interval. The time is adjustable from 0-60 sec. I set mine for about 15 sec to allow the lift pump to run until the engine is running and the OPS takes over. The timer circuit board was installed inside the lower fuse box cover (http://community.webshots.com/photo/77018086/143154350CzJEWK)
http://thumb0.webshots.com/s/thumb1/5/43/50/143154350CzJEWK_th.jpg
and I also applied a coat of ignition sealer (http://community.webshots.com/photo/77018086/143154439QOGmGG) to protect against condensation. The timer relay is wired in parallel with the OPS and manual LP button.
(see schematic (http://community.webshots.com/photo/77018086/143154393zVJoLp)).
http://thumb3.webshots.com/s/thumb2/5/43/93/143154393zVJoLp_th.jpg
Power for the timer was taken from the input side of the <

Why not just use the glow plug timer circuit? A diode in series to prevent reverse current flow and one wire would be all it takes. I haven't done it yet, but may try and see if it works.

Flyboy,


Good idea on the glow plug circuits. I looked at the Glow Plug controller schematic in the 03 Helms manual (page 6-2517/18) and from what I can tell the Glow Plug controller is driven by the ECM. I'm not sure but it looks like the Glow Plug and Intake Heater relays will be on when ever the "Wait to Start Indicator" is on. So, using these circuits would work when the engine is cold but not when it's warm (glow plugs &amp; heater don't come on).


http://www.dieselplace.com/forum/smileys/Geek.gif

Boy, I wish I had known about those add a circuit fuse holders over the last couple years. Think I'll pick up a couple of them just to have on hand. http://www.dieselplace.com/forum/smileys/Approve.gif


Bill, Good recommendation on the timer. I'm very pleased with the reliability. When I installed the Juice w/ attitude my engine became much harder to crank. The immediate pressure up of the fuel has made this problem go away completely. I think once a few members realize this it will become a popular mod. http://www.dieselplace.com/forum/smileys/Thumbs Up.gif

jbplock,


Awsome post!


Thanks! http://www.dieselplace.com/forum/smileys/Thumbs Up.gif http://www.dieselplace.com/forum/smileys/Clap.gif

jbplock,


I purchased one of the ELK 960 timers. I asked the sales person at Fairfax what the operational temperataure range was.


I got 0-70 degrees C, or 32 to 150 degrees F.


Have you, or anyone else (a bear) had a problem with this timer due to temperature?


Do you think that the sales person is wrong (wouldn't be the first time)?


Thanks,


Bert

Bert,


0-70 deg C sounds like a typical manufacturers spec for a consumer electronc circuit but I wouldn't worry about it. Worst case, the timer might not start at cold temps but it won't prevent the engine from starting. My guess is the timer will work at cold temps but the time interval may vary. I confess that I didn't consider the temp spec.


I'm thinking I'll pickup a can of cold spray (the type used to trouble shoot electronic circuits) and test my timer. I'll post results if I find anything.


Also, Tommy lives down south where it's always warm ... http://www.dieselplace.com/forum/smileys/Big Smile.gif


Edited by: jbplock

typical commercial integrated circuits are speced for 0 to 70C junction temperature. That is the device junction temperature within the IC package.


Since, upon Power up, current flows--the devices heat up. The actual junction temperature depends on outside ambient temperature and package thermal resistance.


All that said--I would not worry about it--it will probably function--I would like to get a schematic for the little guy before I buy one and be sure.


Cold spray is kind of tough on the circuits--we use it when we are trouble shooting cold issues--but if does not perform well it does not necessarily mean you have a problem.


Ron

Well if it's 32-150 deg I can surely live with that. http://www.dieselplace.com/forum/smileys/Big Smile.gif

Thanks guys,


I'm only asking cuz where I live I see -15 to -20 at least 2-3 times a winter, and below freezing most nights and early mornings in winter.


In the summer time, I go over to the western slope and see 105-115 ambient temps in the summer.


I bought the timer anyway. I'll keep looking to see if I can find a hardier circuit down the line.


Bert

If anyone is interested, I found a couple of "industrial strength" interval timers that should work.


One is a KIKR series from Infitec. They are $31.09 apiece, but you have to meet a minimum order of about $50. Temperature range is -20 C to 80 C.


Another is a TGL series from Airotronics. They are about $20 apiece but you have to buy 5 to get that price. Otherwise they too have a $50 minimum. Their temp range is -25 C to 85 C.


Both have 10 amp relays.





Bert

Bert,


Good info on the other timers! http://www.dieselplace.com/forum/smileys/Approve.gif Modified also posted a link to www.amperite.com (http://www.amperite.com/) on the other forum and they have a few timers that look like they would work too. Not sure about the price though. I'm still planning to test the ELK-960 with some cold spray. I'm also finding that the pre-run time only needs to be about 5 seconds (like Tommy said). I originally had it set for about 15 seconds but that was too long.


http://www.dieselplace.com/forum/smileys/Geek.gif

Nice to know about the shorter time. I got the prices for variable timers. Fixed timers might be a bit cheaper.





Bert

Update on the ELK-960 timer...
I picked up a can of Cold Spray at Radio Shack and sprayed down the Timer so it was VERY cold (the can said -62degF). The timer still worked fine with no noticeable change in the time interval. Not a very controlled test but it gives some confidence that the timer should work OK in the winter. A better test would be to cold soak and test the PC board in an environmental chamber.
http://www.dieselplace.com/forum/smileys/Geek.gif

:grd: I FINALLY got my timer in yesterday. :cool2: After loosing it for a while and just being plane old too busy, Good Friday was good for the truck. Thanks to jbplock providing the wiring diagram, I knocked it out in less than an hour. Most of the time was spent getting the wire from the manual switch to cooperate. I had to trace it and then splice into it and then lengthen it because I couldn't get my paws into that little spot I had to work in. Censored But, as always with an a bear/jbplock project, it worked out just like they said it would.:exactly:

Thanks as always guys and thanks to the place for keeping such good records for those who don't get right to it. :D