|
Recommend relay for new lift pump?
I have an Airdog FRRP 100 I'm about to install. I have heard the bad comments on them but not until after I purchased. I was told recently by someone there have been ECM failures after installing this pump do to larger amp draw on the ECM and advised to install a relay to take the load off ECM. Anyone have an opinion on this?
Thanks |
That is the craziest thing i have heard in a while, The ECM is only a control circuit for the opening and closing of the relay. It uses the same volts/amps to operate the relay no mater what pumps attached to it.
|
Originally Posted by Jet A Fuel
(Post 1101799)
That is the craziest thing i have heard in a while, The ECM is only a control circuit for the opening and closing of the relay. It uses the same volts/amps to operate the relay no mater what pumps attached to it.
|
Jet
Here is a post I found. This has been covered several times in the 2nd generation engine forum. You can install a relay like I have done like this. Install a relay near drivers side battery. Come off the relay that powers the VP44 injection pump and take this wire to power up the
. Put an inline fuse direct from the
a NO contact on the relay that you installed and on to the lift pump. Now you have taken the lift pump off the ECM and now it will turn on when you turn the key on and run until you shut the truck off. This is how I have set mine up app. 2 years and 50,00 miles ago. I expect this to last forever on my truck. This gives you a reliable source of power and the pump will run when the switch is on without switch bumping or timers. The original design off the ECM to power up the lift pump is NOT fused and the lift pump has been known to drag down the voltage to the ECM. If you use the search forums you will find lots of info on this mod. Also, you should have 12 volts all the time on the lift pump in the factory wiring, not 8 volts. The power when you first turn on the switch is only there app. 1/4-1/2 second so your meter can't pick up 12 volts fast enough before it's back off. |
Originally Posted by noserider
(Post 1101805)
Well Jet A. Good name BTW. I used to fly jets.The way it was explained to me, since there is no relay in the ECM to lift pump circuit it would take 2 amps from the ECM to open a relay (if installed) and the pump would draw 8 amps. Would this not make sense to shift the amp draw to the relay as opposed to the ECM?
Yes it would make sense to power a relay with the ECM as the triger. But I am not sure its needed I run an airdog 150 and never experienced any problem since 2008. Looking at the schematics I did learn that there are two wires feeding the Fuel pump from the ECM from pin 15 and 35 (both yel/wht wires) into one single yellow and white wire. I would assume that this might be a problem if only one of the two wires was used. What do the instructions with the pump say? |
1 Attachment(s)
Here is the schematic it looks like the FP relay wire he is talking about is the brn/wht wire from pin 36 on the ECM
Attachment 30536 |
Originally Posted by Jet A Fuel
(Post 1101810)
Here is the schematic it looks like the FP relay wire he is talking about is the brn/wht wire from pin 36 on the ECM
Attachment 30536 Thanks for the link. My 2002 5.9 ISB is installed in a 38' Class A Diesel Pusher. I'm still learning the differences if any in that application from the Dodge trucks. There is no mention of a relay in the instructions. I spoke with an experienced tech yesterday at Airdog who handles the calls for the commercial truck installs. He was aware of some ECM failure reports after installing the Raptor but did not admit to any liability of course for the pump causing the problem. He thought it would not hurt and be a good precaution to install a relay. I'm not to good on the electronic side of wrenching so I would like to understand the type of relay needed and how to wire it up. |
I would install the relay too if its been a known problem with the raptor pumps. You would need a relay rated for the raptor pump amp draw. It should be written somewhere in your paper work. I would imagine that the ECM in your application would be very similar if not identical to the dodge schematic.
Here is a relay that you could use its rated for 30 amps. https://cimg5.ibsrv.net/gimg/www.die...65b8fe6b9a.jpg Here is the plug for it. https://cimg7.ibsrv.net/gimg/www.die...b47aeddc02.jpg Here are a couple options for an inline fuse, I like the second one it crimps to the wire and could be heat shrinked to seal it. https://cimg0.ibsrv.net/gimg/www.die...4313f23e0f.jpg helpful link: most of these items can be purchased locally at the parts store. 12 Volt Automotive Relays 12 Volt - Wiring Products https://cimg1.ibsrv.net/gimg/www.die...6713defefd.jpg |
I went back and looked at the Airdog installation that I have and the harness comes with the relay and draws its power off of the alternator + post. You could order the harness for your FRRP and should be fine.:tu:
|
Originally Posted by Jet A Fuel
(Post 1102060)
I went back and looked at the Airdog installation that I have and the harness comes with the relay and draws its power off of the alternator + post. You could order the harness for your FRRP and should be fine.:tu:
Hey Jet. I'll have a look. My setup has a fixed harness on the pump with a 2 wire female plug that it plug and play with the male 2 wire it's connected to which goes to the ECM. |
| All times are GMT -5. The time now is 10:23 PM. |
© 2024 MH Sub I, LLC dba Internet Brands
