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Fuel Pump Resistor Data Request

Old Jul 28, 2011 | 02:02 PM
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Fuel Pump Resistor Data Request

I am hoping some of you might be willing to contribute to an experiment I am engaged in at the moment:

If you have a laser-type thermometer that you can point at things and get a temperature, please post up the temperature of your fuel pump resistor after driving the car for any length of time.
The resistor is the ribbed "brick" mounted to the side of the bracket that holds the airpump on the passenger-side of the engine compartment, just above the wheel.

Please indicate if you are on a stock fuel pump or some aftermarket pump and the ambient temperature at the time of measurement. Also indicate any other changes you may have made to your fuel system.

I'm running some system efficiency experiments on the electrical side to see if there is some performance to be had by improving the circuit.

Also, if you are so inclined, measure the temperature of the "FUEL" and "CIRCUIT" relays in the main fuse box under the hood on the other side of the engine compartment.

Thanks.


The resistor looks similar to this:


And is located here:

Attached Thumbnails Fuel Pump Resistor Data Request-clipboard01.jpg  
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Old Jul 28, 2011 | 02:05 PM
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I'll send you some data next week, planning an hour long road trip so I'll try and get you data for each leg of the trip. (ambient temps should vary a bit so we'll see what that does to the readings)
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Old Jul 28, 2011 | 02:05 PM
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Question, IR thermometer that isn't a laser work as well? Or does it have to be a laser one?


Edit: Not just pulling your chain, I can certainly help. Have one at home, and can just keep it in the car and give you a few readings each day.

Last edited by RIWWP; Jul 28, 2011 at 02:13 PM.
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Old Jul 28, 2011 | 02:31 PM
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Originally Posted by RIWWP
Question, IR thermometer that isn't a laser work as well? Or does it have to be a laser one?


Edit: Not just pulling your chain, I can certainly help. Have one at home, and can just keep it in the car and give you a few readings each day.
Anything that will accurately measure the surface temp of the resistor (and relays if so inclined) will work.
Just needs to be a "no touch" sorta thing.

One set of data is sufficient as long as the car has had some time on the road.

Ideally, I'd like to see data from extended periods of time, regardless of load.

Any additional data is welcome - I just outlined the basics in the opening post.
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Old Jul 28, 2011 | 02:33 PM
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From: Pacific Northwest
I love data.

30-40 minutes of city and highway driving each morning and afternoon, easy to get you readings for each.

I assume you would be interested in ambient temp as well any interest on any other data points from my AP for it? Coolant temp for example?
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Old Jul 28, 2011 | 03:01 PM
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Originally Posted by RIWWP
I assume you would be interested in ambient temp as well any interest on any other data points from my AP for it? Coolant temp for example?
Just ambient temp. I don't care what the rest of the engine is doing.
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Old Jul 28, 2011 | 04:30 PM
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From: Pacific Northwest
40min of mixed highway/city
Ambient: 81f
Resistor: 163f
Adjacent chassis: 181f
FUEL relay: 162f
CIRCUIT relay: 162f
Chassis: 85,000 miles, 2005
OEM fueling, original parts
Gas Tank level: Gauge at 1/4 low mark

Last edited by RIWWP; Jul 30, 2011 at 02:40 AM.
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Old Jul 28, 2011 | 07:53 PM
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From: Pacific Northwest
10 min highway, grab some food, 5 min city, some shopping, 10 min highway, get gas, 5 min home

Ambient: 76f
Resistor: 168f
Adjacent chassis: 150f
FUEL relay: 158f
CIRCUIT relay: 168f
Chassis: 85,000 miles, 2005
OEM fueling, original parts
Gas Tank level: Gauge at full mark

Last edited by RIWWP; Jul 30, 2011 at 02:41 AM.
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Old Jul 28, 2011 | 08:03 PM
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Will try to get some data over the weekend.
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Old Jul 28, 2011 | 08:16 PM
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I'm in ... wish I had have seen this before I went out ... just did some data logging
Car has been off for 15 minutes.

Will grab info and post tomorrow
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Old Jul 28, 2011 | 08:31 PM
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Is this intentionally posted in the 2009+ forum? Wasn't sure if you only wanted S2 data ...
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Old Jul 28, 2011 | 09:14 PM
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Originally Posted by TeamRX8
Is this intentionally posted in the 2009+ forum? Wasn't sure if you only wanted S2 data ...
Damn ... I didn't notice that.
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Old Jul 28, 2011 | 09:45 PM
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Originally Posted by TeamRX8
Is this intentionally posted in the 2009+ forum? Wasn't sure if you only wanted S2 data ...
Crap. FAIL!!!

Damnit. Need a mod to move it...

Sorry. I'm not sure how I did that.
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Old Jul 28, 2011 | 10:53 PM
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It's been moved.
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Old Jul 28, 2011 | 11:43 PM
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Originally Posted by alnielsen
It's been moved.
Thanks.
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Old Jul 28, 2011 | 11:57 PM
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From: Streetsboro, OH
Driving Time- 30min
Ambient Temp- 75F
Fuel Pump Resistor- 139F
Fuel Relay- 135F
Circuit Relay- 148F
Fuel system is OEM and original.
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Old Jul 29, 2011 | 07:50 AM
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From: Pacific Northwest
30 minutes of mostly highway

Ambient: 71f
Resistor: 134f
Adjacent chassis: 123f
FUEL relay: 140f
CIRCUIT relay: 148f
Chassis: 85,000 miles, 2005
OEM fueling, original parts
Gas Tank level: Gauge at 7/8ths high mark

I noticed that I got quite a swing in the temp reading on the circuit relay, depending on which side of the top I was hitting. The left side gave me the 148, the right side gave me 127. I figure the highest heat is what you are looking for here, but thought I'd mention it.

Last edited by RIWWP; Jul 30, 2011 at 02:41 AM.
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Old Jul 29, 2011 | 01:47 PM
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Well, so far it seems that most of the components are just slightly above the under-hood ambient temp, with the slight deviation of the "circuit" relay, which is carrying the brunt of the power for the pump.

Hopefully some people with upgraded pumps will chime in.
I'd also like to see data from a track day where the "fuel" relay will be in play more often.
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Old Jul 29, 2011 | 02:58 PM
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From: Ontario
60 minutes of mostly highway, data logging OL cruise

Ambient: 76f
Resistor: 159f
Adjacent chassis: 149f
FUEL relay: 105f
CIRCUIT relay: 125f
Chassis: 75,000 Kilometers, 2005
BHR Fuel pump (Gen I), yellow P1's and Secondaries, Uncapped yellow's P2
Gas Tank level: Gauge at 9/10th's (just filled up with 94 octane oooh ya)

edit:
Fixed Fuel Relay typo of 1050f

Last edited by wcs; Jul 30, 2011 at 07:01 AM.
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Old Jul 29, 2011 | 03:02 PM
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I will try to get some readings for you within the next week (walbro pump).
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Old Jul 29, 2011 | 03:13 PM
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From: Under my car
Originally Posted by wcs
FUEL relay: 1050f
Wow, that is really hot. Was it molten lava?
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Old Jul 29, 2011 | 03:34 PM
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Originally Posted by MazdaManiac
Wow, that is really hot. Was it molten lava?
LOL

Ooooops
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Old Jul 29, 2011 | 03:55 PM
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Don't be silly. Molten lava has to be at least 1300 degF ...
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Old Jul 29, 2011 | 04:15 PM
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Unless its under a vacuum, and as we all know, the boiling point is reduced if its under vacuum .
And now for a stupid question , what exactly does the fuel pump resistor do ?

Last edited by CRO8TIA; Jul 29, 2011 at 10:49 PM. Reason: I got it backwards, thanks Oltmann
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Old Jul 29, 2011 | 05:32 PM
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You got that backwards.

Edit: If you mean melting point, I think it depends on if the material is more or less dense as a liquid or a solid.

Last edited by oltmann; Jul 29, 2011 at 05:41 PM.
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