fuel pump/relay/fuse - Defender Source
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  #1  
Old August 22nd, 2009, 09:42 PM
dfscott
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Daryl Scott
1994 Defender
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Location: Richmond, Virginia
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fuel pump/relay/fuse

I have read lots of posts and still can't solve my problem..

I can't yet determine if my fuel pump need replacing or if something else is still at play here. When I turn the ignition to the second position, (or maybe the third position--the position before I crank the engine) I do not hear the "buzz" signalling the fuel pump is engaged. Instead I hear a "buzz" (or what seems like a buzz) when I turn the ignition to the off postion.

To recap, no buzz sound when I turn ignition to second postion, but a buzz sound when I turn ignition off.

I Tried replacing the relays--I have a 94 and I played around replacing all three relays hanging off the passenger side, near the passenger door where you right foot is placed, if you were sitting. I replace the relays, with generic 5 pin types I picked up at local NAPA store. The 5 pin replacements had the same number setup as the orginal relays. Regardless of what I replaced , I still did not hear the buzz.

I checked all fuses. Check the four max fuses in the engine compartment and checked all fuses behind the shifter, in what I think is called the tunnel fuse box. Checked all 7.5 fuses and they all looked good except they were very very hard to remove. The fuse removal tool did no good--I had to carefully use pliers to remove these stuck very tight fuses. Then I removed the interior fuse box plate and checked to make sure the red thing was not poped (the inertial fuel something, I think).

The car turns over fine. It sounds great, as if it should start. Except it doesn't start. Driving on the interstate last night, truck's engine turns off. Period. It was as if I accidently hit the ignition and turned the truck off with the key. I then had a bit of good luck as I coasted from the interstate down an exit and into the arms of a tow truck.

Also, I'm getting spark to the distributor.

So I guess my question is whether the absence of the buzz sound upon turning the ignition on, is now, after the steps i have taken, an indication that the focus now must be on the fuel pump-- the dreaded fuel pump-- the one sitting in the fuel tank............

I'm hoping there other steps yet I can take before I conclude the fuel pump needs replacing. If its the fuel pump, I'm off the case. I'm not special enough to pull off that repair... Any suggestions? Thanking you in advance.
D.F. Scottt
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  #2  
Old August 22nd, 2009, 10:08 PM
dfscott
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Daryl Scott
1994 Defender
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Location: Richmond, Virginia
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Is that the red pop-up that sits behind the interior fuse box?. If so, I checked that. Also, I have 12 volts coming from the relay plug.

Follow-up Post:

I have not yet removed the fuel line from the fuel filter to check whether gas is coming out from of the line. It would seem there is no need to do this, without first having heard the buzz, signalling the fuel pump is engaged.
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  #3  
Old August 22nd, 2009, 10:20 PM
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atlawson
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Tracy Lawson
94' d90
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Location: Rose Hill, VA
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Relays

I had the same problem a month or so ago. I picked up the relays from a local napa as well. They did not work in my truck at all. I could get it to start with one new relay, but I had to use an old relay in the other one. I know this does not make sense. If I replaced both relays with the new ones the vehicle would not start. I can't remember what the 2 relays are for, but I think one is for the ECU and the other is for the Fuel Pump. The one I replaced with the NAPA relay was the fuel pump relay. The problem I had after changing the relay was that the battery would drain dead after 6 hours.

I ended up getting two new OEM Bosch relays from rover barn and that fixed my problem at least for now. I still get a few stutters when starting out on the road, but once I get to road speed it is fine. I figure I am going to change my filter next. If that doesn't take care of the sputters I am going to break down and get a new fuel pump.

Follow-up Post:

Another thing I remember once I did get it to start it would run smooth for about 3 minutes, then it started having a rough idle and eventually stall out. I ended up checking all the vacuum lines on top of the engine and had one leaking then took the breather pipe off the manifold and cleaned the butterfly valve for the throttle just in case it was sticking. Again I haven't had any starting issues since then. And I hope it stays that way.
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  #4  
Old August 22nd, 2009, 10:37 PM
dfscott
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Daryl Scott
1994 Defender
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Tracy. Your post gives me at least hope the problem is in the relay. I read in a previous post that not all relays are the same, even if for example the pin setup appears identical. The post said that certain relays were specialized depending on function, so maybe I should buy the exact OEM relay and give it a try. But then others said, it didn't matter--a 5 plug works all around the truck. The 5 pin relays at NAPA and elsewhere have the same pin numbers--87, 85, 35, and so on. I find it hard to believe that buying the OEM relay will make a difference, but then again, my conclusions when it ocmes to figuring out the Defender are often wrong. Thanks.
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  #5  
Old August 22nd, 2009, 11:02 PM
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atlawson
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Tracy Lawson
94' d90
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Location: Rose Hill, VA
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I thought the same thing that a relay is a relay as long as it had the same amount of pins and numbers, but it wasn't for me. If I am not mistaken 2 of the numbers were opposite on the relay as were on the OEM relay, but I had to look close to see it. Also the diagram on the relay from NAPA compared to the OEM relays looked the same, but when I looked closer there was a slight difference in the schematic.

I hope this helps you out.
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  #6  
Old August 23rd, 2009, 12:02 AM
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Keith Allen
94 d90 ST
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Rockauto.com has the best price on the Bosch relay. Do not order online as they do not stock. If You call them they will order you one from Bosch. I just bought four last week for $14.97 each. Good luck.
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  #7  
Old August 23rd, 2009, 07:35 AM
dfscott
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Daryl Scott
1994 Defender
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Location: Richmond, Virginia
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thanks Tracy. Sounds like you took a very close look at the plug configuration and there is a difference. I'm going to take Keith's advice and order the real thing at Rockauto.com. Worth a try before I turn this over to my repair shop. DF Scott
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  #8  
Old August 23rd, 2009, 09:45 AM
artpeck
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Art Peck
1995 NAS D-90
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Having wrestled with these relays and learned the same lesson here is what I believe is the answer. The fuel pump relay also control the O2 sensor heaters. So the relay is a two circuit on or two circuit off relay. The generic Napa et all relay is on in one direction and off in the other. If you use the generic you will find that the fuel pump works maybe depending on the relay but the O2 sensors don't (which results both in an engine light after about 30 min of running) and the O2 sensors being on when the circuit is off which of course results in a dead battery over night. It is possible that the reverse could also be the case. Stick with the rover bosch as I couldn't find a replacement that was the proper circuit. And by the way one of the popular rover part vendors sent me a Disco bosch fuel pump relay which I discovered the hard way is not the proper relay for a D-90.
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  #9  
Old August 23rd, 2009, 07:27 PM
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Mike Doligalski
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Registry
Another vote for trying Bosch relays
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  #10  
Old August 23rd, 2009, 09:17 PM
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atlawson
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Tracy Lawson
94' d90
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Daryl,

I bought mine here and had them in just a few days!

http://www.rovahfarm.com/defenderfuelsystem.htm
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  #11  
Old August 24th, 2009, 03:32 PM
dfscott
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Daryl Scott
1994 Defender
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Join Date: Nov 2005
Location: Richmond, Virginia
Posts: 40
another question:

I'm replacing the three relays, the ones haning off the AC unit by your right foot if you were sitting in the 94 as a passenger. From high to low, the relays say "Aromat 30819", "Aromat 30819" and the relay positioned closest to the floor is called a "Sting Pro Rl-5X". These do not sound like original equipment. So the question is do I replace them with identical parts, after all, I know these work, or do I go with the Bosch and if so, does any one have a part number.
thanks
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  #12  
Old August 24th, 2009, 07:07 PM
dfscott
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Daryl Scott
1994 Defender
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Location: Richmond, Virginia
Posts: 40
Tracy. Figured out tBosch number for the relay. Tried Rockauto.com and no luck but found the relay off defender parts manual (afu2913L) and went to roverfarm and ordered. I'm crossing my fingers this works.... Thanks
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  #13  
Old August 24th, 2009, 07:15 PM
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atlawson
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Tracy Lawson
94' d90
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All 3 of mine are the same as yours. Aromat
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  #14  
Old August 29th, 2009, 08:51 AM
dfscott
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Daryl Scott
1994 Defender
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Location: Richmond, Virginia
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I'm still waiting for my new relays to arrive. I'm hoping this solves the fuel pump issue. If it however, does anyone know what it should cost to replace the fuel pump assuming, the bolts holding the skid plate and the like are difficult to remove? In other words a range of costs: from x to y...thanks
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