Fuel Pump Ecu

[Nole65SG]

What all does the fuel pump ECU do in the SC300? Anybody know? Also, where can I get the technical info. for its removal and replacement? Thanks.

[axis8758]

Can I ask you what kinds of problems you are having?

[bean_8044]

Fuel pump ecu regulates between high pressure and low pressure depending on rpm. I think around 4k it kicks over to high pressure on the JZ, not sure about the UZ though. In the backseat, behind the left panel (Drivers side for the US), youll see it hanging there. Just one screw and a small wire harness and its done. Ive had mine bypassed for a few months now with no problems.

[axis8758]

Bean was your fuel pump ecu on it's way out? Hence the reason for the bypass.

[bean_8044]

Yeah, it was randomly pinging and stuttering at very low rpms (2k), so i just hard wired it in. Works great now

[blueviol]

Bean,

Is this a safe solution compared to getting a new one?

What is the usual symptom for bad fuel pump?

My SC400 hesitates when I apply soft gas when start moving.

And it makes vibration and noise at around 2K RPM band.

Over 4K, the engine vibration is noticeable.

Any comments?

Thanks.

Fuel pump ecu regulates between high pressure and low pressure depending on rpm.  I think around 4k it kicks over to high pressure on the JZ, not sure about the UZ though.  In the backseat, behind the left panel (Drivers side for the US), youll see it hanging there.  Just one screw and a small wire harness and its done.  Ive had mine bypassed for a few months now with no problems.

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[bean_8044]

bad vibrations?? That may be a motor mount issue, but the hesitation can usually be taken care of by general maintainance.

[vshape]

For the past 7 months, I replaced 2 fuel pump ECU for my 92 SC400. The first replacement was from 92 SC400 fuel ECU with ~92K. The second replacement was from 94 SC300 with ~60K. Both last less than 5K. What is life span for the fuel pump ECU?.

[bean_8044]

Beats me...mine didnt start to go out till 90k KM.

[Lanaue]

Beats me...mine didnt start to go out till 90k KM.

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How much is the fuel pump ecu.And how do you by pass it? :cries:

[foolproofdog5]

First of all, remove both parts of back seat. Then, remove the trim panel cover under the rear window behind the driver's seat. Take your time and remove bolts or push -in-tabs carefully so you don't break anything! You want to be able to re-use them. If you do break them, any local O'Reillys or Autozone will have some. Now-VERY IMPORTANT- disconnect the NEGATIVE battery cable. Then, let's insure that the Fuel Pump Controller(Module or ECU) is your problem. Take a 10 M wrench or socket and ratchet and remove the bolt holding the ECU bracket to the body of the car just under the window. Then disconnect the wire harness(take your time and push in on the little !/4" square tab and wiggle it apart) Now look at the wires--there is 1 wire that is green and 1 wire that is combination red/black.(These wires should be on one end and be larger diameter than the other wires. Now, take a piece of insulated wire the sane guage as those 2 wires and jump from the green wire to the combination red/black wire. Now, reconnect the Negative battery cable. Now, if possible, have a friend keep an eye on the jumper wire while you try to start the car. If it starts up and there is no arcing where you jumped the wire, you done good.. Now, turn off the key, take a 6"-8" piece of electrical tape and tape the jumper wire so it won't come out. Now, drive the car for a few days and see if that fixes the problem. If so, get on E-Bay and find a good used one that is out of a '98,'99' or 2000 Lexus SC 300.(A new one is about $385.00. Installing is just reverse of removal. DON'T FORGET TO REMOVE NEGATIVE BATTERY CABLE AGAIN. ALSO, PEOPLE MEAN WELL SOMETIMES, BUT DON'T DO THAT PERMANENT BYPASS STUFF! THE ECU IS IN THERE FOR A PURPOSE--IF YOU BYPASS IT, THE FUEL PUMP RUNS ON HIGH ALL THE TIME AND WEARS OUT! THEY COST ABOUT $295.00. I have a 92 Lexus SC 300 that has been giving me fits and by talking to Lexus mechanics at the dealership I learned how to do this, so I am passing it on to you and whoever has the same problem! I also have a 1991 LS 400 4 door Deluxe that I am having tail-light problems with, so if anybody reading this knows anything about that E-Mail me at  charliehesterjr@att.net.  Good Luck! Oh, by-the-way, looks like I have found me an ECU on E-Bay for about $35.00 including shipping!

 

[foolproofdog5]

On 4/13/2005 at 11:27 PM, vshape said:

For the past 7 months, I replaced 2 fuel pump ECU for my 92 SC400. The first replacement was from 92 SC400 fuel ECU with ~92K. The second replacement was from 94 SC300 with ~60K. Both last less than 5K. What is life span for the fuel pump ECU?.

The ECU is only supposed to help the Fuel Pump. So, I would check the fuel pressure on the fuel pump first. Then I would replace the fuel filter (right in front of left rear tire on the underside of vehicle.) If all is well there I would check the fuel pressure regulator--it may be wide open--allowing the /ECU to run all the time. If you are going to replace the fuel filter-E-Mail me first! I had one bad time replacing mine! Now , I know the tips I got from Lexus mechanics I will pass to you! Good Luck! By the way, The ECU's don't like water or moisture. My left driver's window leaked and caused mine to go out. I thought it was my fuel pump! Replaced the fuel pump 2 times! $295.00 each! I replaced with new because it is in the gas tank! By-the-way--there is access hole behind rear seat to get to fuel pump--you do not have to remove fuel tank from trunk!! My '92 has 180K and was working great until the water got in there.

[SC4K]

Also, instead of buying a new fuel pump at Lexus, you could do it yourself and buy it off rock auto for like 30 bucks.