FlameThrowingRotary

well my 97 jeep fuel pump just died on me with 105k on the ticker. It was factory

TT_Rex_7

Well, whatever! I never said it doesn't happen, it's just not very often. Factory pumps are made to last for obvious reasons. I wouldn't consider it a normal "wear and tear" item. I don't think an aftermarket pump would have lasted 105k on your jeep.

-Alex

FlameThrowingRotary

well if I keep it long enough to see it fail again I'll be sure to let ya know

Carl Byck

Keep in mind stock pumps are designed to run at ~9 volts, until WOT, then 12-13.5. Most guys doing a fuel system run 13.5 or higher(if you are doing it right) all the time. if you buy two fuel pump ecus, and use two relays, and run ~9vts all the ime except WOT, then used stock pumps will probably be OK. If, you are not setting them up that way, then expect them to overheat the fuel, and die an early death. This is well documented on Supraforums. Also, good luck finding a low mileage supra pump for sale, most have 80K miles plus on them already. All these set-ups will work set-up right, but after market pumps designed for 13.5+ continous will heat the fuel less, and last longer. Carl

TT_Rex_7

Why would you purchase a used supra pump?! They sell them brand new.

-Alex

Carl Byck

Ever price a new Supra pump? You can buy a Bosch motorsports pump for about the same $$$. Way maore flow under pressure, and designed to run 13.5 continous, not 9vts like the Supra.

Carl Byck

DP

maxcooper

Let me start by saying that this discussion is mostly about fringe occurances since fuel pumps do seem to be pretty reliable. I just like to keep things as simple as possible, and two pumps seems to add unwarranted complexity. That's why I don't like non-redudant, dual pump setups.

Two factory fuel pumps have precisely twice the chance for failure that a single factory fuel pump does. unlikely + unlikely = 2 * unlikely, no matter what 'unlikely' is. But I suppose I agree that Denso pumps are reliable enough that doubling the failure rate still isn't much of a risk.

I have read about trouble with some aftermarket pumps. But I am speaking mostly about using one in-tank pump, like the A'PEXi BNR-32 pump that I have, a Bosch, a big Denso, etc. There are single-pump alternatives with factory-level reliability that are adequate for most people's power goals.

Assuming fuel pumps fail completely (as opposed to slowly losing effectiveness), having one pump fail in a non-redundent, two-pump setup could be pretty dangerous. No one watches their gauges close enough to be alerted to one of their dual pumps failing. You will be driving along unaware that one pump has failed, rev the car out under boost, and perhaps blow the motor. With one pump, your car would just stop working.

You can't really use the "low pressure" alert on a gauge because your fuel pressure follows your manifold pressure. I suppose you could hook up some complex system by which your gauge reads effective pressure, or the alert is based on a pressure differential with your boost gauge. But I've never seen anyone running such a system.

-Max

TT_Rex_7

I can see your point of view here, and agree with you. If you don't require 2 fuel pumps, go with a single. Either way, if it's rare for a factory pump to fail, I really don't see it adding much risk by running a second. However, if the factory pump you use is known to have failure issues, then it would be a much higher risk. Havn't heard of that issue with the factory FD fuel pump, or the Supra pump though.

I do apologize. I took it for granite that you was speaking of an external fuel pump since there really arn't any in tank fuel pumps that can flow enough for high HP applications.

BTW, how much does the A'pexi pump flow?!

True, but if you hand a single fuel pump, and it failed during WOT, I would think that it would also cause damage. However, if you keep an eye on your gauges to make sure everything is in check before going WOT, you *should* be safe.

I don't quite follow you here. Regardless of what it's based off, if a pump fails, the pressure will go down. From what I understand, you can hook a fuel pressure gauge up to an aftermarket FPR, and get "effective" pressure.

-Alex

rizzxx7

iTrader: (4)

Is the Bosch motorsports pump an in-tank pump just like the stock pump?

13btnos

iTrader: (1)

This is from my previous post http://cgi.ebay.com/ebaymotors/ws/e...&category=33555 the guy sells them for $245.00 each and yes they can be adapted to be ran intank. There is a site somewhere that shows you how to adapt it intank. And there is also an intank version of the 044 pump but I don't know the exact part number.

BDC

I've been planning out my own fuel system for about 2 months now. It will use two intank fuel pumps running dual -6 feeds and a dedicated -8 return line. The only thing I am left with at the moment is what types of fuel pumps to use. I haven't decided whether a pair of FD pumps would be better than Walbro's or not. Sure, the Walbro's are skinnier and are cheaper, but my question has to do greatly with their reliability. I am not concerned about pump failure because I don't plan on running the second pump all the time; it will be staged.

B

KNONFS

iTrader: (14)

Is that really the case?

I think there will be more volume, but not pressure. Am I wrong?

KNONFS

iTrader: (14)

Why staged? and can the E6K control it?

TT_Rex_7

Just something to note, it was supposed to say *should* not *will*.

Anywho, i'm going off another memebers responce from another thread. I don't have time to dig it up at the moment, but I remember him stating that when he turned off one pump, or it failed (can't remember which one) his car started idling like crap and everything else. That would be a clear indication that something has gone wrong, and I don't think someone would be going WOT until they figured out the problem.

As far as volume vs. pressure...I would think that in a 2 pump setup, each pump would run a set pressure to flow a specific amount of fuel. Now, if one fails, the pressure should start to fall since the 1 pump couldn't handle the load during WOT. Max should be able to chime in on this though.

Now, if you have 1 pump per rail, then I don't think you'd know if the sec. pump failed until it's to late, since the sec. injectors don't come on during cruising. In this case it'd be best to run them staged so there's less of a chance the sec. pump fails. A stand-alone ecu should be able to handle this via. output on the ecu.

-Alex

Carl Byck

The stock bracket works fine for the bosch pumps. I just fabbed a bracket for my fuel cell, but, i will post my old set-up as well. I believe most bosch pumps can be in, or out, in being a cooler running situation.

I've posted my set-up previously, but its basicly bosch>-6>surge>-6 return;and then>

Surge>-10>A1000>-10>Big SX Filter.-8 to secondary rail>-6 to primary rail. T'd in FPD>-6>FPR>-6 Return to surge

Carl

maxcooper

http://maxcooper.com/rx7/parts_info/...exi_bnr32.html

I agree that you might get damage when the pump fails on a single pump setup under WOT. However, with a single pump, you would know about the failure before you went WOT (because the car would stop running). With two pumps in a non-redundant setup, a failure of one pump won't show up on the gauge until you are at high RPM under full boost.

Consider what happens when you have two pumps:
- Both pumps working:
idle: 33 psi fuel pressure
15 psi boost: 55 psi fuel pressure
- One pump failed:
idle: 33 psi fuel pressure
15 psi boost: 48 psi fuel pressure TOO LOW!

You can't use a simple low pressure warning to detect this failure.

Effective pressure = fuel rail pressure - boost. I've never seen a gauge that reads that.

-Max

TT_Rex_7

Holy crap!! I think you might have just changed my mind on using 2 pumps!!

I'm saying if it all of a sudden failed during WOT it would probably cause damage.

I see what your saying know. I just didn't understand it from your first statement.

-Alex

twokrx7

iTrader: (1)

Pumps don't always fail on/off. I had one that would keep up at idle but not under high boost. Cost me an engine and my turbine wheel during a 2nd gear boost run. Pump had been making a bit more noise compared to new but it had less than 1000 miles and the noise had increased slowly such that it was not noticeable until after engine failure, hindsight ya know.

Sent the pump in to my retailer and he sent it to the OEM, OEM had never seen this type of failure before.

FlameThrowingRotary

I always thought an electircal fuel pump would either work or it wouldn't but when the jeeps went out. it would run fine and then just die on the highway at 70 lol then it'd start maybe die again in a few min or one time it went 2 months between crapping out on me. It's like it'd get hot and shut off. It was weird. Replaced it and it's ran fine ever since all through wot pulls.

maxcooper

I've seen both kinds of failures.

The pump on my 81 Toyota Cressida wagon just completely stopped working one day. Since we're talking about custom pump mounting and wiring in this thread, there's a greater-than-OEM chance for a total failure from wiring or plumbing to consider.

And my friends DSM would idle fine but had trouble when the car was moving. I suppose a leak inside the tank would also give results like an ailing, but not dead, pump as well, which is relevant to our custom pump discussion.

-Max

Carl Byck

Here are some pictures of my system. the surge will be lower, and the pump a little higher in relation to each other when installed. you can see the low fuel indicator in the side shot of the pump setup. Carl

TT_Rex_7

Will the in-tank pump flow enough into the reservoir to keep up with the Aeromotive? Why not just put a sump on the bottom of the fuel tank and just run the Aeromotive?!

-Alex

Edit: Why are there so many fittings?! Also, if one of the pumps fail, will the other pump still flow fuel through the bad pump, and run lean?!

-Alex

Carl Byck

1- the in tank pump returns directly to the cell, so it is working against zero pressure. Even the A1000 @ 65psi cannot outflow the bosch pump at 0-5 psi.
2- a sump on the bottom would work also, but good ones are ~250.00+, and this system is superior in terms of scavenging the last bit of fuel. Also, most are designed to use an in tank pump, and are too small for my pumps to fit.
3- there is one extra bulkhead fitting, as the previous setup had two internal pumps, the remaining fitting is the vent.
4- both pumps need to operate for the system to work
5- This is a proven set-up to prevent fuel starvation, virtually all JGTC/DTM/AU Super cars use a similar system.
6- between my in car Wideband, and my fuel pressure gauge I am confident I will see problems well in advance of damage.

In a nutshell, this is one of the most reliable systems, ther are hundreds of ways to do it, my point is simply o show one proven approach, not so much to debate system X vs Y. However, the statements about supra pumps not lasting at 13.5 continous hold true. These are two competition pumps, installed, and used as they were designed. Carl

TT_Rex_7

http://store.summitracing.com/defaul...=egnsearch.asp

A fuel tank sump is ~$70.00, what would make one any better than the other?! I think RedRx7 has the same type of sump on his car.

Just 2 more question! Could you have used a Walbro 255, instead of a Bosch, to feed the reservoir?! Is there a specific reason why you chose the Bosch?!

-Alex

Edit: I lied, I have one more question. Should you run the return line from the FPR into the fuel tank, or into the fuel reservoir?!