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Twin Bosch 044 pumps over heating fuel!


JamieP

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My fuel pressure has already started playing up, i'm running twin walbros in the tank with an aeromotive FPR. Car hadn't been used in a longwhile, was fine when coming out of the covers and having the mapping checked with Michel in the passenger seat, all was good. As the engine load builds the FPRs leaned off and fuel pressure dropped, it could do this whether on positive boost or not. On idle, the FPRs would be up and down between 11 and 16. Now it seems to be fine, holds fuel pressure and AFRs are fine. We were thinking faulty pump but reading the above, i'm not so sure now. Got some new pumps in case the problem returns

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An American aftermarket FPR? You're brave, they only discovered EFI through legislative force :) I don't see the fascination with these things when Bosch make FPR's that get half the world to and fro work, and most serious race cars to the finish line. Having ranted, if it *IS* a FPR issue it would surely show as a fuel pressure drop, jitter or rise. There are a lot of fake Walbro pumps about, did they come from a legitimate source?

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Lee P already had them at his place and the old ones came from Jamie P car so were 2nd to me but I still have the issue with the new ones from Lee.

 

 

Maybe The FPR is something else we can look at changing even though I don't lose any pressure, it would be something else to rule out.

 

I have change the pumps, stripped the protective sleeve off the lines, changed the bit of hose from the tank to the pump ( I think that's what lee said), new ecu, new ecu loom so there is only the FPR and injectors left.

 

We have talked about fuel coolers, a larger return line and staging the pumps but I don't get why this is happening when JP had no issues last year with a similar set up but different injectors.

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Data Logs are your friend, that's exactly why logging is there. Whilst they may not tell you exactly what IS wrong they sure as hell should save a huge amount of time by showing what ISN'T wrong! If you FP gauge is accurate and reliable then my gut feeling is there's something wrong with the injectors. I test and clean a lot of these things, and although Ryan doesn't like Siemens, I do, and see little trouble wit NEW Siemens, Denso or Bosch units. I see plenty of issues with US ones that are modded for higher flow, or used ones left out of service in a box for months / years. I buy all our injectors from Five O Motorsport in the US. They sell only OE manufactured genuine stuff, not re drilled, and their service is exceptional, their prices competitive. There, I was nice about a US company, my pills must be kicking in.... ;) http://www.fiveomotorsport.com/

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Fuel pressure is fine on ricky's car and when the problem occurs the fuel rail does not feel hot at all. This seems to be a different issue to Jamie as his only happens in traffic.

 

Ricky can be driving the car any way for an hour or so and the problem is there, afr's start to drop slowly untill the car is undrivable.

 

The injector thing is the opposite way round, high impedance should run cooler.

 

Also when the car was first mapped it was mapped hot, this ment the problem was reversed and the car ran fine when after an hour or so and rich before that.

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If the fuel filter is getting near "too hot to touch" then the loss of density in fuel could be as high as 7% , compared with cold fuel .

the rising tank fuel temp could also effect the pumps -the hotter they get the more power they use , the more power they use the hotter they get type circle - but this would not alter flow that much .

AFR would alter by 0.92 @ 14;1 given a 7% density change , how much is the AFR varying?

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The car usually idles between 13.8 and 14.2. As the problem starts you can hear it in the idle and the afs go 15s, 16s and so on till eventually off the scale of the AEM gauge and the car is almost undrivable. This can be over 20-30mins I think but ricky can confirm.

 

At this stage the fuel rail didn't apear to be warm at all, felt cool and fuel filter is warm but now where near hot.

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I'd like to see a log of injector duty and stuff when this occurs. My swirl pot gets very warm after 30 minutes continual track running, it runs only a single external 044, but the in tank (stock type) pump, acting as a low pressure lift pump. will add heat, too. AFR's don't seem affected, and closed loop injector duration isn't going up as the car is run for longer and fuel temps rise. I'd say I see fuel temps of about 110 or so Fahrenheit. Could it be an ecu issue? My Motec will log and show internal ecu temps, if something in the ecu is getting too hot could it be affecting the map? Is coolant temp sensor going berserk after a while and the ecu thinks it's in the Sahara and trim fuel? We need logs....

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I'd like to see a log of injector duty and stuff when this occurs. My swirl pot gets very warm after 30 minutes continual track running, it runs only a single external 044, but the in tank (stock type) pump, acting as a low pressure lift pump. will add heat, too. AFR's don't seem affected, and closed loop injector duration isn't going up as the car is run for longer and fuel temps rise. I'd say I see fuel temps of about 110 or so Fahrenheit. Could it be an ecu issue? My Motec will log and show internal ecu temps, if something in the ecu is getting too hot could it be affecting the map? Is coolant temp sensor going berserk after a while and the ecu thinks it's in the Sahara and trim fuel? We need logs....

 

I have sat in the car and watched it happen. All the closed loop trimming was turned off, Fuel duty was constant and also logged everything to ensure that maybe battery voltage wasnt dropping and causing a difference on the injector dead times and this was fine. Also at the point of when it happened i changed out the loom adaptor and also tried another ecu which was dead cold to ensure it was not the injector drivers getting overworked. Also checked that there were definatly the right impendance injectors.

 

When the problem occurs there is a note change on the pumps so i am sure that something in the fuel system is causing the issue hence why i said change the pumps. I thought it was all sorted and got a txt of ricky to say thanks its fine now but obviously not :(

 

Even though the fuel pressure remains the same on the fuel pressure gauge it doesn't say that there is still the same supply of fuel to the rail... I remember seeing this issue before on Homers old car which dash render then owned and cant remember what fixed the issue but it was something to do with a the Fuel pressure on his.

 

There is definatly something up with the fuel system tho as rickys car has 1600cc injectors and at 750bhp the injector duty was like 80% which if correct was right his car would be pushing around 1280bhp. At the time we thought Injector clinic had sent 1000cc injectors but i not so sure now..

 

This is 100% not Map or Ecu related as i gave up half a day of my time to investigate the issue.

 

Ryan

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Well Im running the same ECU as you guys and tripple Denso pumps in my tank and never had any type of these issues, And i've done runs of up to 6hrs at once with very mixed driving.. This has me wondering though for sure... I'm watching this one with close eyes for sure.

Edited by suprafan72
crap spelling (see edit history)
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Ryan, can you remember a year or so ago when I had the T67 (i think) turbo on with the Siemems 85lbs injectors? At the time the injector duty cycle was very high on them with a Bosch 044 pump. We tried removing the one way valve on the fuel pump outside SRR, but this made no difference. In the end I changed the FPR which seemed to resolve it when re-mapped. Duty cycle dropped from 90% ish to around 70%.

AFR's were all over the place too IIRC.

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Well Im running the same ECU as you guys and tripple Denos pumps in my tank and never had any type of these issues, And i've done runs of up to 6hrs at once with very mixed driving.. This has me wondering though for sure... I'm watching this one with close eyes for sure.

 

I run twin walbros in my race car and mapped probably over 40 car which run the same and never had an issue with the densos or walbros but the Bosch O44 are abit different in Jamies case as the motors are huge in them!

 

I also knew Jamies car was not ecu or map related as he is actually running your map just tweaked on boost :) And i have personally drove your car for over 3 hours on the way back from dyno. Top speed is good with your diffuser btw :D

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I have sat in the car and watched it happen. All the closed loop trimming was turned off, Fuel duty was constant and also logged everything to ensure that maybe battery voltage wasnt dropping and causing a difference on the injector dead times and this was fine. Also at the point of when it happened i changed out the loom adaptor and also tried another ecu which was dead cold to ensure it was not the injector drivers getting overworked. Also checked that there were definatly the right impendance injectors.

 

When the problem occurs there is a note change on the pumps so i am sure that something in the fuel system is causing the issue hence why i said change the pumps. I thought it was all sorted and got a txt of ricky to say thanks its fine now but obviously not :(

 

Even though the fuel pressure remains the same on the fuel pressure gauge it doesn't say that there is still the same supply of fuel to the rail... I remember seeing this issue before on Homers old car which dash render then owned and cant remember what fixed the issue but it was something to do with a the Fuel pressure on his.

 

There is definatly something up with the fuel system tho as rickys car has 1600cc injectors and at 750bhp the injector duty was like 80% which if correct was right his car would be pushing around 1280bhp. At the time we thought Injector clinic had sent 1000cc injectors but i not so sure now..

 

This is 100% not Map or Ecu related as i gave up half a day of my time to investigate the issue.

 

Ryan

 

Your help in this has not gone unnoticed Ryan. I am greatful that you gave up your time.

Edited by Ricky49 (see edit history)
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Ricky is basically running a similar fuel system as me except for the injectors, rail and fpr. Mine has been perfect as well, no problems with the twin pumps lines ect.

 

I think the injectors could be the issue but will have to see. Will post the finding once I have had a play.

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Fitting any larger or more powerful fuel pumps is very likely to overload the stock wiring , the supply fuse is 30 amp , this then feeds the EFI relay and on to the fuel pump ECU then on to the pump (stock system) adding a much larger load such as 2 pumps to the stock old wiring is likely to fail quickly , you could easy be drawing 40 amps on pump start on cables rated far under this , and have many connections to cause volts drops , these will heat and increase resistance ,thus increasing volts drop over time

The result is the pumps drawing far too much current , low life for the pumps and ever degrading wiring and EFI relay

The relay shoud not be running at it full rating the contacts will degrade fast ,it needs a bigger relay ,the FP ecu was not designed for increased current it too needs bypassing , cables should be circa 6 guage cables and high quality (low volts drop) , it should be through a separate cable from Battery(fused) to new relay , and direct to pump(s)

Given the large amount spent of engines ,tuning ,etc , seems daft to risk it all for a few quids worth of cable and a relay

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