Air fuel ratio issues when boosting e8

HermaN

HermaN

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307
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Should have another injector resistor pack to test come Wednesday. Will also check how fuel pressure rises with boost. Yup, the FPR vac line is good, it's just a short piece of hose and does not look split or cracked as the engine bay is all very clean and everything looks fine.
 
sponners

sponners

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keep us posted mate, hopefully it turns out to be something simple.
 
S

steelinator

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37
Yeah, the walbro has the spacer in it, when the original was removed I took the rubber seal off then the white spacer and fitted them to the walbro then once the walbro is pushed in place their is a spacer/packer that takes up the slack before cliping the plastic housing on

we also tried re fitting the standard pump and got the same figures........
 
S

steelinator

New Member
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37
Ok so still having lean afr issue :(

Fuel pressure ok, 3 bar off boost then going up to 4.7 bar on boost (1 bar of boost)

Injector resistor replaced with new genuine mits part

Injector duty going up to 104% when boost is set to roughly 1.5 bar and lean afr 12.3?

running out of ideas ?
 
sponners

sponners

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it is strange, did you check all the fuel pipes to make sure there isn't a kink or fold somewhere that may be restricting flow?
 
S

steelinator

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37
I removed the fuel pipe at pump and at rail and blew through it with no effort so fuel pipe seems to be ok, I put a fuel pressure tester in line on the supply side at tank and im getting 3bar on normal running and almost 5 bar on boost

Do you think I could still have an issue with my walbro 255? I did try re fitting the standard pump and got the same problem.....
 
sponners

sponners

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well you have pressure, but something could still be restricting the flow, whether its the pump, lines, injectors ???

sorry I can't help anymore than that mate.
 
S

steelinator

New Member
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37
Ok so took the injectors out today and cleaned them with air line, carb cleaner and wd 40, powered injector with AA battery to open valve then air feed carb cleaner through them both ways

Also flow tested walbro, removed fuel pipe at rail then held 12.8 volt battery across fuel pump for 60 seconds and it flowed almost 5 litres into a jerry can! so walbro and fuel line is good!!

Im getting a wide band bung welded to decat so Herman can get wideband screwed into it.......

Fingers crossed cleaning injectors sorts it out
 
sponners

sponners

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I assume herman is using a innovate tail clamp to take the afr reading?

if so does he have a 'added' extension onto it? what size is your tailpipe?
 
S

steelinator

New Member
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37
Yeah im sure its the innovate he is using with a bosch wide band sensor

Its a 5" scorpian tail pipe but the system is 3", so it dose have a step in it, Herman has a clap for the tail but it has no extention, herman tried putting the wide band at an angle so it was in the flow of gasses but the afr was the same, This bung I get fitted should eliminate any issues with that. Dont think that would be causing it because the injector duty would be ok but its at 104% at 7000 rpm?
 
S

steelinator

New Member
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37
We replaced the 260 pink injectors for the fq burgundy/red injectors to see if this would cure the fault originally, herman changed some settings for these injectors

What should the injector settings be to run these injectors?
 
sponners

sponners

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Yeah im sure its the innovate he is using with a bosch wide band sensor

Its a 5" scorpian tail pipe but the system is 3", so it dose have a step in it, Herman has a clap for the tail but it has no extention, herman tried putting the wide band at an angle so it was in the flow of gasses but the afr was the same, This bung I get fitted should eliminate any issues with that. Dont think that would be causing it because the injector duty would be ok but its at 104% at 7000 rpm?

I found my innovate tailpipe sniffer quite poor until I put a extension of about 40cm onto it, even then with some exhausts it will read leaner at lower rpm's.

If your not getting a true reading then you will be pushing the duties.

We replaced the 260 pink injectors for the fq burgundy/red injectors to see if this would cure the fault originally, herman changed some settings for these injectors

What should the injector settings be to run these injectors?

I think the 260 injectors are the same as the american ones which are scaled at 513 and the fq injectors are 542.
 
S

steelinator

New Member
Messages
37
Ok thanks for your help, I will let you know how we get on with the wide band bung
 
S

steelinator

New Member
Messages
37
Ok so we got this issue solved now :)

Looks like the lean afr on boost was down to the innovate tail pipe clamp not working well on my 5" scorpian exhaust, I got an o2 bung welded into my de-cat so we could put the wide band directly into the flow of exhaust gasses and hey presto the afr was ritch!!

Thanks for all the advice and help

;)
 
sponners

sponners

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1,128
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glad you finaly sorted it mate and thanks for keeping us updated.
 
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