fuel pressure?

[eyefi]

anyone recognise this problem?

ive still got some testing to do, but the problem is:-

just installed walbro and fse.
setup static pressure to 36psi, idle afr = 14.7
go for a run hit afr's of <9:1
park up and fse gauge reads 20psi at idle. afr = 14.7
?????
go for a run, still hitting <9:1 afr
leave it to cool for a while
restart engine and 36psi at idle again.

ive not adjusted any of the fuel map yet. it looks like a faulty gauge to me, but could b pump or fpr.

something else ive noticed is, when ign is turned to on the system pressurises, it will then slowly loose pressure until the engine is cranked and started. is this normal? im still using the fuel pump ecu as standard.

tia.

[eyefi]

dodgy gauge

[Wez]

My preasure also fluctuates slightly with under bonnet temps, this could be due to heat soak on the regulator.

:thumbs:

[Dragonball]

Mine also flutuates and will show afr at 1 bar (which i understand is correct when operating) and higher when at idle

Interested to the reasoning behind - but doesn't sound unusual

:thumbs:

[eyefi]

i think its the gauge that doesnt function (is not calibrated) when hot.

[Wez]

What gauge do you have, mine is an oil filled job on the side of the regulator.

:thumbs:

[eyefi]

thats the chap, its only intended for setup, it should b removed after. that's what ive been told.

[Wez]

I left mine in and it hasn`t given me any issues, all the big fancy fuel kits have them perm installed too.

:thumbs:

[eyefi]

wez, how much does yr fuel pressure fluctuate by, depending on fpr temp?

[Wez]

Hiya,

Off the top of my head I would say approx 0.5 Bar.

Could be heat soak on either the FPR or the gauge oil, just a thought.

:thumbs:

[eyefi]

mine is fluctuating alot. in my mind an fpr should not fluctuate the pressure at all, no matter what temperature it is. after all, its job is to provide a certain line pressure at x manifold pressure. im gonna have a word with the suppliers in the new year. its impossible to map :(

[Wez]

Are your AFR`s consistant regardless what the fuel pressure gauge is reading, if so I would look more at the gauge as the fault.

Mine deff doesn`t appear to change as much as yours.

Let me know what they say.

:thumbs:

Just curious, how do you have yours mounted?

[eyefi]

at idle, if i turn my o2 correction off (just map no sensor adjustment) my afr will go to 16:1 when it would read 14.7:1 when the fpr is not hot. this wasnt noticable until i turned the o2 correction off.

surely any variation in the fuel pressure will have an effect on the afr?

mine is mounted where yr's is, on its side.

[Wez]

OK I have no O2 correction as I do not have my wideband wired into my AEM yet, just not got round to doing it but I don`t recall seeing a major variation in AFR, i will check today and let you know.

The problem is that when cold it will run richer due to warmup enrichment anyway.

Hmmmm.

:thumbs:

[eyefi]

all the numbers given r when the cold start enrichment phase is over.

doesnt the aem use the stock o2?

[Wez]

It can do but since I installed my wideband in the stock location and removed the wiring mine does not, i have everything ready to run the wideband into the AEM just not got round to crimping the new pin onto the cable yet.

:thumbs:

[eyefi]

right, ive spent the last few evenings looking at this. ive moved the fpr to a cooler location and insulated it, this made no difference, fuel pressure would still drop to 0.5bar from ~2.5bar, when hot (not too hot to touch). the fpr is going back for assessment.

ive gone back to the stock fpr (man, that was a bitch to get back on) and a similar thing happens. let the warmup phase finish and the idle is showing 14.7:1 on the wideband. go for a hard run, to get everything hot, park up with the engine idling and AFR will start to drop. alot slower with the stock FPR but it will still gradually drop to 16:1.

is this normal?

[eyefi]

forgot to add, this is all with NO O2 sensor correction, just the map.

[eyefi]

no-one else got any input with this?