JTECH James

iTrader: (13)

i checked the fuel pressure on the cossie at the weekend, and since fitting the grp a pump it was slightly high, so i adjusted it down to 3.5 bar with the pipe off, and all round the car drives better than before, fuel economy is better, the problem is now the car doesnt start crisply like it did before , it fluffs the first crank and starts the second time perfectly.

Stage 3 closed loop, 7.2:1,

Any ideas?????

bud-weis

Firstly fitting a new fuel pump shouldn't have altered your fuel pressure after the reg....

not sure on why it struggles to start though, faulty temp sensor could be the problem though

JTECH James

iTrader: (13)

all the sensors are new , and its always been a first time starter before i set the pressure to what it should be

JTECH James

iTrader: (13)

dont you check fuel pressure before the reg? line presure, the reg reterns the excess fuel to the tank but keeps the line at the set pressure of 3.5 bar without vaccum or boost.

Andreas

Yes, you check the pressure before the reg. Mine did not change when going from standard pump to group a.

JTECH James

iTrader: (13)

maybe its always been high then? the pump has been on for a week before i checked the pressure, and it was all fine untill i lowered the pressure to what it should be, it drives soo much better now and is 30-40 miles per tank better on fuel so i dont want to raise the pressure again. its set at what it should now so i cant work out why i have a problem, the pump primes up on ignition as it should do etc...

Stu @ M Developments

iTrader: (12)

What exactly happens to it whenj you try and strart it?

NOTHING?

Or is it fluffy for a few seconds, like a missfire?

JTECH James

iTrader: (13)

yep ,it fluffs and doesnt actually run, but turn the key again and its perfect second time....

JTECH James

iTrader: (13)

like a single cylinder cossie!!

JTECH James

iTrader: (13)

i checked the pressure with the engine hot, and the idle at 900rpm... just wondering now if the pressure would be lower with the engine cold maybe thats why?
or maybe i get more or less vaccum at the reg which changes the pressure?

Its only when i start from cold this problem happens ,once its warm its starts first time again

Stu @ M Developments

iTrader: (12)

See how you get on with it, if you are confident that your sensors etc are all sound and a simple fuel pressure increase definately eradicates it, then i can increase the fuelling in your software for the first 250crank revolutions after ignition. That will normally fix this issue.

JTECH James

iTrader: (13)

Or even better, i just book it in and get you to set it up and check it over!!!

Stu @ M Developments

iTrader: (12)

Either option is fine by me. Hell of a drive though mate.

JTECH James

iTrader: (13)

naaa its only ten mins at warp speed, i have six weeks off , so nows the time for me to bring it up, could you do it in a day so i can drive home same day? How much

Stu @ M Developments

iTrader: (12)

Full setup is Ł141 incvat.
Details of what you get are here:
http://www.motorsport-developments.c...ginetuning.htm

If teh software is mine, and i change the crank fuelling tables, then that mod is FOC.

Same day is no problem at all.

JTECH James

iTrader: (13)

cool!
I will speak to er indoors and work out a day , how many years notice do you need for me to get a space!!!

Stu @ M Developments

iTrader: (12)

Just a setup and checkover can be done within a fortnight almost all year, and often within a week.

JTECH James

iTrader: (13)

thanks for your help stu.

Will be weird taking my car to someone else, strange feeling, its never been anywhere since ive had it. but when it comes to set ups its best its done properly

JTECH James

iTrader: (13)

296.8 miles

4 hrs 50mins

I just know your gonna say you want the car by 9.00 arnt you

Stu @ M Developments

iTrader: (12)

11am latest.