WRX Capacity change start up issues 2.0 - 2.5

[binny]

Hi Forum dudes,

I've recently increased my 98 WRX's engine capacity from the stock 2.0 L up to 2.5 L - now I'm attempting to get a start out of it 

Symptoms: on switching on ignition fuel pump primes - 1st crank attempt will not fire, 2nd crank attempt engine fires but immediately stalls - this continues over and over note: ** no intercooler or intake piping fitted **   MAP tune / no AFM  

The car was running the ViPec V44 and Subaru's blue injector (650CC IIRC) with a fairly crappy tune (by me) - with a top mount intercooler, STi VF37 twin scroll turbo (bigger compressor wheel fitted - by Ray Hall) and aftermarket exhaust - seen running below

I've seen I should be adjusting the master fuel table for the increase in displacement - Do I need to also adjust the Crank enrichment, Hold, Post start enrichment, Decay tables??? or should that be it? (or anything else I've missed???) as I can't seem to get a start and run at the moment! (old fuel???)

Any help greatly appreciated 

 

 

I forgot to mention - I have a Innovate Wideband fitted AFR's seem very lean during cranking but possibly due to engine not running (as widen is using crank battery power)

[paulr33]

Have you tried changing the pre fuel mode from pre crank to key-on? I had to do this on my 2.3L evo. If you set the method to key-on the ECU pumps in fuel when you key-on (not start) and gives the system enough time to prime and get ready. Then after 2 seconds at key-on, turn key to start and it should start first shot 

[binny]

1 x issue resolved: Fuel tank vent was capped - probably one reason wouldn't start!

Yes I have key on priming, it is starting now and I can get it to run by modulating the throttle still doesn't want to idle. - I will fill with some fresh fuel and have another go at it again soon

 

I have attached a bit of a log and the tune

WRXSTI2.5 START2.0.pcl Log 13-07-20 2;07;11 pm.llg

[Adamw]

Did you try adjusting the master fuel yet?  I dont know if we can trust your wideband but it shows very lean in the log.

[binny]

Hi Adam 

Yes I have increased the master fuel value as per the increase in capacity

And yes it does seem to be fairly lean (Innovate Wideband) I think I will add some more fuel to the master table now that I can get it to run - and see if the AFR's richen up into target values

[binny]

Found the issue was fuel pump hose had deteriorated enough to start and just idle, but not have enough pressure to run properly - All sorted now!