Well.. heres the setup. y7, obd2, 14b@8psi, secondary o2 sim, MSD BTM, BKR7ES-11's (gapped at .34), dsm 450cc black tops, inline resistors, aem fpr @stock fuel pressure (35ish w/vac attached), Walbro 255lph intank pump, settings -50 . I went to a dyno day to figure out why I wasnt pulling after 4k rpms and see what exactly my a/f was doing. The car feels fine out of boost and idles/drives rich but livable. At full throttle the a/f went below 10 and never came back and my car owned the shop with black smoke. I made like 52hp!!! I recently did a tune up so I dont think thats the problem. I know my wiring is right and the afc sensors are picking up very accurate info. It seemed to get worse after gapping my plugs to .35 but it was always way rich like this. I'm about to go obd1 and uberdata'ed, but I'd really like to know why things are so screwey. No CEL except a rich/lean cel that only occurs at Normal granny driving.

Thanks for the help. I need all I can get. Compression btw is from 187-185ish all the way.

 

drop your fpr a lil and gap your plugs at 28

 

28 seems a little low man. And even still the setup should work without having to drop below stock fuel pressure spec. Theres plenty of obd2 guys running the same thing.

 

i gap mine at .40, .28 is way low....wow i cant believe u have it leaned out -50 at wot and its still sick rich, that is real crazy...that walbro pump is probablly what is causing it, i would say lower yur fuel pressure also and see what happens... def go obd1 and uberdata, u cant beat it!

 

Well the thing is, that since I'm at stock fuel pressure then the walbro shouldnt be affecting it. Its really weird. All my sensors are fine too =\. I'm thinking it may be an ignition issue. Has to be really. Since the fuel system seems adequate.

 

bump

 

What is your fuel pressureat no vacuum? (obviously with the hose DISconnected) The fuel pump will increase fuel pressure even if you have your base fuel pressure at or near stock. Yeah, it could be ignition, but you are getting too much fuel. -50 is a lot. Oh, you don't still have the fuel inrichment circuit OR the JR FMU still attached do you, maybe a stupid question, but ya never know!


Modified by KingDsi at 7:43 PM 5/6/2004

 

I have a boosted d16y7 with the same plugs and mine are gapped at .35 and it works great..

 

Wouldnt fuel pressure at no vac be without the vac line connected? Anyway its 35-37 w/hose and like 42 with the hose disconnected.

Oh. and I never had a fmu or anything like that.

 

Oops, that's what I meant

 

Well, you could try turning down the fuel pressure. The 255 really bumps up the pressure as the rpms rise (not even linear to the stock pump). What is your BTM set at?

 

what you really need to do is ... get a real fuel management....or get to a dyno...or... just lean the **** out of it...keep your fuel pressure up to stock... its best for air to fuel mixture

 

my guess is that your afc map wires are backwords and you really adding 50 points of fuel..... ...... check your afc install... i have done this before thats why i say this.. switch the map sensor wires around****

Start the car.. read the afc and tell me how much pressure/ vacuums you are pulling... let us know ... if you get no reading.. then you map is not hooked up ..

 

put the stock fuel pump back in. when i had my walbro in it was at least 1 afr or more richer than when i had the walbro in. crank up the boost too...that'll help lean it out a bit more too.

 

Do you have a wideband o2 to check how lean you are running.. I have heard that you need to drill out the stock fpr if your using a performance fuel pump..

http://www.theoldone.com/articles/regulator/

Also where are you running rich at, Is it at idle, in boost, or all the time..

 

Keep the pump, your spark plug gap is fine, your fpr setting is fine too

That pretty much leaves the 450cc's and the way they're controlled.

 

Well the map is reading voltage. And is also reading pressure. The afc wont lean out anymore. Dynoying does nothing for the reason that I cant pull fuel. And on the wideband I was under 10afr. I dunno.

 

make sure sensor is 06 in and 06 out or it will run way rich!