Hey all,
I've got a fairly mild 250 Chevy six with 3 39lb. injectors - one for each siamesed port. The req_fuel calculator sets me up at 11.7 with 6 squirts per engine cycle. The bottom number comes in around 3.7-ish.
Ok, fine, starts and runs decent. Loses power at mid-high throttle. So I set the req_fuel to 15 which sets the bottom # to 5.
Runs much better now.
Question is, am I sacrificing idle (going too rich) to get decent power? Or will the narrow-band O2 handle that? I'm going for a daily family hauler, not drag racing.
Should I even adjust req_fuel at all? I don't know if I'm doing the right thing or not.
Thanks!
John
Not sure about changing req_fuel settings....Help?
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Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0). For tuning/troubleshooting questions, please attached a datalog and your MSQ file to your post.
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
The full forum rules are here: Forum Rules, be sure to read them all regularly.
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1950ChevySuburban
- MegaSquirt Newbie
- Posts: 13
- Joined: Fri Jan 25, 2008 7:18 am
- Location: Tucson ARIZONA
Not sure about changing req_fuel settings....Help?
I'll take an inline in mine!
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Matt Cramer
- Super Squirter
- Posts: 2951
- Joined: Sat Jul 03, 2004 11:35 am
Re: Not sure about changing req_fuel settings....Help?
Req_Fuel is a base pulse width, but I would leave it at the recommended setting and then adjust the VE table as needed.
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1950ChevySuburban
- MegaSquirt Newbie
- Posts: 13
- Joined: Fri Jan 25, 2008 7:18 am
- Location: Tucson ARIZONA
Re: Not sure about changing req_fuel settings....Help?
Thanks Matt, I'll try that. I'm not sure where to start with the VE table adjustments.
I'll take an inline in mine!
Re: Not sure about changing req_fuel settings....Help?
Do what Matt says - he is the man.
And yes use req fuel and then use your VE to enrich or lean. Look at your VE table while running and keep moving the values down in the idle area until it leans out (remember, idle areas are weird and based on manifold vac and so forth you may need it rich to idle nicely, if you are letting the O2 correct you may want to move the threshold for correction up out of the idle bin areas and let it run open loop to say 1400 rpm or so - bascially let it correct once you are out of the idle zone).
414cid
And yes use req fuel and then use your VE to enrich or lean. Look at your VE table while running and keep moving the values down in the idle area until it leans out (remember, idle areas are weird and based on manifold vac and so forth you may need it rich to idle nicely, if you are letting the O2 correct you may want to move the threshold for correction up out of the idle bin areas and let it run open loop to say 1400 rpm or so - bascially let it correct once you are out of the idle zone).
414cid