The actual nice thing about EFI is how much you can do without having to tune it at all.
Besides the cost of upgrading the efi stuff for performance, nearly everything out there is a true bolt on.
You'll mostly have to learn the troubleshooting basics.....setting throttle position sensor voltage, reading codes, knowing what the act, egr,tps and o2's all do and how to isolate trouble. It's not all that difficult, and many times the computer will pop a code that leads you the direction you want to go.
As for performance, the stock computer adapts well. I ran gt40p heads, ported gt40 (explorer) intake along with a tfs stage 1 cam and other full bolt ons with a stock computer, and it ran 13's all day long.
When you start making real HP, like 350-400+, then that's when a real tune comes into play. (it's still not 100% necessary, but will help tweak the most out of your combo. I wouldn't bother though unless you're making over 350 or so HP...as it gets costly) Most people take it into a guy who will put it on the dyno, then use his equipement and burn a chip or make a tune for you computer.
If you want to get real geeky, you can do it yourself. The tweecer is one way of several that allows you to get into the actual computer and make changes.
Pretty much, with an EFI car, it'll run forever. Then you simply add your performance parts. The main thing that you'll play with is setting timing...however even that, you'll typically set at 14-16 degrees intial and leave it there..the computer handles the rest of the timing.
This is part of the fusteration behind me and this carb'd motor. it doesn't run the same from day to day. It's inconsistant and needs constant tweaking and tuning.
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Jeremy
-86 ssp X chp 5.0 coupe
-66 coupe,Ford racing crate 5.0 roller engine, t5 trans
-1972 Maverick undergoing full resto
-1970 Maverick Grabber-why did I buy this one??
I'll definitely have to look into that a little more and make sure I have a handle on what I'll have to get (cost), and what initial tuning will entail for me. I imagine it will be pretty smooth sailing once it's all set up.
Adjusted the float and it now starts easily when hot.
Adjusted the timing to 16 and it sounded ok (in the garage).
The idle was smooth and all the sudden it was sporadic. It acted like it wanted to die...dropping to 400rpm and then jumping up to between 900 & 1100 rpm. We played with the timing and it would do that at any timing adjustment. Sometimes it would even out...then a moment later it would be sporadic again.
I checked the dwell and it was 26. I think that may be a little low, but I haven't had time to adjust it. I don't think that would cause this all of a sudden though.
I had the same problem of my car wanting to die on me when accelerating. I had just given it a tune up and didnt think it would of been the spark plugs but it turns out the carb was bad and was flooding the engine with gas and burn the spark plugs, try checking the plugs
I appreciate the feedback. I checked the 8th plug and it was fine. I rebuilt the carb awhile ago. My primary concern at this point is the "erratic" idle that eventually kills it (that I discussed in my last post). I'm thinking that perhaps something has gone bad (suddenly) with the distributor...or I even read of the Power Valve causing these symptoms...of course that is new as well, with the carb rebuild.
I have the same thing happening with my newest project for my daughter (72 Conv. w/302). I have gone through most of everything. Rebuilt carb (2v), new gas, new plugs, wires, adjusted timing and so on. I am thinking it is either my rebuild carb OR the fuel pump. It is very possible the fuel pump may have a diaphram issue. If you don't have consistant flow then the carb will be starved. I agree with the other points on these strings especially the acc.pump but I too am convinced its either fuel pump delivery or the carb itself. Hmm! I decided to look up this tread to see if there maybe answers for me. Thanks for all the postings, it appears trial and answer is the best. I will let you know after I replace the pump first.
ok player... i have a 289 and i experienced exactly everything you mentioned earlier... including the hot and cold startups! i bought a new holley, a one wire mag pickup distributor, new plug wires, and new plugs. This solved all of my problems immediately. Now however, after running this setup some i have noticed the car has started to revert back to its old ways. I am about to start my troubleshooting again and i will let you know what the problem is. Also, does your engine sound like it could be missing? i fully believe our problems are electrical related because i have a brand new street avenger carb that i know cant be failing. Your not in this alone!
I went to start it this morning and it wouldn't even do the erratic idle. I had to give it some gas to keep it going, and even then it sounded rough. Then I let off and it dies. I guess I'm digressing. Does any of this sound familiar to you? I'm thinking it's electrical as well. Just not sure what or why. Maybe Veronica knows the answer!
Why would you new carb, plugs, and wires only temporarily fix it...I'm dumbfounded by this...
So it's continuing to start fine, then promptly die.
I read an article online where someone was having trouble with their car (similar, but not exactly the same), and they changed out their wires for oem and it fixed it.
I'm really really frustrated to have been able to drive it last week with a hesitation, now I can't even drive it. Any expertise would be very appreciated. Maybe I should just start a new thread since my condition has changed a bit.
Recheck the gap on your points, if they have closed up some the engine will act up and your idle will be screwy. I have heard of similar syptoms with the point winding up being the problem after everything else checked out.
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1968 Mustang coupe, Acapulco Blue, 289 2v, C-4, Power Steering.
Hopefully a 1969 convertible or Sportsroof (non Mach or Boss) for next Mustang project
Trying to find my father's 1973 Mustang Grande he bought brand new. 3F04F126773 last known registration and title was in New Jersey, 1982.
