FAST EFI 1.0 question / help

[Steve67RS/SS]

I am having a hard time in one area with this, and was wondering if anyone has any ideas. At low end, traffic / stop light take off, type thing. it seems to be very sensitive, wants to die out, and sometimes does. Once over about 1700 rpm, and up, all is fine, great response. Seems to want to load up in traffic and take off. Ive tried richer / leaner can't get it figured out, and yes I am a rookie on this. I am wondering if cam / stall can have an affect trying to get it dialed in this area. Lean seems to be a little better, but then that brings the heat up in the motor. At stop light in gear idles about 950, cam is 570 / 554 lift. dur. 243 / 257 and 3000 stall. its a 496 BBC. it is great everywhere else, "pretty good" on start up. then on / off gas up to only about 1,600 rpm it wants to stall out, and will. Think the above can have an impact? I'm not sure what to try. Really thinking about going back to a carb. Thanks for any input.

[GregWeld]

Nobody can tune this for you via emails and posts like this. There's just too many variables that we can't see or know.

First I'd ask --- how do you know when it's "too lean" and how do you know when it's "fat/rich"?

What A/F ratios are you trying to achieve? And are the VE's all set?

Is there an idle control motor?

What's your vacuum look like...

What's your timing - initial - total - what's your curve?

Are you running sequential or batch fired?

What size injectors are you running? What PSI is your fuel pressure regulator set to deliver?

[Steve67RS/SS]

Nobody can tune this for you via emails and posts like this. There's just too many variables that we can't see or know.

First I'd ask --- how do you know when it's "too lean" and how do you know when it's "fat/rich"?

What A/F ratios are you trying to achieve? And are the VE's all set?

Is there an idle control motor?

What's your vacuum look like...

What's your timing - initial - total - what's your curve?

Are you running sequential or batch fired?

What size injectors are you running? What PSI is your fuel pressure regulator set to deliver?

Thanks for the input, I now know I am really a rookie on it, I think I will try to find another shop that has the knowledge. I'm here in northern ca, and have tried two shops that came referred (one did the install as well), but nobody can seem to get it dialed in just right. Being a Plumber, unfortunately my knowledge is extremely limited on this, I'm one of the guys who thought, EFI change over sounds nice for the car, right?.... At least I knew enough to have a shop install it, but it just has never been right. Thanks for opening my eyes. I just need to find the right people to get it taken care of.

[GregWeld]

It's really not hard to dial these in --- if you're at the right shop -- on a chassis dyno.... I'm not from that area so can't really help you find a good shop that knows what they're doing.

Hopefully some of the NorCal boys chime in here and know of a good shop near you.

[Angry]

Been reading quite a bit about thiese EFI systems, especially the FAST systems, seems they struggle with vacuum lower than 8 inches...
Maybe yours has low vacuum , seems the systems, especially series 1,.. struggle with low vacuum and that might be your problem.

[69hugger]

Steve,
I have the same system, bought the car with it last winter. I was having drivability issues as well as extreme exhaust temps that blistered the ceramic off the headers and actually melted the urethane out of one of the motor mounts (header tubes run about an inch away).
After fiddling with A/F ratios & such, I took it to a reputable tuner that specializes in F.I. (I'm sure they all do these days).
Within 90 minutes he had leaned out the enrichment circuit (crisped up the throttle response a lot), timing (needed a bunch more advance), and A/F ratios at cruise & WOT.
I left with 130 more RWH, way better throttle response, and a much more drivable car. Oh yeah, the coolant runs about 10-15 degrees lower. It was night & day. Love the F.I. now!
The best $200 I have spent on the car. Take it to a guy that has the tools & knowhow & he will dial it in for you.

[69hugger]

One more thing I would add. These systems are very touchy about correct installation. I was questioned about that repeatedly by potential tuners I was talking to.
Fortunately, mine was installed by one of the most reputable shops in the country, but looking at direct battery supply, proper grounds, and wire routing may be called for if it is not tunable.
But hopefully, you just need a guy that is familiar with this system.

Best of luck!

[Ketzer]

FAST is having an in-house training day on Sept 20 at their HQ in Memphis.
I would go just for the info but have already signed up to work for a friend that day. :bang:


Jeff-