It's official...(maybe not) *UPDATE*

[66gt350]

Re: Re: It's official...(maybe not) *UPDATE*

Thats the wiring harness I used too. It was very easy install. Only problem was its only for mass air setup, and I had speed density too. So I had to convert over. Locating the computer for an automatic was the hardest part. Of course I still have no idea if its all going to work.

Pat,

As long as you stay with a fairly stock setup, efi is great. It's when you start adding parts that is more than the stock computer's adaptive learning can handle is when issues arise. That's when it starts having the problems with the hunting or surging idle. Watching the AFR meter when that is happening, the car is going between really, really rich to really lean. It keeps going until it drops the rpm's so low that the car dies.

There's two basic options: 1. Do like kb3 did and have a tune burned onto a chip that corrects the stock computer for the specific parts, or 2. Go the frustrating, long route of getting a Quarterhorse or Tweecer and a laptop and creating the tune yourself. It's been a long, long learning process figuring out what scalars, functions, and tables to modify to get the computer to like the combination. This way does have it's advantages...I've figured out how to use the stock computer to turn on and off my electric fan at certain temps.

 

[Anonymous]

Can you change the MAP? How much vacuum at idle? IMO if trying to run a stock ecm with a lot of aftermarker mods it's about impossible to get it right without the ability to alter the map. I think if I had all the efi crap on the car I would go ahead and invest in a Tweecer or some other piggback tuner. I will tell you that running a lumpy cam will make tuning almost impossible. For my preference I like running stock cams with forced induction. They act like a granny car right up until the point where you hit the gas and the boost kicks in. Also keep in mind that a cam with less than a 112* LCA will be almost impossible to tune. It can be done, but the engine may wonder around from time to time (bouncing vacuum) if using a MAP. The cam selection is the most critical element in getting a efi system to run correctly. Good luck, the more you learn about efi, the easier it gets.

 

[kb3]

Re: Re: It's official...(maybe not) *UPDATE*

Pat,

As long as you stay with a fairly stock setup, efi is great. It's when you start adding parts that is more than the stock computer's adaptive learning can handle is when issues arise. That's when it starts having the problems with the hunting or surging idle. Watching the AFR meter when that is happening, the car is going between really, really rich to really lean. It keeps going until it drops the rpm's so low that the car dies.

There's two basic options: 1. Do like kb3 did and have a tune burned onto a chip that corrects the stock computer for the specific parts, or 2. Go the frustrating, long route of getting a Quarterhorse or Tweecer and a laptop and creating the tune yourself. It's been a long, long learning process figuring out what scalars, functions, and tables to modify to get the computer to like the combination. This way does have it's advantages...I've figured out how to use the stock computer to turn on and off my electric fan at certain temps.

I figured I would go the easy way the first time. But I am intrigue about the "tuning yourself" method and plan on learning more about that before my next install.

 

[LastDeadLast]

I'm still baffled. I head out to the garage tonight to start ripping and tearing out the efi, when I thought I'd read the computer codes even though the "check engine light" didn't light up. It came up with two codes 34 and 96.

34 - insufficient EGR flow or EVP voltage high (SONIC) or PFE sensor voltage high or out of specification
96 - Fuel pump secondary circuit fault / high speed fuel pump relay open

I had a code 96 for awhile.. I checked everything and never could figure it out. Eventually I figured out that an injector driver was bad on my ECU. I replaced it and the error went away.

I can very easily relate to your frustration, I've only recently (like two days) got the EFI right... It was dyno tuned last week, I'm running an SCT chip.. this took care of my idling issues and mid-range issues, but I still was suffering with high RPM missing. It took a Crane ignition box to fix that.

But the car now starts and idles at any temperature without me having to touch the gas, and that's with a steep cam and quite a few mods. The mid-range driving is flawless... just as nice as a new car. The power is nothing short of amazing considering the parts that I've assembled.

Would I do it again??? I'm not sure. I've sunk a lot of money into this mill just go get it start easy and run well. It's cool to show and it was a neat exercise to see if I could do it, but I doubt it was worth the trouble. But the way I see it, a carb is the easy way to go .. I like them, but they're a dime a dozen.. at any given show that I go to, there are usually only one or two EFI conversions present.

Good luck!

-Shannon

 

[66gt350]

I'm not sure, but I may have found some/part of my problem. I was out working on the car, with the radio on both doors open for maybe 30 or so minutes. All of a sudden the radio stopped and I noticed my WB gauge reading E-9 (bad voltage). And when I would cycle the key, the electric fuel pumps sounded weak. With the key off and doors closed, I was reading 11 volts. Open the door and it would drop down to 10 volts. I'm wondering if my battery is getting weak. But with the engine idling with everything on, It's reading 12.7 volts.

I think I need a beer (or several)....

Can you change the MAP? How much vacuum at idle? IMO if trying to run a stock ecm with a lot of aftermarker mods it's about impossible to get it right without the ability to alter the map.

Your correct. The MAP sensor does not like alot of changes to the engine. With a Mass Air computer, I don't have a MAP -- I have a BAP (Barometric Air Pressure). It's alot more forgiving than the Speed Density computers with a MAP. With a tweecer or quarterhorse, you should be able to modify the MAP tables to fit your vacuum.

I figured I would go the easy way the first time. But I am intrigue about the "tuning yourself" method and plan on learning more about that before my next install.

If you decided to go this route, let me know. I've learned alot (but still have a lot to go, obviously or my car would be running perfectly), and I can point you to several helpful websites.

I had a code 96 for awhile.. I checked everything and never could figure it out. Eventually I figured out that an injector driver was bad on my ECU. I replaced it and the error went away.

Shannon -- injector driver? what computer are you running? I'm running a A9L for an EEC-IV.

 

[LastDeadLast]

Shannon -- injector driver? what computer are you running? I'm running a A9L for an EEC-IV.

Yeah.. I'm not sure if that was causing the code.. could be totally unrelated. But I had an issue with one of my injectors not firing. Replacing the ECU cured the injector and the code. I'm using the A9L as well with a SCT chip. If you haven't gotten it tuned by anyone, I highly suggest it. Especially if you've modified the engine.

-Shannon