I had this problem too. It can be fixed.

What is happening is as the rpm goes up, you get MORE vacuum (yes more, because your throttle is still closed during idle). As you get more vacuum in your 950 rpm column your probably giving less fuel which causes the engine to lean out and falls back to your 750rpm and the ECU richens the mixture which starts the whole process over again.

You need to play with the vertical column (vacuum column) to get rid of the hunting.

Changes with the laptop are easy so play around with it.

Imagine trying to tune this problem with CIS, carbs, or MFI :rolleyes:

EFI rules....

Thanks again Tony. The startup and idle issues are worked out now. Creating two rich points on either side of the target rpm at 750 and 1500 in the first column has gotten rid of all hunting.

Goodies added this weekend:
1. Lighted Switch for turning the log on and off. DTA can log 8 parameters for up to 30secs (more time with fewer parameters)
2. Lighted Switch to turn Wide Band Lambda ON/OFF. I had only been monitoring this before. Now I can use it to make a correction map.
3. LED's to indicate the ECU, Injectors, Coil and Fuel pumps are each getting power. (Push Switch simply turns the lights out)

http://forums.pelicanparts.com/uploa...1106010232.jpg

RESSURECTION! What is the common path to an EFI conversion now?

No common path. It's still wild wild west.

There are several Megasquirt installations that have been completed this year or are in the process (mine is just getting started). Glad you brought this thread back to life. It has some good information.

Mike

Steven at Imagine Auto now sells a rail and injector block kit with an Autronic setup

Just wanted to bump this thread to see how all the pioneers are doing with CIS to EFI in your 930's. There seem to be alot of combinations out there and quite a price range as well. What seems to be working well and what are the problem areas?

6500 miles so far and still going strong. I can't speak for other systems since I have only used one (DTA P8). It is easy to use and tweak. There are not really any problem areas just areas that are more difficult to tune then expected, such as the startup issues documented above in this thread. I have recently been trying to squeeze a little more fuel economy out of the maps which has been successful. I had been getting around 12mpg with CIS, with EFI I was getting 15.8mpg last summer, with a little tweaking I now get around 18mpg, I have just made a few more tweaks this weekend for warmup conditions which I hope will improve mpg even more. (Of course when the boost is on it sucks fuel)
Other small problem areas are a very slight miss at light cruise, its barely perceptible unless your ears are "tuned" to your engine. I have heard others having similar issues. This may be because of the type of injector I have or poor flow in the stock 930 intake when the throttle is barely open, however once you put your foot down... lets just say I hope your seatbelt is fastened!

David,

Are you running resistor plugs? If not try them out. They cured my slight miss.

I was running Bosch paltinum w3po but these seemed to get fouled very easiliy so I am now runing bosch silver w4cs plugs. They don't foul, but I don't think they are a resistor type plug.
What kind are your running?

NGK BPR7ES or BPR8ES. I don't remember exactly. The R is for resistor.

I'm running the NGK BKR7EIX plugs (iridium). I've got about 3000 miles on them and the CIS-EFI conversion. The 7s are one step colder than the OEM 6 series plugs (the BKR7ES are about the same as what I'm using).

My ECU is a Megasquirt II system with dual plugged EDIS spark. My tuning experiences sound similar to Magic930's. It's pretty easy to get a functional, fast car. It takes a while to tune it so that it is as smooth as a modern factory computer.

David,

So what were the net benefits to this project? Have you dyno'ed the car to see changes? I was told by the "shop" that EFI (vs. CIS) is necessary for truly improved HP numbers but personally I like the idea of improved off-boost fuel consumption. The car has power now on boost but sucks gas like a drunken sailor even when off boost.

Net benefits depends on your reason for doing it in the first place. For me it was the challenge of the project just as rebuilding the engine was. I was half way thru my rebuild waiting for parts to arrive when I got the bug to try and make the switch to EFI. It was a rewarding experience for me and I met a lot of great people during the process. Doing it for fuel consumption really is not cost effective unless you can amortize it over 80,000 miles or more although I have heard of one guy who claims 25mpg highway, I have not been able to get that good! What I like the most is the ability to hook up the laptop and make small adjustments to tune particular parts of the map... this can also be a downfall for some people as the twiddling never ends. But isn't that what a Porsche is for?
Overall I have better throttle response, more low end torque which helps in town driving with the 4 speed and the ability to produce a lot more horsepower than stock at the top end if I want it. My car is a street vehicle however and although I built it with all the right components for high horsepower I was more concerned about longevity than anything else. If your goal is more horsepower from an EFI conversion in a turbo, then you must rebuild the engine at the same time. If you don't rebuild then you may as well stick with tweaks available to the CIS... although fuel consumption would get even worse. As for dyno tuning, it is really essential to get the most from any system... but I have not done it yet.

If you don't do the work yourself, beware, the rebuild always takes twice as long and cost twice as much as the homebuilder (ahem) engine builder says it will. My car is almost done and I can tell you if I had the hard numbers in front of me I would not have done it, but on the other hand it would be worth the ride.

Well I have some semi-hard dyno #'s for you.

Ok, before EFI on a Dyno-crap, I mean Jet dyno. I got 328 rwhp and 318 lbs. I also got 13.7 mpg.

After EFI on a DynoDynamic dyno. I got 352 rwhp and 321 lbs. I now get at least 14.7 mpg to 16.4 mpg. I am still falken around with the tuning.

The car is WAY faster with EFI. I have recently turned the boost up a hair. So it might be gettin a lttle more power than above.

Don't use fuel consumption to justify EFI. The throttle response is soo much better you will be buring more fuel just to keep that silly grin on your face. At least that is what I do.

I had a Porsche mechanic drive my car and he called it scary fast. He claims the throttle stuck on him. I am sure the throttle did not stick it just responds soo much faster than he expected from a turbo. My car does not have high dyno #'s (400/400) but it does come on quicker than you expect which feels great.

FWIW my dyno numbers were 379RWHP and 375ft/lbs torque before the conversion. I am anxiously awaiting the completion of the build and the tuning stage to see where we end up.

Ayone know the depth and the internal diameter of the OE plastic turbo injector blocks?

Thanks Steve