[DeTomaso] EFI

Jerry R Knotts knottsj at galstar.com
Wed Oct 5 12:29:04 EDT 2011


I have the usual Project From Hell.  I decided in my infinite wisdom to put 
a 393 Windsor in my '95 mustang.  Cutting out large pieces of the 
frustarting story, I jump to the laptop dyno tunning in Omaha at BJs.  We 
thought something was wrong with the MAF since I was using an EEC tuner 
board.  I had to adjust the flow numbers much differently than I had 
previously calculate.  About the time we were making headway one of the 
multidisc clutches burned up from the torque.  Later found it had been put 
in backwards and had stripped the female splines out of half of it.  Took 
the car back to Oklahoma and worked on the tuning for about 6 months,  In 
that time I found the the EEC tuner that I had bough from the manufacturer 
did not data log as it was supposed to so I bought an auxilary data logger. 
Had extreme trouble getting the idle to work.  After about a year I took it 
to OKC for another dyno tune.  At the tuners we found that the engine shop 
in Omaha had iinstalled a set of 30 lb injectors instead of the 36lbers I 
had taken.  Also that the EEC tuner working on a W4HO box that I bought at 
the Omaha was for an auto and worked quite differently from the T4MO box 
that I had had.  Later I found the addresses for both decoded boxes were 
incorrect so a number of the changes that I had been working on wer not what 
the boxes used for the combustion process.  There is much more to the stoy 
but the car still sits in the back of the barn with the idea I will start 
work on it again.

On the other hand the box I modified with LSTuner runs like stink in my LS1 
RX7.

Go figure,
Sitting here with my sharp stick waiting to polk it in my eye,
jerry knotts
----- Original Message ----- 
From: "Kirby Schrader" <kirby.schrader at gmail.com>
To: "Mikael" <mikael_hass at mail.tele.dk>
Cc: <detomaso at realbig.com>
Sent: Wednesday, October 05, 2011 9:38 AM
Subject: Re: [DeTomaso] EFI


> Good suggestions. Sometimes there are really strange things. I am trying 
> to
> tune my Pantera and was having difficulties. Turns out my 13 year old MAP
> sensor is reading 45kpa when it should be saying 101. And it seems to be
> intermittent at that. Makes for difficult tuning.
>
> As a comment though... most systems I know about and have read about are
> only closed loop during cruise.
> I could be wrong, but they all switch off closed loop during full throttle
> and fall back to a map.
>
> These so called 'self learning' systems are all BS as far as I'm 
> concerned.
> You have to get close manually before you can go closed loop. There's no 
> way
> the system will compensate for something that's completely out in left
> field. No way. I don't care what you read in the marketing blah blah blah.
>
> This is the same as a carburetor. You have to pick the right type of carb,
> CFM and jetting to get close and then you start tuning for YOUR engine. I
> bought a carburetor once that was supposed to work as is. My car would
> hardly run.
>
> And remember... when a new EFI system is put on a production car, the car
> companies literally have a full team of engineers and technicians who run
> the engine on a dyno and then take the cars out to all parts of the 
> country
> and run them through tests in all conditions. Altitude, cold, hot, humid,
> etc..
> Why? To set up the maps and feedback loops so the system works as you 
> would
> expect it to when you buy it off the showroom floor.
>
> Ever seen the documentary on the development of the Ford GT? They couldn't
> even get the engine to START the first time around!
> The 'EFI expert' of Ford ended up using what I think I remember hearing as 
> a
> program from a Crown Vic! Just to get it running! Then they started 
> tuning.
>
> So even the experts have to work hard to get a EFI system set up the first
> time around.
>
> And we're talking about each an every one of us having a completely
> different engine. Different heads, cams, compression, bore, stroke, blah,
> blah, blah.... so each and every map and setup will be different.
>
> OK, I'm off my soapbox now... I like my EFI setups and will continue to 
> use
> them.
>
> FWIW,
> Kirby
>
>
>
> On Wed, Oct 5, 2011 at 09:06, Mikael <mikael_hass at mail.tele.dk> wrote:
>
>> Suggestions: I was sitting here thinking, can I suggest some remedy for 
>> the
>> lean and severe bogging. Justin, I'm sure you've done all the sensible
>> things, so I'll give you a few totally weird suggestions, forgive me.
>> -Some EFI systems work strange if they don't get enough juice
>> (electricity).
>> Is your alternator fine? Grounding? Are there grounding wires from engine
>> and gearbox to chassis?
>> -I once had a car that did the same, but with a carb. It turned out to be 
>> a
>> wire that was neither isolated nor fastened properly, so the g-force made
>> it
>> short against the engine
>> I know, weird suggestions.
>>
>> Some comments, from many angles, from a carb fan:
>> -Not many people can feel the difference between a properly tuned EFI and 
>> a
>> properly tuned carb
>> -On non-fuel-economy cars, I'd never do EFI. Why add complexity? Why 
>> spend
>> money?
>> -All carbs I've had have on an O2 meter shown a little lean when
>> accelerating, and still have excellent throttle response
>> -Buying things partly because the company claims to have experts sitting
>> waiting to take your call is very optimistic. These are slightly trained
>> call center employees, with targets on number of calls per day. My
>> experience is that you quite soon know more about their product than they
>> do
>>
>> Question: Are any of those EFIs closed loop? That's how OEM works, and if
>> it
>> is, then tuning should be unnecessary
>>
>> Mikael
>>
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