[Gmecm] Re: Early and Late DIS compatibility (was: ECM Choice: Sequential V6...)

Tue Sep 12 11:15:04 UTC 2006

The 7148 is a C3 ecm which uses a MAF sensor.  The code is embedded on a ROM inside the ecm case.  Rob Rauscher has developed a plug in board for the tbi C3 which, along with some other hardware, replaces the OEM ROM with his own code.  He may be able to provide something similar for the 7148.  

I'm not sure what "early" and "late" DIS means considering that "late model" cars today date back to maybe 2003?  The "late" DIS systems in current use are generally incompatible as coil sequencing and triggering are all handled within the pcm.

IIRC the 3.8 uses a hall effect cam signal.  Service information for a 96 Corsica w/ 3100 shows the same type of sensor in use.  As with other OBDII vehicles, the ignition module's chores are handled by the pcm, so you'll need to install an ignition module from an earlier model engine.

Is there an OBDII pcm used with the sequential 3100 / 3400 and supported by Tunercat which can be installed in a minimalist fashion?  You might even be able to eke out more mileage through better fine tuning.

Factory service manuals often have good descriptions of the systems they cover.  A timing diagram may be available in GM training literature.  

Zaphod
-----Original Message-----
From: william.lucke at highspeedlink.net
To: gmecm at diy-efi.org
Sent: Mon, 11 Sep 2006 7:13 PM
Subject: [Gmecm] Re: Early and Late DIS compatibility (was: ECM Choice: Sequential V6...)

Ok, from the Turbo Buick forum, I learned that the Turbo Buick ECM is the 1227148 and that the turbo version uses $T31 code which is available from Tunercat. 

How compatible are the signals of the early and late DIS between ignition module and ECM? What resources are there for timing diagrams and explanations of the early system? 
What kind of cam sensor does the 7148 expect? What kind of cam sensor does the 3100 have? 

How easy/hard is the $T31 code to work with? 

Will 

> From: William Lucke <william.lucke at highspeedlink.net> 
> Subject: Re: [Gmecm] ECM Choice: Sequential V6, hydraulic transmission 
> with lockup convertor 
> > A 6000 is a larger, heavier car than Cavlier, is all wheel drive and > this particular one is running reasonably sticky 245 tires on the front > (205's on back) that already cost me 1.5-2 mpg compared to cheap 195's > all around. 
> > If I can hit 25 mpg with the chain ratio change (24 is more likely), the > best that a 16.5 AFR could theoretically do for me is 28 mpg. I won't > see that because the real world isn't theoretical ideal (the real world > has hills that will cause me to get into PE and convertor unlock with a > 2.39 final drive). 
> > As I said before, I can do better than I am, but if sequential is worth > anything at all, I want it. Since my engine will come with sequential > sensors & wiring, actually running that way sounds as simple as picking > the right computer. Would a turbo Buick unit accomplish this? 
> > A '93 Z24 has the TH125? WTF? 
> > The shutter wheel in the opti-spark distributor used on the LT1's is > quite 8 cylinder specific. I can see code that interprets that signal > being difficult to convert to 6 cylinder operation. 
> > > > Will 
> > > >> From: Jay Vessels <jay at vessels-clan.com> 
>> Subject: Re: [Gmecm] ECM Choice: Sequential V6, hydraulic 
>> transmission, with lockup convertor 
>> 
>> Hi there! 
>> 
>> Production 3.1V6 Cavalier had either the THM125 or the Getrag 282 >> 5-speed manual. 
>> 
>> Comparing fuel economy numbers across cars and drivers is almost >> impossible, but considering the mileage I got from my '94 Z24 >> convertible ($A1/5-speed) and what Dad gets from his '93 Z24 convertible >> ($A1/auto), I will second the notion that decent fuel economy (30 MPG >> highway) can be had from multiport systems. I'd recommend tuning with a >> wideband O2 sensor, regardless of system, to maximize the benefit of >> whatever system you choose. 
>> 
>> As an aside, has anyone used LT1 ('8051) code for a non-V8? Is there a >> V6 or 4-cylinder version that is as flexible? 
>> 
>> Jay Vessels 
>> 1982 Chevrolet S-10 Sport, 2.8V6 TBI 
>> 1984 Chevrolet S-10 Blazer Sport, 2.8V6 (TBI pending) 
>> 
>> William Lucke wrote: 
>>> I assume that your Cavalier has a 4 speed transmission? Do you have >>> functioning EGR? 
>>> I'm stuck with a 3 speed AWD that currently gets 22 hwy/19 city. Gearing >>> changes might push me to 24-25. If sequential is worth 0.5 mpg, I want it. 
>>> I also think the 3100 is a fundamentally better/more efficient engine >>> than the 3.1. With the roller cam and better heads/intake, it's >>> certainly more responsive to boost. 
>>> 
>>> 
>>> Will 
>>> 
>>> 
>>> From: "Brendan Patten" <bpatten at centurytel.net> 
>>> Subject: RE: [Gmecm] ECM Choice: Sequential V6, hydraulic transmission 
>>> with lockup convertor 
>>> 
>>> I'm getting over 30mph highway with my 3.1L $A1 Cavalier. Highway mode 
>>> fuel AFR 16.5:1 and a bunch of timing added. (still no knock) 
>>> 
>>> I'm trying to convert to $8D mask on my 3.1L right now for more BLM 
>>> cells. But no sequential. 
>>> 
>>> There was also the Turbo Grand Pri in 1989 with a 3.1L, $8F mask. Not 
>>> sure of how many blm cells there 
>>> 
>>> $58 mask could be adopted to a DIS engine, you'll get 16 cells and 
>>> boost, still no sequential. 

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