1227165 ecu with custom code much better than stock ecu. (Page 13/26)
engine man APR 30, 07:44 AM
now you say it will run 4,6 or 8 cylinder engine i have a 91 -93 3.4 DOHC engine not in car yet but will it run it correctly due to the high rpm
Rick 88 APR 30, 06:23 PM
I am interested in this ECM swap. I have an 88 GT 5-speed Getrag with 3.4 PR swap running a distributor and stock 88 manual ECM and chip. While it runs very well, there is a slight hunt at idle and it seems to be slightly rich. It will soot up the exhaust tips over the period of one week driving every day. On a recent trip using the A/C constantly it averaged about 28 MPG. Would this ECM help with my issues?
engine man MAY 02, 08:29 AM
I just looked back through this thread and see he him self is doing a 3.4 dohc what he has done will be a great help for swaps maybe he could get it to run some of the vvt engines like a 3.6 if he has extra pins
chetw77cruiser MAY 02, 08:47 AM
For those interested in using this to replace the stock ecu in a vehicle that has regular emission testing, this is probably not going to be your best bet. This swap is more of a "for off road use only" type of swap. The biggest issue is that there is no native EGR function. The other issue is that the testing facility will not see the proper ecu and information when connected electronically. There are programmable tables that could control the egr valve, but all of the intricacies of the OEM are not present.

As for the 3.4 TDC/DOHC engine, it will control it without any trouble. The range of the code is somewhere near 9600 RPM, so you will run out of engine before fueling and spark. There are a few that must be changed to use this code with a DIS system, but nothing to worry about.

With the right tuning and paying attention to the details, I would venture to say that on average a person would be able to attain an average increase of 3 to 5 MPG. Remember though, results may vary.

[This message has been edited by chetw77cruiser (edited 05-02-2012).]

engine man MAY 02, 09:24 AM
Ok on the wiring harness for a 3.4 dohc would i just repin the stock fiero harness and then hook it up to the 3.4 dohc sensors ?

[This message has been edited by engine man (edited 05-02-2012).]

armos MAY 03, 06:40 AM

quote
Originally posted by chetw77cruiser:
For those interested in using this to replace the stock ecu in a vehicle that has regular emission testing, this is probably not going to be your best bet. This swap is more of a "for off road use only" type of swap. The biggest issue is that there is no native EGR function. The other issue is that the testing facility will not see the proper ecu and information when connected electronically. There are programmable tables that could control the egr valve, but all of the intricacies of the OEM are not present.


In many areas, emissions are only tested at idle. In that case, EGR function isn't important since it's inactive at idle anyway. That limitation is a good point though.
I'm curious what the process is for the test station and whether they really would know the difference in the ECM type. I can only speculate, perhaps they select the car type before connecting, and in that case it might fail to connect and they'd see an error.
If it really is a problem, at least it looks like it would be pretty painless to swap to the old ECM for test day.
armos MAY 03, 07:36 AM
I've been reading this
http://californiasmoginstit...Check_Procedures.pdf

and I found some good news and bad news.
Good news is, from what I can tell, in CA they don't connect to the ECM unless the car is OBD-2. They just look at the check engine light.
Bad news is, for those of us who only have an idle test, the inspector is instructed to separately test the EGR system using "procedure prescribed by the vehicle manufacturer." I don't know what data they have on that, or if they really follow through with it, but the test procedure in the 1986 service manual would catch an EGR that simply doesn't operate.
It's a little weird to me and hard to believe that they do this.. if they're going to all that trouble to function test the EGR, it seems it would be simpler to just do the dyno test like the city dwellers get.
I expect in most states the EGR wouldn't be directly tested, just the tailpipe, so for them this wouldn't be a problem.

[This message has been edited by armos (edited 05-03-2012).]

engine man MAY 03, 10:24 AM
well you can all move to NH they just look to see if the check engine light is off unless it is an OBD 2 car 1996 or newer they get pluged in so emissions test is realy not done
FieroWannaBe MAY 03, 01:38 PM
I have some questions, I did some looking on the delcohacking.net forum, but an overall observation didnt answer all of my questions, and since you have been operating with the 7165, I was wondering:

How does the fueling work for this code mask?
I am starting a 4.0L Northstar swap, and my main interest is the fueling difference between your setup and the $A1 for the 7730,
I am assuming this is all based on the $12P code mask.

Pulse width strategy for the $A1 code mask:

quote
Originally posted by ryan.hess:

ftp://ftp.diy-efi.org/pub/gmecm/manuals/1227749/Turbo_P4_Doc.pdf

This is for a turbo, but boost specifics aside, it works exactly the same. The fuel algorithms are outlined in the document.
Basically:

BPW = BPC * MAP * T * A/F * VE * BVC * BLM * DFCO * DE * CLT * TBM

Where

BPW - Base Pulse Width
BPC - Base Pulse Constant
MAP - Manifold Absolute Pressure
T - Temperature
A/F - Air Fuel Ratio
VE - Volumetric Efficiency
BVC - Battery Voltage Correction
BLM - Block Learn
DFCO - Decel Fuel Cutoff
DE - Decel Enleanment
CLT - Closed Loop
TBM - Turbo Boost Multiplier

all of these terms are laid out in the document and calculated according to input from sensors.

The PE mode is entered when some throttle condition is met (I believe) e.g. throttle > 50%, enter PE.
Idle VE is only used when there is no throttle signal present (it's idling)
Main VE is used for everything (see above)
Base pulse constant is used for everything (see above)
Ve adder gets added to the above, I believe.

It's been a while, so forgive me.



I am wondering if this is the same fueling stategy for the code mask you are using as well. The car this motor is being used in will see only track use, and the 7730 fueling becomes less refined as RPM and MAP is increased, Exactly where I want the best fueling strategy, so that my mileage is amplified on the track. Idle, and part throttle AFR arent my biggest concern as the motor will spend the majority of its life above 4000rpm. I care about the ability to control pulse width above peak VE to maintain a strict AFR in power enrichment, and to keep accel and deccel enrichment responisve and econmical. the modified $A1 mask can control most of my needs, but I dont like the PE enrichment as it is only a scaler array added to the main VE table after peak VE (which ends in $A1 (4000) before the northstars peak VE (4400)) and fueling control ends in the 7730 after 6400 rpm. where i can see benefit on a road coarse to keep fueling control up to 7000rpm.

[This message has been edited by FieroWannaBe (edited 05-03-2012).]

chetw77cruiser MAY 05, 01:44 AM
This code is using pretty much the same style of code, but with a few minor tweaks allowing for the use of a wideband sensor. There is no PE mode per se; this is mainly taken care of in the VE table and AFR table. If the VE table is tuned correctly, the fueling will take the desired AFR and enrich the mix to match what it thinks is the correct AFR. Using a wideband is needed to verify that the VE and desired AFR are actually correct as far as what the engine is seeing. The AFR table also is a 20 to 100 KPA and 400 to 9600 RPM 3d table. Matching VE and AFR data points is easy considering the tables are the same style and scales. I hope this covers what you mainly wanted. Unless one has been indoctrinated in this stuff, it can be a bit confusing at times.

Someone also asked about repining the harness and plugging it into the 3.4 TDC. To answer that question:
Repining – yes
Direct plug and play – most likely not
This is assuming that a Fiero v6 harness is used.

Now if a stock harness has been modified to work on the 3.4, or the 3.4 harness is used, possibly. I would need a bit more information to form a more definitive response. Also, not having a 3.4 TDC and a harness lying around make measuring things a bit more difficult. Anyone want to make a donation?