84-86 EZF chip socket issue
09-24-2012, 03:26 PM
#1
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84-86 EZF chip socket issue
A note for folks exchanging their stock chips for S300s, SharkTuning, AuthoThority, etc. - be very careful removing chips from the socket.
Lever one side at a time, lifting just a little, until the chip (EPROM) is free. Do not pry under the socket by accident!
I have found a problem with EZF ignition brains where the EPROM socket is poorly (cold) soldered to the motherboard.
If you change the EPROM frequently or are particularly aggressive about removing it, socket pin(s) can separate from the solder, causing no-start or random stutter/stalls.
I have damaged two EZFs this way (I change chips hundreds of times.). A couple of people have removed the entire socket by accident.
It is an easy fix - just reflow the solder around the socket pins - but it can be really annoying to trace down.
The issue can be replicated by tapping hard on the steel case of the EZF, while the engine is running. If the socket is loose, the engine will stutter or stall.
Lever one side at a time, lifting just a little, until the chip (EPROM) is free. Do not pry under the socket by accident!
I have found a problem with EZF ignition brains where the EPROM socket is poorly (cold) soldered to the motherboard.
If you change the EPROM frequently or are particularly aggressive about removing it, socket pin(s) can separate from the solder, causing no-start or random stutter/stalls.
I have damaged two EZFs this way (I change chips hundreds of times.). A couple of people have removed the entire socket by accident.
It is an easy fix - just reflow the solder around the socket pins - but it can be really annoying to trace down.
The issue can be replicated by tapping hard on the steel case of the EZF, while the engine is running. If the socket is loose, the engine will stutter or stall.
09-24-2012, 03:47 PM
#2
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Early EZF vs. late.
Lower, late, has the EPROM socket.
(Earliest versions have the EPROM directly soldered to the board.)
Lower, late, has the EPROM socket.
(Earliest versions have the EPROM directly soldered to the board.)
09-24-2012, 08:35 PM
#4
Had this exact issue on a car after the owner put new chips in it. It would only cause the car to fault out when he hit a bump.
09-24-2012, 09:56 PM
#6
Three Wheelin'
Thanks for the heads up Ken. Just installed the 4.0 set (3.6 chips are enroute back to you). Some initial feedback. The car rockets off the line and pulls HARD... I thought it was fast before! BIG SMILE while "testing" them out yesterday. It did stall this morning after starting - 1st time ever. I'll keep an eye on it and if it happens again I'll send you a pm. The chip has "89 Octane" on it so I filled up with 89 today. No pinging (lower octane gas) and the car ran great all day - 250 mile round trip - at this pace I'm gonna have to get some new rear tires soon!
09-25-2012, 02:47 PM
#7
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V4.0 is completely new, so you may have to readjust the idle speed/CO.
FWIW, here is a little (boring) background on where that 'magic' power came from.
The stock S3 EZ and LH maps/tables have generic RPM divisions (columns).
The main fuel map has the same columns as S2 and some SAAB models!
The main ignition map has a bunch of unused low rpm columns.
For max output, you have to be able to change the columns to target the engine's unique requirements, so the computer doesn't have to 'guess'.
EG. I bracketed the S3 harmonic airflow peaks at 2700 and 5200, which require much less advance or it will knock, with extra columns, so I could add more advance around the peaks.
As it turned out, 1900 and 2300 RPM needed more advance, which 'magically' produced a whole bunch of torque that wasn't available before.
Stock EZF: 6000|5500|5000|4500|4000|3500|3000|2700|1900|1300| 950| 760| 570| 500| 440
S300s V4: 6200|5700|5450|5200|4950|4700|4200|3500|3000|2850|2700|2500|2300|1900|1300|950
Unfortunately, it has taken me years to understand the (assembly language) code for the RPM scaling which makes the column divisions.
More confusing, RPMs are read by the CPS in a curve, which looks like a temp sensor scale, not in a straight line.
As soon as I figured this stuff out, tuning became so 'easy'.
FWIW, here is a little (boring) background on where that 'magic' power came from.
The stock S3 EZ and LH maps/tables have generic RPM divisions (columns).
The main fuel map has the same columns as S2 and some SAAB models!
The main ignition map has a bunch of unused low rpm columns.
For max output, you have to be able to change the columns to target the engine's unique requirements, so the computer doesn't have to 'guess'.
EG. I bracketed the S3 harmonic airflow peaks at 2700 and 5200, which require much less advance or it will knock, with extra columns, so I could add more advance around the peaks.
As it turned out, 1900 and 2300 RPM needed more advance, which 'magically' produced a whole bunch of torque that wasn't available before.
Stock EZF: 6000|5500|5000|4500|4000|3500|3000|2700|1900|1300| 950| 760| 570| 500| 440
S300s V4: 6200|5700|5450|5200|4950|4700|4200|3500|3000|2850|2700|2500|2300|1900|1300|950
Unfortunately, it has taken me years to understand the (assembly language) code for the RPM scaling which makes the column divisions.
More confusing, RPMs are read by the CPS in a curve, which looks like a temp sensor scale, not in a straight line.
As soon as I figured this stuff out, tuning became so 'easy'.
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09-25-2012, 07:59 PM
#9
Three Wheelin'
Hey Bob!! I'm lovin' the new chips! Damn car is eating my rear tires (Hankook Ventus V12) like there is no tomorrow. My fronts will be good for another year... 
Ken, The local tire guy likes your chips too!!!
Ken, The local tire guy likes your chips too!!!
