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Starter bypass G241a, S25, T1 and T2 Motronic ECU test points

The black G241a two purple and purple-black wire connector jumper is to bypass N45 antitheft unit in trunk so starter relay will always work. It is along center console area close to gray greenish cruise control ECU and orange air bag ECU. I just cut wires going to rear of car and splice together (same color wires on 24v models).

The red S25 two-wire connector is for telling computer if car is an A/T or 5-speed model. No jumper for A/T models and jumpered for 5-speed models even though I have seen some 5-speed models without jumper wire (no S25 for 24v models)

T1 is the black oval connector to hook up to Marelli Fiat Lancia Tester (FLT). Same on 24v models.

T2 is the black square connector on USA models to go to square test button wiring on left side of steering column to pull codes in memory and to run injector and idle actuator tests (no T2 on 24v models). The Link to How to run test on 91-93 models in this post http://www.alfabb.com/bb/forums/5344273-post3.html

Unmarked ECU is for 91-93 ABS (none for 24v models here it is in ABS pump in engine bay.)

S11 marked ECU with red label is Motronic engine ECU -117 for 164B/L and -130 for 164S. The 24v models have different numbers for these motronic ECUs (USA 94 164 -663 and 95 164 -287).
 

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It don't know my IS from my IT it seems and that isn't all I did!
Thanks for answering my statement that got written as a question.

I meant to say "OBTW [it] is a EMI shielded cable with wire braid like the crank sensor cable". Instead of OBTW is it a EMI shielded cable with wire braid like the crank sensor cable. Seems like I GOT MY IS BEFORE MY IT!...
LOL, yeah it did seem weird you asking me a question instead of the other way around :001_smile:
 
Still playing with my Fiat Lancia Tester on both BB1 and BB2. Figured out how to clear 1223 code from ECU memory with it and then I can get it to run through complete test procedures now but still haven't been able to get system to run cleanly without issue with O2 part of the system. I have retrieved a complete good spare ECU pin 24 O2 shielded cable from a spare fuel injection harness. I hope to find a way to feed it through firewall and then hook it up to pin 24 at ECU and O2 sensor cable in engine bay.

Meanwhile I retested BB2 my 164S and found out that my wide open throttle (WOT) switch was not actuating on with "pedal to the metal" of accelerator pedal down stop. So I removed threaded down stop from the floorboard threaded insert and ran a M8x1.25 die on threads so I could thread it closer to floorboard so now min/max switch makes contact in WOT position. Haven't had a change to drive it yet and see if the WOT 4-barrel kick in the butt effect makes BB2 scream louder and haul arse more better. If so I am sure it will be reflected in lowered miles between gas fill ups.
 
Discussion starter · #25 · (Edited)
Concerning your O2 sensor problem (and bad starting), have you tried an overnight disconnect of the battery? I have noticed that short disconnects don't alway seem to clear "bad habits" the ecu has stored. Discovered this recently when one of the hoses on the intake wiggled loose, causing a vacuum leak, leading to very worrisome bad starting. After trying many things it was an overnight battery disconnect that got the ecu to finally normalize, now the car starts almost instantly again, cold or hot.
 
I can try that pretty easy now that I have installed the Summit Racing battery disconnect switch. Sure glad I have cut my antitheft siren wire though as cutting power to car sets off siren side of system unless I disable system with key inserted in siren in trunk.
 
Well, I wasted a few hours today running a new used good pin 24 O2 sensor wire from engine bay to engine motronic computer in center console under dash today and got same result with Marelli Tester and same 1223 check engoine light.

So, it is a fly gripe and I will continue to use RML coolant test sensor overide variable resistor to start cold engine.

I had taken a pin 24 shielded wire out of spare injection harness sometime ago to get ready to do this.

Today was the day to install it and see what happens. No change, Bummer!

How I did it was run new wire next to A/T shift cable housing through fume seal. I had to remove engine ECU. ABS ECU and Air bag ECU to be able to take fume seal cover off and feed a hollow rubber hose into engine compartment and then insert new used wire into hose and pull it back into ****pit so I could hook it into pin 24 socket after I unlocked original pin 24 wire.

First two pix are fume seal show and tell with spare A/T shift cable housing and fume seal on work bench and next one shows new wire through seal and cover under dash in car and last pix shows new used green covered pin 24 cable in place of original pin 24 cable in multi-pin connector to motronic engine ECU.

All I proved was I could do it didn't change Jack s**t as far as how car idles and flips on CEL.
 

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When you say "No change, Bummer" you mean CEL still goes on, but what about starting issues, is that okay now?
No change but actual starting was never an issue. The issue is rough idle as soon as started until warmed up unless I use the RML variable resistor box to overide coolant temp sensor. CEL light still comes on with a 1223 code.

Even warmed up idle is not real smooth and RPM goes between 760 and 720. CEL will come on at stop lights waiting in Drive. I usually put car in N or P at long lights.
 
Marelli Tester vs Diagnostic Software

Great that you got it to work :)

This behaviour is what I would expect, compared to what I have seen on the 24V. Also, clearing error codes must be possible (as on 24V), since you can diagnose if there are anything stored.

I used it also for monitoring while driving, but since I tested Wilco's diagnostic SW for my Q4, the Marelli module has not been used much.
Allan,

Since you know both diagnostic systems, has the Wilco/Dimety/Arjen Alfa 164 Diagnostics 1.0.16 software made the Marelli (aka Fiat-Lancia) tester obsolete for the 94-95 24V LS/Super?
 
Allan,

Since you know both diagnostic systems, has the Wilco/Dimety/Arjen Alfa 164 Diagnostics 1.0.16 software made the Marelli (aka Fiat-Lancia) tester obsolete for the 94-95 24V LS/Super?
Firstly, I will point out that I have only used Wilco's diagnostic sw on 24V 164's. I think others here can comment on the use for 12V models.

The only things I cannot connect to in my Q4, is the 4WD and suspension. The 4WD is not important to you and Pinino is covering the suspension part very extensively! :)

I have had Marelli modules hooked up to ABS on a 24V QV (no airbag) and airbag on my Q4 (not the ABS as that is a different module I don't have). Those 2 situations have worked ok for me, but using Wilco's sw is much easier, as you just have to change tab in the program when you connect to another diagnostic plug and because you can make screen dumps of what you find (or use other screen capturing programs).

For the Motronic part (at least 24V), Wilco's sw is SO MUCH BETTER!!! You can monitor and log different parameters while driving (for analysis afterwards) and it is easy to read out and delete error codes. You can also get a calculated number of the fuel consumption on the Q4, but I am not sure that is such a good thing... :blink:

The Marelli system on the Motronic can be hard to work with some times, as the instructions on the screen might not always lead to being able to monitor parameters.

So if you don't have adjustable suspension, I don't see a need for the Marelli system.
 
Discussion starter · #32 · (Edited)
Recently I've been working on an English trans. version of the wonderful 32-p. German manual for the Fiat Lancia Tester which contains many flow sheets for specific tests. While this thread (Fiat-Lancia Tester for Motronic ML4.1) outlines some of the basic things the FLT can accomplish (posts #1 & #8), work on the translation has revealed additional and useful techniques that allow you to "drill down" on a fault, or what the manual calls a "hidden fault", one that the FLT does not reveal as an "active" memory-stored fault. Case in point, testing the CTS (coolant temperature sensor): First of all there are obvious tell-tale signs, for example, a reading of -30°C is an indication of open circuit; a reading of >99.9°C is an indication of a short circuit. (You could also induce these conditions, compare the values, to help determine if something is amiss in the wiring.) If the car has been sitting overnight you can compare the air and coolant temperatures. For example, if both read 15°C (or air a couple of degrees higher depending upon how much the coolant is storing the night's temperature), you can be pretty sure you don't have an air or water sensor problem. If we get a reading of 22°C (71.6°F) for the coolant and doubt it, instead of answering "OK", we press "OXK" (not okay), and then the FLT will prompt you to insert the special "R1" reference sensor in the plug that attaches to CTS. The R1 has a resistance of 810 ohm (= 50°C), and the FLT is calibrated to check the integrity of the wiring via this value. So if it fails this test, it prompts you to "check the wiring, pins 11 & 29"; after rectifying the wiring if it fails the test a second time, it then prompts you to "replace the control unit". When using the FLT it is important to pivot from "basic function"—the one that reads ecu memory and alerts you to a fault"—to "guided function", the one that allows you to hone in on a particular system, dig deeper, and systematically rule things out.

Here is the flow sheet for the CTS hidden-fault test.
 

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Discussion starter · #33 · (Edited)
Further tests of the ML 4.1 system

So far on this thread we have used the FLT with MA1A module to test:

  • battery voltage at the ECU*
  • current air intake temp
  • current engine coolant temp state of MIN throttle
  • state of MAX throttle
  • status of anti-theft system
  • compressor switch
  • compressor
  • engine RPM
  • injection time
  • lamda probe
  • air flow valve
*as we have learned from other threads battery voltage is extremely important for the ECU, especially in recovering idle speed after a particular demand is placed on the system. Anything below 10v at the ECU can spell trouble.​

All these tests were performed within the FLT’s Function C (“guided diagnosis”) or D (“additional information”, entered by pressing FC)

By entering Function E (= “help” or “active" diagnosis) 4 additional tests can be executed:

  • idle speed actuator
  • injectors
  • timing variator (T-spark 4 cyl. engines only)
  • evaporation solenoid valve (only on cars with cats)


Car must not be running — To begin these tests, after confirming the presence of a catalytic convertor press M (M stands for mechanical-acoustical tests). The FLT will display:

* TEST *
ACTIVE
(?)

carry out?
--------------------[press OK]

IDLE ACTUAT.
(?)
you want to test?
--------------------[press OXK or ↓ to scroll down to injectors]

INJECTORS
(?)
you want to test?
--------------------[pressing ? describes the test procedure]

COMMAND
INJECTION WITH
OPENING TIME

OF 2 SEC (?)
--------------------[press ? again, followed by OK ]

INJECTORS
Test in Progress
Test OK?
--------------------[you will hear injectors clicking then...]

INJECTORS
Test over
Test OK?
--------------------[press OK; pressing OxK will allow you to test individual injectors]

DURING TEST
DO YOU FEEL AT
ONE INJECTOR
--------------------[press OxK] [if pressing OK, skip to **]

* TEST *
INJECTORS
shall we check?
--------------------[press OK]

TURN KEY OFF
CHECK WIRING
BETWEEN PIN 14
ECU AND
INJECTORS ↓

AND BETWEEN
INJECTORS
AND RELAY S128
OK?


**CARRY OUT TEST
OF THE SINGLE INJECTOR

(OK)
--------------------[press OK]

DISCONNECT ALL
THE INJECTORS
DURING TEST ↓

CONNECT
ONE AT A TIME

OK

So that’s the upshot of the injector test using the FLT.

Testing the evaporation solenoid valve and idle control valve are much easier, executing the tests sends electric impulses to the components and clicking noises confirm their operation. The FLT stimulates the evaporation solenoid valve 60 times, in the case of the idle speed actuator, the test sends a square wave at .5Hz (90% ON and 10% OFF, 90% OFF and 10% ON) 30 times. It's best to do this with the ICV removed and propped up on the intake plenum (with wires still attached) so you can observe the valve and notice any malfunction during the 30-some test.

Image


If you can believe it these tests can be performed using the blink tests of the built-in "self-diagnosis" of motronic ML 4.1 (procedure B), an extremely tedious task that will likely send you to the insane asylum. Using the FLT interface is a snap.
 

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Discussion starter · #34 · (Edited)
Clearing a CEL with the Alfa Tester

To further document the Alfa Tester (FLT) with MA1B module here are screen shots showing the clearing of a CEL fault.

Upon hooking up the tester it immediately signals a hard fault in RAM (if there is one!). It may be a fauly CTS reading (for example if you accidentally connector the plug), or a problem associated with the O2 sensor (= "imperfect formation of mixture").

In each case the tester suggests a number of reasons for the fault. In the case of the O2 sensor it will suggest: dirty/clogged airfilter, improper fuel pressure, faulty AFM, ignition misfiring (fouled plugs, bad wires, coil), faulty O2 sensor. Notice that it says "FUNCTIONAL/ in order", thus a faulty O2 sensor, last on the list, is the last suspect.
 

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Clearing a CEL with the Alfa Tester

To further document the Alfa Tester (FLT) with MA1B module here are screen shots showing the clearing of a CEL fault.

Upon hooking up the tester it immediately signals a hard fault in RAM, in this case a problem associated with the O2 sensor or "imperfect formation of mixture".

The tester suggests a number of reasons for the fault: dirty/clogged airfilter, improper fuel pressure, faulty AFM, ignition misfiring (fouled plugs, bad wires, coil), faulty O2 sensor. Notice that it says "FUNCTIONAL/ in order", thus a faulty O2 sensor, last on the list, is the last suspect.
I prolly should have kept that tester and all the 24v modules but I let it go for real money along with the 12v 164 cartridge you made for me but I needed to let go of some 24v stuff and get back to my 12v fighting weight.
 
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