ECM repair & valve seals

[jtgh]

yes, absolutly 95-16v car.

my ecu test page is clear (maybe?) but i will elaborate.
Ecu basic tests.

1: KEY on , lamp must be ON ! the CEL lamp turning on , signafies self test passing !
2: Key on, start, idle. no lamp , if lamp on , you have codes. read them ,next.
3: jumper placed , get code 12 = normal or some other code or codes.

i go one step further , I create a failure.
unplugging something will make that happen.
the safest is to unplug the ECT or IAT temperature sensors.
IAT is best. DO NOT FORCE THE CONNector, IT HAS A lock, all EFI parts are locked and have presslevers.

16v IAT is in Air cleaner, 8v is behind ECT (Front, >stat housing,> ECT and> IAT)
1.8L is mounted in the middle of main induction large pipe.

you should get error = DTC = 23 or 25 , i vote 23 too high error.

there are many tests and many things that can go wrong with any ecu
my pages are only for the more common. (11 outputs on 16v that can malfunction)

i recommend working the symptoms and finding the culprit.
(base on money saved, but if you want to throw parts say so)

only to paths to car repair,tedious or shot gun methodoly.

time or money.

the latter only works 50% of the time.

let me explain that jumper

it can be used 3 ways (not in book)
jumper planted (paper clip scan tool is all you need on any 95) LOL !
1: key on , no start ( shows whats in memory for failures)
2: cranking can show code 41 or 42 , bad CAS or Bad Ignition !!! secret test.
3: idling or running can show any codes , present or past.

that is it for ecu. unless you have fancy tools like a scope
with a scope we can look at IAT and see if ECU is trying hard to control idle.
if ecu is quiet on the IAT , that means its stuck in limp home mode.

LIMPHOME is when the ECU detects that something horrible is wrong (and no DTC codes)
and then mimics a Carbarettor with drilled out jets.(rich as a pig)
and Distributor advancing springs welded closed. (no ot poor advance)
an ugly place that is.


lets work the symptoms

dark exhaust, car is running like a pig, NO? HOT , COLD or both you didnt say.
tell what car does good and bad, (not just bad , ok)
this can be many things. (please dont go out and buy all these, OK ?)
1: ETC bad (very common on pre 96s)
2: Fuel press reg. stuck closed, (rap it with a plastic hammer, back side of screwdriver)
3: cracked exhaust man. causing O2 sensor to rail lean,which causes Ecu to go rich.
4: ECU bad,or some input is shorted to it making it go in to LIMPHOME.

tell me more about how car runs ,starts, idles both hot and cold.
how it drives up hills, does it die, does it ??????
all the facts , can result in an accurate place to begin diagnosis.

cheers.

[kingfish]

yes, light is on before jumping the connections to read the code. Light does not blink as it should when connections are jumped., just stays on.


upon looking in my service manual, i think it may be the wires going to the DCT terminal. a black and blue/yellow wire. checking into to that right now

[jtgh]

95-16v
it dont think so , how could they be bad?, they go in to loom and come out behind ECU.
what could damage those? (anythings possisble.but....)
?
do you have 4 pin or 6 pin DLC? conn. you didnt say.?

did you properly indexed the connecter.? find the pin 1 side?

you also didnt say was the engine running or not, during your jump.
please tell what and how you do things. the context is important.

if the DCL pins refuse to flash out code 12, or others, then ECU is dead, or has a power loss.

yours should be 6 pins. jumping pins 2 to 4 is Diagnostic call up.
but first you need to find pin1 , on the DCL.
send me a close in photo of it , we dont have one. would be nice to have it.


the manual shows index pins are on the 1,2,3 side of DLC connector. or a lock tab.

if the correct pins are jumped and the lamp dont flash, the
ECU has a problem

replace the Capactitor called. C103 , and you might be surprised.

33 cent fix.
fixes most. in fact almost all, save the few that have blown up injector drivers.

the cap is polarized. must be installed only 1 way.

http://carfix.stufftoread.com/ECU/ECU-16v-92w.JPG

[kingfish]

I will try to explain everything
1995 geo tracker 2 door 4x4 1.6L 16 valve mutiport

I was driving the car when the check engine light came on, a week after the mention battery problem. When i got home I jumped the DLC(6 plug) with a paper clip in the proper slots(i did this before and it worked) The check engine light stayed on steady. no blinking. The car still runs, but not correctly. Takes longer to warm up, shifting different. rmps 500 rpm high then normal, car seems like it has less power. other then that it seems ok

I checked grounds 107( on fire wall), 106(starter bolt) and one behind battery, they all seem to check out. still need to check others


this

[kingfish]

this is what service book says....the good one from chevy
and the path i was lead to


turn key on not mil.....on steady...........jump DLC cavity 2-4........on steady

next part is part i have not tested yet

turn key to lock, disconect ECM connector C1( the white one), turn key on, note mil.......

Mil Off


Turn key to lock
Reconnect C1
Backprobe ECM C1 with fused jumper
To cavity A17
IS mil flashing code 12 or any othe code?

No = replace ECM

Yes = repair Blue/Yellow wire DLC-ECM
Or
Repair blck wire DLC -ground 110


Mil ON

Check for short to ground in puple/yellow wire I/P Cluster (?don‘t know what it is??) -DLC-ECM
IF good replace I/P cluster printed circuit board

[jtgh]

yes, the FSM is very good, it assumes nothing.
but, 99.9% of all mil failures are.
1: lamp out (or some yoyo pulled it to pass smog)
2: bad ECU.

go ahead and follow that logic map, it is valid.

they assume the ground is bad at the DLC ( as likely as getting hit by lightning)
they assume the Diagnostic conn. diag callup wire is open, (like winning lotto)
but it is valid.

the CEL lamp is connected from power (fuse) and the ECU.
the ecu has a transistor that enables the lamp.
if it glows its ok. (keyon no start)

next is that diag, jumper path.

you could check pin 4 on DLC , to ground with an ohm meter (key0ff) and make sure it is grounded, .5 ohms or less.

then the diag jumper is . pin 2, on DLC, this is a blue/yell wire, I dought it is open.
but
you could jumper A17 at the eCU (same wire) and see if you get code 12.
as the fsm shows.

if it dont flash out , morse like code 1, 2, then the ECU is bad.
the only exception to that is is if power is bad to the ECU.

this ECU is really friendly that way.
all it takes is power and ground to the ecu and then anyone shorting A17 to ground and it will always spit out that CEL code.

of course the CEL Lamp must be conneced and have power too.

PS:
on my
My ECU is bad, now what?
page:
see mid section,it hase a table ,that says, PAGE 1 , PAGE 2 ,.... Page 4
if you click them ,
it is the 4 pages showing how to measure every pin on the ecu.

Check the following pins.
voltmeter ,neg.lead to ground (shinny metal of car body)
red lead to:
ECU:
B1= 12V
B2 AND B3 (NC) <= 0.5V (GOOD GROUND)
A23 ( ABOUT 5V)
B7= 12V
B9 = 12V
B10 <= 0.5V ANOTHER GROUND.
B15 , ABOUT .7VDC (0 TO 2V IS SPEC)
A4 <=0.5V (CALIFORNIA CAR ONLY)


http://carfix.stufftoread.com/ECU/P&G.JPG

IF THE ABOVE NODES MEASURE GOOD KEY ON.
AND THE CEL GLOWS, BUT DOES NOT FLASH ,WITH DIAG ENABLE JUMPED.
THEN THE ECU IS malfunctioning.
summary:
11 pins must be good.
and the diag pin wired to DLC
and the CEL lamp connected from power source and ECU (known to be good )
DLC pin 4 is grounded.

that is how it works.
in fact i have a test jig that works with only those pins connected ,sitting on a table.

cheers.