2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

"Check Engine Light" while ECU grounded ?

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Old Oct 24, 2003 | 08:14 AM
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From: Savannah, GA
"Check Engine Light" while ECU grounded ?

Yesterday I wanted to readjust my Idle, so I ground the
the green 1 pin test connector to the frame. The Check
Engine light flashed in a continues pattern.

( 1 flash, pause, then 2 fast flashes ); (1 flash, pause,
then 8 fast flashes )!

It kept repeating this cycle until I ungrounded the test
connector. Does this mean anything relating to the ECU
codes.
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Old Oct 24, 2003 | 10:27 AM
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From: NJ
http://www.1300cc.com/howto/how2/codes.html
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Old Oct 24, 2003 | 10:51 AM
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Those two sets of flashes are engine codes that you are telling the ECU to display when you ground that wire. This is the self diagnosis feature its great you don’t have to pay someone to tell you what is wrong with you car .

1 long flash with 2 short flashes = code #12
1 long flash with 8 short flashed = code #18

Code 12 is: Full range sensor on the TPS
Code 18 is: Narrow range sensor on the TPS

Sounds like you got a bad TPS on your hands

- Dana “Damn you TPS, Damn you to hell!!”
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Old Oct 24, 2003 | 11:34 AM
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From: Savannah, GA
Thank's Turbonut,

I hope the TPS isn't bad, because I just replace it a month
ago. I bought a new Mazda TPS, not an after market.
It adjusts according to the FSM, and I just readjusted it
yesterday. I'll check the adjustment again!
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Old Oct 24, 2003 | 11:52 AM
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From: NJ
Don't forget to clear the codes. It could be an old code. Clear by disconnecting bat cable for @ 1 minute to be sure, and some say step on brake pedal while cable disconnected to be sure residual voltage gone. Replace cable and codes should be gone until recognized again.
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Old Oct 24, 2003 | 12:36 PM
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From: Savannah, GA
Originally posted by Turbonut
Don't forget to clear the codes.

Thank's again,

I don't think my battery has been disconnected since
I installed it in May 03. I replaced the TPS last month.

PS : I researched batteries and came to the conclusion that
the Di-Hard had the best ratings. I paid about 90.00
for it + new post clamps, and it seems to be doing a hell
of a job. I hate getting cuaght with a dead battery.

I read about a test performed by an independant lab
were they drained batteries dead in hot water to simulate
the heat of an engine. The Di-Hard came out on top, being
able to withstand more cycles of draining and recharging.
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Old Oct 24, 2003 | 12:58 PM
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Bought my '89TII new in May '89. Original bat was replaced 1995. Was fine, but after 6 years I thought is was do. Replaced with a Die Hard-Still in there 8 years and going strong. Not bad 2 batteries in 14 1/2 years!
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Old Oct 24, 2003 | 01:12 PM
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From: Savannah, GA
Originally posted by Rotary Racer
. This is the self diagnosis feature its great you don’t have to pay someone to tell you what is wrong \

- Dana “Damn you TPS, Damn you to hell!!”

Maybe not, or maybee you have to do the circuit tracing
yourself. The only reason the ECU picked up the TPS
is, because after I spent hours testing parts and found that
the TPS was bad. I disconnected it because it was killing
my idle. At this piont the check engine light came on for
the 1st time. Even though my TPS was fried, no reading
& killing my gas milage, fouling my plugs, and killing my
idle. I never even got a blink from the ECU, "Check Engine" until I unplugged the TPS completely!!
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Old Oct 24, 2003 | 01:16 PM
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From: Savannah, GA
Thank's Turbonut,

That seemed to clear the codes!!!
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Old Oct 24, 2003 | 01:19 PM
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Great-Have a nice weekend...Hopefully with no problems!!
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Old Oct 24, 2003 | 01:26 PM
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From: Freakmont, CA
Originally posted by Brad89RX7
Maybe not, or maybee you have to do the circuit tracing
yourself. The only reason the ECU picked up the TPS
is, because after I spent hours testing parts and found that
the TPS was bad. I disconnected it because it was killing
my idle. At this piont the check engine light came on for
the 1st time. Even though my TPS was fried, no reading
& killing my gas milage, fouling my plugs, and killing my
idle. I never even got a blink from the ECU, "Check Engine" until I unplugged the TPS completely!!
What I ment by that comment is if you DO have a check engine light code (a code that the ECU sees as a problem) you don't have to go to a dealership or shop and pay them to pull the code for you.

- Dana "Every time I post someone puts me down"
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