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

How do u test ECU with lights?

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Old Sep 25, 2003 | 03:49 AM
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Question How do u test ECU with lights?

For those of you guys that have the 2 lights to check engine codes. How do you guys test? When the car is off but ignition on? When the car is running, but the car is parked? Or, when the car is running and moving?

I happen to have my test lights inside my car, connected at ALL times. The reason for me asking this question is (back to the stupid subject ) When i turn my car on, the lights light up for about 3 seconds, then shut off. But sometimes, as soon as i get into 1st gear, the o2 sensor code pops up, but will shut off after i rev it up past 3 1/2 or so. I also notice that this usually happenes when the car has been sitting overnight. This confuses me, because my connection from the o2 to the ecu are for sure good. and because if the o2 was bad, wouldn't it blink ALWAYS?

Anyways, now i'm considering taking it to Tri-point, but i'd hate not being able to figure it out myself, because i don't have very much green.

Thanks for reading
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Old Sep 25, 2003 | 08:11 AM
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I've got lights inside the cabin. Yeah, you keep an eye on them while driving, that's the whole point of having them inside.

I get the same behavior about the O2 sensor.

FYI, I have brand new sensor and it is properly grounded.

I get O2 sensor fault on my lights once in a while when cruising (not a cold engine), I have no idea why. It comes and go for no apparent reason.

It used to drive me crazy but now I just ignore it.

Maybe NZ knows.

Hugues -

Last edited by hugues; Sep 25, 2003 at 08:13 AM.
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Old Sep 25, 2003 | 08:46 AM
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I don't know the answer to your question but, am curious
if you hooked the two lights up yourself and if so what
are they feeding from.

Brad89RX&
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Old Sep 25, 2003 | 09:18 AM
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The feed is the green connector near the leading coil.

FYI,
it's not very useful. It won't detect much unless something is unplugged.

This stuff is explained ad nauseum on the web and on this very forum and on the FAQ's. It's also explained on my web page under 'my own faq'->'diagnosing'

Hugues -
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Old Sep 25, 2003 | 09:31 AM
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Talking Lights

My light setup and my air temp guage.







Yeah it sucks tho. I need a damned O2 Sensor. I have go through mine and a spare I had in about two months
Santiago
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Old Sep 25, 2003 | 09:37 AM
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Santiago:

what 's the 3rd led for ???

DANGER TO MANIFOLD

Hugues -
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Old Sep 25, 2003 | 01:19 PM
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How many miles do you fellas usually get from full tank till the light "low fuel" comes up?
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Old Sep 25, 2003 | 01:21 PM
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Originally posted by hugues
Santiago:

what 's the 3rd led for ???

DANGER TO MANIFOLD

Hugues -

That is a POWER ON Light for the LED lamps.


I get around 280-315 miles to a full tank. Light comes on around 260-270. But right now I need an O2 sensor!

Santiago
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Old Sep 25, 2003 | 01:25 PM
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If you're getting that kind of mileage, your O2 sensor is just fine. O2 sensors aren't that complicated.

You're reading too much into the factory diagnostics - the ECU codes for the '86-88 cars are damn near useless.

It's likely throwing a code when cold because the sensor isn't up to temperature yet. Again, the ECU isn't that smart.

Dale
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Old Sep 25, 2003 | 01:28 PM
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You're getting 280 in city driving ??

If yes, that's pretty good.

hugues -
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Old Sep 25, 2003 | 01:32 PM
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Originally posted by 1987RX7guy
I get around 280-315 miles to a full tank. Light comes on around 260-270. But right now I need an O2 sensor!

Santiago

Daaaaaaammmnnn. I take it your n/a, right?

Well, so u guys think i should just move on, huh? My o2 is fine (I changed it about a month ago, btw)? Everything is stock, i was thinking that maybe my cat could be screwed up, too.
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Old Sep 25, 2003 | 01:55 PM
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O get that kind of mileage driving roughly 45-55 miles per day half of it in the city and half of it on open road going to my house.

THe reasone I think I need an O2 sensor is 1 the code shoots up even after warm. and 2 my fuel light came one at 220 miles after pumping gas which will net me around 260 miles to the full tank.
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