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Fail Safe Mode In Your Ecu


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14 replies to this topic

#1 manxsta

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Posted 05 May 2006 - 06:41 AM

Does anyone know what the bare minimun of sensors needed to run to keep your ea82 t ecu out of failsafe mode.....what i have done is stripped an ea82t harness down to the engine wires only...it runs like this and seems all good with good power and clear/crisp.. but i only have the injecters/ coolant sensor/ air temp sensor/ knock sensor/and oil water senders connected......and i think it may be in failsafe mode..as removing the coolant plug does nothing..nor does removing the air temp sensor plug..engine still runs smoothly.....any ideas if im good to go.... or should i hook up more..like idle up solinoid...etc??


also i found a small air bleed type ball in line with the front vacuum pipes..
the ones in front of the throttle body...this was between the distributer pipe and the vacuum supply close to a t junction..i moved it to between the intake pipe and the vacuum line and wow..my timing vacuum advances now where as i think someone put it in the wrong place before....anyone ever seen on of these things jammed down the vacuum line..( its like a small brass ball around 3mm round with a hole in it...it looks factory..but which factory:lol:

#2 subiemech85

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Posted 05 May 2006 - 08:06 PM

are you pulling off the front or rear cts?

what year are you using

flapper or hotwire maf

you will also need tps and lambda

#3 nipper

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Posted 05 May 2006 - 09:28 PM

Does anyone know what the bare minimun of sensors needed to run to keep your ea82 t ecu out of failsafe mode.....what i have done is stripped an ea82t harness down to the engine wires only...it runs like this and seems all good with good power and clear/crisp.. but i only have the injecters/ coolant sensor/ air temp sensor/ knock sensor/and oil water senders connected......and i think it may be in failsafe mode..as removing the coolant plug does nothing..nor does removing the air temp sensor plug..engine still runs smoothly.....any ideas if im good to go.... or should i hook up more..like idle up solinoid...etc??


also i found a small air bleed type ball in line with the front vacuum pipes..
the ones in front of the throttle body...this was between the distributer pipe and the vacuum supply close to a t junction..i moved it to between the intake pipe and the vacuum line and wow..my timing vacuum advances now where as i think someone put it in the wrong place before....anyone ever seen on of these things jammed down the vacuum line..( its like a small brass ball around 3mm round with a hole in it...it looks factory..but which factory:lol:


You need an O2 sensor, otherwise you are going to damage the cats (if you still have them) if not you are going to get really poor gas mileage. Without the o2 sensor you will stay in an open loop (limp mode). The o2 sensor is the nose of the fuel system. Some of the ecu jobs is to monitor things with coils to make sure they dont go open. The idle up solenoid is required for A/C.
What are you going to use this for, it will help us with what to tell you. Also what have you decided to leave out. Tell me what you left out and i can tell you if it is in the loop or just a fine tuning element.

nipper

#4 manxsta

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Posted 05 May 2006 - 10:36 PM

are you pulling off the front or rear cts?

what year are you using

flapper or hotwire maf

you will also need tps and lambda

yes i have tps still..forgot to mention that one...i was pulling off the rear and only coolant temp sensor..not the coolant sender.....and it is flapper type

#5 nipper

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Posted 05 May 2006 - 10:44 PM

you will also need tps and lambda


lambda?

nipper

#6 manxsta

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Posted 05 May 2006 - 10:49 PM

You need an O2 sensor, otherwise you are going to damage the cats (if you still have them) if not you are going to get really poor gas mileage. Without the o2 sensor you will stay in an open loop (limp mode). The o2 sensor is the nose of the fuel system. Some of the ecu jobs is to monitor things with coils to make sure they dont go open. The idle up solenoid is required for A/C.
What are you going to use this for, it will help us with what to tell you. Also what have you decided to leave out. Tell me what you left out and i can tell you if it is in the loop or just a fine tuning element.

nipper

Hi, this is going to be used in an offroad set up...so no a/c

it might be easier to mention what i am using..it is running at the moment and quite well i might add...but i want it to run as economical as possible with the factory gear....ok here goes,,i have /injecters/tps/coolent temp/air temp..the one on the thermostat...this is the air temp? / knock sensor/ oil and water senders even though these dont go through the ecu/im sure, correct me if im wrong....idle up is connected to ecu but has an auxilary wire going to a relay which i have removed from the plug...

i have ignition relay but fuel relay is not powering up fuel pump yet..( i will connect this soo) i have the fuel pump powered up by other means at the moment as i have run this in my garage to check all is well before fitting it to the vehicle...obviously all distributer and knock box is attached....
i have 2 cables that are coax protected..one goes to the o2 sensor and the other to the coil neg....are these interferance protected or simular?

an ecu piunout for a 3 plug ecu would be sooo good at this point...anyhoo like i said it is all running but i want to be sure the o2 is functional and all is as it should be before i wrap it up with tape....also some idication of which diagnostic plugs to keep wouyld be good....i cut out all the extender test cables that stop at dead end plugs.....i think these are for testing units for ohms..etc but i can backprobe units easily now as the engine is on the rear of this vehicle and easily accesable...thanking everyone in advance for all replys..cheers

#7 manxsta

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Posted 05 May 2006 - 10:53 PM

lambda?

nipper

lambda as in o2 hooked up yes

#8 nipper

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Posted 05 May 2006 - 10:58 PM

i dont know what to tell you, if it was a US spec car i could help further. its possible what you think is the ecu temp sensor is the engine temp sensor. i also dont know if the older ECU will kill the engine with no temp input like the newer ones do.
i'll see if i can dig up a US digram if that would help. What year is this engine.

nipper

#9 nipper

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Posted 05 May 2006 - 11:01 PM

lambda as in o2 hooked up yes


ah never heard it called that before :)

nipper

#10 manxsta

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Posted 05 May 2006 - 11:01 PM

i dont know what to tell you, if it was a US spec car i could help further. its possible what you think is the ecu temp sensor is the engine temp sensor. i also dont know if the older ECU will kill the engine with no temp input like the newer ones do.
i'll see if i can dig up a US digram if that would help. What year is this engine.

nipper

86 flapper with separate knock box....this is this type of wiring but i noted the engine has 4/87 casted at the rear...forget this date though..go with the first details.....thanks

#11 ausubaru92

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Posted 08 May 2006 - 03:12 AM

The bare minimum you should have hooked up is "injectors for fuel delivery, disty for ignition pulse, TPS to tell it how open the throttle is, MAF to calculate how much air there is, coolant temp to tell help it idle when it is cold, o2 to fine tune mixture, and knock sensor will retard timing if there is pinging (although i was under the impression that the 3 plug ecus didnt control timing as it still has a vac and mech advance unit on the disty)
Any less than this and your engine will not run at its optimum.

Now, in fail safe mode it should run on just injectors, disty and tps (the tps will substitute for the maf) but it wont run well.

I think you may be confused, lambda is the symbol for wavelength (looks like this λ)

If you are thinking air/fuel mixture, maybe you mean "stoich"

#12 calebz

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Posted 08 May 2006 - 05:09 AM


I think you may be confused, lambda is the symbol for wavelength (looks like this λ)

If you are thinking air/fuel mixture, maybe you mean "stoich"


Not confused.

Some carmakers (volvo comes to mind) refer to their O2 sensors as Lambda Sensors

#13 manxsta

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Posted 08 May 2006 - 07:05 AM

thanks for the info...my set up is the very first type from what i gather,and it has a vacuum advance yes..but also has a knock box separate on the passenger side of the car attached to the aircond unit under the dash.....anyways..i have all that set up......but even steve rising sun does not known and he is a soobi specialist..with all the plug in gearfor our models ..i went to see him today with my loom to figure out a few loose ends..and he scrached his head then shrugged his shoulders like they never made this model..as he only goes back to early 87...anyhoo it runs well but i want to make sure i am out of limp mode to get primo economy......lambda is the constant correction of air fuel message sent to the ecu from the o2 sensor for stoich to occur....amongst other tec terms.....sooooo
anyone out there ever set eyes on a pinout diagram for this model....
its close to the miles fox version for most but missses out on colors for cal switch and a handful of other pins i would just like to know if there may be some others to hook up to make it all shmick....

I wish nipper would get back to me as he dissappeared when i mentioned the o2 term also.:confused: ..all the same i am getting the feeling that there may not be a pinout diagram in the hands of any of us....:slobber:

#14 leon

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Posted 08 May 2006 - 07:25 AM

Lambda is what they the race engineers use. i believe it is 14.7 to be stoich balanced. lambda is the proportion to this so that a 11.1 would be 0.75 lambda. exhaust gas is useful for tuning but you do not need the sensor.
manxsta if your interested i am involved in formula SAE at my uni, which is basically building a small scale F1 car.
the sensors are kept to a minumum for simplicity and weight loss, but some of the important ones are tps, injectors, wheel speed and coils.
even amp (absolute manifold pressure) can be correlated back to tps. and once the car is heated up to correct temp, the thermo's dont change much.
hope this helps

#15 manxsta

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Posted 08 May 2006 - 07:32 AM

Lambda is what they the race engineers use. i believe it is 14.7 to be stoich balanced. lambda is the proportion to this so that a 11.1 would be 0.75 lambda. exhaust gas is useful for tuning but you do not need the sensor.
manxsta if your interested i am involved in formula SAE at my uni, which is basically building a small scale F1 car.
the sensors are kept to a minumum for simplicity and weight loss, but some of the important ones are tps, injectors, wheel speed and coils.
even amp (absolute manifold pressure) can be correlated back to tps. and once the car is heated up to correct temp, the thermo's dont change much.
hope this helps

sound interesting leon...i would prefer to run a map sensor..manifold absolute preasure, this way you can eliminate the afm and run a pod straight out of the turbo(inlet) there are map calibrated kits for this conversion and are graphed to acheive good mapping of throttle load...

But a wolf 3d is what i would go for first...anyone with a resonably priced wolf 3d version 4 out there for sale....??? the mega squirts sound interesting..:)




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