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The mkiv Supra Owners Club

Is The Ecu Knackered?


GLENN STONEHAM

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MIL and red warning lights are on and got bad overfuelling.

Tried the usual error code check but the MIL (orange warning light) stays on permanently. It therefore is not able to show me any error codes. Have pulled the fuses to clear the ecu etc.

Does this indicate that the ecu is faulty & that a proper scan test will also produce no info? :(

Anyone else ever had this problem :Pling:

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Been working on the car Ian so just got your reply/question.

 

I short cicuit E1 & Te1 in the diagnostics port with my trusty paper clip. Turn on ign. toturn 2 (the one before start up & where the other warning lights are also on.) Turn off the immobiliser and watch the orange mil light (next to abs,oil etc lights)

Done this a few times in the past ie for the code 42 fix.

Usually if no error codes stored the mil blinks consistently. Now however it stays on all the time.

Taken the ECU out just now having never seen it before & all looked like new in & out.

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It sounds more like it's not going into diagnostic mode, do all the other dash lights come on like a normal startup? Can you check the diagnostic pins E1 and TE1 have actually got a connection - or use the diag port under the drivers side dash, just as a test?

 

-Ian

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Did what you suggested Ian & used the int diag. port & hey presto got blinking mil & overdrive off light (till I pressed o/d switch). BUT... it has gone a/f again , having spent the last hour observing the mil . The car was cold when I checked & the ecu would be clear cos I havent started engine since reconnecting ecu last night hence consistant mil flashing till it started to go erratic after ign. on for a while (10 mins or more). whilst it was seemingly ok . when I turned ign off then on the mil wouldnt start blinking for a while (on continuously)but the delay time was not consistant , say 15 to 45 secs not in any pattern. As time went on turning ign on to activate warning lights (which all work by the way) the mil became progresively erratic, blinking oddly at times & eventually staying on all the time every time. Seems once elec circuits warmed up no signal produced. All the other times I"ve done the error check was when the car had been run so thats why no blinking mil probably. Not started the car today yet cos no point til I can work out if ecu or else is a.f.

Its running vey rich & rough (overfuelled ) so I am not happy about driving it to a garage for reasons you know.If diagnostics come to me they may not get a reading (unless car is cold perhaps it now seems).

Spent 4 days checking everything I could but like many I am not a whiz kid with elecs & ecu"s etc. Had the car nearly 10 years so I know its history but do expect that things must go wrong with age (much like me!).

Thinking that if I could try another known good ecu that might be the next move .

By the way Ian , although I dont post alot on here i read a lot of the forum content & always think that it is a few very very knowlegeable people that dedicate much of their time that are the backbone of this club.You especially on the tech side.

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That does sound odd - did you try resetting the ECU again and seeing if it behaved itself for half an hour again? And the immobiliser point is a good one :)

 

If someone near you has an ECU to try swapping out it's not a difficult job and it's help disprove that :)

 

-Ian

 

flattery will get you everywhere btw

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Thanks guys, noted what you all said & had another go yesterday afternoon & today. Thought I had a breakthrough with error codes not showing but it didnt last. Noticed the battery was nearly flat after I last posted & thought that was problem so removed battery & put on charge for an hour and then reconnected as I left windows open & it was getting dark/damp.Closed windows & did code check & yes the MIL flashed so was hopeful. Deciding that batt might not be in good nick so installed a new one 2day expecting to find that the error code function worked & I could get a proper scan done by a suitably equipped diagnostics man to maybe signify where the system fault is.

With new batt. in switched on & flashing mil, horay.BUT after starting engine to activate fault codes in ecu , turned ign off to do error code reading & the bloody mil just stayed on continuously again. Tried both ports then pulled efi fuses & still the same. For f**k sake I"m going mad & blood pressures up.:taped:

Back to overfuelling / bad running prob. (car will hardly pull in D gear, lots of black smoke etc) I manually operated the idle control valve (ICV) by rigging up + & - connections to the ICV terminals & adj. valve with motor running to set a better idle as it all warmed up. When using throttle in various ICV positions there still wasnt a real improvement to the overfuelling & in gear it was still struggling.I still believe the ICV is not being controlled by the cars system & cannot detect it clicking etc when engine turned off.

I am trying to get a mobile electrician/fault finder to come to me & at the same time source/borrow an ECU to see if mines at fault.

Any one got one for an n/a auto ??

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UPDATE.

First thing this morning with engine cold overnight did error code check & got a result.... code 31. Air flow circuit fault. After 5 mins or so of ign. being on ( whilst testing air flow circuit voltage which was 5.1 volts engine off but ign. on with new fullycharged battery) the error /fault code function failed to show again , just as before. It seems that if ign. cicuit on for a while then code reading fails . I put ECU in fridge yesterday when this happened to see if it was returned to cold , would it work? It did not but this morning it did for a while as stated above.

Error code reading probs aside, code 31 probs I have reviewed on tech. forum & there is some confusion & vagueness about the air flow meter for a j spec n/a. Most of the data is from U. S model reports not "j " spec. with different names suggested ie MAF , MAP & VAF for the sensors/metering involved for the n/a.

Is the sensor in question for code 31 the one shown in pics of my engine attached? Simple looking sensor close to air filter box. Could this , or its circuit or the ECU be causing my serious overfueling & auto gearbox selection problems???

Anyone (especially Ian Chris & others that know) confirm this is the air flow meter. resistance test showed 2.5 K ohms to 2sensor terminals but voltage was only 5.1 as said above. Test data on here states a "gray" wire for sensor but the 2 wires are not grey at all'

 

resistance test showed 2,5 K ohms

21102007260.zip

21102007262.zip

21102007263.zip

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