Question about MAF wiring.

[sideshow]

make sure u have everything that is connected to the blue/rfed unplugged

sometimes traction con trol tps might use the blue/red

ive had similar prob before whre there was no power to blue/red

so i just cut nd ran it to the blue red at ecu

fixed problem

u might have a break in the wiring loom

do u have correct diagram

just double check the blue/red doesnt go anywhere else


is it a crown?

 

[thenewmexican]

I checked ALL Blue/Red wires on the car.
EVERY. Blue/Red wire has ground on it.
What is up ??



Thanks.

 

[sideshow]

well it must be shorted to ground

which means stripping loom down

did the loom look like it had been damaged anywhere

 

[thenewmexican]

The loom looks like it could be damaged in a few placed inside the engine near the fire wall. How would I spot the problem. What should I look out for.


Many thanks.

 

[thenewmexican]

Not sure if this makes a difference in understanding my problem. But. The previous owner removed the Traktion control box from under the hood. I compared with another of the same vehicle year/model. And. Noticed the Traktion control box under the hood on the drivers side.

 

[sideshow]

if the blue/red wire is shorted somewhere u can spend many days trying to find where

u r best off pulling harness back thru firewall into engine bay and checking it there

if its a cnversions sounds like who ever did it did a crap job
like 90% of jobs i fix up
and lets hope u have not fried the 5v output on the ecu
diagnosing problems takes 5 times as long as getting the running if u dont know how everything works

i think yr best to pull harness off the engine sit it on floor and remove most of the tape and covers and go over it very well

cause if u have more problems u will be spending the next year trying to fix them
when its easier to fix them all in one go
get a diagram and them check every single wire from the computer

 

[thenewmexican]

I checked all blue/red wire inside the vehicle. No short to be found inside the passenger cabin. Only when the blue/red wire
emerges from at the firewall is it shorted.


One question.
How do I determine if the 5V output coming from the ECU is fried.


However. I'm going to follow your suggestion.

 

[thenewmexican]

Hi All.
What I found out today is, the incorrect ECU is in the vehicle.
I called the Dealership, and based on my VIN# the correct ECU that should be in the car is 89661-50032.

What I have in there now is 89661-5042.
Going to find an ECU that fits my car. Not sure if this will solve the problem.
But. I'm optimistic.

 

[sideshow]

how did u get an earth on the blue.red when yr ecu was unplugged

 

[thenewmexican]

The readings were taken when the ECU was plugged in.

 

[Peewee]

how did u get an earth on the blue.red when yr ecu was unplugged

He didn't.
When he unplugged the ecu the problem went away, but the problem remained with a replacement ecu.

But if the ecu was wrong in the first place...

 

[thenewmexican]

Hi All.

Opened up the wiring harness. It has been butchered to high hell.
Splices going everywhere. And. Some wires are cut, and, go now where.

I might as well go out and find another wiring harness.

How difficult is it to install.

 

[Peewee]

Harness is pretty easy to install, but time consuming to get your hand into wierd places to undo bolts and clips.

If you are still running an autobox and the loom goes down there (and its not disconnectable at the back of the engine, some 1uz looms are) then you'll have to jack the car up and get under it to undo all the plugs/bolts. You'll probably need to get under there to unclip the o2 sensors anyway.

Just make sure you get a loom from the same model and year as yours.

I don't know how hard it will be to pull the loom through the firewall either, as LHD and RHD differ greatly in that respect.

 

[sideshow]

wrong ecu

thats the usual wreckertech workers in the jappp import industry

heheheheheheeh

 

[thenewmexican]

Is it possible that another sensor could be causes the short to ground.

 

[cjsupra90]

I just re-read every post in this thread and its unclear to me about one thing, when you unpluged the ecu, did the Earthing / grounding of the blue/red wire go away? You said that all pins went negitive, what do you mean by that....

Also, what is the resistance reading that you are getting, is it very high or low / perfect continuity?

 

[thenewmexican]

I used the incorrect verbiage to describe my findings after the ECU was unplugged.
By negative. I meant, that there was nothing measurable, ground, or otherwise on the MAF connector, after the ECU was unplugged. So. In essence. Yes. The ground went away once the ECU was unplugged.

 

[cjsupra90]

ok, but when the ECU is plugged, there is a trace to ground. Did you get or measure a resistance between the Blue/red and ground, was it showing straight continuity or was there a pretty high resistance?

 

[thenewmexican]

I didn't check that.
I'm a novice at the electrical stuff. And. To be completely honest.
If it wasn't for the good people like you on this forum.
I would be completely in the dark.

So. I should check for resistance between the blue/red and brown ground wire ??

 

[cjsupra90]

Yeah, but with the ECU plugged in. With it unplugged, you should get nothing just as you did. With it plugged in and all the sensors AFM, TPS, and so on, you should get a real high resistance to ground (dont recall what should be but you should get...)

Basically the circuit is ECU supplied 5v, through the sensors, then return to the ECU via E2 then to ground via E1.

Did you actually try checking the voltage at the blue/red (VC) wire with the key on to see if your getting 5v?

The other thing here is still the whole issue of you not having the right ECU for the car. But that could just be a simple matter of addition things that your car has or doesn't have (example: traction control).. I dont think that that will change any of the sensor wiring though..