check engine in my 1.5!

[onepointfive]

need help guys.. I'm not that good with mechanic nor electric work yet... still learning and reading here helps a lot. thanks paul woods for this forum. :)

the cel codes that I got were..

1.) 32 (air flow meter signal )
2.) 41 ( throttle position sensor signal )
3.) 43 ( starter signal)
4.) 52 ( knock sensor signal )

things i tried doing...
1.) replace ecu with a good one ( working from a different car )
2.) replace afm ( from a working car too)

but still the same.. I still got the check engine light on. I re-set the ecu too then tried to start it up again but same thing.. The car still runs though. Thanks mate.

[GregLeBon]

Thats a lot of sensor faults...!

Perhaps its worth checking the sensor ground signal at the ECU end...

..or the rev voltage sent to the AFM / TPS, for that matter...?

From what I can tell, the sensor ground (E2) is at one end of the 16-pin ECU connector, and the sensor ref V is the pin opposite this......?

Maybe your ECU connector has worked loose at that end?

I would suspect that both of these vital sensors failing at the same time is not really likely, and the ground / ref signal is common to both...so a good starting point..?

If you have a multimeter, you can buzz out the loom from ECU to the 2 x sensors (i'm not sure which pins on a 3S-GTE), but if you buzz each in turn at the sensor end, to the ECU connector 16-way, you should get a beep from one wire in each sensor connector....

I'm sure someone more knowledgeable will be along soon......:blabla:

[onepointfive]

i know it's a lot of sensors to just suddenly pop up! I don't know what to do.. I'll try to look for the e2 ground and the ecu connector..

anyone have more ideas?

[GregLeBon]

The ECU should be in the boot, behind the card panel over the panel that separates the boot from the engine......

The ECU is the big square box, with 3 connectors plugged in the bottom.
One of these has 16 pins: check it is plugged in properly (and the others, too!).
The 16-pin one will have a brown wire at one end (sensor ground): it is the wire opposite this one (same connector / other "row") that has the 5v ref.

Put a multimeter, set to "buzzer", across this pin and each of the contacts in the TPS / AFM connectors in turn.

You should get a beep from one in each connector.
Where are these connectors...?

Well, the TPS is bolted onto the throttle body (surprisingly), and should be easy to see. Unplug the 3-way connector.

The AFM is even easier: it has a 5 or 6-way connector plugged into somewhere between the air filter and the throttle.

The voltage ref wire will be red with a blue stripe, and the ground will be brown...

[onepointfive]

I've check the brown (ground wire) and it seems to be okay. I'll get a multimeter soon. I'm not familiar with those, does it have to be a specific one?

I also noticed that sometimes it won't start. No crank no anything. I just hear the fuel pump turning on.

And also this morning it had a hard time starting but there was crank. It did start after 4-6 tries.

So, I'm assuming this is fuel related. Not sure?

help please!

[AlunJ]

I've check the brown (ground wire) and it seems to be okay. I'll get a multimeter soon. I'm not familiar with those, does it have to be a specific one?

How've you checked the earth, if you don't possess and are unfamiliar with a multimeter?
Any cheap B&Q or Halfords multimeter can do the job, you should never attempt electrical diagnosis without one (it's arguably impossible to check most electical systems without one).

Replacing electrical components that you haven't actually checked is a very very expensive waste of time and won't fix anything if the wiring is at fault.

I'm with greg on this one. Check all your power feeds & earths, especially to your throttle position sensor and the AFM before you go replacing any more parts.

[onepointfive]

thanks alunJ.. I'll go to home depot now and get one. Hopefully you guys can help me learn how to use it. Btw, I just check if anything is loose.

Thanks for the help guys

[onepointfive]

just got my multimeter.. I got sperry instruments Digital Multimeter. 17 ranges and 5 functions.

Is this good enough? now, how do I check and use this? sorry.

[onepointfive]

http://www.amazon.com/W-Sperry-DM350A-Function-Multimeter/dp/B000ET5VYC

exactly like this.. Not good enough?

[GregLeBon]

Yeh..that'll do; almost any meter will, TBH.....

If it has a beeper / continuity setting, then thats the one to use.

If not, then "ohms / resistance" does the same job (without the sound).

[onepointfive]

I believe I don't have a buzzer setting... I have the link there and that's exactly what I have. Sorry, this is the first time I'll be using this so please bare with me.

What do I "try" to do now. Remove the plugs from ecu then check through the wires? or remove sensor and test from there? where do I put the red and black wire from the multimeter?

thanks so much for your understanding.

[AlunJ]

I'm sure I've got a copy of the tech manual for that engine poking around somewhere, I'll have a rummage and find ya the test procedures for the AFM etc during the day tomorrow if I can :)

[onepointfive]

alunJ,

thanks so much! :) really appreciate it mate. If it's okay to tell me what settings I have to put my multimeter also.

Thanks again

[AlunJ]

Some good info on this page here
http://www.mr2-tech.com/bgb/mechanical/volume1/efi_system/5.htm
(and the index page that links to that one)
http://www.mr2-tech.com/bgb/mechanical/volume1/efi_system.htm

One thing that the sensors you've mentioned appear to have in common is a shared earth. I'd go through the first link above and check every reference to the E2 wiring first, and then the various supply voltages to each part.

Probably the fastest way to check that particular earth is ok is to unplug the airflow meter, look into the connector on the loom and check the resistance between the third connection on the left and the negative terminal of your battery (if it's in the boot, if not a clean bolt / screw in the chassis will suffice). It should be near zero.

To check resistance:
On the multimeter, attach the black probe to the connection labelled "com" on the meter and the red probe to whichever one has the symbol Ω (this symbol, omega in the greek alphabet, is used to denote resistance values and is usually also marked with a V as it's the same terminal used for voltage checks). Turn the dial on the multimeter until it's pointed at the value 2k, in the area also marked Ω (this puts the multimeter in resistance measuring mode, with a max value of 2,000). This'll be fine for continuty testing (where you want the value to be as near 0 as possible), if you need to read a higher value turn it up to 20k (so a max value of 20,000).

To check voltages:
connect the probes to the multimeter as above (same connections are used for checking voltage as for checking resistance), but turn the dial so it points at the number 20 in the area marked V. This sets you up to read up to 20 volts.

Sorry if it's a bit vague, but it's not something I've had to explain before. Hopefully it's some help to ya.

[onepointfive]

Hello,

thanks so much for the help AlunJ.
But I'm having a trouble understanding this.. I read it but it seems complicated maybe because this will be my first time using a multi meter. I'll try to do the AFM you were saying.. which third one, the socket itself or one attached to the afm?

the checking of voltage and resistance you explained perfectly. :) Now, I just need to know to where to use it.

thanks again.

[AlunJ]

You want to be checking the one inside the socket itself (fairly sure it's the 3rd from the left looking into the connector). Use the resistance mode, you want a very low (or zero) reading between that pin and a good earth on the chassis (or direct to the battery).

[onepointfive]

so, if I remove the socket... will it be the one I removed or the one that stayed on the car? sorry!! :/