another issue

Damo · Post by **Damo** » Fri Jun 15, 2012 3:54 pm

Just to clarify that a little bit. ANY misfire weather caused by overly rich or excessively lean will show up as lean on a afr meter. The sensor only looks for oxygen and a miss fire won't burn the oxygen in the charge, so the sensor registers excess oxygen lean condition.

Damo

poeticjustice88 · Post by **poeticjustice88** » Fri Jun 15, 2012 5:49 pm

lil update.

been driving it for the last week, and it honestly hasnt been too bad. i hadnt put my foot down at all, probably topped 3500 rpm in the last week, and it had not been stuttering like it was. may have one little session, but it was not continuos.

so i started thinking maybe it was boost/fuel map issue. but then i drove to my other house to check mail, and it drove fine. it was off for 20 mins maybe, then went to drive home, and pissed and farted the whole way home.

is it possible that maybe a temp sensor could be dodgey, as people have thought of on this topic before, or maybe a fuel map, that is not resetting itself back to a non load map after i hit boost ?

Michael

Post by **tassuperkart** » Sat Jun 16, 2012 9:15 am

A quick look at the handpiece will confirm if a CT/IAT sensor is not behaving.
IIRC, the ecu will revert to a preset temp and consult a particular water map if the CHT is disconnected.

No. fuel maps dont "reset". The ecu simply looks up maps based on MAP sensor output and applies any corrections set in the coolant, air, wide open throttle and cruise tables over the basic fuel tables.

Im sure I have mentioned this but are you POSITIVE that the AIT and CT sensors are earthed back directly into the ECU via the Microtech loom?
These two sensore are extremely prone to RFI and earth looping and any noise back in to the ECU from these inputs can mess with the head of the ECU. Sometimes dudes just earth the tems sensors to the engine and RFI and earth looping are your friend.

Next, what are the ignition dwell settings set to and what kind of coil and trigger are you using?

L8r
Oracle

poeticjustice88 · Post by **poeticjustice88** » Sat Jun 16, 2012 10:19 am

no idea on the ignition dwell settings, that would be a question for damo. I know that the manual says not to touch fuel pump, or injector dwells, so if it is the same deal, then they would be base i believe.

the coil is an hec 716 i believe, the trigger i have no idea, no writing on it.

i dont have an air intake temp sensor, but i will have a look into the coolant sensor wiring. where do they earth to in the microtech loom ? is there a common earth wire ? or do i simply earth to the same place as the microtech is?

Michael

Post by **tassuperkart** » Sat Jun 16, 2012 10:36 am

Wiring diagramme is your friend!

http://www.microtech-efi.com/downloads/21.pdf

Do you have a Microtech handpiece?

Oracle

Post by **tassuperkart** » Sat Jun 16, 2012 11:58 am

OK
Its no use clutching at straws by swapping out injectors and such random acts which have no bearing on anything.

This issue MUST be approached logically.

So far you have replaced most items in the system that will cause dramas.

Now going back a bit, It was mentioned that there was some strange behaviour of the handpiece.
I have had this drama back when and it was missed by Microtech themselves when the ECU, wiring loom AND dizzie were sent to them to diagnose. They even replaced the motherboard in the ECU and reflashed and loaded my tune and the same drama happened time and again.
I redid every bit of power supply wiring in an efforet to eliminate any drama but still the fucking cunting thing would randomly not start, missfire occasionally for no reason or just shut down.. usually half way across a busy intersection. 3 fucking times that setup went back to Microtech with NO change.

Firstly, WHERE exactly is the Microtech loom earthed?
Dont know? Off you go and find out.
The stock ECU is earthed on the plenum. Looking from the passengers side here:

And most guys feel they are smarter than Microtech et-al and earth to there just because the factory does. WRONG. Microtech and most other ECU makers specifically state to earth the ECU grounds to chassis. The reason will take too long to explain, just DONT do it. If everything is not equal on the earth side of the car, then overheated ECU, blown injector outputs and burnt circuitboards are the results.

Did you strip out all the wiring from its plastic casing and seach for earth side issues???? If not, why not?
THIS IS CRUCIAL to the reliable operation of the ECU and the VERY FIRST place to start looking.

Just reveal the wiring in place, unwrap any plastic tape and PISS IT ALL OFF and follow the black and brown wires. These are the ECU system grounds.

You will see they are soldered together at various places and a main black wire will travel from the ground point 9wherever that is) directly to the ECU.
The BROWN wires will connect off to the 2 temp sensors and to the TPS.

My advice is to pick these earth wires out of the loom and cut and resolder the various joints. Dont just reheat the joints, cut them back a little and re-solder them.

If your Microtech system earth is to the engine plenum as in the pix above, then take it off and run the earth lead down to the chassis grounding point located on the chassis rail down below the washer bottle.
Here:

The main battery earth strap should connect there on its way to the engine. Lots of turkeys remove it and run a new earth strap directly to the engine and so create earthloops.

Or up here where youll see a group of black leads terminating there.

It depends on the car. On my Rat, the earths are all grouped together down on the chassis. On wifeys ET the earths are up at the washer bottle. I prefer to have as many earths as possible at the single point to eliminate any additional resistance from rust and paint so run the entire group down to the chassis bolt. The stock earths are long enough to re-route down to the chassis.

On the other side of the engine, there should be another decent size black lead bolted to the chassis rail and connects to the back of the head. Make sure its connected and the chassis connection is not grubby and corroded.

Now, once you have done these tasks, which should take less than an hour, you can be certain that you have eliminated any earth side faults.

Power the car up and see what you get as far as gibberish on the handpiece!
Pull the wiring looms at the ECU plugs this way and that to see if you have any loose terminals in the plugs.
On my Microtech, this is an issue and pulling the leads near the plug can cut system power so dont automatically assume that the Microtech plugs are not at any fault.

L8r
Oracle

poeticjustice88 · Post by **poeticjustice88** » Sat Jun 16, 2012 12:25 pm

the ECU is earthed underneath the dash to mighty big bolt, right next to where the ecu is sitting, which is behind my centre console.

I did strip out all the wires from the casing, i trimmed up and retaped the unused wires, making sure they can not make a connection with any metal or other wires.

my battery is in my boot, so i cant help but retain some small resistance through multiple grounds. it has a solid ground in the boot.

The engine is grounded from the engine block to the chassis, and my gearbox also has a ground from box to chassis, at seperate locations to each other.

I will go through the bay again, once i have finished mowing, and do what you asked. with any luck, it will stare me in the face !

Michael

Post by **tassuperkart** » Sat Jun 16, 2012 12:44 pm

Cut and resolder those earth side joints in the Mtech loom.
That is important.
If you have the ECU grounded to chassis that way then thats fine.
Im so hoping that what i have mentioned before due to dodgey earths/installation in the past has not already happened. That would be a serious arse.
Your last shot is changing out the ignition triggger transistor but Im seriously doubting thats the issue due to the gibberish reported on the handpiece.
Thats usually earthside power supply or a fried ecu. Fingers crossed.
being an LT, its repaireable.

L8r
Oracle

poeticjustice88 · Post by **poeticjustice88** » Sat Jun 16, 2012 1:43 pm

its an MT :S

its not a constant problem however, the only time i have seen it do that, and it is in clear view when i am driving, is that one night with damo.

with the trigger, i know you have told me before what it is, but due to my current internet, could i bother you for what type and where to get it again please, also a guesstimate on price, $5,$20,$First Born Child.

only because it would take me an hour to go searching for the info, and i simply leave this page open and reload it, make a coffee, then read

Michael

Post by **tassuperkart** » Sat Jun 16, 2012 1:54 pm

Ah.. my bad, I thought it was an LT. Well if its knackered then throw it and get another.
I just bought another one with a handpiece for 250 bucks. They are rubbish actually but are good enough to run the engine at least.

Trigger is:

BIM027 (0 227 100 124)

Set coil dwell to TIME and 3.5Ms dwell.

Oracle

poeticjustice88 · Post by **poeticjustice88** » Sat Jun 16, 2012 3:32 pm

i dont think that is the same wiring harness diagram. i know i am not the best at reading diagrams, but the colours just dont seem to match up to me.

Michael

Post by **tassuperkart** » Sat Jun 16, 2012 4:24 pm

Make sure your looking at the correct drawing.
You have to match up the colurs on the diagramme with the pinouts on the top (separate) V2 drawing.
The main drawing shows the older vers 1 pinouts but all the colours are the same for vers 2 just different positions on the ECU

Note that one of the black wires is the IAT sensor wire so make sure that has not been connected with any of the other black/brown wires.
Its a bit of a trap that one which I neglected to mention before.

Now, something for you to ponder. You have 2 injector drivers connected and 2 missing.
Im guessing that someone has connected 2 injectors together on each driver......not very good. It wont run sequentially and if wired in series along with the resistor then Im surprised the injectros are triggering at all.

Do you still have the stock injector dropping resistor connected up on the injector +ive side? Silver box thingy on the firewall?

What a frikken nightmare.................................

Oracle

poeticjustice88 · Post by **poeticjustice88** » Sat Jun 16, 2012 6:59 pm

Lol, you think thats bad? BAHAHAAHA, I'll take apic of the wiring in the bay tomorrow.out at the moment, so cant check for the injector solver box thing, but I can't remember seeing it, injectors are wired directly into the loom

zoomzoom · Post by **zoomzoom** » Sat Jun 16, 2012 7:48 pm

time to bite the bullet m8
up on the trailer and off to the shop,might cost you another $300 but you'll be driving it

zoomzoom

poeticjustice88 · Post by **poeticjustice88** » Sat Jun 16, 2012 10:14 pm

No need for a trailer, I can drive it. But no shop wants to touch it,already tried going down that road