3TGTE Issues

[Hulk]

Following up on what I thought was a stock 3TGTE ECU problem, but have replaced it with another stock item with no positive results. (Along with a list of other bits)

The Problems

1. - Any where between 2500rpm, my engine gets a huge flat spot and then only comes back to life if you give it more throttle and then a little further up the rev range happens again.

2. - Strangely enough, when boost kicks in, these dead spots don't happen. - BUT - on boost the whole engine (sometimes) suddenly cuts out when I clutch in between gears and (sometimes) when spooling. I thought I had fixed this problem before with a new battery (seemed to work for a while) but it's back!

3. - After Engine cuts out, the only way I can get it started is if I unplug the smaller plug from the ECU, start the car (it starts and runs for a second then stalls) replug ECU and starts fine until next hissyfit.

Problems 2. and 3. are random but 1. is constant.

These are things I have done after the problem with no positive results: I will add to this list as we go.

• Replaced Ignitor and both coils (they don't get too hot)
• Replaced TPS and adjusted and re-adjusted and......meh
• Tested with different stock ECU
• Replaced leads
• Replaced spark plugs
• Oil & filter
• Cleaned out fuel tank (already looked quite clean inside)
• Replaced all vacume lines I could see
• Blocked off vacume line to PC Sensor
• Disconnected Knock Control
• Grounded all 3 pressure switches (fuel cut, enrichment, knock)
• Compression test - All 4 within 3psi of eachother.

Here are some things I've noted that may/may not be related:

• Big air bubbles in coolant after throttle off.
• Noisy injectors (no.3 may be leaking)
• Fuel Pump becomes noisy after warmup.
• movment of ecu plugs causes something to tick on injection side of engine (when key is on acc but car not started) - found out it was TPS - Fixed now.

I have been chasing this gremlin for a while now and I think I'm getting out of my depth........




save me jebus

[TA22 GT]

I would check the following -

-Fuel pressure at rail, should be around 275kpa at idle.
- Check the earth on the fuel cut pressure switch. If you don't have a good earth this can cause this problem.
- Get you injectors cleaned and flow tested
- Check the small 5th injector under the plenum is not stuck open
- Check air flow meter internally as the swipe arm or internal board maybe corroded or damaged in some way.
- If you have the knock control, unplug it and see if the problem goes away. The 3T GTE will run happily with the knock ECU unplugged.

Hope this helps,
Simon

[Hulk]

* Fuel pressure - Will check as soon as i can get a fuel pressure guage

*Earth on fuel cut switch - Can someone post a pic of where theirs is grounded? Mine seems to sit on a bracket with just the wire to ecu coming out the top.

*Cold start injector - I've tried unplugging this, but no change.

*AFM - I will check this after I get some good glue to seal it back up again.

*Unplug Knock Control - No change.

The main problem at the moment I am chasing is the dead spot.
Consistently at 2500rpm. I'll try and post a vid to demonstrate.

[TA22 GT]

The fuel cut is earthed through the bracket. Unbolt it and make sure it is clean before bolting it back down again. I don't like the stock fuel cut, if it was me I'd just earth the wire going to the sensor as this will completely over ride the fuel cut.

Cheers,
Simon

[thechuckster]

maybe check that the VR sensor in the dizzi doesn't have anything loose?

#1 & #2 do suggest AFM as that's the sensor that indicates engine load to the ECU


fuel cut on gear-change (#2) is what the efi system should do? decel fuel cut until rpm reaches a high idle of about 1400-1700rpm - triggered from the IDL switch in the TPS?

[TA22 GT]

fuel cut on gear-change (#2) is what the efi system should do? decel fuel cut until rpm reaches a high idle of about 1400-1700rpm - triggered from the IDL switch in the TPS?

The stock ECU used 3 sensors. 1 is for fuel enrichment, from memory its set to 2.2psi, at this point it adds something like 10% more fuel.
Then theres the fuel cut which again from memory is set to around 7.5 psi, problem with this is it simply cuts the fuel when it reaches high boost. This isn't too smart as you have the potential for more damage doing it this way.
Finally the knock control has a pressure switch, this is set up so the knock control doesn't function under vacuum situations, eg under gear changing. If nothing changes when you unplug the knock ECU then this is not your issue.

Hope this helps,
Simon

[rke_011]

hey..
i think i had the same problem with my tt142 when i put a bigger exaust and cooler on it.
when it hit boost it kinda died sounds the same as what is happening to you..

i cant remember what exactly i done but i disconnected a line that somehow regulated the boost i think..

as far as i remember it was three or 4 vacume line things going to seperate things...

hahaha
i dont know what it exactly was but someone on here told me about it and it fixed it..

if someone has any idea what thing im talking about please explain.. because its dark at my car and it would be to hard to see it and explain it..


if you cant sort it out and no one knows what im talking about let me know and when its light i will try to either a)get a picture for you or b)explain it a bit better...

cheers
Mat

[rke_011]

this is a link to the old forums where i was asking about a problem..

if its the same one it may help you..


http://forums.toymods.org.au/index.p...t=0#msg_449298

link should work..

i hope

[3t-RA40]

The stock ECU used 3 sensors. 1 is for fuel enrichment, from memory its set to 2.2psi, at this point it adds something like 10% more fuel.
Then theres the fuel cut which again from memory is set to around 7.5 psi, problem with this is it simply cuts the fuel when it reaches high boost. This isn't too smart as you have the potential for more damage doing it this way.
Finally the knock control has a pressure switch, this is set up so the knock control doesn't function under vacuum situations, eg under gear changing. If nothing changes when you unplug the knock ECU then this is not your issue.

Hope this helps,
Simon

When I got my engine/computer (not half cut) it was missing said sensors. When I had my stock harness modified to suit put in the RA40 the guy who done the wiring earthed all the sensors so the computer worked fine. With 2.5" exhuast and good intercooler I was running around with nearly 13psi with no issues. My bet is these sensors or wiring issues.
Cheers,
Neil.

[TA22 GT]

When I got my engine/computer (not half cut) it was missing said sensors. When I had my stock harness modified to suit put in the RA40 the guy who done the wiring earthed all the sensors so the computer worked fine. With 2.5" exhuast and good intercooler I was running around with nearly 13psi with no issues. My bet is these sensors or wiring issues.
Cheers,
Neil.

I agree. I'd recommend removing 2 of the 3 sensors. Eg the Fuel enrichment and fuel cut sensors as say don't do much anyway. Doing this will mean the engine is always running a little richer and that you will never get a fuel cut situation as the sensor wire is earthed.

If you really want to use the stock knock control then the sensor is ok as it doesn't allow the knock control to retard the spark under vacuum conditions. You could earth this sensor too and it just means the knock control will be active all of the time...

Cheers,
Simon

[rke_011]

haha, i guess nothing i said helped..

atleast i tried!

Mat

[Hulk]

OK, thanks to all for your help so far.

I tried 3 things and one of them has helped problem 3.

*Went round and tightened up all clamps on the induction side ( I read somewhere that L-Type Toyota EFI will chuck wobblies if there is unmetered air in the system)

*Last month I had adjusted the timing chain tensioner as I am not using a cam-cover gasket and she was a little rattly on startup. I now have readjusted this back to aroundabout where it was before.... i think.
Now here's something else I would like to clear up - when adjusting this, does this have any effect on my timing? or is it just for tension as the name suggests?

*Lastly, I've grounded the PC (fuel cut) Sensor line from the ECU.

please excuse dodgyness, still testing things.


The dead spot is not totally gone but has moved elsewhere and become faint and not so predictable. (bit hard to explain). But an improvement none the less.

[Hulk]

haha, i guess nothing i said helped..

atleast i tried!

Mat

+Rep 4 u mang.

[TA22 GT]

Now here's something else I would like to clear up - when adjusting this, does this have any effect on my timing? or is it just for tension as the name suggests?

.

The tnesioner does "tension" the chain but as the timing chain wears it does also change your cam timing.
Given you are having issues, I'd recommend you take the valve cover off and check the timing. To do this you set the crank to TDC, at exactly this point the 2 notches that you will see on the front of each of the cams should be facing upwards.
There is a special tool for this, but I find resting a 6 inch steel ruler right on this notch is just as good as you can check that the level of the ruler is the same on both cams. If its out of timing, then there is a pin and a number of holes on the front of the cam that you can use to make timing adjustments.
It is important to get the crank right on TDC and the notches exactly facing upwards at this point as well. Near enough isn't good enough so check it properly....
Hope that makes sense,

Cheers,
Simon

[TA22 GT]

Another thing, your sensors look like they are well earthed to the bracket, BUT is the bracket well earthed to the body of the car?

EG did you remove the paint from under where the bracket touches the chassis? If not, try this too as you need a good earth to the body of teh car itself.

Cheers,
Simon