4AGE 20v Blacktop missing/flooding/stutter etc

[MR220Vblacktop]

Hi I have an AW11 MR2 that we have done a Blacktop 4AGE transplant into

It has a miss between 2000 - 3000 rpms almost like some has pulled on the handbrake and then it takes off, revs out great but when you are cruising between the 2000-3000 rpm rage with your foot just leaning on the accellerator it stuuters and jitters.

This had be disscussed in a previous thread but no-one seems to have an answer.

I have new

spark plugs
leads
distributor cap
oxygen sensor

Does anyone have any ideas or has had this fault and actually fixed it?

Cheers
Lee

[MR220Vblacktop]

Note: for those interested

Read on another website "TOYOTA NATION" in the U.K. about the Knock sensor cable becoming fractured over time and causing the engine to incorrectly feed false signals to the ecu. ie the car thinks you are disconecting the knock sensor sort of. Anyway..... Replace to cable from the knock sensor (single shield OFC audio cable) to the ecu and it seems marginly better, was fine last night, still played up a little.

Not convinced yet, Any other suggestions appreciated

Lee

[big_boy]

i would be checking for a flat spot in your MAP sensour have seen that before

[sergei]

Put the ECU in diagnostic mode (jump T1 and E1 in diag. connector), check if the the flat spot is still there. Check if you don't have any error codes at the same time.
Check all the ground cables are attached properly (one next to dissy and other one is between gearbox and body/battery). Check if spark plug tubes don't have any water in them, check if the distributor cap is dry inside. Listen carefully at the coil, for arcing noises, if it is dark (at night) check if you don't see any coronas arround ignition bits and inside or on the coil.
If you have multimeter handy check if TPS position is not messed up - with throttle closed check if the voltage between one of the middle pins (I think blacktops don't have IDL switch) and earth is 0.5V.
Check for broken vacuum pipes especially the MAP sensor one.
Check the ignition timing (or get some one to do it for you, don't forget to jump T1 and E1).

[MR220Vblacktop]

Have checked all of the earths including block, gearbox, head, ecu and signal earths, have checked the vacuum lines.

Will check the leads for water and check the distributor cap, I have got a multimeter and will check the timing(with timing light in diagnostic mode) and tps, will do it tonight and will let you know how I get on tomorrow.

Cheers
Lee


P.S. because it is a transplant and not original I have the C-52 Trans on it and am using the original speed signal supplied from the dash to the ecu in the 1984 MR2 style, I have heard that the speed sensor can cause this sort of fault, any truth to this? and if so would the standard pulse be acceptable or is the output from the 20v trans different?

[sergei]

It is misconception that ECU feeds directly from speedo sensor on gearbox.
Actually what happens sensor feeds signal to dash and dash converts it to square wave. The SPD signal from dash should be fine. No SPD signal causes lower rev. limiter (and nothing more).

[slighty_sykotic]

It is misconception that ECU feeds directly from speedo sensor on gearbox.
Actually what happens sensor feeds signal to dash and dash converts it to square wave. The SPD signal from dash should be fine. No SPD signal causes lower rev. limiter (and nothing more).

No, thats wrong sergei.

If you don't have a speed signal with a blacktop it WILL affect it, big time.

Been there and proved that with my own blacktop into aw swap.

And yeah, the feed from the std dash on the aw is fine.

--Sykotic

[matt dunn]

This had be disscussed in a previous thread but no-one seems to have an answer.
Cheers
Lee

are you meaning this thread?
viewtopic.php?t=46052

Does you car have that same problem?

[MR220Vblacktop]

Yes, I mean that thread, all six pages of it, and yes my car has the same fault

[MR220Vblacktop]

By the way, had to work last night, will be going over the car tonight, will let you know how I get on with the suggestions.

P.S. Has anyone got a GOOD guide to the TPS adjustment on the 20V Blacktop

[7rib]

TPS has got a 5v feed in /a siganal volts back to ecu /and earth.Disconnect plug at tps and check for 5v feed with volt meter then connect neg lead of voltmeter to pos terminal of battery then connect pos lead on meter to earth wire on plug you should have 11.5 to12.0 volts if not you have got a voltage drop fault check earths make sure you know the earth wire dont hook like this to volts in wire or volts back to ecu the earth wire is black and white most of the time but double check .Plug tps back in and check out volts back to ecu it be .5 volts closed and around 4.5 fully open when opening do slowly and watch voltmeter reading should be a steady climb up in volts if you see a jump in volts like 1.5v to 2.2 then there is and fault in tps and this can cause a flat spot also what fault codes have you got.Go to batauto.com this site has got most vehicle fault codes

[matt dunn]

TPS has got a 5v feed in /a siganal volts back to ecu /and earth.Disconnect plug at tps and check for 5v feed with volt meter

To check the 5V reg circuit in the ECU you need to do it with the TPS plugged in so there is a load on the circuit.
Sounds like you are doing it the book way not the real way.

the earth wire is black and white most of the time but double check .

Toyota earths are white/black, however,
Sensor and ECU earth are always Brown.

.Plug tps back in and check out volts back to ecu it be .5 volts closed and around 4.5 fully open when opening do slowly and watch voltmeter reading should be a steady climb up in volts if you see a jump in volts like 1.5v to 2.2 then there is and fault in tps and this can cause a flat spot also what fault codes have you got.

There is also the TPS swith which is more crutial that the actual output voltage. They need to be set on the switch not the voltage.

[7rib]

So you are saying that if you unplug sensor and use voltmeter there is no voltage at any of the wires.This method is not from a book it is a method i have used for years and is a good basic test for all modern resistor tps sensors and i have had a good sucess rate with it. But you right the test showen in most books are sh*t and can be misleading only takes 5mins to do test

[sergei]

Oh BTW blacktops don't have idle TPS switch (the TPS itself will have it but loom does not have wire going to it).

[matt dunn]

So you are saying that if you unplug sensor and use voltmeter there is no voltage at any of the wires.

No what I am saying is that if the 5v reg is the ECU is on the way out,
you need a small current draw on the 5v wire to check it's output.

The time I tried to fix this fault in a transplant i found that leaving the tps unplugged made the problem go away.
It also made the VVT not work though.

Does the AW11 have the speed sensor wire hooked up?

[slammed_integral]

is your car still using the factory catalytic converter?

[MR220Vblacktop]

No cat. But sensors kept and still wired. Car has a custom exhaust manifold and exhaust complete, yes the speed sensor wire is plugged in, sorry its taken so long to get back, haven't tried testing the 5v reg on the ecu p.c.b., haven't opened the ecu yet, is it just a standard 5v reg in which case I'll just replace it precautionery, I have a 100MHz oscilliscope and a temperature controlled soldering iron with a 0.1mm tip so testing and replacing the reg should be simple enough. LM7805 or something similar I bet

Cheers for the advice

P.S. After driving it for a while the replacement of the knock sensor wire certainly has made a difference, its still a bit hesitant when cold but then seems ok when up to temperature