HI Rolla Club

 

I have a 1994 Toyota Levin GT Apex, 4AGE Slivertop which we have just converted into a Youth Saloon for racing Speedway in NZ.

The mistake we made while removing the wiring loom was we run the engine and if we cut a wire that stopped the engine we would join it mark it and carry on, not giving "Limp mode" any consideration!!

While tunning the engine I noticed it retards the timming about 7 degrees, the engine is also running rich.

 

Over the past few weeks I have studied and tried to fix the issue, I did find a very helpful web site which involved a 4AGE Jet boat conversion.

 

Here's a list of things I have already checked

* The TPS, AFM, O2, and Knock sensors are all wired correctly back to the ECU

* Taken the above sensors out of our spare car and tried them in the speedway car

* Tried another ECU

* Tried simulating the issue in our spare car by disconnecting sensors

 

Its got to be simple I have missed.

Does anyone know the causes of "Limp mode" in a 4AGE 20v engine

Note you have tried another ECU without sucess, but you might like to have a look at this Utube vide, if you haven't already found it, as the fault sounds very similar to yours.

 

 

Hope this assists.

 

Cheers Banjo

Note you have tried another ECU without sucess, but you might like to have a look at this Utube vide, if you haven't already found it, as the fault sounds very similar to yours.

 

 

Hope this assists.

 

Cheers Banjo

 

Thanks Banjo

Yes Ive seen that link thanks, but he obvouisly had issues with the ECU itself.

 

Our issue is different the engine still revs fine, its just running rich and due to the timming retard also under powered.

I have read here on an old topic about the ignitor coil, which I have not yet tried

do you have a check engine light hooked up? if so have you been able to get any codes out of it? (i can't remember the procedure, but its fairly easy, hit the google machine)

 

If you don't have a check engine light hooked it up, i'm fairly sure you can just put a regular bulb to the ECU pin output and the other side of the bulb to ground. Just double check the wiring diagram. I hooked up a temporary check engine light on my old 4age 16v ecu to get codes out, but that was 5yrs ago....

Edited November 14, 20169 yr by ke70dave

do you have a check engine light hooked up? if so have you been able to get any codes out of it? (i can't remember the procedure, but its fairly easy, hit the google machine)

 

If you don't have a check engine light hooked it up, i'm fairly sure you can just put a regular bulb to the ECU pin output and the other side of the bulb to ground. Just double check the wiring diagram. I hooked up a temporary check engine light on my old 4age 16v ecu to get codes out, but that was 5yrs ago....

 

Thanks Dave!

No I don't have the dash or engine light, but will google search the engine codes and ECU output codes etc

In general terms the stock system is very fussy and you wont be able to remove any wiring to do with any engine control system, or the stock ecu will trip up and either go into a pre programmed limp mode or as you say stop running. Does your racing class require a stock ecu? if not you can go aftermarket and greatly simplify the wiring down to just the sensors, ignition and fuel systems, however then its you who is responsible for a tune...

In general terms the stock system is very fussy and you wont be able to remove any wiring to do with any engine control system, or the stock ecu will trip up and either go into a pre programmed limp mode or as you say stop running. Does your racing class require a stock ecu? if not you can go aftermarket and greatly simplify the wiring down to just the sensors, ignition and fuel systems, however then its you who is responsible for a tune...

 

 

Yes we do require a stock ECU, do you know what the minium requirements for the ECU are, I tried simulating this on our parts car.

For best results i would be aiming to mimic the oem setup to get the best out of oem ecu. Which sadly suggests all sensors including a speed sensor perhaps.

For best results i would be aiming to mimic the oem setup to get the best out of oem ecu. Which sadly suggests all sensors including a speed sensor perhaps.

 

The speed sensor is well gone, but it must be something like that.

It would be good to know what causes Limp Mode I could narrow things down thatn way

Greddy emanage blue from what I'm reading it would appear to take control on the engine, although I don't understand what the standard ecu would have left to control

The blue is just an interceptor type ecu, waste of time i reckon.

 

Still relies heavily on the ecu, so if the stocko ecu doesnt work properly the emanage blue isnt going to help much.

 

Hows that check engine light coming along?

 

 

Hows that check engine light coming along?

 

I won't be able to check engine check light untill Thursday or Friday, but I will

Being that you are trying to simply use toyotas own system, then you should be able to download the ae101 levin manual and look for std service data to fix it.

I have tonight put the engine in diagnosis mode by joining TE1 and E1 on the ECU output, I then put my test light on the W ECU terminal and the test light earth clamp to the battery positive terminal ( found this on another circuit )

 

Very excited to get two codes!!

 

12 & 14

 

Both are related to the distributor and ignitor coils

 

Over weekend I will fault find those two codes and also report back.

Ive also learnt as I don't have a speed sensor connected the warning lamp would flash at high RPM and reduce the limiter from about 8000rpm to 7000rpm, which I don't think will be a problem although I will check that once I have fixed 12 & 14

Ive cleared code 14 by replacing the ignitor coil.

 

I can't clear code 12 !! I Replaced the distributor and also checked continuity of wires from distributor to ECU