4AGE BT 20v Check Engine Light

[shem_lexluger]

Hi bros,

Need some help to pinpoint why my check engine light is on. I'm using BT engine from 6spd but attached to 5spd gearbox with BT 5spd ECU.

My car just released from bengkel for transplant job for about a week. First time the check engine light came on randomly during driving and no power loss or no other effects can be felt physically. Everything normal other than my own uneasy feelings. But the light remained on. So went back to bengkel to check. After some checking by shorting some pins in the diagnosis port and looking at how many times the CE light was blinking, and then referring to some manuals, the mech came up with a conclusion either MAP sensor or knock sensor is faulty.

So pulled out a MAP sensor from another 20V waiting in the bengkel and plugged into my car. Drove around abit then light still came on.

Then opened all the intake manifold to locate the knock sensor and replaced it with one knock sensor unit borrowed from halfcut shop. Then drove around and CE light no more. So I bought that sensor for RM120 and went home feeling relieved.

So 2 days gone by without any CE light. Then today the CE light came again. It came on about 5 times. What I meant by this is if I turn off my engine and on again, then the light will off. Once while climbing hill using 3rd gear revving till 3k rpm speed probably around 40+. The other 4 times occurred while speedo just above 80kmh in 4th or 5th gear. My driving style is normal, revving max occasionally till 3.5k rpm. Like previous one, CE light came on and no difference whatsoever. Everything is normal physically but light remained on until I turn off the engine. I still can drive at 100kmh on hiway and feel perfectly normal.

I don't know if this is relevant at all. But I haven't changed my piping yet. Still running the piping I installed when my engine was 4AFE with size about 1.8" and a center bullet. Of course when rev till 3.5k like that can hear the exhaust rattle a bit.

So I hope with this detailed info sifus in here can provide some insights.

Thanks

---------- Post added at 11:12 PM ---------- 6 hour anti-bump limit - Previous post was at 07:33 PM ----------

Just an update. I went to mamak just now and CE light came on. Then after I got inside the parking space and turn off my engine, it runs on for a bout 1.5 sec before shutting down, similar feeling like having a turbo timer. Now that's scary.

Wikipedia reference Engine knocking - Wikipedia, the free encyclopedia

On the way home from mamak, CE light came on also but pre-ignition didn't happen.

 

[xMika]

Previously for my case, is the ECT sensor already broke into half ..

I solved my engine check light from here

Troublcodes.net Trouble Codes OBD & OBD2 Trouble Codes and Technical info & Tool Store. By BAT Auto Technical

Your check engine light blink how many times ? Sometimes there are multiple error codes ..

 

[shem_lexluger]

Hi bro xMika,

I forgot the blinking pattern, Maybe like 4-2-2-4 or something.

But after seeing how the mech did it that day, I think I can short the pins myself to confirm the blinking light pattern first thing tomorrow. Perhaps I could even record a video and post it in here for second opinion.

About the ECT, what are the consequences of not replacing it?

Thanks

 

[ragerunner]

Paging for sifu levin818 here..

One thing for sure, it's not your exhaust.. I ran my BT with stock 1.4-1.6" exhaust for more than three months and the engine check light never came on..

 

[levin818]

If you have a check engine light but found out that the related fault sensor is in good condition, it is time to check your ECU immediately. There is a possibility that you have a faulty ECU. It happened to the ECU that make from year 1992~1996, ie:
- SVT auto/manual
- AE101 4A-GZE
- BT BZG auto/manual (5sp)
- SEG 4A-FE 16V
- 1JZ-GE/GTE
- 2JZ-GE/GTE
- 3S-FE/GE/GTE

If you want to have free checking on your ECU, feel free to drop by Kota Kemuning.
Hope this help.

 

[shem_lexluger]

Thanks bro ragerunner for clarification.

Bro levin818, that's great Kota Kemuning is just 15 min away from my place. Will contact you privately.

 

[shem_lexluger]

Update for today.

Ran the diagnosis myself and seems like it was showing error 42 which is the vehicle speed sensor. Attached short video.

Also took out all spark plugs to check condition. Damn lots of carbon on the plugs for an engine running less than 1000km. Plugs were brand new NGK iridium heat range 7. Perhaps the over-run last night was caused by this incompatible heat range. Need to switch to 6?

YouTube - 4AGE Blactop 20V check engine light

 

[shem_lexluger]

Update for today.

Went to meet sifu levin818 to inspect my ECU. Very nice guy. My ECU is good for about a year generally. But TPS position is a bit off according to him. The engine also has noticeable knocking at higher rpm and there's a slight lag in terms of throttle response.

So he kindly adjusted the distributor to retard the timing (it was too advanced) abit and also recalibrate the TPS. The most noticeable improvement is no more knocking sound (it sounded like krik krik krik to my ears). Then smoother power delivery across lower gears with slightly better response.

Thanks sifu levin818 for the help! TT is on me next time around. I'll send in my ECU maybe in 6 months time.

However my engine over-run problem still need to be looked into. It usually lasted less than 2 seconds. I can foresee top overhaul is imminent.

 

[cuscostrutbrace]

When doing conversion(for kacuk or kahwin wiring),always try to give all the input the ecu needs,i have seen a lot of conversion not connecting all inputs,they only connect what need to run the engine,it may be fine to drive,but it will gives 'small small' operational problems...

The most common is not connecting the speed sensor,the O2 sensor,and electrical load signal...

 

[shem_lexluger]

Yes cuscostrutbrace that's true.

Went to see a mech at JMS jln kebun today to check the wiring and the signal from dashboard meter to ECU is not connected (purple wire). Simply wire that and then no more error code.

He also did a quick check on my timing using a timing light and found out it's advanced to 13 degree. This is during idle. Kinda high to me but I may need second opinion from the sifus here.

Now just need to troubleshoot the engine over-run problem and my rich engine mixture.

 

[cuscostrutbrace]

It is advisable to set all to factory spec (most of the 20v i've done i seen the timing is always being advanced more than factory spec by other mechanics),some mech also advance the TPS as well.Both of these 'advancing' timing and tps will not gives huge power gain but only produce knocking...factory standard spec is good enough for daily driving,mod the intake and exhaust to seek a little more HP.

For over run or rich mixture,check you injector it might be leaking...check fuel pressure and spark plugs(follow factory spec).

 

[shem_lexluger]

Just an update.

FC seems to improve from 280KM for 35litre to 400-480KM for 35 litre. Gotta be the ECU working.

 

[suma_]

Yes cuscostrutbrace that's true.

Went to see a mech at JMS jln kebun today to check the wiring and the signal from dashboard meter to ECU is not connected (purple wire). Simply wire that and then no more error code.

He also did a quick check on my timing using a timing light and found out it's advanced to 13 degree. This is during idle. Kinda high to me but I may need second opinion from the sifus here.

Now just need to troubleshoot the engine over-run problem and my rich engine mixture.

Bro, mind to share - where is JMS jalan kebun? gps coordinate/google map if possible.
:hmmmm:

 

[me2kimi]

hehe...sy pun nak tahu jugak

 

[shem_lexluger]

JMS stands for Jawa Motorsports.

Contact person: Hazrin (0162852027)

I think somewhere around here (look at the green arrow) 2.979216,101.513273 - Google Maps