Error codes 14/34/52.... intermittent cut out at mid range coming onto boost.

[doctor_tom]

Hi,

I spent the weekend sorting out my MR2 as it had poor throttle respons, cbad fuel economy and the wastegate was catching on the down pipe. So I found a leak and ground the downpipe down. I also found the lamda sensor wire was brunt through!! Causing the poor fuel economy.

I also had a MIL light on, so did the diagnostic thing and have errors 14/34/52.

The car drove a lot better after the leak was fixed and the throttle repnce is better at low revs.

However, there is now cutting out at 2-4,000 rpm. I imagine this is due to error 52 and the ECU retarding the ignition. I am running 1 bar boost on a rev 1 turbo and 95 octane.

I'll get a new sensor.

Errors 14/34 Ignitoin and STA indicators seem to be having very little effect.

I found some links to excellent guides on how to fix on this forum.

Just wondered if anyone had any input on this?

[SonicSW20]

95RON is not enough for a JDM turbo engine. You need to run it on 98RON.

[Al-sw20]

Code 34 is overboost. That will go away if you clear codes and don't hit it again.

Code 14 is the ignition signal, it's probably not the ignitor, so my money would be on a leaky cap in the ecu. Try and swap your ecu with a known working unit.

Your code 52 is the knock sensor. Just make sure you fit a genuine Toyota unit. Many an engine has failed when people fit a GM or other generic knock sensor and it doesn't work as intended.

[doctor_tom]

Hi thanks,

How do I clear the codes? I couldn't find a guide for that.

I bought a new ignitor recently. It may be from the old one.

Code 34 is overboost. That will go away if you clear codes and don't hit it again.

Code 14 is the ignition signal, it's probably not the ignitor, so my money would be on a leaky cap in the ecu. Try and swap your ecu with a known working unit.

Your code 52 is the knock sensor. Just make sure you fit a genuine Toyota unit. Many an engine has failed when people fit a GM or other generic knock sensor and it doesn't work as intended.

[Ryan S]

Disconnect the battery, some folk say stand on the brakes or turn on the headlamps to get rid of residual power but in my experience disconnecting the battery is enough 👍🏾

[SonicSW20]

Don't even need to disconnect the battery, just pull the EFI fuse and leave it for a bit.

[Ryan S]

Don't even need to disconnect the battery, just pull the EFI fuse and leave it for a bit.

Man what am I thinking! Of course, I did this the last time I had a problem too!! Been a while since I've done work on an Mr2 😂😂

[doctor_tom]

Excellent.

Thanks.

Don't even need to disconnect the battery, just pull the EFI fuse and leave it for a bit.

[doctor_tom]

Hi,

Just remembered I have a code 43 too... STA indicator.

[SonicSW20]

Fill it with 98RON (Shell V Power or similar), reset the ECU first, go from there, especially as you've replaced parts and not reset the ECU since.

A turbo will trigger the knock sensor under boost on 95RON fuel (especially as you're running more boost than stock), which will cause it to pull timing. No point just replacing the knock sensor when it's probably doing its job correctly and detecting knock and pulling timing.

[doctor_tom]

OK chap.

Seems the most logical course of action and I'm not into wasting money.

I'll report back in a few days.

I leave the EFI fuse out for an hour?

Fill it with 98RON (Shell V Power or similar), reset the ECU first, go from there, especially as you've replaced parts and not reset the ECU since.

A turbo will trigger the knock sensor under boost on 95RON fuel (especially as you're running more boost than stock), which will cause it to pull timing. No point just replacing the knock sensor when it's probably doing its job correctly and detecting knock and pulling timing.

[SonicSW20]

Won't even need that long. I'm not sure how long it actually takes, I usually pull it when I'm doing work that requires a reset. Last time it was TPS, which took around 15 minutes or so I guess to remove / replace / calibrate.

[Willenium]

When I reset the ECU I pull the EFI fuse and both the ECU fuses (one in the front fusebox and one in the rear). Usually leave it about 10 minutes and put them back in.

[mr2nut123]

Did it work just out of interest? As said above, never put 95 in there. It causes all sorts of issues with Turbos, even if not immediately obvious.

I don't reckon you'll need to replace the knock sensor either, they very rarely go wrong on mildly tuned tubbies.

[doctor_tom]

Hi,

duly noted, I will be running 98 from now on.

I found there was an air leak, the bolt on the fuel rail had worked itself about a half inch loose. Tightened this up and there is still a leak, WD40 proved it.

So, I'll have to take the intake manifold off this weekend and make sure everything is tight.

An earth lead had almost melted through too and a loose connector on the coolant sensor.

I'm hoping the air leak was causing the Ignition and STA codes and the 95 RON with the leak caused the knock sensor.

Once everything is tight and sensors fixed, I'll put in the 98 RON and give it an ECU reset.

I need to burn through the last bit of 95 RON first.

[SonicSW20]

Sounds sensible to me - get all that sorted and see how it runs. Even if it doesn't fix all the issues it's going to be running a lot healthier once that's sorted, and if there are any remaining issues it should be easier to identify them