1UZ-FE VVTI Surf conversion - stuck in 'limp mode'

[Warren]

Pretty much finished with a 1UZ-FE VVTI Surf conversion. Everything is hooked up and working (V8, manual box, exhaust etc).

I'm using a non-security ECU out of a 97 Crown and it's all wired up and the surf starts up fine and runs, but after a short while or short drive the check engine light comes on and retards the timing/puts the car into limp mode.

I have replaced pretty much every sensor there is, coils, plugs etc and still no luck. Keep getting knock sensor code come up on the diagnostics.

Any ideas?

Cheers,
Warren

[Mr Ree]

Have you checked a different knock sensor?

[Warren]

Yip, tried another one out of a running 1UZFE VVTI still no luck. And then tried a brand new one :\

[Mr Ree]

How about the wiring to the sensor? Did it perhaps get damaged during the transplant?

Also does it just have 1 knock sensor, or two?

[evil_si]

seeing as there is still a code for knock sensor you reslly have to start there, pointless changing other sensors etc.

They have 2 knock sensors one in each bank
Check pin outs from ecu to each knock sensor, pita having to remove intake etc i know but its where i would start,
Confirm good continuity In the wiring to each sensor
Check the resistance of the sensors,

What has been done to the wiring loom? All the excess cleaned out of it? Or still stock?

[Stu-]

If you get really stuck give Brendan at Convert Ltd a call - what he doesn't know about 1uz no one does

[Crucible]

If you were to let it idle without any load, will the check lamp still come on? Or are you finding it is only setting the code while driving?

[edwagon]

What exhaust are you using?

Or any mechanical noise?

PERHAPS the knock sensor is detecting near-constant knock (real or otherwise) and pulling timing - and then reaches a threshold where the ecu judges the 'knock circuit' to be faulty

I had basically the same thing with an H22A accord - collapsed and blocked rear muffler making the car as weak as a kitten, and after a few mins of driving (even nursing it) it'd log a knock sensor code.

[Warren]

The surf starts up and idles fine, but when you give it a bit of gas/bit of a rev/drive it, it retards the timing and the check engine light comes on.

The exhaust is a brand new full system - log headers etc

I have taken the Surf to EFI Tech on the North Shore in Auckland - hopefully they can find something...

[ryanfels]

If you get really stuck give Brendan at Convert Ltd a call - what he doesn't know about 1uz no one does

Pretty much this!

[Warren]

Got the Surf back from EFI Tech in Albany this morning and nothing electrical has come up... They think it's a mechanical issue as to why the timing is retarded... :\
I'm getting very frustrated with this thing, I'm out of ideas and it's too close to Christmas for this ish!!!

I need my car running now!

[Mr Ree]

Can you borrow an ECU to eliminate that from the list of possible culprits?

[Warren]

Yeah, I tried that a couple of weeks ago... but it didn't work

[Stu-]

Give Brendan a call if you get really stuck, seriously he knows his stuff and is very professional. Hes based in Greenhithe.

[Mr Ree]

I know you mentioned replacing lots of sensors, but you didnt elaborate on which ones.

Did you replace the water temp sensor? I have read about them being faulty causing the ecu to retard timing on certain Toyota engines.

[Crucible]

They think it's a mechanical issue as to why the timing is retarded... :\!

Does it pull ok until the check light comes on or is it flat right through?

Try taking both sensors off the block and mount or cable tie them away from any noise. Dont think they will need to be grounded but you can always run a couple of jumper wires to earth them. If the problem still occurs then at least you know it isnt mechanical noise causing the problem.

[edwagon]

Triple checked the cam timing?

Run it with open headers or just front section to test - I have seen exhausts cause all sorts of weird issues - and at least it'll sound badass for a few mins

[YeMs]

Id check all earths for a start. Definately quadrupal check your cam timing if youv changed the belt. Have you modified the loo atall? Iv also heard that if theres no speedo input to the ecu it goes into limp mode, not 100% sure on that one though.

[Warren]

Is there a phone number for Brendan? Thanks!

[Stu-]

Will send you a PM shortly