1UZ 4runner power/exhaust issues and code 12

[nathanshnoz]

Hi All,

Just finishing up my 1UZ into Toyota 4runner conversion. When i drive the car even for a short distance and not driving it hard, the headers start glowing red hot (custom headers). The motor sometimes doesn't run properly and seems to kind of miss a beat every now and then. Sometimes it will idle and sometimes it does not like to idle, although lately it seems to idle ok. During acceleration it will be very sluggish and does not like to rev at all past around 3K. Foot to the floor the car struggles to get to 3/4k. It has a manual toyota gearbox behind it. I ran fault codes and only got one code (12) which i believe is knock sensor?

Any help appreciated not sure whats going on but it should be running a lot better than it is. I can only assume either the timing is retarded for some reason or its running lean or burning exhaust gas too late.

 

[gloverman]

Code 12 is RPM circuit which normally means the cam timing is incorrect. Happens alot. After that who did the wiring? Cheers

 

[nathanshnoz]

Timing should be right I've pulled it apart and checked/re did it a number of times now. A mate did the wiring he has done many different engines and is pretty good at it. Where does it say code 12 is RPM signal? Most of the charts I can find say it is crank/cam angle sensors

 

[gloverman]

scroll down to the bottom of the page and look in "engine specs and diagrams" to find diagnoses with codes. RPM signal is Cam/Crank.

 

[cruising]

Your person who did wiring
Maybe he do timing as well
Not very good

 

[gloverman]

have you physically check the ignition timing as well. The looms are a little bit prone to poor connections where the main engine harness plugs into the front cam/crank sub loom on the LHF of the engine. Cheers

 

[nathanshnoz]

i've checked the ECU internals for visible damage and i can't see any. I will check the cam timing tomorrow or saturday and let you know how it goes. not sure what else it could be at the moment. i suppose faulty cam angle sensors could also cause some of those symptoms

 

[nathanshnoz]

OK so a mate and i spent the evening with a few spare parts and a timing light and we have worked out the following:

- timing belt and cams are NOT out a tooth and are correctly aligned
- it is not the AIR FLOW METER (dan had a spare the same as mine which we tested on both his and my engine and there was no difference in the two of them)
- the engine timing is retarded quite a significant amount. dans 1uz ran at approx 30-35 degrees advance under a decent amount of throttle. mine is lucky to run between ZERO and 3 degrees advance with a bit of throttle.
- we have tried a few things but have not been able to diagnose what is causing the above timing issue
- we checked the resistance on both cam and crank angle sensors and they are all showing good resistance (we don't have an oscilloscope to check the signal)
- the leads are all in the correct order, the dizzy caps, rotors buttons, plugs etc. are all installed correctly and are all brand new.
- the engine is definitely running in base mode due to the retarded timing. this issue would be the problem behind our lack of power and most likely the cause of the headers heating up so much.
- i have pulled apart the ECU and nothing looks damaged in any way and i do not believe that this is an ECU issue
- the wiring to one of the cam angle sensors we believe may have an earth somewhere along it. We ran a separate wire to try and test the issue but so far haven't had any luck (by the time we gave up for the night)
- still getting code 12 and cannot diagnose why (unless above wiring is the problem)

if anyone has a good amount of experience with these motors and can offer assistance it would be appreciated.

 

[gloverman]

I would suspect wiring. Ive done a few with the retarded timing issue and a few with the code 12 but never both together. Has your mate ever wired a 1uz before?

 

[nathanshnoz]

can you recall what the causes were for the retarded timing and the code 12? No he has not wired a 1UZ before, but has wired a few dozen motors including a few for me in the past.

 

[gloverman]

I remember the most of the vehicles and the most of the issues. I have a workshop and spend all day working on 1uz conversions. As it is my main income selling parts , selling information and fixing conversions I only give away so much help for free sorry. Cheers

 

[nathanshnoz]

yeah right.

well since your in NZ and i'm in AUS it would be a bit tricky for you to come look at it for me. I have sourced another ECU which i will try and have established that there was not a problem with the cam sensor wiring. All the wiring and sensors for the Code 12 have been checked and all seem to be operating fine. Workshop manual says next step is replace ECU so i'll try this and see what happens

 

[gloverman]

I just helped a customer fix his vehicle and he is located in the UK. http://www.lextreme.com/forums/showthread.php?t=15558&page=11 HAve helped quite a few so far and I am about to do another one this weekend. The internet , facebook chat etc are great diagnostic tools. If you get totally stuck then I would be willing to help for a fee. Changing the ECU is a good thing to try. Cheers

 

[pajman]

With my beast I found simple things , wire in wrong place , coils with no power wire, once I traced each wire and corrected MY mistakes , things are fine touch wood. Having the correct diagram and making sure everything matches up it should go . It may mean a few dollars spent to get it diagnosed .

 

[nathanshnoz]

Okay so i sent the ECU off to be diagnosed and repaired and they said the capacitors were leaking. Which is suprising because they did not appear to be leaking to me. Anyways ECU has been refurbished and repaired and i have got it back and plugged it back in. I need to double check with a timing light but i'm pretty sure the timing is still retarded and i still have a code 12

i have to assume that one/both of my Cam sensors are cooked (even though they showed good resistance when tested) as i don't think anything else would cause the code 12.