1UZ Conversion Power Issues

[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.

[dumbass]

sounds like u got an ignition problem
code 12 is rpm

did u do a timing belt as ive seen guys fit the timing belt a tooth or more out of timing and this makes the headers get hot
is the air flow meter correct one and is it working
was it a complete kit or halfcut
have u changed rotor buttons and ignition leads
has it been wiring correctly for a manual

knock sensor is code 52

[nathanshnoz]

sounds like u got an ignition problem
code 12 is rpm

did u do a timing belt as ive seen guys fit the timing belt a tooth or more out of timing and this makes the headers get hot
is the air flow meter correct one and is it working
was it a complete kit or halfcut
have u changed rotor buttons and ignition leads
has it been wiring correctly for a manual

knock sensor is code 52

yes i replaced the timing belt but i am certain that it is not out by a tooth as i re-did it a number of times to be sure it was correct. airflow meter is the correct one and i believe it is working fine. i purchased the motor with all accessories, wiring, ignitors, AFM, etc. it has brand new rotor buttons and leads and they are definately in the correct spot. As far as wiring it for a manual i assume so since i only get one fault code (12). I wonder why i though the code was knock sensor? one forum i read on they said 12 was knock sensor? hmmmmmm interesting

[dumbass]

ok cool
normally u get code 13 if timing belt if out
code 12 might be one of your crank or cam sensors
or u might even have a dud coil breaking down under load

these types of problems are a pain to fault find u just have to keep changing parts
im wondering if one of your coils is faulty and shutting down thats y it wont rev

take covers of motor to get to leads
then with insulated pliers while motor is running remove one coil ignition lead at a time slowly
and see how far the spark can jump
a faulty coil will fail after afew mm of gap

[marc280]

It may also be worth checking the ecu for leaking capacitors if you haven't already. I had a problem with mine where the idle was hunting and issues with the way it drove because of leaky caps.

[nathanshnoz]

How do I know if the caps in the ECU are cooked? I'm kinda thinking maybe timing is out, I guess that makes sense if the exhaust port is partially open during combustion it would heat up exhaust very quickly and probably cause a fair loss of power also........but I was so sure it's correct.....hmmm

[AE3SGTE]

Is it a celcior motor and ecu?
One of the early engines with the 26p 16p 22p 26p?

[nathanshnoz]

Is it a celcior motor and ecu?
One of the early engines with the 26p 16p 22p 26p?

hey mate,

it's out of a 1993 LS400. The pin configuration is 4 plugs 34P 22P 16P 28P

[dumbass]

Open up ecu and look for the little black cylinder things
See if any have black tar shit coming out of the bottom

Then double check your timing heheh

[marc280]

How do I know if the caps in the ECU are cooked?

Have a look at this site, as it has pretty detailed info

http://www.clublexus.com/forums/ls40...capacitor.html

If the timing belt was out I would have thought it would cause the car to idle poorly all the time, so I would think it is more likely to be electronic.

[George]

Borrow another ecu to see if it's the caps or not. I would recommend to replace the caps anyway after you're done with the basics.
Also, I'd double dumbass with whether or not it's wired correctly for manual.

[nathanshnoz]

Have a look at this site, as it has pretty detailed info

http://www.clublexus.com/forums/ls40...capacitor.html

If the timing belt was out I would have thought it would cause the car to idle poorly all the time, so I would think it is more likely to be electronic.

I checked the caps they seem fine no visible damage at all. Will double check timing belt but I don't think it's likely I stuffed it up again....but I may have

[GT1978]

Don't know anything about the 1uz other than I want one in my celica but a hot exhaust and power dropping off at 3000RPM sounds possibly fuel related, like its running lean. Which still could be ECU related. Have you checked fuel pressure?

Glen

[Hurricane]

ive been helping nath out with the build from time to time and my bro is doing the wiring with my help, just to help out with some of the info.

its had new rotors and caps, new leads and plugs.

nath has done the timing belt (im goin to check it when he has it off next)

its doesnt brake down under load, and its not a solid miss at idle, just not as smooth running as mine.

somtimes its idles fine, other time low, other time not at all.

the headers do get rather hot (red hot) after driving for 5 mins or less.

the fuel pump is just wired off ignition power atm (not sure how to control it without the fuel pump ecu wired in)

the exhaust flow is fine

free reving seems fine.

power out put is low, there is none at all really, id say it would be lucky to hold 80km/h

when we first got it going it went alot better, i removed the exhuast rear half and air box setup it was running and went better again, since then the mid section of the exhuast was changed to flow better and the twin cats removed, ever since then after starting it up it ran with no power.

there is a plug on the ecu that runs from the OEM body loom thats missing, atm the wiring was ran to the corect pins but straight into the ecu pin till a plug is found.
the other day before runnig the car nath had them out, put them back in the wrong spots and the car didnt run, blowing the EFI fuse. its now sorted but may have damaged the ECU?

unsure on the fuel pressure, fuel ratio or ignition timing as ive got nothing to read it. (though i could run a timing light of #1 cylinder lead for timing and sit on the motor) haha

i disconnected the vacum to the fuel reg in an atempt to up the fuel pressure - no change for better of worse

my guess is a lean fuel ratio or retarded ignition timing, possibly the cam timing or ECU damaged?

lean ratio = more heat
retarded ignition timing = later burn of combustion if im correct
cam timing = lack of power, unsure on the exhuast temps?


dan.

[nathanshnoz]

OK so dan (hurricane) 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.