1UZ Ignition timing problem

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wireless

New Member
Messages
5
Location
New Zealand, Auckland
Hey guys,

Long time reader, first time poster. I have searched for hours without success..
The car in question uzz30 1992 JDM soarer converted to manual, standard ECU

The problem, after getting the two mid mufflers removed, the engine has been playing up, I can only compare it to what boost cut feels like, real violent, head banging hesitation. After weeks of fault finding with no results I decided to download the toyota car tester, wired it up and found I was getting 55 degrees ignition timing.. when I unplug the airflow meter the ignition timing is steady on 30, both idle at 10 degrees. I confirmed this finding with a timing light.

I opened the ECU, replaced one leaking capacitor, however no fix.
I am now wondering if the welding damaged the ECU in some way or a sensor is bad? I cant find any ECUs to test unfortunately.

Any help would be greatly appreciated

Cheers
Jason
 
I have a tester for Soarer ECU's. I repair quite a few so have made a test loom to plug it into my drive vehicle. Now after the ECU has been bench tested it is also road tested.
 
Wireless,

Post it off to Kelvin.

May cost a few bucks but worth knowing your ECU is working correctly and leaking caps won't destroy it like mine did.
 
what about the 02 sensors , the manifold ones and also the ones further along the exhaust (I know Lexus have the extra ones) , these may have been interfered with by your exhaust people
 
only has two o2 sensors, however I'm sure they are working correctly. I've seen them working on the toyota tester and I have a wideband o2 sensor installed and it all lines up nicely.
 
I would check the fuel flow (and pressure if you have a gauge). For flow remove the return line and put into a measured container. Run engine at idle for 30 seconds. I would like to see 120litres/hour so 1 litre in 30 seconds. 100l/hour is just enough , at 80 there are generally flat spots and at 60 there is normally large power lose at revs and poor cold performance.
Next check the TPS - you may be able to monitor this on the tester. Check it is spanning from 0 at idle with the idle switch on through to 80-85% at revs. Toyota's commonly don't get the full 100%. This is normally an idle voltage of 0.5 volts through to mid 4 volts at full throttle. I have seen as low as 4.32 volts at full throttle.
Have you tried some coils?
 
I do have a fuel pressure gauge but the sender is 1/8npt and I'm finding it hard to find adapters.

Initially I thought it could have been a fuel problem, however it can still get down to 10:1 A/F @ WOT.

I took it out the other day, with the AFM unplugged and timing on 30 it goes well, very sharp response and plenty of power. With the AFM plugged in and the timing anywhere between 10 and 55 it is very sluggish, slow to respond, down on power and knocking badly, which seems to get worse after running for a while.

The issue seems to be with the timing..
If you have a stock 1uz, working normally, would you expect the timing to retard when you unplug the AFM? or would it stay the same with no effect on the timing? I imagine the timing coming back to 30 when the AFM is unplugged would be open loop mode? the toyota tester shows feedback turn off when the AFM is unplugged.

could a cam sensor be faulty and causing this, without throwing a code?
I might be able to get access to an oscilloscope in the near future, to check the signals from the sensors.

I have tried coils, no luck. Checked spark leads, all measure ok.
 


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