Wednesday, October 04, 2017 - 01:56 pm, by: Ian Miller(Rellim)
'92 1UZZ31. Car had been running perfectly. No miss, idle good, easy starting. One day went to start it and it cranked but no firing at all.
Checked fuel – ok No spark. No codes on ECU just “--” when diagnostic port bridged.
Checked crank angle sensor which tested within spec.
Checked coils and igniters for 12 v power. Tested ok.
Checked ECU and found a couple of leaky caps so had all but the difficult one under the ECU body replaced. Tracks were ok.
After much hunting for diagnostic hints, found that IGF 1 and 2 pins at the ECU are only 0.15v not the required 4.5 – 5 v.
Further checks show that IGT 1 and 2 pins show 0.03 v “ish” instead of the required 0.5 – 1.0v (Neither 0v 0r 5v acceptable).
M-Rel pin on CPU drives the EFI relay
To me, this points to a faulty ECU. Does this sound right to the people on the forum with more experience than me? Are there any other tests I can do ? Are there more likely issues I could address? Could there be a non ECU reason for IGF voltage to be so low? Could the one capacitor not replaced be causing the problem?
I've put a wanted to buy ECU request on the forum in the hope that someone has one they do not need.
Further problem. My suspension has now lost air. I didn't have this problem previously and wonder if this has been caused by lots of cranking. Is there an easy access point to an air line which I could modify to pump the suspension ?
Thursday, October 05, 2017 - 02:01 pm, by: Ian Miller(Rellim)
Mike, A few photos of circuit board. I note 4 per post. This gives an idea of the board around the caps. One photo shows a fair amount of discoloration around other components, particularly resistors but this discoloration is not apparent under a magnifying glass. I can post more but I'm disappointed with the quality. If you think it's worth posting let me know.
Thursday, October 05, 2017 - 06:41 pm, by: Ian Miller(Rellim)
OK Thanks Mike I'll do my best to check that area of the board. I'll try and get better photos too. I hadn't thought of leakage like you suggest, not that it is of much consequence as I suspect it's not designed to be removed and refitted.
Thanks for your help. I guess I just pray for an ECU to come up.
Sunday, October 08, 2017 - 01:40 pm, by: Ian Miller(Rellim)
I've got a guy lined up to have a look at the board in the next few days. He repairs these types of boards and much smaller as a full time job. I'll keep you informed as to what he does and what he finds. My computer went down on Friday so just up and working again.
Monday, October 16, 2017 - 02:07 pm, by: Ian Miller(Rellim)
CPU board has now been checked. Capacitors close to chips such that careful examination was not possible were removed and replaced. Examination showed slight previous leakage damage on the board with the single cap but tracks had not been damaged. No track damage around any of the other caps and no damage near the HC345 component. CPU reinstalled into car. No start. No 5v reference voltage so looks like a blown chip. My guy is going to try and trace the 5v circuit but with little or no identifiers on the components repair doesn't seem encouraging. So still looking for a replacement cpu
Tuesday, January 08, 2019 - 03:22 am, by: Tsai lue(Tsai606)
Hi guys
I have a soarer and it cranks but won’t start. I have no engine light on my dash and no spark. At some point I had fuel going to the motor too. Any ideas on a fix?
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