Saturday, October 11, 2014 - 08:20 am, by: Mees Godwaldt(Mees)
Hello all,
My Toyota Soarer is running rough. Recently decided to change the spark plugs as the seller claimed that this would fix the rough running. As I was pulling out the old plugs I found that the plugs of the centre 4 cilinders (3,4,5&6) were completely black. I thought this was strange but put the new plugs in anyway.
With the new plugs I'm still experiencing nasty misfire's. I hooked up a oscilloscope to check the injector signal's. And I've found that the centre 4 injectors get 2 signals. So they are opened twice instead of once. Resulting in a way too rich mixture in those cilinder's, resulting in misfire's.
A little bit of research led me to believe my ECU might be faulty. We hooked up the oscilloscope to the ECU internals to see where it's going wrong. (Risky I know). The transistor signals from the driver chip (transistor array chip) seem to be in order. But somewhere in the end stage powertransistors for the injectors, the signals of two injector groups get combined.
I'm now looking for a replacement ECU (pn. 89661-24220) but I can't seem to find one ANYwhere.
I just found a SC400 unit from 1996 (pn. 89661-24453) and I'm wondering if this will work.
Also, if you need an ECU fixed (recapped) - give this guy a call. He will do it for $75. A friend had his done a few months ago and his car came back to life. No issues so far.
Sunday, October 12, 2014 - 12:47 am, by: Jamie Richards(Nwb40gt)
My car is jap-import as well, i got the ECU plugged right up pulled the main fuse gave it some time to reset and she fired right up. The only thing i notice with my car now is that its not as aggressive as it use to, the power is there but comes in a lot smoother now, which i believe is because the Lexus would have a smoother power curve because its all about luxury. But other than engine still runs great
Sunday, October 12, 2014 - 08:52 am, by: Mees Godwaldt(Mees)
Tom we measured the removed caps with a Phillips PM6303 RCL meter. And the capacitors we didn't remove in fear of damaging the multilayer printboard we tested with the capacity function of a multimeter.
Tomorrow we're gonna hook up the oscilloscope again. To make sure we're not missing anything. At the end of the day this stuff is my dads profession. And he can't comprehend why we haven't figured it out yet .
If we're still drawing a blank tomorrow I'll be ordering a replacement ECU.
Sunday, October 12, 2014 - 12:39 pm, by: Rob Charles(Pearl_white)
Hi Mees, a sign of a bad ECU is also that it overfuels and causes misfires on certain cylinders - and your plugs die.
I highly suggest replacing ECU capacitors regardless if it checks out 'ok'.
The ECU's in these cars (the caps) break as they get old. Caps burst and leak over the board. Caps might also not have any evidence of failure. "This is an age and standing up issue - A junkyard ECU won't fix it".
You should seriously consider getting the ECU recapped by the person i mentioned above (or walk in to any electrical tv repair shop...)
Most ECU's break after around 12 or so years. All Soarers are over 12 years old now.
If somebody works on your ECU and breaks it - They will replace the part for you via warranty, if they work in a shop or what not.
The other thing which I read the other week was that If you have alternator issues with the soarer, plugs can foul, and cats can glow.
At $75 for a full ecu repair, you should consider it before you go spending hundreds on something you don't need.
Remember - a junkyard ECU is going to be ruined also due to age. So either recap your current one, or buy a junkyard ecu and recap that instead. This way at least you have your current ECU to fall back on
Sunday, October 12, 2014 - 03:08 pm, by: Tom Richards(Tomr)
not a 100% test what you have done.( you are not testing any change due to temp, and not under voltage. I am not sure if your device checks leakage or only capacitance)
You will find "really stuffed" caps but not the "I am working at below 100%" ones.
Sunday, October 12, 2014 - 04:15 pm, by: Matthew Salkeld(Munkymatt)
I don't think there are any caps on the injector output channels anyway; there's a real gung-ho attitude on soarercentral which declares that any problem that might be related to the ECU is caused by bad caps... I think any competent electronics repairer will be able to figure it out.
Many of the injector related problems I've read about concerning soarers come back to degraded wiring and shorts of that nature, so it might pay to look past the ECU (unless you've isolated the problem to the ECU already).
Monday, October 13, 2014 - 05:28 am, by: Mees Godwaldt(Mees)
Well today was a bit of a bust. We took de ECU apart again to replace all remaining caps. We also extensively checked the injector wiring. No anomalies could be found (with a multimeter). We also tested the injector groups by manually connecting the female ECU pins to ground and listening with a stethoscope. I'm now sure the wiring is not the issue.
When we then put the ECU back in and tried to start the car again the battery died. So grabbed another one and got the car started. The misfire problem is still there, no change. However we managed to screw up the ecu connectors of the car with the measurements. So when I rotated the ecu to hook up the oscilloscope the car started running even worse. Eventually stalling.
So now we have two problems
I just contacted another forum member about a refurbished ECU.
And I'll be replacing the bad ECU connector (female) pins this week.
Monday, October 13, 2014 - 10:28 am, by: Dave Rose(Sand_groper)
Sounds as though the car is in cold startup mode ? extra signals to rich up mixture , could be a sensor problem , Jamie, the US one would be sequential injection same as 96-97 JP ones ,should be better on fuel.
It was a bit of a wait but that's not a surprise as I live in the netherlands. It was definitely worth it however. I did end up putting the old sparkplugs back in as with the new plugs the engine was still not running completely as it should. Turned out the sparkplugs I bought were not the right ones.
Thanks everybody for you're help!
Peter Nitschke Junk Filterer South Australia UZZ30 UZZ31