1998 petrol 1.8 Avensis starting problem

August 13, 2016

Hi, my lovely Avensis station wagon has a starting problem, i only see in the mornings.

When i turn the key on, the starter runs fine, so i assumed the Battery was fine.

As i kept trying, after a while i had a short fire up in the engine, but at that point a think i may have drowned it, if that's possible.

Then after several attempts it came up running, but certainly had it problems running steady, then after a few minutes it was steady, all day. No starting problems the whole day.

Next morning, the same thing happend. I suspect some moist in the ignition cables, and changed these along with the spark plugs, as they have runned more than 100.000km at that point. I checked the plugs, they seemed to have the right look according to the Haynes manual.

Next morning, same problem! Now i took the ignition wire off from one of the high voltage transformers(there are two) and had a wire going from the one output of the transformer, close onto the chassis to see if there was ignition when i turned on ignition key. It was clearly very unstable, but after some while it came on and acted the same way as the day before. Then it ran steady.

I can drive all day, turn on the engine any time without starting problems. Next morning it's the same.

I checked the connectors to the ignition coils, they look fine. I measured the resistance between the secondary coils, it's about 13 Kohm on both coils. I measured a 12volt DC and a 5Volt DC on two pins going into the ignitions coils, coming from the ECU box.

Then, i tried taking the connectors out from the ECU box to check if it had bad connection, (had followed the cables backwards and checked them for any signs of tear, but they are fine) it looks very fine, and as i plug it in and turn the ignition, the engine fires up and runs fine! Aha! i suspect the connectors or the ECU box, i split the ECU box apart and takes a visual inspection, and it looks very very fine, no corrosion on any pins or on the PCB, and apparently no cold soldering. But of course, i can go them through with a soldering iron to be sure.

So it leads me to the conclusion it may be the connectors, i sprayed with Contact 61, which i have good experience with. This did not solve the issue, the next morning it's the same. I unplugged the connector from the ignition coils going into the ECU box, and expect it may solve the matter if i wiggle it. But no! i just don't get the logic in any bad connections but after a long time suddenly the engine starts up after a long time with absolutely no firing up on any cylinders. The unplugging and plugging in does have an effect.

I have search for errors on the Internet, and am now interested in asking you guys for what to look for. I checked the connector on the camshaft sensor, and checked the connectors for so many things and still suspect moisture as it does this in the mornings after a night with humid.

Can i read out any code from it? I can't find any text saying it's ODB2 certified, but i find a diagnostic plug right above the fuses in the drivers side (left, European)

I have multimeters, oscolliscope, Haynes manual with some schematics, but i am a bit lost now where to go next. It's an old car, i bought it fairly cheap and i am really really happy for it, and kind of like solve these things myself before i throw the towel into the ring, and drive it to Toyota. If i can drive it :-)

What would you recommend to check, of scanner tools, or how to read out diagnostics without.

Best regards, Michael A. Jensen, Denmark