intermittend Check Engine Light ... code unobtainable (1 Viewer)

[hatzlibutzli]

97 FZJ 80, European spec., delivered to Finland, no OBD2, 1FZ with 360 000 km on the clock.

for the last 2000 km (starting in the dunes of Grand Erg Oriental/Sahara desert) the CEL came on intermittendly. When trying to get a code with the paperclip method: continuous blinking and after restart light was off.
Then some loss of power again intermittendly.
After retorquing the exhaust flange after the Catalysator: everything gone for 500 km. After the ferry over the mediterranian it came on again, after a restart complete normal behaviour for 600 km.
No oil comsumption, no coolant loss, temperatures never over 85°C/185°F.
I am inclined to blame the O2 Sensor getting sometimes air enriched exhaust fumes.

Any ideas, where to start the troubleshooting?

Thank you very much!

Regards Simon

 

[hatzlibutzli]

Sorry, may I pop it up again. Nobody with an idea?
Change fusible links on just suspect?

Thank you for your brains!

 

[Irish Reiver]

Have you checked the basics such as vacuum leaks or identified other symtoms such as poor idling, increased fuel consumption?

 

[Broski]

I don't thing it's the fusible links I would check the O2 Sensors first
Do you have a FSM ? if not you need to down load it !

Your not giving much to go on and that's most likely why your not getting any help.
There are guy's way smarter then me on the board that should chime in

 

[hatzlibutzli]

No vacuum leaks, no poor idling, idling @650 rpm, fuel consumption was ok with 23 Liters/100 km in heavy dunes and 16 l/100 km on the highway.
Yes, I have all the FSMs.
I would love to give you more, like a CEL-Code ... but they are not obtainable ... when I check with the paperclip method they are gone and I do not have a OBD 2 port, where I could retrieve them while driving/running.

Thank you!

 

[Irish Reiver]

If you are not getting anything consistent to work with AND you have no other symptoms then leave it until it starts to register a code proper. No sense in chasing ghosts for no apparent gain.

 

[hatzlibutzli]

Thank you for your efforts.
In the remoteness of the central sahara (comparable to the trails of central Australia) I maybe get a little obsessed with the reliability of my vehicle.
Please be lenient
I will try to uncover the mistery by dayly driving it here in central Europe! I will report back!

Regards from the Alps ... Simon

 

[BILT4ME]

Thank you for your efforts.
In the remoteness of the central sahara (comparable to the trails of central Australia) I maybe get a little obsessed with the reliability of my vehicle.
Please be lenient
I will try to uncover the mistery by dayly driving it here in central Europe! I will report back!

Regards from the Alps ... Simon

What conditions were you operating when the CEL would first come on?
Full throttle
Half throttle
Idle

25 KPH
50 KPH
100 KPH
150 KPH

From a stop to speed
Driving steady
Going uphill
When decelerating

Look at your intake tube from the air filter to intake manifold. It may be cracked.

How many KM on the truck?
When was the last ignition service (cap, rotor, plugs, plug wires and are they Toyota)

 

[hatzlibutzli]

CEL came first on while drivin heavy dunes, Throttle pos. maybe half, not more than 10 km/h (6,2 mi/h), gearbox locked in 2. gear (2nd start and 2) then again 2 days later, same conditions. Then 3 days later constant driving on highway 110 km/h (68,3 mi/h). That one was constant for 2 days and came on only, when the car was warmed up @ 80 °C (176°F) Then after retightening the exhaust flange after the cat (it was rattling) the CEL was gone for several days an 500 km (310mi). Came on again on the first acceleration after idling in the customs queue for 1 h. Again spontanous repair for more than 600 km (372mi) after stopping for taking a leak.
Intake tube is not cracked, but I will look again.
360 000 km on the truck, (224 000 mi).
All ignition parts new with original Toyota parts about 8000 km (5000 mi) back, Plugs are NGK Iridium

Thanks Simon

 

[mudplacement]

Ive had a similar random phantom check engine on odb1 truck, turns out there was an exhaust leak which was upsetting the O2 sensors. Was apparent in colder temps and when left idle overnight. Listen for your exhaust leaking and fix that if you can.

 

[BILT4ME]

CEL came first on while drivin heavy dunes, Throttle pos. maybe half, not more than 10 km/h (6,2 mi/h), gearbox locked in 2. gear (2nd start and 2) then again 2 days later, same conditions. Then 3 days later constant driving on highway 110 km/h (68,3 mi/h). That one was constant for 2 days and came on only, when the car was warmed up @ 80 °C (176°F) Then after retightening the exhaust flange after the cat (it was rattling) the CEL was gone for several days an 500 km (310mi). Came on again on the first acceleration after idling in the customs queue for 1 h. Again spontanous repair for more than 600 km (372mi) after stopping for taking a leak.
Intake tube is not cracked, but I will look again.
360 000 km on the truck, (224 000 mi).
All ignition parts new with original Toyota parts about 8000 km (5000 mi) back, Plugs are NGK Iridium

Thanks Simon

I would agree that it's pointing towards O2 sensors and it's giving either a lean condition or rich condition.

Definitely check over the exhaust and look at the eye on the exhaust down pipe, as they are known to crack there. It could be letting in oxygen and messing up the readings.

Fix all exhaust leaks.

The FSM should give a list of non-permanent codes. I believe lean condition will not lock in, but may show a light until the condition clears.

 

[hatzlibutzli]

Found the exhaust gasket after the cat crumbled to pieces. Now replaced ... I will report, if it solved the problem permanent!

Thank you for all your valuable comments ... Simon