Hi folks new by to the 80 scene and already in need of some help , purchased a 1993 1FZ and all was fine for a day or so but now the car will stall when stopping at junctions and unless I’m 90% throttle or above it will slowly die almost like it’s running out of fuel. I’ve swapped fuel pump and filter when I got the vehicle due to mileage but I’m thinking it can’t be fuel as it will drive all day at full throttle, the problem I’m having is the check engine light doesn’t seem to work to extract some codes I’ve swapped bulbs and still nothing so I’m kind of at a loss really
Check engine light not working (1 Viewer)
- Thread starter guygreenwood
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- engine light stalling
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voodu3
SILVER Star
Does the light come on at all? If you don’t have CEL when you turn the key to on before you start the truck it’s most likely a bad ecu. Look at the ecu trouble shooting in the FSM it will help.
- Thread starter
- #3
No light at all. Not when key on or when diagnostics are linked out
voodu3
SILVER Star
No light means the ecu isn’t getting the correct signal from the EFI relay. I’d unplug the relay clean the contacts and put it back in after 10 minutes or so and see if you get cel. Attached is the ECU pages from the FSM. Follow the service hints for troubleshooting.
If the EFI relay was faulty, this engine wouldn't run at all (no power to fuel pump/sensors/etc).
Without the CEL with the key in the ON position before cranking the starter, this engine wouldn't run at all.
There's something else going on here.
Is the 10 amp GAUGE fuse intact?
If the OP can't get the CEL to illuminate while checking for codes, then either the bulb that he replaced is faulty, the traces on the cluster are faulty, or there is no continuity between the ECU connector E7-4 and the CEL.
As stated in a previous thread, the OP should be able to see a logic low on pin 2 of the diagnostic connector on the firewall when the CEL should be illuminated.
Or he could ground that pin with the key in the on position and the CEL should illuminate. That essentially removes the ECU from the equation.
- Thread starter
- #6
Thankyou mate I shall do some checks and report back
Welcome. Please follow jonheld's advice; he *really* knows what he's talking about.
- Thread starter
- #8
Hi mate, the 10a gauge fuse is intact as I checked that whilst changing the bulb. I’ve tested the bulb in another slot and illuminates but nothing more as I wasn’t sure which direction to head in to be honest so came to here for some help
- Thread starter
- #9
Carried out some checks today and it turns out the wire out the ecu to the CEL had been spliced into for what I can only imagine was an old lpg kit. I removed the splice and now I have a CEL but reading codes just gives me a repeated flash which I understand means no faults , now my issue with the vehicle is that on 100% throttle it will rev and have plenty of power but as soon as you ease off the throttle to say 80% after a coupe seconds it starts to die and will eventually come to a halt with what sounds like popping from the exhaust until you let off the throttle and try again which it will take off fine but then the whole process of slowly dying starts over again. As I said I’m good mechanically but I’m really lacking in the diagnostics and testing of an old 1FZ so any help would be greatly appreciated
I am no expert and someone may have to correct me on this. But I believe the OBD1 rigs have to be cycled with 2 separate drives before you will see codes. The first time the codes are thrown the ECU stores it into what im guessing is the "RAM". And once the codes are thrown a second time is when the ECU will display them on the CEL light.
If my statement is correct. You could possibly have a really out of wack Throttle Position Sensor. But it seems unlikely if your rig drove alright for a whole day. I would start at looking at vacuum hoses first.
I would also suggest going through the FSM. Possibly the most useful thing when diagnosing issues.
If my statement is correct. You could possibly have a really out of wack Throttle Position Sensor. But it seems unlikely if your rig drove alright for a whole day. I would start at looking at vacuum hoses first.
I would also suggest going through the FSM. Possibly the most useful thing when diagnosing issues.
