presterone
Well-known member
Ok so 92 6-bolt. No codes stored in the ecu. CEL comes on sometimes but only on Decel and then goes away as soon as I step on the gas.
When I am cruising the car bucks harshly intermittently and when it happens my AFRs peg to like 10.0-12.5 at highway cruising speeds. It seems to do it less when the coolant temp sensor is unplugged but it still does it. The whole car jerks when this happens and it will do it so randomly. The only thing I can link this condition to is maybe the coolant temp.
I have been having this issue where I am driving on the highway and the ECT will climb to the last notch on the gauge so (3/4 of the way maxed out on the gauge) and then the thermostat opens or something and the ECT gauge drops rapidly and stays in the middle where it should. This condition happens even after a five minute drive or so. So the surging will still happen before the car gets up to normal operating temp (sometimes once again its very intermittent). So about the setup. New cylinder head after T-belt snapped,OEM MLS headgasket, ARP studs, big 16G turbo with speed density ECU(jackal) so there is no Air flow meter in this car. New OEM thermostat, aluminium ebay radiator, coolant system flushed several times. New NGK BPR7 or whatever the one step colder plug is.NGK wires, 720cc injectors.Fuel lab adjustable FPR New 255lph inline pump. Swapped a power transistor from a good running 1G laser.
Note: I had a TPS code a while back and since adjusted it and I have no reoccuring fault codes. Note: I have a very slight coolant leak near my coolant distribution pipe. So I am thinking maybe there is air getting in my cooling system causing the fluctuating coolant temp.Bad waterpump? ECU getting a funky signal from the temp sensor? Maybe a loss of spark intermittently is causing the AFR to go really rich? I am just trying all ideas because its so sporadic and is such a bitch to diagnose.
When I am cruising the car bucks harshly intermittently and when it happens my AFRs peg to like 10.0-12.5 at highway cruising speeds. It seems to do it less when the coolant temp sensor is unplugged but it still does it. The whole car jerks when this happens and it will do it so randomly. The only thing I can link this condition to is maybe the coolant temp.
I have been having this issue where I am driving on the highway and the ECT will climb to the last notch on the gauge so (3/4 of the way maxed out on the gauge) and then the thermostat opens or something and the ECT gauge drops rapidly and stays in the middle where it should. This condition happens even after a five minute drive or so. So the surging will still happen before the car gets up to normal operating temp (sometimes once again its very intermittent). So about the setup. New cylinder head after T-belt snapped,OEM MLS headgasket, ARP studs, big 16G turbo with speed density ECU(jackal) so there is no Air flow meter in this car. New OEM thermostat, aluminium ebay radiator, coolant system flushed several times. New NGK BPR7 or whatever the one step colder plug is.NGK wires, 720cc injectors.Fuel lab adjustable FPR New 255lph inline pump. Swapped a power transistor from a good running 1G laser.
Note: I had a TPS code a while back and since adjusted it and I have no reoccuring fault codes. Note: I have a very slight coolant leak near my coolant distribution pipe. So I am thinking maybe there is air getting in my cooling system causing the fluctuating coolant temp.Bad waterpump? ECU getting a funky signal from the temp sensor? Maybe a loss of spark intermittently is causing the AFR to go really rich? I am just trying all ideas because its so sporadic and is such a bitch to diagnose.
