Weird starting problem until AFM kicks in...
10-23-09, 07:09 AM
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Weird starting problem until AFM kicks in...
Ok so I have this weird problem. When the car is cold, meaning has been sitting for 12 hours or more, if I want to start it, it will, but it'll shut off immediatly...and this 5 or 6 times with the throttle lightly pressed to get it up to 3000rpm for around 10 seconds (or else it dies continuously). After these 10 seconds the car is 100% fine, rock solid idle, perfect, like nothings wrong.
It would seem that the car has a real hard time staying alive on until the afm kicks in...or it would seem. A/F readings are in the 18s and above and throttle play is incredibly sensitive for those first few seconds...Just a bit to much or not enough throttle and it dies just like if I ran out of gas...
The car's an 88TII, no emission, racing beat exhaust, 12PSI (SAFC, 720, the works...), removed cold start system, still has BAC valve and coolant through TB, Double throttle removed, TB is fine all checked, grounds are all perfect, fuel pump is rewired and......some other stuff I will surely remember when you guys ask...
Any ideas?
Spec.
It would seem that the car has a real hard time staying alive on until the afm kicks in...or it would seem. A/F readings are in the 18s and above and throttle play is incredibly sensitive for those first few seconds...Just a bit to much or not enough throttle and it dies just like if I ran out of gas...
The car's an 88TII, no emission, racing beat exhaust, 12PSI (SAFC, 720, the works...), removed cold start system, still has BAC valve and coolant through TB, Double throttle removed, TB is fine all checked, grounds are all perfect, fuel pump is rewired and......some other stuff I will surely remember when you guys ask...
Any ideas?
Spec.
10-23-09, 08:47 AM
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18 afr is Really, really lean. Is it that lean when the engine is fully warm at idle?
AFM should be the main delivery tool once the rpms are over 500rpm. Below 500 rpm there is a internal START map for fuel and the AFM isn't used below 500rpm.
You might check the water thermo sensors input to the ECU on pin 2I (green/white wire). It should read something like 2-3vdc with a stone cold engine and read approx a half volt with a hot engine.
If 2I reads real close to 5vdc when you check it, then the sensor is disconnected at the back of the water pump. Check the voltage by backprobing the wire with the plug and all other plugs connected up to the ECU.
In other words I don't know but try the above to give you a clue.
One of the first things I think of when a COLD engine won't stay running or is hard to start, is if the water thermo sensor is working/connected up and if pin 3B (Blue/Black wire) is seeing batt voltage when the key is HELD to START. Either of those items can cause difficult cold starting.
AFM should be the main delivery tool once the rpms are over 500rpm. Below 500 rpm there is a internal START map for fuel and the AFM isn't used below 500rpm.
You might check the water thermo sensors input to the ECU on pin 2I (green/white wire). It should read something like 2-3vdc with a stone cold engine and read approx a half volt with a hot engine.
If 2I reads real close to 5vdc when you check it, then the sensor is disconnected at the back of the water pump. Check the voltage by backprobing the wire with the plug and all other plugs connected up to the ECU.
In other words I don't know but try the above to give you a clue.
One of the first things I think of when a COLD engine won't stay running or is hard to start, is if the water thermo sensor is working/connected up and if pin 3B (Blue/Black wire) is seeing batt voltage when the key is HELD to START. Either of those items can cause difficult cold starting.
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