runs for 1 second

[tuck80]

Just bought an 83 supra that was running in Nov last year.
It is in reasonably good nick (owned by a lady) and has only done 122000km's, it was sold to me cheap as it wasnt running when they tried to fire it up at the start of january.

After a bit of fresh fuel and a new battery I could get it to run for about 1 second before it cut off.

My brother is convinced its the AFM but were trying to get a hodl of a wiring diagram so he can prove it before I go out and buy a new one.

I saw a link on the forum to a TSRM for a '86 supra.. is the 86 mk2 the same as the 83?

Also today I went to change spark plugs/leads on the car and found some serious corrosion under the lead going to the coil.
Going to try to source a new one of those tomorrow.

Could that be the problem ..? Just a bad connection to the coil?

I'm just starting to learn about these cars so this might sound a bit clueless..

[oldcorollas]

that one second could just be the fuel injected during cranking perhaps?

[river]

Hi,

A common problem with a engine starting, then running briefly, and then dying is the ballast resistor. Check the ballast resistor and make sure it has clean connections and that it's not open-circuit.

seeyuzz
river

[hi-ace]

An old trick that I use to determine if an engine starting problem is fuel or electrical. Is to have someone try to start it, while you give it a couple of sprays of "AEROSTART" down the air intake. If it starts and runs, it's a fuel problem. If not then it's electical.
Remembering, that most of my experience has come from PRE-EFI motors.
Someone more up on EFI might be able to confirm this.

[JustCallMeOrlando]

It *does* sound like the AFM. My car would do that whenever I disconnected the AFM. First thing I'd do is check all the connections are good and not corroded, and if you're handy with a multimeter it wouldn't be hard to work out if it's not working.

[EldarO]

An old trick that I use to determine if an engine starting problem is fuel or electrical. Is to have someone try to start it, while you give it a couple of sprays of "AEROSTART" down the air intake. If it starts and runs, it's a fuel problem. If not then it's electical.
Remembering, that most of my experience has come from PRE-EFI motors.
Someone more up on EFI might be able to confirm this.

did this for mine, although my mate nearly set his hand on fire when it backfired...

but yeah, what hi-ace has said sounds very much like a good idea, as is what river said.

i know with my AFM disconnected, i could drive it down the street before it died (15 meters max), but maybe the karmaan vortex and flap types are different.

Eldar.O.

[Dylo]

I had this problem, and it turned out to be a massive vacuum leak in the break booster line.

It could be many things, this is just another idea of something to check.

Dylo

[thechuckster]

running for one second suggests the fuel-pump switch in the AFM isn't working so the engien is trying to run off the cold start injector.

edit: this might be wrong - maybe the power to the injectors isn't working so the only injector firing is the CSI

[JustCallMeOrlando]

The circuit opening relay has two triggers, one from the AFM, and one from the starter signal. It's not always the cold start injector, sometimes it's trying to run from the bit of fuel provided by the starter running the fuel pump.

Failing that, it could be a dirty great leak, the AFM's are so fussy.

[wilbo666]

I like the chucksters take on things.

Cheers
Wilbo

[parrot]

I'm with chuckster too. Check your injector circuit, especially voltage at one of the injector plugs when cranking. Should be battery voltage. If not, trace back and find out why, if yes, injectors mabe dried out and clagged and need a good out of car clean. I reckon it is running on the brief squirt of fuel you get from the cold start injector. Presumably unlikey that the circuit would go down, unless someone before you bought it was playing with it. But if it has been sitting with little use, i would suspect the injectors.

[tuck80]

alright thans guys.... will take that on board..

I have been able to ascertain that the injectors are pulsing and you can smell fuel.. the rest of I'll check out this weekend... appreciate the advice

[thechuckster]

fuel smell could be the CSI .. disconnect the connect or the back of it and try again... if it does the same then ignore everything i say



oops, some more advice (feel free to ignore):

nearly forgot, take air filter off front of AFM, get person to sit in back of car, put ignition to IGN (but not star), you push air flap in/out and see if the person in the back hears the pump turn on/off. You can also check this by bridging the 2-pin connector in the loom right next to the AFM connector.... this is to check fuel pump operation.

If pump is good, undo fuel line on back of CSI, does fuel spray everywhere (breifly)? if so, then you have good fuel pressure. If not, then put connector into a sizable container (e.g. 2 litre coke bottle), disconnect the power leads to the coil (sparks at this moment would be very bad for all involved), put ignition switch to IGN, short connector noted in previous paragraph, see how long you take to get 1 litre of fuel... this should happen reasonably quickly otherwise pump is not doing well.

You could put a pressure guage in place of the CSI fuel line instead of the dodgy flow test suggested above and see how much pressure you have with IGN power on and conenctor shorted (should be 30-38psi).

note: to do 2nd item, please have fire extinguisher or hose handy - and put out any cigarettes or other kerboom-inducing items.

[Hydra]

Usually, the fuel pump is switched on when the engine is cranking, and once it starts the AFM FPR switch takes over, keeping the fuel pump running.

That single wire has always being a pain

[love ke70]

have u tried unbolting the fuel rail and lifting the injectors up, then crank the motor.
they should shoot little squirts of fuel across the shed

if they do, try something else. if they dont, bonus, problem identified.

id be changing the plugs and leads on a motor that has been sitting anyway, esp. if there is corrosion.
thats just gonna make things harder