4AG starts, runs and dies condition (almost there) EDIT : IT RUNS NOW!

[Nilezy]

Good stuff

Its always good to find thats its something simple as blocked injectors, but can be hard to find sometimes!

Cheers,
Nilezy

[Nilezy]

opps, sorry for the double post!

[Grega]

Well, I've rebuilt the motor completely now. I have oil pressure as my idiot light is going out so thats all good.

I have a small problem though
I have a no start condition. Almost.

When I flick the ignition to ON, I'd suspect I should hear the fuel pump buzz OR the circuit open relay click - i get nothing. No click of relay, no buzz of pump.

I turn to start, car turns over. It sometimes fires, runs, and then proceeds to stall.

On start, I grab circuit opening relay, can feel click in the relay when key is turned to start and can hear fuel pump buzz (buzzes after car stalls) when ignition is flicked back to ON or RUN if you like.

I checked my coil for +12v in the RUN or ON position - and sure enough there is no voltage there.

From my faithful wiring diagram, there is a B-R wire which goes to AM2, which, should be flicked over to energise IG2 (RUN on ON if you prefer). I havent checked my injectors I suspect they will also be without power as the same source which powers the coil has no power.

What makes that strange is that the car does run and die, which, tells me the coil is getting power as are the injectors. Wierd.

I tried a search on here but 50 million results come up I think we need to revise the search indexes here as I'm sure I've read something similar to this before with someone.

Any help/comments/flames/thoughts appreciated.
Ideally I don't want to jump wires between here there and everywhere I want to understand whats wrong before probing things with said multimeter. Jumping wires between things may produce a result but can also lead to letting the smoke out of the wires and other undesirable effects

Cheers

[too_quick]

My pump only comes on while cranking, I can flick the key on and the pump does nothing.

Does it just cut out quickly or run shit then stall ?

[Grega]

oh OK.
must be a toyota thing
i am used to stupid VN pump firing up when i put the car to ON

she runs smoothe as - purrs - then dies

[parrot]

Check your voltage at the injectors with ignition on. Should be approx 12 volts. If they are zero, it is probably starting on the cold start injector only which only squirts a second or so.

[Grega]

parrot, injectors will be 0v also as the coil (which gets its power from the same place) has no power either...

[Cuzzo]

Check your voltage at the injectors with ignition on. Should be approx 12 volts. If they are zero, it is probably starting on the cold start injector only which only squirts a second or so.

id say thats your reason why its starting.


Harness from donor engine/car or standard harness modifyed?

[Grega]

cuzzo/parrot.........yeah thats why its firing and starting - the cold start injector is priming and i'm getting enough spark for a short period to actually run the thing then die.

the harness is completely stock AE92 SX/GTi jobbie.
I have patched it into my AE92 4AFC body loom (i ripped the stock AE92 4AFC loom out with the motor)

Some of the colors of wires actually do match up - some have had to be changed for different colors b/w the two looms which is to be expected. I do have a few wires though that are not used in the 4AGE AE92 SX/GTi ECU loom which i havent connected to the body harness such as the aircon wires.

Question : if the knock sensor is not connected would this cause a no start condition? I'd have thought the ECU would have gone into limp home mode (and the engine run) but it could be as its seeing no sensor signal that its shutting down....?

[Grega]

i have +12v at coil AND all injectors in the RUN or ON condition.
still starts runs and dies

i'll assume there is spark as it runs then dies
as cuzzo said its running on the fuel i reckon pumped in via the cold start injector ; i need to check fuel supply and the injectors are actually pulsing

[Grega]

more checks tonight
i have fuel - it circulates via the fuel rail and back into the tank no probs - u can hear it
i have 11.9v at the coil and injectors at RUN
there is 9v there when cranking/starting

i bypassed the circuit open relay as post cranking the fuel pump was shutting down - same result so thats OK

the car WILL RUN if i pump aerostart into the inlet manifold - albeit not too well which tells me i have a fuelling problem

i heard my injectors clicking/opening and doing their thing so the ECU is indeed closing the injector circuit as it should. i checked and the right injector plugs are on the right injectors.

so ; a penny for my thoughts as i'm a bit stumped

1. are my injectors possibly seized closed? i'm going to pull the rail off late tommorrow, disconnect the coil, fill the valley there with rag and see if i can get them to spray fuel?

2. i do not have a speed sensor hooked up (not using the factory ae92 SX/GTi dash) - could this be an issue and causing a fuel cut condition (but then why does the car run on aerostart?)

3. is the coil/ignitor not sending back to the ECU a succesful ingition event so its shutting things down on me?

man i'm getting confused. i have spark and fuel ; they're the things u need to make it work.

thoughts/comments ect really appreciated

[timbosaurus]

Hey Mate, I understand your frustrations... I've been going through them too

So is the coil and injector voltage 0V or 12V? Info seems to be conflicting.

Can you check the fuel rail to see if fuel does into squirt out when you try to start?

Edit: your post beat mine

[Grega]

coil and injector voltage are +12v mate no issue
and yeah fuel cases out when i try to start of the return line

[3jcelica]

Grega,

AFM or MAP? if AFM then doesthe fuel ump come on if you hold the AFM vane open? AFM systems run the pump during cranking and then have a switch in the airflow meter that holds the pump on.

Passing the previos test then try below.

Get an led with a pull up resistor(~680 ohms) and plug into one of the injector sockets. Does it blink during cranking? If so you can rule out ignition events and fuel injector events.

speed sensors from my knowledge on other systems (delco) are only used for idle control and maybe cruise. I would not think this is your issue.

Roger

[Grega]

thanks roger

its a MAP sensed 4AG 100kw motor

i'm going to get myself an injector tester tommorrow if i think on (got a busy day)
i also found another set of 100kw injectors too

yeah i come from a delco background hence my question (the usual stall coming up to a stop due to no speed sensor signal)