hi guys. hopefully someone will come up with some fresh ideas i haven't tried yet. when i bought the car it was perfect. started first time after very minimal cranking. cold, warm, hot, it didn't matter. then out of the blue one day it decided not to start when cold. If i treat it like a carby car and give it some throttle when i start it (i know your not meant to) it will fire up on the 2nd or 3rd attempt but will backfire and pop and carry on initially and then the revs will flare up. i sort of stab at the throttle while its doing it until the revs do normalise which is normally about 5-10 secs. have fiddled with cold start enrichment. tried richer. leaner. no real difference. all sensors seem to be reading o.k. in that they are giving the right sort of figures. coolant temp, air temp, tps etc. after 2 minutes after starting everything will be o.k. idle is o.k. if you turn it off it will start ok. if you leave it for a couple of hours it will be ok. after about 6 hours it is showing signs of being a pig but will still start normally. only when left o/night is when it has issues. (or for similar lengths of time) injectors don't seem to be leaking. running out of ideas.

plugs and leads and all that sort of stuff is o.k. factory ecu is replaced with one from brad's (waggin) eb 5.0 that he wrecked. old one was no good. i'm also running microtech in a piggyback setup. settings are staying constant now with new factory ecu but still no cold start. like i said before. once it fires up and you help it to idle for about 2 minutes, then it is fine.

someone must have some ideas!

Sounds like your ISC on the throttle body may be the problem. Have you tried cleaning it? Or the MAF sensor, try giving that a clean too.

isc is fine. no maf. mafless. thanks for trying though. that is what i'm after. people just throwing some ideas out there

why is it mafless? tuned without one?

yeah it is tuned without one. not exactly legal but you get that.

most quick gen3's run mafless as did the 300kw gts from factory. not sure what setup ba's have and fpv's.

Seems like the tune...
If you say its popping while cranking, and if you need to open the throttle to get it to start, try advancing your cranking ignition timing.

Check your cranking pulsewidths when cold, it might be dumping in too much petrol while cranking.

Check your timing, did you play with the distributor? Maybe you moved it back, and forgot about it?

I don't think its any sensors, because it goes into cold start/cold run mode, so it sees the temperature, and then it runs fine so the other sensors should be fine aswell.

When did it start doing all of this?

Cheers

PS - Why did you choose to go mafless? huge mods? So Im assuming you're using Alpha-N for tuning?

Not all aftermarket ECU's support MAF, and those that do don't always support OEM MAF's.

i'm not the one doing the tuning. i don't have a hand controller. even if i did i wouldn't know what i was doing!!

all modifications were done prior to my purchase. it has stage 3 crow cam(not sure of number) and apparently the previous owner was told factory ecu wouldn't cope. when i bought it and for the first week i owned it it was fine. started and idled like a factory setup. then one day i came out of work and it wouldnt start. no warning. just out of the blue. have replaced factory ecu and trans is much better now and also more economical (prolly due to trans better). tuner (boostworx) needs to get his hands on it when its cold and i haven't been able to give him the car yet. hopefully it is just a tune thing. tried going 10% leaner and then richer and it seemed better when richer.

dizzy hasn't been touched. timing is apparently controlled through the microtech. ( i asked the question)

thanks guys. i think i just have to leave it with him o/night so he can see what is happening when cold.

timing would be controlled with the microtech, but the base timing is still a variable.

But yeah, give it to the tuner to assess, doesn't seem like a hardware problem to me, but who knows.


Cheers

I have the same problem, and after spending over tw0 grand replacing parts that didnt need replacing and hefty labour charges all under the reccomendation of notable mechanics, I have learnt to live with the problem. Sorry I couldnt be of more help, but Im now penny wise and pound poor.

Try the fuel pump relay under the coolant reservoir.

I had the same problem replacing the relay fixed the problem.

This relays turns on at start up to prime the fuel rail and if faulty causes low fuel pressure.

i thought about that but then talked myself out of it because i thought that a relay either works or it doesn't. they are an $80 part so i don't really want to try if it doesn't work. what exactly does the relay do. the fuel pump primes o.k. is there a way i can check the relay.

You can check if the relay is working by shorting out a pin on the diagnostic pin.

Its the top right pin, very right.

Fuel pump relays can be sometimes intermittent, but I dunno. Worth a shot I guess.

Oh, and by short out, put a jumper on the very top right pin, and bring that to ground. You should hear the fuel pump start running.

If you can hear it run (which you probably will), and still have doubts, get under it and find the fuel pump relay (the green one under the coolant overflow bottle from memory), and short out the two fat wires.. they should be Green/Yellow on one side, and Black/Yellow on the other.

This will bypass your fuel pump relay completely. (make sure you use a big enough guage wire so nothing melts/catches fire).

Cheers

Under fault conditions if you tap the relay with a screw driver you'll hear it "chattering" if its faulty. That was how I finally found the problem with my EB.

Prior to that I replaced everything from fuel pump to ignition components.