Very Hard To Start Cold

[Flash89]

ok ok, on my rb20 180sx, it is very hard to start when its cold,

here how it goes

first crank, engine will just turn

second, engine will turn with some sound of it firing

third, this time with foot flat on the acc it will fire up cough a lil then stall

forth, same thing but try to play with the acc lil

fith and sixth, pretty much just play with the throttel till it actually starts.

once its warm its much easier to start but i still have to give it a lil throttel tho.

sooo any ideas

[mad082]

ok, few things to start of with,

does letting the fuel pump prime before turning it over make any difference?

how old are the plugs and what heat range? and have you pulled them out to see if they are fouled at all?

tried cleaning the AFM?

tried cleaning the IAC, AAC and cold start valve?

[Flash89]

plugs are new, cleaned the aac and the cold start valve, still the same. and tried another afm.

car starts easy when you have it in limb mode (with out the afm plugged in) whats the iac????

Edited January 10, 2010 by Flash89

[mad082]

IAC = idle air control.

but if it is starting without the AFM plugged in that the AFM may be the issue. also how long do you let the car crank for each time?

[Flash89]

been a while but still having this prob, i let it turn for about 5 sec or so. the colder it is the harder to start even with the afm unplugged now.

[central coast person]

Definatly a sensor of some sort or regulator, probily faulty I-AAC.

I had to price one for a skyline today having the same problems. Its about $700 new from Nissan.

If you pull out the throttle position sensor plug aswell it should go into limp mode as well (just to confirm it is not your AFM pull the Throttle position sensor plug out, the ecu should just be going into limp and running of a maped graph)

[Flash89]

pretty much the same deal when i unplugged the tps.

i got a custom forward facing plenum and i am running stock ecu, would this have anything to with anything?

[pipster11]

try unplugging the coolant temp sensor (2 pin connector on the thermostat housing)

pulling this make the ecu think its cold and put it into cold start map

also sounds like you're getting low voltage to everything if its struggling to turn over the first time

try and borrow a big battery from something like a commodore and start it with that and see how you go

also, b4 you start it, turn the key all the way forwards, leave for a few secs then turn it off - repeat this a few times to prime the fuel pump, you could have a leaking fpr

[StealthX]

I thought pumping the accelerator did nothing in EFI cars?

It shouldn't make a difference when you're cranking the engine over...

[Flash89]

a weird thing with the car, the fuel pump doesnt prime, it stays on.

also i got a massive 4x4 battery in the car

Edited June 26, 2010 by Flash89

[pipster11]

a weird thing with the car, the fuel pump doesnt prime, it stays on.

also i got a massive 4x4 battery in the car

mine primes for about 10-15 secs, it seems like a long time if your waiting for it

what ecu is it running? stock rb? or aftermarket?

[Flash89]

running stock rb20det ecu

[Flash89]

i have unplugged that 2pin connector, no difference.

i have even primed.

[Zardos]

how about getting console and running a diag on the car.

This will tell you what sensor is at fault, from there if there is a senor or two that fails, you could borrow the parts and re-test.

This will also show you if parts of the wiring is damaged,

I hope this helps you.

[central coast person]

I have the exact same problem as stated above and i run a OBD scaner in my car everwhere i drive and i never has picked an error up except when my coilpacks failed once. Which said error 21.

The problem is when the engine is shaking and about too stall its not reading the right amount of air - fuel and being so in the morning on a cold start it is using somthing known as the secondary air system and not the throttle body and induction pipes.

The secondary air system is a IACV-AAC valve a few pipes and a IACV- air regulator, they open and close as the temp rises to adjust cold idle. The only problem is on start up they are feeding tghe wrong message and causing a rough start until you tap the accelorator and use the throttle body and throttle position sensor to adjust the idle up.

One of those two parts or even both could be stuffed on your car and thats why its such a rough start up. Its about $428 (my price) Retailing ($900+) for a AAC valve and i cannot price the regulator up yet as the part number is a dead end and ill need to use the 2010 FAST program at work as i only do mazda parts in the office up the road and only have old fast on my home computer.

[Flash89]

http://justjap.com/store/product.php?produ...=332&page=3

is this the other thing you are talking about.

i thought i will also let yous know when the car is running, when i try to adjust the idle screw the revs dont change.

so could that link above have anything to do with that?

[central coast person]

Thats one of the 2 parts. That regulator is the GTR one and is not the right one you want, 22660-08u00. I will price it at work tomorrow.

You should definatly look into the AAC valve more so because it should adjust when you turn it because you are opening the valve, It may just be conjested ........ still mine is faulty and it adjusts idle

You should take it off and check it.

[central coast person]

dealer price is about $125 so retail would be $200-$300

[larlok]

Sounds like it is flooding check if the vac line to the fpr is full of fuel if it is, it needs replacing, also if it has been flooding best to replace the plugs because they will be coated in fuel residue.

Joe

[pipster11]

on my 32 i thought the old start valve (one you guys are talking about) was dodgy so i plugged up the line running to it and disconnected the electrics to it

grab some carby cleaner and take the idle valve off (its on the back of the plenum)

give it a good clean but make sure you dont loose any of the springs

it could be caked up with carbon/grime deposits