idle & BOOST problem

[fez200]

just had my car converted from auto to manual.

drove it for the first time today....yeeha what a difference.

the only thing is that i have a few problems now:

firstly once i back off the throttle or slows down it nearly stall everytime, it already has cut out twice..any ideas

also my car seems to be over boosting way more than it used too.

[Wolf In Sheep’s Clothing]

Had the same problem with idle dropping i tightened the bov spring so it dosnt open as easy that fixed it.

With the overboosting id just check all vaccume lines.

[LUP15]

problems might be related to each other. check all vacuum boost lines

[Budgie]

Indeed, go over the vac lines with a fine tooth comb.

I fixed another problem with mine earlier this week.  Had been incorrectly connected for months.

[fez200]

i wound the BOV right up and still no difference.

my car has sorta always done this. but ive noticed it more now since i got the manual conversion done.
eg. if you give it a quick rev in neutral, then watch the revs drop way below idle, (nearly stalls) then picks up again.

i thought it could of been my distributor cap as i took it off and the points on the inside of it look unevenly worn. but it could be something else.

i have replaced the plugs/oil/air cleaner recently with all hi performance items.

as with the boost problem, we think the new computer from the manual trans conversion or the old boost solenoid has a problem. but not to worry im getting my dual electronic boost setup installed this weekend. 

[Craazy]

the prob with idle is coz of the BOV, its venting to atmosphere isnt it?

try putting your stock one back on and see what happens, this is a common problem with hotwire AFM equipped cars and nissans especially

but the boost prob will more than likely either the boost solenoid or the wastegate, have you turned the boost up?? what are you doing to do so and how is it setup coz there are many wrong ways and one right way to do it

[JelloBello]

care to share the one right way?

[fez200]

this is really shitting me now.

the car is idling at like 1200rpm now. and has coughed and spluttered at high revs.

[Craazy]

ah i know your problem!!!

it is your AAC and IACV playing havick!! my engine does this...
cost 400 new from nissan for both parts direct from japan. check your TPS(throttle position sensor) aswell as this could be playing with your tune, if the tps is giving out the wrong signal then it uses the wrong part of the maps in the ecu and runs really badly. could also be your temp sender being stuffed, get your car hooked up to a consult, this will diagnose straight away

[fez200]

ok, so where & how do i check these.??

what is an AAC & IACV ??

its running crap eh. i checked the plugs and bought new leads today. still no difference.

[Craazy]

yeah, the IACV is the idle air control valve and is located low on the plenum near the firewall. will have a hose running from just before the throttle body down to it, the hose is about 10-20mm in diametre.

the AAC has the idle control screw in it and is generally on the timing chain end of your engine right next to the oil filter, at least is on mine anyways. this is a little harder to play with as has limited space....

now you can get the IACV out and have a look, but there is not really anything distinguishable that'd show you its stuffed, but you can test resistance and stuff like that. see if your idle control screw will turn aswell, mine is unturnable as i have found out so i know mine is screwed literally

[fez200]

you may have hit the nail on the head there.
it seems to be hesitating slightly on hard acceleration, and the idle can be either like 800, 1200 or 1500rpm

anyway i can do these repairs, how do i test resistance etc on the IACV.

or has anyone got a consult? or do i have to goto nissan?

[Craazy]

hmm im in melbourne and have a consult, noss in qld has one, but no one in between.

maybe best bet to get nissan to hook it up and have a look

cant remember best way to test but its a simple setup on the plug with a multimetre

[omad]

Just a thought, but if it wasn't doing this before (apart from it dropping off after rev, usually due to a vent to atmo BOV) perhaps the computer you have in there is incorrect for your car? It may be reading the sensors incorrectly and running the mixtures all wrong.. ?

Do you still have the old auto ECU? Would it hurt to stick it back in and see how it goes? Or would that produce much the same results as what is currently happening?

Edit - I could be completely wrong here, but it almost sounds as if the ECU you have is for an N/A car. As you are over-boosting, it wouldn't have the control for the boost solenoid, as it doesn't exist on an N/A car. And as for the running crap and hesitating etc at high revs... there's no maps for that amount of air etc on an N/A. It'd just be shitting itself wondering WTF is going on..  Possibility?

[fez200]

yeah Omad i have thought about that. i still have the original Auto ECU

however the manual gearbox & ECU was taken from a HNU13 attesa as they are the only gearboxes that will fit into correctly into another attesa and trust me from the troubles ive had with the conversion and chasing parts to fit i have had to learn the hard way.

so you would have to think that the ECU is correct as i don't think the U13 attesa AWD came out in a N/A configuration but hey i could be wrong...

[JelloBello]

You can get n/a U13 ATTESA's ... i came accross quite a few on carsales etc. in the search for my attesa, they just have the sr20de.

[fraz]

just run the auto det ecu on the manual loom. it will work as the starter motor lockout is controled by the switch on the auto gearbox and the manual loom does not have the wiring for it