Welcome to the SR20 Community Forum - The Dash.
Register
SR20 forum logo

Thread: Popping and backfiring after IACV/AAC VALVE replacement

+ Reply To Thread
Posts: 21-30 of 43
2014-07-11 16:02:20
#21
Originally Posted by se200
You keep saying you didn't touch anything but the title of this thread says iacv/AAC replacement. In my book replacing the iacv/AAC is touching something. So to clear things up, did you or did you not remove and replace the iacv?

If so that is the factor of change and should be the first route of correction. Like I stated above this sounds like a vacuum/boost leak. You also stated you see no vacuum while cranking the engine over, you won't see full vac(19-20) but you should see some change. Double check your map sensor and it's source of vacuum.



You are right, i did change the iacv and the aac valve.

however in relation to vacuum lines and boost piping, and all that, NONE of that was touched. also nothing was touched in the calibration of the tune either, not one thing. and tunes done just change and settings just dont change themselves, so that can be ruled out imo.

simply put the iacv on and aav on and pushed it off the ramps that was it.

i mean like i said and i keep saying it, it just doesnt make sense because i was driving this car but like a week ago with no issues other than the iacv and aac but it never stopped the car from starting or idling, you just had to keep your foor on the gas a little till the idle caught up.

ive been going over every aspect of this engine and its easy because i know i didnt touch this or that, those can be ruled out easily.

the thing i thinking is i dont feel im getting enough spark, and the cap and rotor button have like 2k miles on them, so they are good.

so things i went over:

vacuum lines
boost piping
couplers
clamps
connections to ignitor
connections to coil
connections to distributor
connections to Map
Vacuum Line To Map
Connections to IACV
Connections to AAC vavle

Things i went over in AEM Sensor wise:

Map sensor
AIT sensor
TPS
Coolant Temp Sensor
Made sure all fuel injectors were all getting the same voltages

i Manually checked the Distributor rotated it around and checked to see if the fuel injectors pulsed


i think about just throwing the old iacv and aac on, but i dont see how that could make a difference the engine should still start and it should still be trying to fire the gas.

its really starting to look like its going to need to go to the performance shop which sucks because in going to get charged $90.00 a hour to basicly go over things ive already went over like compression,hoses,pipes,clamps ect ect ect. and you never really know if a shop is going to be legit and try and find the problem right away or if they are going to milk you, and like i said i already spend over 1k with tuning and fabrication work, i would have to have to shell out another 400-500.00 to figure out what is wrong with it. esp if its something stupid
Last edited by GT2871RBLUBIRD on 2014-07-11 at 16-03-43.
2014-07-11 19:50:56
#22
The first thing I would do is put the old iacv and AAC back in just to rule that out. You stated that you didn't mess with the vacuum lines or piping but the iacv and AAC are part of the vacuum line/ manifold system so you did mess with it. Swap the old parts back in double checking everything alone the way and let us know if anything changes. Good luck man. FYI 1200$ for some welding and a tune is crazy high pricing next do what I did a few yrs ago, buy a weld and do it yourself.
2014-07-11 20:04:29
#23
Popping is probably from excessive fuel in exhaust

Did tuner set up the tps startup fuel table so if you floor it, itll stop injecting fuel to clear a flood situation??


Use a spare piece of hose from your mouth to the MAP sensor and see how the sensor (in the aem software) reacts to you applying pressure and vac with your mouth just to see if its doing as expected.

If it is, and you still dont see any vac build when you begin cranking, there has to be a leak somewhere. A smoke tester will help you check for leaks.

Have you also checked the impedance of the injectors to make sure they are all the same?

You also said you had positive fuel pressure... but that doesnt mean much if its wrong... was it 3 bar?
Last edited by unijabnx2000 on 2014-07-11 at 20-10-20.
2014-07-11 23:19:51
#24
Originally Posted by unijabnx2000
Popping is probably from excessive fuel in exhaust

Did tuner set up the tps startup fuel table so if you floor it, itll stop injecting fuel to clear a flood situation??

Yes the startup table us setup for injectors to when the throttle is WOT the Injectors shut off

Use a spare piece of hose from your mouth to the MAP sensor and see how the sensor (in the aem software) reacts to you applying pressure and vac with your mouth just to see if its doing as expected.

If it is, and you still dont see any vac build when you begin cranking, there has to be a leak somewhere. A smoke tester will help you check for leaks.

Have you also checked the impedance of the injectors to make sure they are all the same?

You also said you had positive fuel pressure... but that doesnt mean much if its wrong... was it 3 bar?



Did tuner set up the tps startup fuel table so if you floor it, itll stop injecting fuel to clear a flood situation??

The Fuel pressure is 3 bar.

The Sync stat's comes on when cranking

The start cranking comes on when cranking

i checked the spark again and the coil ALONE produces white spark

However the coil connected to the Distributor Produces a orange spark which is not good.....problem is i have 2 distributors and the same problem what are the odds of having 2 bad diztributors

the fuel injectors all show the same pulse. i dont have my meter with me its in my girlfriends car.

im really leaning towards ignition problem, however the white spark with coil and orange spark with distributor is kind of confusing. im also looking to maybe the ignitor?
2014-07-12 05:13:54
#25
Originally Posted by unijabnx2000
Popping is probably from excessive fuel in exhaust

Did tuner set up the tps startup fuel table so if you floor it, itll stop injecting fuel to clear a flood situation??


Use a spare piece of hose from your mouth to the MAP sensor and see how the sensor (in the aem software) reacts to you applying pressure and vac with your mouth just to see if its doing as expected.

If it is, and you still dont see any vac build when you begin cranking, there has to be a leak somewhere. A smoke tester will help you check for leaks.

Have you also checked the impedance of the injectors to make sure they are all the same?

You also said you had positive fuel pressure... but that doesnt mean much if its wrong... was it 3 bar?


while this will work, I'm picturing this guy sitting in the drivers seat sucking on one end of a 8ft long vacuum line while staring at the gauges and it cracks me up.
2014-07-12 14:11:58
#26
Originally Posted by se200
Originally Posted by unijabnx2000
Popping is probably from excessive fuel in exhaust

Did tuner set up the tps startup fuel table so if you floor it, itll stop injecting fuel to clear a flood situation??


Use a spare piece of hose from your mouth to the MAP sensor and see how the sensor (in the aem software) reacts to you applying pressure and vac with your mouth just to see if its doing as expected.

If it is, and you still dont see any vac build when you begin cranking, there has to be a leak somewhere. A smoke tester will help you check for leaks.

Have you also checked the impedance of the injectors to make sure they are all the same?

You also said you had positive fuel pressure... but that doesnt mean much if its wrong... was it 3 bar?


while this will work, I'm picturing this guy sitting in the drivers seat sucking on one end of a 8ft long vacuum line while staring at the gauges and it cracks me up.




Wouldnt be the first time i did that my VOLVO 740 has the gm map sensor did that with that car.

i am thinking of just getting a new distributor and coil and seeing if that fixes the issue
2014-07-13 18:09:25
#27
Is there any other components that effect the ignition system other than:

Distributor
Spark plug wires
Distributor cap
Rotor
Spark plugs?

The alluding thing to me is I am getting a bright white spark at the coil but then when checking the the distributor hooking up the coil wire the ignition spark is orange.

Since the distributor its self doesn't produce any spark and the coil is what distributes the spark I would have to say that if the coil seems to be good and then the distributor puts out orange spark then it has to be distributor related.

I had this happen once other time was simular to this the distributor CAS went out and the car wouldn't start. Now the performance shop I wents to said they rebuilt the distributor but they could have easily got a junk yard distributor. But the symptoms of the bad cas was orange spark and a no but still getting fuel.

I know the question I asked is super basic but I am trying to get back to basics and make sure I don't miss anything and then recheck everything.
2014-07-13 18:29:51
#28
So you tried putting the old iacv and AAC back in and that didn't work?
2014-07-13 18:35:05
#29
Originally Posted by se200
So you tried putting the old iacv and AAC back in and that didn't work?


Yeah. I don't think it's a aac or iacv problem. The fact that the distributor is putting out orange spark weak spark orange weak spark.

So it's leading me to believe that somewhere along the lines the ignition is failing putting out orange spark either the distributor cap Rotor button spark plugs or coil
2014-07-13 18:50:04
#30
Ok but spark color is not 100% definitive of spark issues. These cars are know for having weak spark at high hp. The car should idle even with weak spark, your going to spend money buying new parts when you could spend an hour if your time swapping the old parts back in. This would be a free way to confirm it's not the iacv/AAC. It's your car and your money but tossing parts at it may not by the best option. I'm not the only person that said try the old parts first and you have ignored that this entire time, I hope your correct and the new parts fix your issue but if they don't please try using the advice given by a few of us. Good luck.
+ Reply To Thread
  • [Type to search users.]
  • Quick Reply
    Thread Information
    There are currently ? users browsing this thread. (? members & ? guests)
    StubUserName

    Back to top