Thread: IACV and Initial Timing

I finished the install of my head last night and attempted a first start.

Yet again, the car started and held at 2000 or so for a few seconds (cold fast rev, or something like that as I understand it), and then it just died. While it's revved I'm not hearing any misses or anything and if I feather the throttle a bit, I can keep it running for a little longer. I only did so for a few seconds as a didn't want to break anything. Tried this a couple of times, same result.

I put the car in timing mode (via my Nismotronic) and it was able to chug for about 10 seconds between 500 and 1000 after the fast rev on the subsequent starts.

I have about 50 lbs of fuel pressure, so I'm pretty sure it is either the idle air control or timing. When it was just barely holding on, I heard what sounded like a small backfire... so timing.

When I installed the cams, I did the whole intake key at 10 degrees, exhaust at 12 degrees, and 20 link pins between the dots on the cam gears. I screwed up a bit when I installed the chain on the bottom, so it's not a perfect 10 links between them. Would this be an issue? I read somewhere online that 20 link pins in the chain was the same thing so long as #1 was at TDC.

When I put the distributor on, I put it in the dead center of the adjustment area. I'm assuming that this isn't 100% perfect for all motors (as it didn't work in my case). If the timing is out enough that it won't idle correctly, is there a safe or correct way to determine whether it needs to be advanced or retarded a little? I just need to get it to the point of idling so I can put my timing gun on it and dial it in.

Also, are there a certain number of turns from all the way down for the idle are that I should have for a stock or "default" setting for the idle air? Is it safe to just adjust it a bit and try to start the car again?

Thanks guys, she's almost there!

vacuum leak

Yeah, that's what I've come to after thinking about it today. I reviewed the start-up vid that we took. I could hear what sounded like one then, and I can hear it in the video. I'm going to do my own poor man's smoke test on the intake and see what I find. The PCV is blocked off on this valve cover, so I'm going to take the cap off of the intake, hook up a good bit of hose, and use one of my hookah's to blow smoke into the intake (through a PCV I'm going to pick up today).

I read about them doing it with a cigar somewhere online. A hookah makes a lot more smoke than a cigar ever would, should make it that much easier to find the leak.

This definitely requires a picture.

Okay, so I got it started. As it turned out, I completely missed the vacuum connection on the backside of the throttle body (doh!).

Now to set the idle...

So.. The car will idle (ish) if I'm not in timing mode. In timing mode it was tanking and dying immediately. I adjusted the idle screw nearly all the way out, but I have to stay on the throttle at about 1-2% to keep the car running. Even in timing mode, the idle bounces between 850 and 950 (as read by my nismotronic). I can't get the idle to even out to save my life... any ideas?

glad you found the vac leak. Sounds like you need to make sure the iacv is functioning properly. If it checks out then I would verify mechanical timing again. Forget the colored links yada yada. Put #1 at tdc of compression stroke 10 and 12 o'clock on cams with 20 pins between. If you're ignition timing is in the center of the adjustment it should run just fine.

Can you take a log of the issue and shoot it over to my email?

Also, what are the specs for the setup (injectors/MAF)?

How To: Boost leak tester for $5.02 - evolutionm.net

This will help you not only find leaks in the intercooler piping, but also any vacuum leaks on the intake manifold. Block off PCV(already done) and any breather hoses coming from the valve cover and going into the intercooler piping during the test, otherwise you will pressurize the crank case.

Get a coupler size equal to your compressor inlet pipe off the MAF. Basically, just unbolt your MAF and stick this on...I wouldn't recommend to do it like it has in the evo thread right off the compressor.

@gomba, Thanks for the link. I've found quite a few designs online for these. It did seem strange that this one would tell you to remove the intake piping to the turbo inlet... I guess it wouldn't matter much if you had a blow through MAF and a solid pipe to your filter though... as you know, not my case. Thanks again for coming and taking a look last night.

@jktunning, It's funny that you mention that, I was telling @gomba last night that I should record a log of the idle and post it on the forum. I'll get a log this evening and send it over. I'm running 550cc injectors (or so I'm told, I got them with the car), a Z32 MAF, and a Walbro 255 HP. My S4 cams are out of the picture, but I am running the cams from my DET, so they should be a little hotter than the stock DE cams... I would think. I asked you for a tune a little while back for this setup with the S4 cams, I believe that is the one I'm still running. Could that make a difference?

We're thinking that the fuel pressure is turned up a bit high... I'll be stopping by HF to pick up ANOTHER 10mm wrench. Ugh. I honestly need to spend some of my car funds on a decent tool box.

I'm also going to get new spark plugs. I'm sure the ones I have a fouled and could be causing part of my problem. I was told to pick up some BKR7E plugs. I'm also going to keep the factory gap for now so I can work out this idle issue.

Thanks for the help guys! I can't wait to get this baby on the road. I'm looking to test drive this weekend.

One more thing. After reading a bit on the proper way to have the vacuum lines setup (connections on the throttle body and such), I'm going to verify that everything is good in that regard. AFAIK, my waste gate vacuum is not attached to my IC piping anywhere, and there is a WHOLE LOT of stuff attached to the vacuum line that goes from the TB to the FPR.

I think my best route would be to take the vacuum lines down to the bare minimum + my boost/vac gauge and see what happens. I just want to make sure I eliminate everything on the outside of the motor that could cause my low vac and rough idle issues.

Also, my current diagram for the vent/vac lines on the IC piping and catch can looks like this... the blue lines are the hoses, and the BOV is vented to atmosphere... I'm going to add the vacuum lines as they currently are later...



Any thoughts on how I should improve on this? Everything I have read tells me that having the BOV vent to atmosphere with a draw through is a bad idea...