Anyone know if using an LS iacv will cause a high idle? I just did a lsvtec (B18B bottom and pr3-3 head) I went with buddyclub spec 3 plus cams and BC valve train. My throttle body is a BBK 62mm. Performer X intake manifold. I use aem ems to tune and when I lower the idle% vs. rpm. nothing happens. Its allways -20% idle learnd value. I found a way to lower my idle and get my idle learned value to -7% which is perfect but the only way this will work is if my ignition map is 3 degrees BTDC in cells from 500- 1300rpm and below 46.21 kPa. (areas where my engine idles).

Also when driving under WOT conditions around 5000rpm. I can hear knocking or pinging noises (stuttering). My AFR is at 11.8:1 and ignition at 17.3 degrees at the most under WOT conditions.
I am using 91 Octane fuel and my compression ratio is at 11.5:1 (Wiseco pistons).

Im hoping that the problem is because of my LS iacv. If so Ill try and find a b16 iacv and hopefully that will solve this problem.

Please help me out! Im out of ideas and theres no such tuners at all on this island. Thanks!

 

I'm no tuner, but wouldnt too little timing lead or "advance" result in higher EGT's which might trigger detonation?

You might try posting this in the tuning forum as well.

 

Yeah, my egt at WOT is around 12-1400 degrees. Could a vaccume leak cause this? Im also using a LS distributor. Not sure if that could also be the problem to this.

 

As i say, im not a tuner but a vac leak could be the reason for your idle issues and would pose a problem in accurately tuning this thing, I would think. As long as your dizzy is connected properly I dont see that being an issue as long as your base timing at idle is correct (14-16 btdc).

What are your ECT's (Coolant temps), are you over heating after WOT pulls? Just my personal opinion, but I would say that you might not be running enough ignition lead at WOT which may, or may not be elevating your EGT's to a point where detonation could be resulting from a hot spot in your combustion chamber. Again this is just a guess.

As far as EGT's I'm sure they could also vary depending on the motor/setup, and I dont know whats typical for combustion temperatures so I would say make a post in the tuning forum and ask.

Theirs knowledgable tuners there that might help to give you better insight at best.

 

My base timing at idle is 3 degrees btdc. If I up it to 14 it idles high 2000rpm. and my iacv tries to lower my idle by going -20% idle learnd value, but nothing happens. Ill try a hondata im. gasket to see if it helps at all.

I understand your not a tuner, I just want to see if someone knows or had this problem so maybe they could shed some light. At this point Im guessing its a vac. leak. I changed my Throttle body gasket today and i found a spot on the bottom of the gasket that looks like it wasn't seald. When I put the new one on it lowerd my idle to 1300rpm. and my ignition timing was set to 14 deg. btdc. But still my iacv could not lower my idle at all. Next I will change the IM gasket, going with hondata gasket this time.

 

why is your base timing so low?

 

I set it to 3 deg. btdc. because thats the only way My idle will stay low (900rpm) If I set it to 14- 16 deg. btdc. it idles high 2000- 2200rpm. Until I find a the problem thats causing this, its the only way my motor will idle at 1000rpm.

 

Yeah your definitely putting a band-aid on a broken leg. Check for vac leaks, but also is your PCV valve installed correctly?

When I first got my (B18A1) LS/V running, it idled roughly 1500~2000, then I realized that I hadnt installed the PCV valve. I hooked it up, and the idle dropped to a normal 800~900.

 

Could this be caused from using an LS iacv? The part numbers on a b16 iacv is diffrent from a LS iacv. My block has two ports on the back of the block and one on the valve cover for venting out crank case pressure. Theres a little smoke coming out of the breather can, but that should be normal.

Anyone here ever used an LS iacv with no problems on a ls/vtec build?

 

I hate to admit it, but I'm currently using an LS IACV even though its only held on by one bolt (very tightly). Its a possibilty and I wouldnt rule it out espeacially if the seal is worn, but mine is working although I keep telling my self to just go ahead and buy a B16 IACV which would bolt up properly.

What breather can are you using, an aftermarket or just the oem breather system box (B18A1)?

The reason why my PCV valve affected my idle was because it's connected to the intake system therefore without it, I was allowing a vacuum leak into my intake manifold via the crankcase/oem breather box which kicked up my idle. Once I had the valve in place it dropped to where it needed to be.

 

its an aftermarket breather can. I have a performer x IM and I used a plug on the port thats suposed to be hooked up to the pcv valve. Its eather leaking from the IM gasket or iacv. Ill find out as soon as my IM gasket comes in.

 

installed a b16 iacv, idles at 1000 rpm perfectly with ignition set to 14 deg. btdc. BUT still poping at 5000rpm. Once it gets past 5500 it pulls strong. Could this be caused by my spark blowing out? Would it be better to gap it at .03?

 

I run .04 gap at just over 12:1 on my motor. So the IACV was defective, huh? Glad you got that solved, now its just a matter of fine tuning.

Have you tried listening for detonation wth detcans, just to be sure that the popping or pinging is actually detonation and not your exhaust system?

DIY electronic detcans
http://www.d-series.org/forums/diy-f...5-dollars.html

 

Im not 100% sure it's detonation but it sounds like a high pitch pop or stutter. It only happens at WOT. I will try and play with the timing maps and see what happens from there. Thanks for the link

 

Just some other suggestions, but you could also check for detonation on the plugs if you know what to look for. Just do a WOT pull until it starts pinging then immediately kill the ignition while at WOT.

If the plugs are clean and granted you're having detonation then you should see shiny silverish specks in the porcelain near the center electrode.

Also, If I were trying to diagnose this issue I would take the car for a drive a higher elevations provided you can where you live to see if this occurs at higher altitudes at WOT.

 

I did check my plugs and they looked okay. It was a bit black on the threads and the middle part looked normal (white). I advanced it to 22 deg. btdc. and the same thing happens. I even gapped the plugs to .030 and nothing changed. Is this a sign of a bent valve?

 

Honestly I couldn't tell ya, but i would think a bent valve would effect your compression which would cause problems, but I couldn't see how detonation could occur from inadequate compression due to a bent valve.

Do a compression test to be sure.

 

Truthfully I always hear this sort of pinging/rattling sound around 4500-5500 on my motor while under acceleration, and my car is professionally tuned.

I've checked the plugs after doing WOT pulls and they look fine, but where I live its hard to do this without getting out on a major highway where its kind of risky killing the motor than checking the plugs on the side of the road.

I'd honestly like to know if its slight detonation too, so I intend to make a set of detcan's, but I also plan to get a CAI (which I should have anyway) to lower IAT's since mine can get up around 120F during afternoon temps here in central FL.

I've also thought that this sound might mearly be my resonator from my exhaust, because it doesnt feel as though I lose any power when this happens briefly.

 

Yeah thats exactly where mines ping. Right around 4500-5500rpm. It feels sluggish and if I retard timing, it kind of goes away but it dosent even pull hard because of the retarded ignition map.

I also tried dumping a lot of fuel. Around 11.1 AFR and it still happens. It seems that neither ignition nor fuel adjustments do anything to stop this from happening. I am going to try something tonight, Ill disable vtec and see if it still pings. It sounds like a solenoid clicking on and off really loud. It could be my vtec kicking on and off for some odd reason. Ill let you know what happens.