So i finally got the turbo ls/vtec build up and running.(Woohoo!) However i can not seem to get it to idle for nothing. b18a1 block/b16 head/intake. If i crank the car up and hold the gas pedal barely in i can hold it around 900-1000 and it runs very nicely. I thought maybe it was my tps because whenever i was pushing the pedal in i was reading 0% on my hondata datalog however i calibrated it and it is working like it should now (0 at close, 99 at full open). I am throwing 4 error codes. Vtec spool, oxygen sensor heater, IAT, and IAC. So just for kicks i switched around the iac and iat plugs, knowing that they are in the right place because i had it running as a lsvtec non turbo before this, and somehow the car idles immediately with the IAT plug plugged into the IACV. This didnt fix the IAT error but it did make the iacv error go away. Doing this makes the iacv hum constantly and makes the car idle super rough. It bounces between 500 and 1500, super choppy, wants to die constantly. As soon as i unplug the IAT plug from the iacv the car stops "idling" and dies. My fuel pressure regulator shows 45 psi of fuel. My base map is set up for the 1000cc injectors i have and what not. No vacum leaks that i can find. I messed all around with the idle screw to no avail. My tuner is dealing with this corona stuff right now so i was hoping you guys had some ideas for me. Mainly i want to know what your guys' thoughts are on why switching the two plugs made it idle (although horribly) whenever i know for sure they arent supposed to be that way.

 

Pull a diagram and make sure you have the correct plug in the correct sensor. Verify wire colors. It’s hard to say without actually looking at it. But are you still using the FITV or is it gone?

when it plugged in correctly, what does your IAT read?

 

I looked at the ecu pin out and checked the wire from there up to the plug and had no cuts or shorts or anything. Black/yellow going to IAT and green/red going to IACV. FITV is still there and coolant is routed through both fitv and iacv. When plugged in correctly the IAT says 123 degrees no matter what. These were both working just fine three months ago whenever the N/A lsvtec was running and had no error codes. It seems both the iacv and iat are having issues at the same time, I don’t understand.

 

Have you double checked grounds, especially the thermostat ground?

 

Couple questions..
1- What ECU are you running?
2- Are you using a wideband 02 sensor?

 

I’ll go through and check ground right now, they’re pretty well buttoned up though.

i am running a p72 maybe? It’s obd1 using a conversion pigtail. I know I had a hondata S300 in stalled in it. I am not running a wideband currently as my tuner said I wouldn’t need one after the tune necessarily and they’re up there in price. I also don’t have an exhaust fabbed up yet so idk what I would attach one to.

 

A couple things that run across my mind. Double check your basemap and is try to disable closed loop. So it won’t use your o2 sensor to make adjustments for now. Since your IAT is reading, as long as it’s correct I’d leave it alone. Double check what your idle rpm is set at. Do you by chance have another IACV you could install to at least rule out a faulty part real quick?

If your fine on your electrical side, and we could assume components are good as they worked before, can your tuner email you a good basemap he can set up? I’m a novice when it comes to engine management, but I know there are a lot of important settings that I would imagine would be at a point where your car would at least run when you start it. But things like IAT and ect fuel corrections, cranking fuel, or certain things may be playing a part in it. But I would imagine generating a fresh map it would have good enough ball park figures to get you started.

 

I messaged my tuner and asked about the o2 thing. I dont have an exhaust right now so obviously i dont have an 02 sensor or an afr gauge yet. I think you may have not understood the above post, my IAT isnt working. Its throwing an error and regardless of the temp outside it says 123 degrees, not sure why because it was just fine last time. Idle rpm on basemap is 850 or so. I do indeed have another iacv and i installed it and it still didnt fix the problem or change anything. My tuner is the one who sent me the base map i am running now, he is confused as to why it wont idle neither. Basically told me i need to take care of the error codes first and go from there. I ordered a new iacv and iat sensor so we will see if those fix it. If not i will run new wires from the sensors to the ecu pins to be 100% sure everything is fine there.

 

Ok, yeah I did misread what you wrote. Key on, looking at live data. Unplug your IAT, does it change? I’d also jump the two terminals and see what it reads. I don’t remember if it’s open is zero or max. But at least get this issue resolved before you move on.

 

Hondata s300 has a "failed IAT circuit" delete box which allows one to set a fixed/static value for the ECU tune to use... the default is 123'F. It is likely that your tuner checked this box because you had the IAT error code. What colors are the wires going to your IAT sensor ?

 

Idle issue resolved, replaced iat and iacv and reran wires to the ecu for both.

 

Hi all, the turbo civic is finally moving under her own power! It’s been a long process but she’s getting there. For a quick run down I have a 98 civic hatch with a turbo b18/b16 lsvtec swap. After months of wrenching I finally got the clutch and axles installed lastnight and got it rolling up and down the driveway under its own power. One problem I have had for a while now is that after the car runs for about 9 minutes give or take it shuts off out of nowhere and will not start back up until it cools back down. Whenever it cuts off I still have fuel pressure but no speak, it’s like the heat kills the spark. I have a hondata S300 and have no safety parameters or anything I can think of that would cause it. All new sensors, no error codes except for my o2 sensor but that’s because it’s not connected. (No exhaust yet). I’m ready to drive it give it a few break in miles before it goes to the tuner/dyno next weekend and my tuner is a couple hours away not exactly able to take a look at it at my house right now. Any thoughts at all? Thanks in advance.

 

A bad coil or ICM could cause no spark when they get heated up, so my first thought is something dizzy related if you’re sure there’s no spark when it warms up. Try out a buddies dizzy if possible to see if it changes anything

 

ill look into those two things unless those are a part of the dizzy. I put a brand new dizzy on it whenever I rebuilt it. New wires, plugs, dizzy, mostly all new sensors, not much stock left on this engine lol.

 

what brand distributor? If it is a cheap china one, they can be bad right out of the box. I had 2 fail back to back in a short amount of time.

 

I got it from PartsGalaxy, through amazon. I emailed them earlier about a warranty return because it is still under warranty and the more I look into it I think it was the icm. Whenever I let it get to temp again and it shut off I data logged it on my hondata s300 and I watched the ignition fall off steadily at 181 degrees within about 1sec and I got a “disterr” (distributor error) signal at the moment it shut off. Looking to replace the whole unit but geez $230 at oreillys. Maybe look to rebuild but given I don’t have an oem unit to rebuild I may just buy a new one.

 

I've had luck with the Duralast Gold distributors from AutoZone. Yes, $250ish, but it is a lifetime warranty and I have put one on two of my Hondas in the last 2 years and they have not given any issues yet. I've also heard good things about the AIP Dragon Fire distributors.

 

My distributer crapped out as well. I’m currently using the higher end option that Xenocron offers. I believe it runs $300, I picked it up on sale for $250. I’m not certain who makes it, but it’s made with all japan made parts and so far has been great for me.

 

I'm also running the same, using a TD44U. I believe they are from Distributor King, typically Hondata COP setups have issues with non OEM distributors but I've been running that too with the distributor.