S13 red top sr runs like crap after changing coolant lines under intake manifold

[Drifternate240]

After finding the coolant leak under my intake manifold I pulled it off to access the coolant lines that run underneath it. I cleaned the intake manifold and collector and iacv and replaced the associated gaskets and then when everything was bolted back up I had missed the vacuum line to the fuel pressure regulator. (I know I'm an idiot). So I ran it without that vacuum line hooked up trying to diagnose why it was running so crappy. Later that day I found the vacuum line problem and got that issue resolved thinking for sure that was the problem. I left the battery disconnected overnight hoping that would reset the ecu and the next day it would get back to normal. It did not. So basically I'm wondering if cleaning the iacv could have damaged it because now the idle is high and very rough and fluctuates between 1300 and 2k and it runs really rough through the revs. Any help would be appreciated greatly.

[john89s13]

Spray carb cleaner around where the intake runners meet the head. If the idle audibly changes, you'll know your new gasket is leaking.

[ultimateirving]

It does sound like a vacuum leak.
I would alsocheck to make sure the tps hasnt moved from being disconnected and that all the couplers are tight too. Make sure the iacv is hooked up properly as well, that big hose that goes to it from the cold pipe.

[fliprayzin240sx]

Like already stated, sounds like a vacuum leak. Also, I'd double check your TPS. You might have accidentally bumped it and its off.

[Drifternate240]

Yea thats what it seems like to me but ive sprayed everywhere that i can think of. Ill try to be very thorough this afternoon when i get a chance. About the TPS...Ive read about checking voltage going to it but i wasnt sure what I should be getting. I've read that it should be .5v at idle and Im not sure about wide open. Also the iacv is connected properly. If i unplug the iacv harness and the idle changes is that a good sign that it is working properly? Also same with TPS. The idle should go up if I unplug the TPS? And about voltage to the iacv...what should i be getting for it? Thanks for all the replies and hopefully I can fix it today because Im tired of her sounding like a bad subby when she was purring and pulling strong before i had the coolant leak.

[Drifternate240]

So I sprayed everything i could think of with carb cleaner and cant seem to get the idle to change indicating a vacuum leak. I sprayed every coupling of my piping even the stuff I didnt touch or take off. I sprayed my bov cause ive heard of those leaking at times. I sprayed everywhere around my intake manifold and where it mates to the collector cause I changed that gasket while it was off. I sprayed around my iacv that has a new gasket and my throttle body because i replaced that gasket too. I sprayed all of my vacuum line connections and every t that I had. I checked my tps voltage and I was getting .523 v at idle which from what ive read is about right. I also tested voltage and it rose smoothly as i slowly opened the throttle all the way up to 4.3 at wot which ive read is supposed to be closer to 5 but that shouldnt affect my idle. I checked my maf voltage and I was getting 13.93 v at idle which ive read should be around 12 but like i said before the thing was running beautifully for 8 yrs before the coolant leak forced me to pull the intake mani. I had taken out the idle adjust screw a few days ago and ran about a half a can of carb cleaner through it then compressed air in hopes that maybe if some chunk of crud got caught that it would dislodge it. And when I pulled the screw out it was about a quarter turn from all the down so I put it back to that and have even messed with it and screwed all the way down its still idling at about 1500-1700 when warm. Another thing is that i can get the idle to go down by almost completely crimping the line coming from the cold pipe that goes into the iacv. Which to me still sound like a vacuum leak or maybe the iacv is bad because thats about what it idled at when cold before but it always dropped down to 700-800 when warm. I hope all of this helps in your opinions of a diagnosis and/or solution. Thanks in advance for the help.

[Drifternate240]

So I found my rough running problem. One of the injector connectors was loose so when I plugged that in correctly it fixed the miss. Anyway, the idle is still kind of all over the place anywhere from 900 (which I wouldnt be too unhappy with if it would stay there) to up to 1500-1600. Im goin to spray every inch of it down tom with carb cleaner and hopefully now that it is firing on all cylinders maybe ill be able to detect changes in the idle when sprayed with carb cleaner. My only question is if I dont find a vacuum leak, what is the easiest way to determine if my iacv is bad? Thanks for the input

[Drifternate240]

I sprayed the entire engine down with carb cleaner along the entire intake tract from the maf to the intake manifold and every vacuum connection and couldnt get a bump or bog out of it. It held steady at 1600 rpm. But when driving it will surge up to almost 2000 and drop down as low as 1000 at times. I dont know what else to do if I cant find a vacuum leak. My next project is to build a boost leak tester just to see if I can find any leaks that way. Other than that Im stumped without just replacing parts for the hell of it which I would prefer not to do considering they were all working fine before the coolant leak

[Drifternate240]

So after driving it around idling high for a couple weeks finally got a boost leak tester built and found a IC pipe coupler leaking bad. Also my flange on my BOV was also leaking bad as well as a pinhole leak in a section of my IC piping. After JB welding the problem areas and fixing all of the couplings I was able to fix all of my leaks in my intake track. Also my SAFC had been reading 3-3.5% at idle so I figured even though my TPS voltage was in the range that I would dial it down so that the SAFC read 0% at idle. After all of that the idle has not changed at all. My ecu is not throwing any codes either. I dont know what else to do. Thinking of throwing a new Coolant temp sensor in it just to eliminate that as a problem. I have eliminated everything else and like my first post it was idling fine before pulling the intake mani and cleaning everything and replacing all gaskets. Any additional input would be much appreciated. Just stumped on this one

[OnTheChip]

Check the ground wire that bolts to the intake.

[ultimateirving]

Idle is controlled by the iacv. So I would take it off, clean it thorough make sure the little valve is free of any debris and put it back together. You would be better off setting the idle by properly getting it into timing mode. Rev the engine a few times disconnect the tps and wait for the idle to go up then settle a little. Then as you turn the iacv screw into the unit the idle should drop. Get it to about 8-900 and the. Turn the car off. Reconnect the tps and if you like can check voltage at the tps to make sure it's around .45v

[RalliartRsX]

................Remove the SAFC and use a proper ECU

The way it works is it tricks the ECu in regards to flow readings from the MAF, so the ECU is also in a battle with the SAFC (I had one, drove it for a few hundred miles, hated it, ditched it and went to a eprom ECU)

[Mikester]

................Remove the SAFC and use a proper ECU



^^This^^

msglngth