moto-m Posted July 25, 2011 Share Posted July 25, 2011 (edited) I built a custom intake for my 98 R50. I relocated the IAT sensor (from the air resonator behind the front driver fog light) into the new intake tube just behind the MAF sensor. So now it goes filter, MAF, tube with vacuum ports and IAT sensor, throttle body, engine. Running great and idling smoother than ever but now I am getting engine codes P0505 and P0325. Anyone know what would cause this and how to fix it? Does the IAT need to be back outside the filter? I didn't think it would have this affect from relocating it. Edited July 25, 2011 by moto-m Link to comment Share on other sites More sharing options...
moto-m Posted July 25, 2011 Author Share Posted July 25, 2011 Here are some pics. It was at night so not the best quality. You can see in the second one on the right where I located the IAT (had to extend the wires). Link to comment Share on other sites More sharing options...
XPLORx4 Posted July 25, 2011 Share Posted July 25, 2011 P0325 is the knock sensor code. You may safely ignore this code. P0505 indicates a problem related to the idle air control valve. I'm not sure how the IAT sensor on your '98 works, but on my '97, the IAT is not used for engine operation (as mentioned on page EC-111 in the FSM), so relocating the IAT as you have done may not have been necessary. When I installed my Pop Charger intake, I relocated the IAT sensor "nearby" the air filter element. Link to comment Share on other sites More sharing options...
moto-m Posted July 25, 2011 Author Share Posted July 25, 2011 P0325 is the knock sensor code. You may safely ignore this code. P0505 indicates a problem related to the idle air control valve. I'm not sure how the IAT sensor on your '98 works, but on my '97, the IAT is not used for engine operation (as mentioned on page EC-111 in the FSM), so relocating the IAT as you have done may not have been necessary. When I installed my Pop Charger intake, I relocated the IAT sensor "nearby" the air filter element. Yeah, I am trying to figure out exactly what the IAT does on my truck. Even if relocating wasn't necessary, it was easy and it's a nice clean install in the intake tube. I'm just not sure why I'm getting the idle air control valve code. Is it possible the computer needs time to adjust? Link to comment Share on other sites More sharing options...
01silvapathy Posted July 26, 2011 Share Posted July 26, 2011 Leave the battery negative cable undone for 12 hours. That will clear out the codes, my iat sensor is just zip tied in my engine compartment lol. Gave me an issue for a bit til I cleared the code and it never came back. Link to comment Share on other sites More sharing options...
180sx Posted July 26, 2011 Share Posted July 26, 2011 My IAT isnt even near my filter. Link to comment Share on other sites More sharing options...
moto-m Posted July 26, 2011 Author Share Posted July 26, 2011 Even if relocating it is causing an out of range reading, shouldn't it be a different code? I don't think the problem should have to do with the IAT sensor. I will check for any kind of vacuum leaks, run some sea foam spray cleaner through the throttle body, and reset the ecm. We'll see what happens. I wonder if during the new intake build the IAC got dirty or something. I have noticed that the idle is less than it used to be (between 500-750 rpms now). Link to comment Share on other sites More sharing options...
XPLORx4 Posted July 26, 2011 Share Posted July 26, 2011 (edited) It is possible that you have a vacuum leak where you've installed the IAT sensor. Try removing the IAT sensor from the hole you drilled in the intake tube, and temporarily placing duct tape over the hole to see if the engine idles better. As I mentioned earlier, the IAT contributes nothing to the engine operation on earlier model R50s. If the behavior changes, repair or replace the intake tube with one that hasn't been drilled for the IAT. Edited July 26, 2011 by XPLORx4 Link to comment Share on other sites More sharing options...
Radwaste Posted July 27, 2011 Share Posted July 27, 2011 Intake Air Temp Sensor for the 98 R50 is a P0110. I'd start with removing the IAT sensor from the intake and resetting the code. If it comes back as P0505, troubleshoot the Idle Air Control. Link to comment Share on other sites More sharing options...
moto-m Posted July 28, 2011 Author Share Posted July 28, 2011 Well I think I fixed it. Seems like it was just a vacuum leak. I went over everything and noticed the tubing was larger than the vacuum ports. Even though they were tightened down with hose clamps i decided to get larger ports that fit the hoses tighter. I drilled larger holes and sealed the rubber grommets to the intake tube with silicone. I also sealed the ports when they were inserted in the grommets. Then I wrapped some electric tape around the IAT sensor body to give it a snugger fit when it was inserted into the rubber grommet. While I was in there I cleaned the MAF and IAT sensors. Code hasn't come back on yet. Link to comment Share on other sites More sharing options...
moto-m Posted July 28, 2011 Author Share Posted July 28, 2011 I lied, light is back on. Try again tomorrow....bed time Link to comment Share on other sites More sharing options...
blkpathy Posted July 28, 2011 Share Posted July 28, 2011 Make sure that the wires that you previously disconnected are connected properly(they just might be loosely connected)had that problem when I installed an CAI on my R50. Link to comment Share on other sites More sharing options...
moto-m Posted July 28, 2011 Author Share Posted July 28, 2011 Make sure that the wires that you previously disconnected are connected properly(they just might be loosely connected)had that problem when I installed an CAI on my R50. Thanks, but checked all that already. When I extended the IAT sensor wires I soldered them and they are solid. I am thinking it isn't a problem at all with the IAT. I cleaned and reoiled my filter when I installed the intake and am starting to think I went overkill on the oil and it has fouled the IAC sensor. Will try and clean throttle body and run some sea foam through it today. Hopefully it will clean up and isn't permanently damaged. Truck is running damn good though besides the idle. More power and hopefully gas mileage improvement. Love the sound of the intake and can't wait to hear it after the exhaust. I also cut a hole in the front bumper near the foglight and ran some flex tube to the opening where the old resonator ran. If anyone is thinking about doing this go to the section at autozone where they sell all the universal intake stuff and get two 3" flanges and a flex tube (all made by spectre). The flex tube comes with two rubber couplers (you can only see one in the package but there is another inside the tube). You get everything you need except two hose clamps which you'll need for the connection to the flanges. Screw one flange on the backside of the bumper where you want your hole (I did this first then cut out hole with exacto knife following lines of flange), drill holes and screw the other flange under the hood, then connect. Works great. Yes I know you can do this for cheaper but I wanted to keep it simple and a nice clean install. Link to comment Share on other sites More sharing options...
moto-m Posted July 30, 2011 Author Share Posted July 30, 2011 Just an update. I am flashing 6 codes now! P0325, P0505, P1490, P1105, P0446, P1400. Not sure what the hell is going on. I have been having slow starting issues, replaced the starter yesterday but doesn't seem to have completely fixed it. I have a quest alternator that I will be installing soon so we will see if that helps. Battery is not very old and has good voltage. Anyone know if it is possible to have some kind of electrical problem that would be sending bad readings to all these sensors and flashing the codes? Link to comment Share on other sites More sharing options...
devonianwalk Posted July 30, 2011 Share Posted July 30, 2011 They have to be related. No way a whole bunch of problems just hit you immediately. Link to comment Share on other sites More sharing options...
XPLORx4 Posted August 1, 2011 Share Posted August 1, 2011 The P0325 knock sensor code is the only one you can ignore. As for the others, it's very unlikely this is just coincidence. Hmmm. The first thing I would do is to remove the IAT sensor from the intake tube and put it in the flextube that you installed in your bumper and replace the tube that you drilled out. There must be some good reason that the IAT sensor was not located after the MAF. When you extended the wires for the IAT sensor, how did you insulate them? Check that they're not shorting. Check the other hoses going into your custom intake tube to see if those don't have a vacuum leak as well. Link to comment Share on other sites More sharing options...
moto-m Posted August 2, 2011 Author Share Posted August 2, 2011 Finished Quest alternator installation and Black Magic electric fan install. Still seem to have slow starting issues even after starter and alternator. Maybe battery is going bad after all or I have a short somewhere. I even wonder if my ECM is flipping out. I do have to remember this all started with the intake, so I will have to do what XPLORx4 said and mess with the IAT first. Link to comment Share on other sites More sharing options...
moto-m Posted October 6, 2011 Author Share Posted October 6, 2011 Still dealing with this by the way. Just been driving it as I haven't had time to work on it. Pretty much thinking my ECM is bad at this point. Problem is it is the california emissions manual transmission version and I can't find a replacement anywhere. Part # MECM-W420. Does anybody know if I can use a federal ECM? What are the differences? I know I have the extra resonators after the cats but am wondering if there are any other differences? Link to comment Share on other sites More sharing options...
moto-m Posted October 17, 2011 Author Share Posted October 17, 2011 Turns out it was a fuse! #16 was missing. I had posted another topic about an inconsistency in my fuse panel. I still don't know exactly what happened and how the fuse was missing. I can only imagine that the events went something like this: 1. Installed the custom intake and engine flashed P0505 (possibly due to over oiling the filter) 2. While troubleshooting this I checked the fuse panel. Somehow I must have not put all the fuses back in or one fell out and engine flashed multiple more codes. 3. Replaced the IAC valve but engine still flashed all codes because the fuse was missing. So, probably had an IAC valve problem the first time and replacing it would have fixed it if the fuse wasn't missing. Still can't believe I would have done that with the fuse cause I could swear I checked everything and put it all back just as I found it. At least it's finally fixed! Hope this can help someone in the future if they start flashing all those codes. Check the #16 fuse first! And find a mechanic you can trust as I even told mine I thought it might have been the ECU which would have cost a lot more than a half hour of labor to find out it was a fuse. Link to comment Share on other sites More sharing options...
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