Infosecdad Posted January 18 Share Posted January 18 Not sure how much wire you need, but iwire sells the MAP connector with pigtail. https://iwireusa.com/collections/5-9-pin-replacement-plugs/products/mass-air-flow-sensor-maf-plug-a?variant=40734171562137 If you need a lot, maybe you can ask them to give you a couple foot of wire for the pigtail. In the meantime, maybe you could unwrap the current harness and isolate each of the wires so they aren't shorting on each other? 1 Link to comment Share on other sites More sharing options...
Tehnation Posted January 19 Author Share Posted January 19 Does the MAF line go straight to the ecu? I am thinking I want to replace the entire line all the way to the ecu. Cause everything up to the firewall is questionable. I just know getting through that ball grommet thingy is gonna be a pita. Cause now nothing is working, it started this morning and then died, and I can't get it start again. So something with heat is in play. Link to comment Share on other sites More sharing options...
Tehnation Posted January 19 Author Share Posted January 19 So taking off the plastic cover and all the electrical tape and pulling the wires apart like you said worked..... get on the road to get to tuner and 15 minutes later cracked rim.... oh my god, my life is a drama. Off to the junkyard to get a used wheel, hopefully I can salvage the tire. Today was a complete sht show...... I wiggle, rub and shake these wires and nothing happens now. I don't know why this problem is random, only clue I have is it seems it happens when things get warm, I remember smelling some plastic smell when it happened yesterday. Why would wires short when they get hot? Normally I just drive the car short trips around town, yesterday I actually went on a longer drive, hit the highway etc. Never did it before on longer trips either but it was always an issue, I've respliced the connections several times already. Could the wire casing just be shot? I am just going to hack it all off up to the main harness and hopefully iwire can send me a maf plug with 4-5ft pigtail. A ground issue wouldn't cause this I don't think? Link to comment Share on other sites More sharing options...
Tehnation Posted January 19 Author Share Posted January 19 Anyone know what gauge wires are used for the maf? I think there are 2 different sizes. I going to grab some wire just in case iWire doesn't come through, I'm waiting for a response to my email. Link to comment Share on other sites More sharing options...
xt2005bonbon Posted January 19 Share Posted January 19 I recall the OEM wires are sligthly thicker than what iwire provides on their pigtails. I did use their pigtail as I was having trouble at my MAF connection. The problem was not necessarily on the longer portion of the wires. Rather, it was at the MAF plug where the wires meet the plug. I think the ground was getting bad when the car was warm, making the car runs super rich. I could see it on BtSsm live. I made the change on two cars. Problem solved. 1 Link to comment Share on other sites More sharing options...
Tehnation Posted January 19 Author Share Posted January 19 This is a brand new plug and pigtail from iWire, I installed it last year. I can't see it going bad that quickly. Link to comment Share on other sites More sharing options...
Tehnation Posted January 19 Author Share Posted January 19 could it be my maf sensor? Link to comment Share on other sites More sharing options...
xt2005bonbon Posted January 19 Share Posted January 19 (edited) I did not catch that you did that. I did this also last year or the year before. So far so good. Although I recall that for one of them, my crimping job was not done well. So it still acted up until I fixed the latter. Edited January 19 by xt2005bonbon Link to comment Share on other sites More sharing options...
xt2005bonbon Posted January 19 Share Posted January 19 Do you have BtSsm or an AP? Are you able to view live what's going on in terms of your fuel trim corrections? Link to comment Share on other sites More sharing options...
xt2005bonbon Posted January 19 Share Posted January 19 1 minute ago, Tehnation said: could it be my maf sensor? Not sure. I never had to change my MAF. Still original for both cars (180k+) Link to comment Share on other sites More sharing options...
rhino6303 Posted January 19 Share Posted January 19 There are 3 wires from the maf that go straight to the ecu. Pins 2, 3 and 4. See the attached image. 1 Link to comment Share on other sites More sharing options...
Tehnation Posted January 19 Author Share Posted January 19 @xt2005bonbon I have an AP. I guess I need to find my multimeter....ughh I hate wires... @xt2005bonbonYou might find some hp if you put in a new one I hear. @rhino6303It gets to the ecu through the main harness right? That might be a pita if I have to get into that harness in the ball grommet thing, can you even mess with that? I hope the issue is on the engine bay side and not the ecu side. How would I even test this... . the problem is intermittent, and I am tired of breaking down on the road lol. Link to comment Share on other sites More sharing options...
xt2005bonbon Posted January 19 Share Posted January 19 5 minutes ago, Tehnation said: @xt2005bonbonYou might find some hp if you put in a new one I hear. I don't know. I am always starring at BtSsm when I drive and my long term fuel trims are very close to zero. They've remained quite consistent since I fixed the wires. Link to comment Share on other sites More sharing options...
rhino6303 Posted January 19 Share Posted January 19 9 minutes ago, Tehnation said: @xt2005bonbon I have an AP. I guess I need to find my multimeter....ughh I hate wires... @xt2005bonbonYou might find some hp if you put in a new one I hear. @rhino6303It gets to the ecu through the main harness right? That might be a pita if I have to get into that harness in the ball grommet thing, can you even mess with that? I hope the issue is on the engine bay side and not the ecu side. How would I even test this... . the problem is intermittent, and I am tired of breaking down on the road lol. Only way to test would be to remove the connector from the ecu and the corresponding connector at the maf and check the continuity. Should be near zero. 1 Link to comment Share on other sites More sharing options...
Tehnation Posted January 19 Author Share Posted January 19 Do the 2 IAT wires produce a different cel code or is it all the same maf code? If there are separate codes then it just involves 3 wires. The power and maf signal lines are a lower gauge or thicker wire, they are the middle and wire to the right with plug connected and top of the maf facing you with the wires pointing down. I asked iwire to lower the gauge wire for those thicker lines, the power and maf signal. They could make a longer harness for an extra 10 buck, thats for 4 or 5 feet, they said same price so 5 ft it is. 1 Link to comment Share on other sites More sharing options...
Tehnation Posted January 19 Author Share Posted January 19 You can check fuel trims with AP like the learning view app? If so, please share! I think someone told me this before but I'm getting old... Link to comment Share on other sites More sharing options...
Tehnation Posted January 19 Author Share Posted January 19 So my dilemma is the issue seems random. Would testing for continuity work regardless if the issue is present or not? I want to just replace the entire line but its spider webbed into the main harness and I really don't want to mess with that or even replace it. The weird thing is the heat, when that happens normally I think a device/sensor is failing, not a wiring issue. But shaking wires and rushing to get things done in the dark in the middle of traffic made it hard to really get a solid diagnosis. Shaking the line and connecting and reconnecting the maf sensor could have done anything, but it got results, so the maf connection seems plausible. OMG so many things, I just last year had this kind of issue and redid everything, I installed a new maf sensor, Denso 1976040, and iWire pigtail. Link to comment Share on other sites More sharing options...
xt2005bonbon Posted January 19 Share Posted January 19 1 hour ago, Tehnation said: You can check fuel trims with AP like the learning view app? If so, please share! I think someone told me this before but I'm getting old... I don't own an AP, but you may be able to check this parameter list and see what variables your AP can view. 1 Link to comment Share on other sites More sharing options...
Tehnation Posted January 20 Author Share Posted January 20 So iWire sent me a link which may be the issue. https://iwireusa.com/blogs/iwire-university/what-is-shielded-wire-and-how-to-install-it?_pos=1&_sid=664255fb8&_ss=r The maf and power line are shielded which is why they are thicker and I don't think I trimmed the shield wire, so that may be causing some kind of short when things heat up and expand. Link to comment Share on other sites More sharing options...
Tehnation Posted January 20 Author Share Posted January 20 Are there 1 or 2 cel codes related to the MAF? Like one for the maf and one for the iat. Link to comment Share on other sites More sharing options...
Tehnation Posted January 22 Author Share Posted January 22 So only the maf signal wire, the middle wire, is shielded, and the only lower gauge wire is the power line. The maf signal line is shielded which is why the wire is bigger. I undid all my splices for that wire and saw that I had just wrapped the shielding over the inner wire splice and shrink wrap. Wish I took pictures but it was cold as hell and I just wanted to get it done. So when you splice shielded cable you should trim the shielding wire and not just wrap it over the splice. Not sure if thats the issue but it sure as hell wasn't done the right way so I am going to guess and say it heated up and signal wire made contact with the shielding wire. 1 Link to comment Share on other sites More sharing options...
rhino6303 Posted January 23 Share Posted January 23 4 hours ago, Tehnation said: So only the maf signal wire, the middle wire, is shielded, and the only lower gauge wire is the power line. The maf signal line is shielded which is why the wire is bigger. I undid all my splices for that wire and saw that I had just wrapped the shielding over the inner wire splice and shrink wrap. Wish I took pictures but it was cold as hell and I just wanted to get it done. So when you splice shielded cable you should trim the shielding wire and not just wrap it over the splice. Not sure if thats the issue but it sure as hell wasn't done the right way so I am going to guess and say it heated up and signal wire made contact with the shielding wire. Correct in that only the sognal wire is shielded. For future reference for anyone who sees, you can see this in the diagram above by the dashed "cylinder" around the wire. Any wire with this is shielded. Ypu can then see the shielded wire itself is grounded at the ecu. 1 Link to comment Share on other sites More sharing options...
Tehnation Posted January 31 Author Share Posted January 31 Looks like that may have fixed it, but now I'm traumatized again and scared to drive it anywhere lol. I am also going to try adjusting the fuel pressure to see if that gets rid of the hesitation. I didn't have it on the original etune I got to get the car started with the new engine build, then all of a sudden after the dyno tune its happening. I don't think the fuel pressure will do anything but why not, lets find out. Link to comment Share on other sites More sharing options...
Tehnation Posted February 1 Author Share Posted February 1 I checked some other things, like my FPR and intake manifold, because the hesitation was very violent. I realized my bolts for the tgv and intake manifold needed to be re tightened, all of them had become somewhat loose, as in I had to snug them down a significant amount. Also, my fpr was leaking, so I tightened that as well. Now its running much better, the hesitation is there somewhat but not nearly as bad as before. So I am thinking that hesitation may be a vacuum or fuel pressure thing, which would throw off a tune. If you have the notorious Subaru hesitation I would inspect the tgv and intake manifold gaskets as well as the bolts. That 2-3k rpm range is right around when you start to build boost, so vacuum issues may play a part in the hesitation cause everything is controlled by vacuum levels, ie the turbo, BPV, and FPR. So if your vacuum is wonky it seems like it effects other things. Now that I tightened everything up, I am going to next check if increasing the idle fpr does anything. Stay tuned! Link to comment Share on other sites More sharing options...
LegacyGT007 Posted February 8 Share Posted February 8 Any luck with your hesitation? I read through your posts. Builds like this always have their growing pains. Have you had your injectors flow tested and matched? What brand are they? Smoke test/pressurized your intake system yet? I would upgrade your whole engine bay with 6AN and parallel fuel setup. I built and set up my fuel lines. I attached my dyno sheet just for reference as to where my set-up got me. I see you are a fellow NYer. Link to comment Share on other sites More sharing options...
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