wstefan20 Posted January 3, 2018 Author Report Share Posted January 3, 2018 lol well, I just proved my point by being an idiot. I forgot to actually put the hose for the pcv intake on and left it open! Basically, I was sucking air into the pcv intake on the throttle body. That's why it didn't show up as a vacuum leak too. Unfortunately that only got me down to 8-9% ltft. stft is still good now. I'm curious after I relocate the map sensor how things will read with the catch can restriction. For now, catch can is removed. I still can't account for the rest of the lean condition though. I pinched off the hvac line and nothing changed so I know that isn't a leak. I pulled the brake booster check valve and the booster was still pressurized after sitting and the valve operates and holds a seal so that's not the issue. I also went round and sprayed carb cleaner and used propane and found nothing. At this point, I'm wondering if this percentage isn't due to the fact that the L36 is an oval intake and the L26 is round, and I port-matched the two and removed the turbulence lip so I have a gradual hole from the throttle plate to about 75mm for the intake. I'm wondering if this changed the air pattern enough to throw off the fuel trims, along with the larger engine bore? Idk. I'm grasping at straws now. Bottom line right now, I'd like to know whether switching to the L26 intake and porting through to the throttle body can affect fuel trims? Quote Link to comment Share on other sites More sharing options...
scottydoggs Posted January 3, 2018 Report Share Posted January 3, 2018 its gonna take a day or so of driving for the trims to relearn, its not gonna be real accurate right after a fix like that. or pull the neg cable for 30 minutes, or if you got a code reader clear codes, this resets the fuel trims. Quote Link to comment Share on other sites More sharing options...
Imp558 Posted January 3, 2018 Report Share Posted January 3, 2018 If this was a first Gen I'd be looking at the Vacuum ball in the LHS bumper. Lol Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 3, 2018 Author Report Share Posted January 3, 2018 its gonna take a day or so of driving for the trims to relearn, its not gonna be real accurate right after a fix like that. or pull the neg cable for 30 minutes, or if you got a code reader clear codes, this resets the fuel trims. Ok! I'll clear them and take them for a drive and post the results. Thanks Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 4, 2018 Author Report Share Posted January 4, 2018 Well, strange turn of events, now the stft are between +-5% and the ltft are actually bouncing from +8 to -12%. Car drives MUCH better though. I'm going to give it a few more days and monitor it. At least the stft are good! Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 4, 2018 Author Report Share Posted January 4, 2018 Something on a side note, I know it's cold outside, but after I opened up the lower intake manifold side port, I'm running at 87-89 C (188.6-192.2 F). I used to run nearly 10-20 degrees F hotter than this before I ported the coolant passage out. I'm running the stock 195 degree thermostat and stock gt 5/8" radiator. I've replaced everything from the heater core to the water pump, all hoses, blocked off throttle body passages. I just wanted to know if this was too cold or whether others have these temps too. Quote Link to comment Share on other sites More sharing options...
Imp558 Posted January 4, 2018 Report Share Posted January 4, 2018 Seems cold for a 195 stat. I bet it's stuck open. Running a 195 stat with the fan set to 205 I run 198-202. What are your fan temps? Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 4, 2018 Author Report Share Posted January 4, 2018 Seems cold for a 195 stat. I bet it's stuck open. Running a 195 stat with the fan set to 205 I run 198-202. What are your fan temps? That's what I thought. Fan temps are stock. Think that's 210? It's cold out, so I'm not expecting much higher than the thermostat. Do you think porting the coolant side loop opened things enough to drop the engine temps? And why would it be stuck all of a sudden? It's not even a year old! lol Quote Link to comment Share on other sites More sharing options...
Imp558 Posted January 4, 2018 Report Share Posted January 4, 2018 It should be hotter than 210 for the fans, even if you ported and polished all the coolant passages they are still waiting for the stat to open at 195. The temp is pretty good for a 180 stat or maybe a 185 (which are weird but exist) Quote Link to comment Share on other sites More sharing options...
Imp558 Posted January 4, 2018 Report Share Posted January 4, 2018 I wonder if you have a bad cts? Colder false reading should generally equate to a richer condition though. It might be a good idea to check it with a DMM against a truth table. Nas Escobar 1 Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 4, 2018 Author Report Share Posted January 4, 2018 The order number said it was 195, but do you think it could have gotten mixed up? Is there any harm running it at this temp? Would this explain the new rich long term fuel trims? Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 4, 2018 Author Report Share Posted January 4, 2018 I wonder if you have a bad cts? Colder false reading should generally equate to a richer condition though. It might be a good idea to check it with a DMM against a truth table. How do you mean? If it was bad, wouldn't it not show the temperature climbing gradually? I've heard all the aftermarket ones are junk like half the other sensors for our vehicles. Would it be beneficial to pick up one at the junkyard? I just really don't want to have to bleed the coolant again... Quote Link to comment Share on other sites More sharing options...
Imp558 Posted January 4, 2018 Report Share Posted January 4, 2018 Cooler stat or colder false reading from CTS usually runs richer. Test the cts and the IAT would be nice to test. Quote Link to comment Share on other sites More sharing options...
Imp558 Posted January 4, 2018 Report Share Posted January 4, 2018 Find the truth tables, temp vs resistance and test the cts rather than replace it. It's simple. wstefan20 1 Quote Link to comment Share on other sites More sharing options...
Imp558 Posted January 4, 2018 Report Share Posted January 4, 2018 Same truth table for both the IAT & CTS Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 4, 2018 Author Report Share Posted January 4, 2018 Thanks! I'll have to test these later. What's the best way to accurately raise the temperature without damaging the sensor? Quote Link to comment Share on other sites More sharing options...
Imp558 Posted January 4, 2018 Report Share Posted January 4, 2018 Run it. I use a cheap IR thermometer to get a temperature that's real world Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 4, 2018 Author Report Share Posted January 4, 2018 I've got a cheap ir scanner, do I just point it at the intake manifold near the sensor? Quote Link to comment Share on other sites More sharing options...
bluegtp91 Posted January 4, 2018 Report Share Posted January 4, 2018 From everywhere I ever read about the L26 swap, the top back port needs to be vented. Pegged fuel trims usually indicates a vacuum leak, regardless. I had to trim my intake gasket when I did my L26 to L36 UIM. So, there's that. Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 4, 2018 Author Report Share Posted January 4, 2018 I had to trim my intake gasket when I did my L26 to L36 UIM. So, there's that. Hm... trim your gasket? Please explain. I thought the gaskets were identical between L36 and L26? It fit good for me. Sprayed carb cleaner and used propane to no avail around the whole manifold. From everywhere I ever read about the L26 swap, the top back port needs to be vented. Yeah. That's the really confusing part of our engines that no one has really taken the time to understand. That port is the pcv intake, which stock for L67/L36 runs to the throttle body to a small intake hole before the throttle plate but after the maf sensor so it is metered air. The only difference is that the L26/L32 use an external hose to connect to the intake. Most of us confuse this with other pcv system hoses because we forget that it's doing the same exact thing as the L36/L67 system and taking pre-metered air to vent the pcv because the L32/L26 uses a inline maf sensor not one on the throttle body. Therefore, while it looks like it's just a regular vacuum, it's actually the pcv breather. Only difference is one is internal and one is external. The correct way to hook up pcv intake is to meter the air since the computer is already compensating for this air. Putting a breather on it throws this off, and it adds another item to service down the road. While you can tap an intake of your own, the throttle body spacer I bought actually taps into the stock trottle body pcv air intake passage so it eliminates the need to drill and tap another metered air intake (aka anywhere before throttle plate but after maf sensor). The strange thing is that now my long term fuel trims are oscillating from -5 to +5% (+5 is usually at idle or decel and -5 is acceleration): Quote Link to comment Share on other sites More sharing options...
bluegtp91 Posted January 4, 2018 Report Share Posted January 4, 2018 Humor me and vent it. Because if you say that is the correct way to hook it up, then your car should be running correctly, am I right? My car ran just fine with it vented; Reptile tuned it. I had the manifold tapped post MAF just like you and ran the OEM vacuum line to it for the EVAP. It was done just as everyone else had done it in the past. I never tuned anything so I can't give you a chart or a graph on how it operated. I ran without EGR (eliminated any chance of the stovepipe issue) and had no vacuum leaks, fuel trims spot on. I never used a TB spacer, just an adapter plate. Wasn't enough space to tap that, so following all the DIY threads from back when I tapped the neck of the UIM. I'd venture to guess that there is a vacuum line routing issue or the catch can has something to do with it. We don't have an "oil in the intake" issue like plenty of say, LS motors do. EGR causes the carbon build up anyways, so get rid of that and tune the code out. As for the gasket, some of them needed trimmed from the L36/26 conversion if the tabs didn't seat properly, or if you were using an HV3. Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 4, 2018 Author Report Share Posted January 4, 2018 Humor me and vent it. Because if you say that is the correct way to hook it up, then your car should be running correctly, am I right? My car ran just fine with it vented; Reptile tuned it. I had the manifold tapped post MAF just like you and ran the OEM vacuum line to it for the EVAP. It was done just as everyone else had done it in the past. I never tuned anything so I can't give you a chart or a graph on how it operated. I ran without EGR (eliminated any chance of the stovepipe issue) and had no vacuum leaks, fuel trims spot on. I never used a TB spacer, just an adapter plate. Wasn't enough space to tap that, so following all the DIY threads from back when I tapped the neck of the UIM. I'd venture to guess that there is a vacuum line routing issue or the catch can has something to do with it. We don't have an "oil in the intake" issue like plenty of say, LS motors do. EGR causes the carbon build up anyways, so get rid of that and tune the code out. As for the gasket, some of them needed trimmed from the L36/26 conversion if the tabs didn't seat properly, or if you were using an HV3. Ok. It's worth trying. I'll post the results when I get time. As far as tapping the throttle body, if you tap before the throttle plate, that's not vacuum. Vacuum only exists after the throttle plate. I'm tapped into after the maf but before the throttle plate. The spacer tap doesn't go all the way through, it makes a right angle and hooks to the stock L36/L67 pcv air intake I mentioned. So I'm not running vacuum to the pcv valve air intake, that would not be good. Never had an issue with the gasket, but maybe I got lucky. I've taken apart far too many uim to not notice the sludge. It's not carbon buildup I'm talking about either, it's oil sludge. Believe it or not, with a $15 ebay catch can, I caught a few milliliters after only a week of running it! Stuff was disgusting. Quote Link to comment Share on other sites More sharing options...
bluegtp91 Posted January 5, 2018 Report Share Posted January 5, 2018 As far as tapping the throttle body, if you tap before the throttle plate, that's not vacuum. Vacuum only exists after the throttle plate. I'm tapped into after the maf but before the throttle plate. The spacer tap doesn't go all the way through, it makes a right angle and hooks to the stock L36/L67 pcv air intake I mentioned. I understand that. I didn't tap the throttle body. I tapped the UIM for the port. Tapping after the MAF but prior to the throttle blade is most likely the issue. I'd have to look again but the post MAF vacuum lines should go to the FPR and the EVAP, like I had ran and just like factory and vented the PCV location. I'm not saying I'm correct, however I never had any fuel trim/vac leak issues. This car was hooked up to HPT/Aeroforce gauges at all times even before the tuning; even prior to the swap as well. I did find a Bonneville club post showing the PCV hose routing around how I think you're describing yours. Hell, you're in ****ing Raytown. Bring it by one day and we can look at it. Why not LOL. Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 5, 2018 Author Report Share Posted January 5, 2018 I understand that. I didn't tap the throttle body. I tapped the UIM for the port. Tapping after the MAF but prior to the throttle blade is most likely the issue. I'd have to look again but the post MAF vacuum lines should go to the FPR and the EVAP, like I had ran and just like factory and vented the PCV location. I'm not saying I'm correct, however I never had any fuel trim/vac leak issues. This car was hooked up to HPT/Aeroforce gauges at all times even before the tuning; even prior to the swap as well. I did find a Bonneville club post showing the PCV hose routing around how I think you're describing yours. Hell, you're in ****ing Raytown. Bring it by one day and we can look at it. Why not LOL. Oh ok! lol yeah, I tapped where the evap used to go for vacuum. The port that I'm using for pcv intake is completely stock. The pcv air intake is normally drawn through the throttle body and passed into the uim then to the lim which leads to the cylinder head to supply fresh air to the crankcase. The stock L36/L67 is routed internally through the throttle body and the L26/L32 is routed internally until the uim where it has the stovepipe and it goes external to right before the throttle body but after the maf sensor. Not sure why they did that, maybe to save manufacturing costs or something. That being said, you're right, I've tried almost everything else so it's worth a shot! And DUDE! I completely forgot you were near me!!! lol I'm pretty much completely free until the 16th so just let me know! Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 7, 2018 Author Report Share Posted January 7, 2018 Well, I was hoping that by some miracle that using the breather versus taking metered air would help, but unfortunately my original theory was proved. If I could have overlapped the graphs, they would be identical. One thing I'm thinking for negative fuel trims. Could my fuel pressure be too high? It's 60psi running and 70 with vacuum removed (max pressure). As far as the temperature measurements, everything matched up correctly for the iat, but since I painted my lim, the readings for the coolant temp sensor was strange where the lim measured lower than the reading and the external reading directly on the sensor was higher than the reading. So not sure if that's normal? What about an exhaust leak? I don't hear anything, but if the exhaust manifold gaskets were leaking it could throw things off. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.