Max Capacity Posted November 12, 2021 Share Posted November 12, 2021 Have you reached out to "m sprank" yet, send him a PM. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
xt2005bonbon Posted November 12, 2021 Share Posted November 12, 2021 Well, there is still something off since the ECU is adding so much fuel. Is the 02 sensor new? No exhaust leak at the up pipe? Link to comment Share on other sites More sharing options...
Tehnation Posted November 12, 2021 Author Share Posted November 12, 2021 (edited) Both front and rear O2 sensors are new Denso's. No exhaust leaks. When I first got it back on the road it was running and driving fine for 20 miles, then one day on an open stretch of road I hit the gas and it just died mid acceleration and ended up towing the car home. It had happened once before that but it started up like a minute later so I didn't think anything of it, figured it was learning. It did it a 3rd time and once again I had to tow it. So it seems like an issue that was there, got worse, and now something is completely shot and the car wont run for more than 5 minutes, as soon as it warms up it dies and wont start until it cools down. Edited November 12, 2021 by Tehnation Link to comment Share on other sites More sharing options...
xt2005bonbon Posted November 12, 2021 Share Posted November 12, 2021 Did you plug the air feed hose off the air filter box past the MAF ? I have used a pint size paint can to plug that hose. I still use this method too to check for leaks: plug that hose as mentioned above and blow through the bypass valve hose. Then wait to hear hissing. Link to comment Share on other sites More sharing options...
xt2005bonbon Posted November 12, 2021 Share Posted November 12, 2021 Both front and rear O2 sensors are new Denso's. No exhaust leaks. OK. No leaks at the exhaust flange closer to the front O2 sensor? Link to comment Share on other sites More sharing options...
Tehnation Posted November 12, 2021 Author Share Posted November 12, 2021 I still use this method too to check for leaks: plug that hose as mentioned above and blow through the bypass valve hose. Then wait to hear hissing. I used the vacuum line for the fpr, I capped it off at turbo inlet hose and instead of blowing I just shoved the smoke tester into it to see if smoke came out anywhere. So its adding smoke and some pressure as well. Link to comment Share on other sites More sharing options...
Tehnation Posted November 12, 2021 Author Share Posted November 12, 2021 OK. No leaks at the exhaust flange closer to the front O2 sensor? Not that I can notice, I don't see any smoke, or hear anything. Is there a way to tell an exhaust leak other than just seeing smoke or a louder engine? Link to comment Share on other sites More sharing options...
Ratmilk Posted November 12, 2021 Share Posted November 12, 2021 Have you ran a compression test recently? Link to comment Share on other sites More sharing options...
Tehnation Posted November 12, 2021 Author Share Posted November 12, 2021 Have you ran a compression test recently? Motor was just rebuilt, I did a leak down prior to installing the motor and everything was good. Haven't tested it since, but I doubt its compression. It wouldn't work at all if that were the case. It fires right up and runs fine when cold. I don't think these kind of symptoms are common to bad compression. Not even a misfire. Link to comment Share on other sites More sharing options...
JoeInOregon Posted November 12, 2021 Share Posted November 12, 2021 No idea if this is your problem but is common on old VW's......vapor lock can be caused by problem in the evap system ......try taking your gas cap off and letting it warm up Sent from my Pixel 3a using Tapatalk Link to comment Share on other sites More sharing options...
Tehnation Posted November 12, 2021 Author Share Posted November 12, 2021 No idea if this is your problem but is common on old VW's......vapor lock can be caused by problem in the evap system ......try taking your gas cap off and letting it warm up Sent from my Pixel 3a using Tapatalk Thats what I was thinking, but I never heard of vapor lock being an issue with the 4th gen's, and the amount of fuel this pump is pushing should work against vapor lock, but I don't know because my fuel rail setup is Macgyvered. All the funky issues I had with fuel pressure, plus xt2005bonbon pointing out that my log looks like a vacuum leak makes me wonder if something is going on with the evap line to the tank and vacuum leak. I am not sure how the evap system is setup on the car. Is there a charcoal canister in these cars? But if that were an issue it would throw a code. I will try running it next time without a gas cap. It seems to be starting at a certain temperature and operating for a consistent amount of time. Its all clockwork, I will try the new ecu I just cloned tomorrow morning. Link to comment Share on other sites More sharing options...
Ratmilk Posted November 12, 2021 Share Posted November 12, 2021 (edited) Motor was just rebuilt, I did a leak down prior to installing the motor and everything was good. Haven't tested it since, but I doubt its compression. It wouldn't work at all if that were the case. It fires right up and runs fine when cold. I don't think these kind of symptoms are common to bad compression. Not even a misfire. If it was just rebuilt and leak down tested then definitely not compression. TGV's stuck closed? I have a feeling it's something electrical then. Edit: TGV's stuck closed is usually accompanied by a CEL Edited November 12, 2021 by Ratmilk tgv Link to comment Share on other sites More sharing options...
Tehnation Posted November 12, 2021 Author Share Posted November 12, 2021 If it was just rebuilt and leak down tested then definitely not compression. TGV's stuck closed? I have a feeling it's something electrical then. TGV deletes lol, so no TGV valves or motors or places to fail. Link to comment Share on other sites More sharing options...
xt2005bonbon Posted November 12, 2021 Share Posted November 12, 2021 Btw, have you driven the car yet? Just wondering how it behaves under mild load. And did you secure well that small vacuum hose on the intake manifold right above cylinder 4? I believe the other end connects to the fuel system or something like that. Did you verify every single screw securing the fuel hoses are nice and tight? Link to comment Share on other sites More sharing options...
whitexc Posted November 12, 2021 Share Posted November 12, 2021 Running with the gas cap off should trigger a CEL....correct? Just wondering if you can double check you have a working ECU that way as well....thinking via type. Shoot me down! Sent from my SM-G996U using Tapatalk Link to comment Share on other sites More sharing options...
Ratmilk Posted November 12, 2021 Share Posted November 12, 2021 Sorry to keep throwing things at a wall, really odd that you don't have a CEL, but JoeInOregon may be right about vapor lock. Always worth checking Cam and Crank position sensors too. Link to comment Share on other sites More sharing options...
Tehnation Posted November 12, 2021 Author Share Posted November 12, 2021 Btw, have you driven the car yet? Just wondering how it behaves under mild load. And did you secure well that small vacuum hose on the intake manifold right above cylinder 4? I believe the other end connects to the fuel system or something like that. Did you verify every single screw securing the fuel hoses are nice and tight? The hose on cylinder four goes to my mechanical boost gauge in car. I replumbed the fpr vacuum line to feed from the bpv line. Originally it was capped off but it was a perfect source for my boost gauge. I drove it for 20 miles in multiple trips with no issues. It had one hiccup towards the end of that 20 miles, and it restarted a minute or 2 later, then another day I was driving it died and wouldn't start and I had to get it towed, and then a 3rd time which was right after the 2nd time, it happened again and had to be towed. Now that I'm thinking about it the last 2 times I had it towed, I only drove it for about 5 minutes and then it died. It basically can only run for 5 or so minutes then it needs time to cooldown or for something to reset. But for the 1st 20 miles I was driving it fine for well over 5 minutes and restarting it was no issue. Something happened that 1st time it died, and I do believe I was giving it some gas and it hasn't been right since. Link to comment Share on other sites More sharing options...
Tehnation Posted November 12, 2021 Author Share Posted November 12, 2021 Running with the gas cap off should trigger a CEL....correct? Just wondering if you can double check you have a working ECU that way as well....thinking via type. Shoot me down! Sent from my SM-G996U using Tapatalk I pulled the maf sensor plug trying to get it to start and a code came right up. I replaced the coolant temp sensor with some autozone brand sensor which turned out to be shit cause it threw a code as soon as I installed it so I returned it. I get codes! I unplug anything and I get a code, so the CEL's are coming when they should for the things that I have touched. I can't say its working for everything but its been triggered for everything I tampered with. Link to comment Share on other sites More sharing options...
Tehnation Posted November 12, 2021 Author Share Posted November 12, 2021 (edited) Sorry to keep throwing things at a wall, really odd that you don't have a CEL, but JoeInOregon may be right about vapor lock. Always worth checking Cam and Crank position sensors too. This is why its such a pita, fueling is usually the culprit when you have no codes because it has the least amount of sensors. No codes, I was thinking crank positions sensor maybe but that would throw a code hella fast. Likewise with the cam position sensor. I don't think the engine is getting hot enough to cause vapor lock, you need some high temps for that. Edited November 12, 2021 by Tehnation Link to comment Share on other sites More sharing options...
xt2005bonbon Posted November 12, 2021 Share Posted November 12, 2021 So to me, it seems that the ECU is fine and there is something going on with fueling which in turns makes the computer thinks you are running lean. This, again assumes zero vacuum leak, no exhaust leak, good O2 sensor and good MAF. Link to comment Share on other sites More sharing options...
rhino6303 Posted November 12, 2021 Share Posted November 12, 2021 Has anything changed hardware/tunewise between the last build and now? It is adding quite a bit of fuel once warmed up and running closed loop fueling. MAF/injector scaling could do this if fueling isn't the culprit. If nothing has changed, you might reach out to your previous tuner with that log and all of your information. Link to comment Share on other sites More sharing options...
Tehnation Posted November 12, 2021 Author Share Posted November 12, 2021 So to me, it seems that the ECU is fine and there is something going on with fueling which in turns makes the computer thinks you are running lean. This, again assumes zero vacuum leak, no exhaust leak, good O2 sensor and good MAF. Thats a very fair assessment! All 3 of those sensors are brand new, and I don't see or hear any exhaust leaks. I have a A/F gauge apart from the ecu A/F readings and they are withing .5 of each other. I'm idling at around 14-15. Link to comment Share on other sites More sharing options...
Tehnation Posted November 12, 2021 Author Share Posted November 12, 2021 Has anything changed hardware/tunewise between the last build and now? It is adding quite a bit of fuel once warmed up and running closed loop fueling. MAF/injector scaling could do this if fueling isn't the culprit. If nothing has changed, you might reach out to your previous tuner with that log and all of your information. Nothing's changed hardware and tunewise, but I have replaced a bunch of parts with the same parts since trying to track down this issue. I sent this log to the tuner earlier today, and they are looking at it. Wondering if the tune was done on bad data/faulty parts, and now that they are fixed its causing issues. I will see what the tuner says hopefully by Monday. Link to comment Share on other sites More sharing options...
Pleides Posted November 12, 2021 Share Posted November 12, 2021 Can you add some of the factory tunes back to your Accessport and putter around on the “Economy” map? Don’t drive aggressively, just drive for the sake of seeing if it’s a tuning thing. Link to comment Share on other sites More sharing options...
Tehnation Posted November 13, 2021 Author Share Posted November 13, 2021 I'm not puttering anywhere until this car can idle for more than 10 minutes lol. Link to comment Share on other sites More sharing options...
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