What's up guys, I'm posting on here after 2-3 months of troubleshooting and various different issues. So let me explain, I have a 92' JDM FD, and I'm running a single Borg Warner turbo with ID1050cc primaries and ID1700cc secondaries. I'm on a Haltech 550 and the motor was built by Vargas. After I got the car running and tuned, it ran great for like a month or so. When I was taking it on a 2-and-a-half-hour road trip I noticed a weird hesitation when accelerating sometimes which was accompanied by a strange sound that sounds like anti lag almost. When this would happen the car would not accelerate or increase RPMs or at least it would do it at a super slow rate. it also popped and banged a bunch during this and ran super-rich. If I gave it enough gas it would instantly snap out of this weird state and run like nothing even happened. It slowly started happening more and more as I drove the car until one night I drove it to Taco Bell and it did it while idling and while I was trying to enjoy my crunchwrap supreme. when it happens at idle the car just sputters and the RPMs fall and it shuts itself off. This particular night the car would not start at all. I plugged my laptop in because I keep it with me usually and the ECU was going nuts. every 5v sensor including the internal map sensor and all the 12v ones were jumping around like crazy and reading crazy values. I got it towed and troubleshooted for a bit and figured out that the 5v from the TPS was somehow grounding to the signal ground before the sensor. I bypassed the 5v of the harness cable and went straight to the TPS since it's the only 5v sensor that I need in my car and it seemed to fix the problem. No crazy values or jumping around. I was able to start the car and it ran fine for like 10 - 15 minutes until it started to try to die on me again. However, this time I had my laptop out and everything looked normal. No weird voltages anywhere. I replaced the leading coils and still no change. As it sits right now the car will start and idle just fine while it's cold. It'll even pull just like normal. It makes around 380-400 wheel depending on the boost and it feels like it's making normal power. Then after 15 minutes of running, it tries to die and starts getting into that weird mode where it runs super rich spits fire every and barely revs. Eventually, after I keep it alive long enough by giving it gas, one rotor will just entirely cut out and I'll be running on just one rotor. I have no idea what is causing this but it feels very electrical to me. This is because when it did this the most was while that one 5v reference was getting grounded somewhere intermittently. I fixed that issue but the problem still remains so I don't know what to do. It almost feels like once it's warm one of the leading plugs stops firing right until it eventually fully cuts out. I say this because when the issue occurs there is a ton of unburnt fuel coming out the back creating a lot of drama. If it was fuel-related like a clogged primary injector I feel like it would cause one rotor to lean out. correct me if I'm wrong here. either way, I have no idea what's causing it and if anyone has any guesses or has experienced something like this I would love to hear about it. Also, the TPS sensor creeps from 0-0.8 now for some reason until I blip the throttle and then it goes back to 0. when it does this the rpms at idle increase and it runs richer since the car thinks I'm on the gas but the throttle body isn't open. Not sure why this happens either but another reason why it seems like something electrical. I calibrated it warm by the way.

 

there are others on the forum that will be way better than me as to zeroing in on your problem but i will start things off...

according to your observations you had a 5 volt problem... and you go on to say you wired around it for your TPS. but you also mention you saw the internal MAP sensor was also effected. (it runs on 5 volts).

it is essential for the ECU to know the correct boost. for example, if you are at 15 pounds of boost your timing should be around 10 to 15 advance. if the ECU is not able to position the motor correctly on the boost map due to a 5 volt problem the ECU might, as example, position the motor at zero boost where the ignition advance might be in the mid to high 20s.

too much advance and you get pre-ignition and/or detonation. i suggest your warm the motor until you get the negative symptoms and then do a compression test.

 

Thanks for the input. A compression test is definitely gonna be done in the next few weeks or so. The map sensor works fine now. It was affected by the original issue which was causing the car to not start however since I've re-wired the shorting cable to the TPS, the map works normally and reads the correct values while I'm driving around or while in boost. I have a boost gauge to compare it to as well and everything seems normal with the map. I have a data log for when the car was trying to die on me and I was keeping it alive. I'll see if I can upload that here.

https://drive.google.com/file/d/11Je...ew?usp=sharing

here's a link to the data log if anyone wants to download it. The car should idle at around 1200 rpm anytime it drops below 1000 is when the problem happens and I have to give it gas to keep it running

 

Disregard That link here is a better example of the issue for anyone who has haltech data log viewer
https://drive.google.com/file/d/1bVE...ew?usp=sharing

 

Will review later tonight and get back to you with my thoughts.
Do you have an idle control valve? and does this work as intended?

Howard has touched on this, if the 5v trigger has an issue, you need to fix this immediately and do not hit boost until you do.

 

here is a video of the car having the issue. all data on the log looks perfectly fine up until it happens than everything reacts. everything in the ECU is working as it should (from the log) to keep the car running. There is no weird ignition angle or sudden cut in fuel. when the issue happens though I've now noticed that it leans out a bunch, this makes me think the fuel is getting cut off even though it doesn't show it on the log. Not sure how this could happen. My other thought is that it's cutting ignition completely but that also doesn't show on the log and if that happened it would cause a rich scenario, not a lean one. let me know what you guys think. it sounds like the ignition is still working because the engine like sputters to a stop as if it ran out of gas. this could also be an effect of the leading plugs stopping and the trailing ones continuing to fire as the rpms slow down. Not sure which but the sound is unique. take a listen. (also ignore the exhaust leak the gaskets are shot but it's been running fine for a month like that. replacing the this week)

https://drive.google.com/file/d/1x2m...ew?usp=sharing