Do you see voltage drop in the logs?

 

I haven't looked into that, I'll look at that tonight. However, I forgot to mention that I swapped the battery last week, back to an AGM battery. So that should remove the battery from the equation. My tuner did say I have a sizeable draw on the battery though with the key off, so I need to look into that again. I have several fuses right off the battery running to different things I've added (stereo, dashcam, etc), and I pulled all of those fuses and made no difference, so it must be in the stock fuse boxes somewhere.

 

I looked at the logs last night and saw the battery voltage drop out, as well as manifold air pressure. Now I'm going to look at every single thing and see what all is dropping out. Makes me wonder if the ECU is bad now. But first I'm going to get some new logs with the changes I've made, including the battery and the wideband sensor I replaced last night.

 

I got a couple more logs last night, and the issue was still present. I haven't gone through every metric yet, but nothing I looked at had dropped out. Not battery voltage, MAP, wideband. I didn't look at crank triggers because I couldn't find it on the list.

However, I did compare TPS and fuel tuning, fuel pressure, MAP, and RPM Limiter Active and RPM Limit - Fuel. To my untrained eyes, it looks like fuel pressure is dropping while TPS is steady at 99%, and I'm going to kick my own *** if it's something as obvious as a clogged fuel filter or a bad pump. The fuel filter (ID F750) is only two years old, so I didn't even consider that as being a problem. But the fuel pump (Walbro 450) is about 10 years old, maybe a little more. I've been considering getting a 525, but I heard they had some issues occasionally. Anyway, I plan to check the filter tonight at least. I'm not sure how I could test the pump rather than swapping in a new one to see if it fixes the issue. I could apply varying voltage, but I have no way of measuring flow.

 

Injector cleaning services usually can flow-test pumps too.

 

Oh good to know, thank you! Maybe I'll send off my older injectors to get cleaned as well.

 

My tuner said that he was seeing a cyclic pattern in the triggers that looks like noise from an outside source and suggested moving the CAS wiring further away from the alternator, and I finally did that last night. I also wrapped the wires with foil tape and grounded that tape to the chassis and engine.


I wrapped the sensor wires as well, and grounded them to the same place as the wrap on the other side of the connector.

I grounded this with the other ground cable seen in this pic that goes to the chassis.


The wire goes into the wrapping. I checked continuity from the terminal to the foil wrap to make sure it's working.


I took the car out tonight and got a few more logs. The first few pulls were really good with just a few slight hesitations, but they were so minor they were almost imperceptible. But the problem came back after the first few pulls.

I jacked the car up the other night and looked at the gauge on the filter and it looked good. Then I watched a video saying to idle the car when you check the gauge, and that makes way more sense since it's a pressure differential gauge lol. So I'm going to put the car up again and run it this time, but I'll probably end up swapping the filter anyway just in case. I'm also going to check the pick up on the fuel pump, and if the problem still isn't fixed, I'll send the pump off to get tested, or just buy a new one. I've been considering going brushless and PWM, but I'm not sure I'm interested in that amount of work during the only months I can drive the car.

 

I checked the fuel pump gauge while running and it looked good, but I swapped the filter anyway, and I swapped in a new pump as well. I got the pump from Summit and it had different stamping so I thought it might be fake, but I couldn't find any evidence either way. I thought I'd heard Summit was selling fake pumps but they are an authorized distributor. It does work, but I still have the issue.

I talked to Chris Ludwig and he'd had issues like that before and asked if I had a spare ECU to swap in to test it, but suggested creating a new map from scratch because the current one could be corrupted and said that worked for him in the past. I'm just not sure if I should use an older map from before I started having issues or if I can recreate the most current map. He did say that the logs from when I had good pulls didn't show any issues, so that gives me hope.

I also still have to make the changes for the new knock sensor.

 

Do you still have the logs with your bad/problematic pulls? You can upload them here. I'd like to have a look too.

 

I'd love to! How? lol

 

Attaching the file to your post ?

 

Thanks for the tip! The 23 May log shows the issue I'm having, the 30 May log doesn't, according to Chris. And the 30 May didn't feel bad either, it felt like normal. After that pull I had the issue again, but I didn't get a log that time.

 

I think your problem might be car running too rich during pulls if we rely on your wideband. Also too rich can cause misfires and trigger errors. If you take plugs out and have a look, they may give you some insights about this.

 

I also noticed AFR looked really rich during pulls and thought maybe the wideband was bad, but those logs are after I replaced the sensor. So that could be the case. Although the map hasn't been changed for quite some time unless it was corrupted somehow. I still need to build a new one from scratch and see what happens. The plugs looked good when we pulled them a few weeks ago when we were troubleshooting trigger issues, a bit worn but not even too bad in that regard either. I might replace them anyway just to start fresh.

 

I finally uploaded an older map, from June of last year, and that didn't work at all lol. I think I'll be picking up another ECU on Black Friday just in case.

 

I bought a 2500 during the sale to test out. I uploaded the current map on it and tested it today, and it didn't work. I got a CEL for trigger reference error again. I was talking with my tuner and sent him a pic of when I built the harness and had issues getting the ground wire for the CAS into the connector. I was wondering if it was too damaged, but he noticed some stray copper wires and asked what I did with the green negative wire and I couldn't remember, I think I just cut it off flush, and he's wondering if it's making contact with the shield/signal ground wires. I disconnected that terminal at the ECU connector and I'll test again tomorrow. If that doesn't fix it, I guess I'll build a new harness and have the car tuned again from scratch.

Also, I bought a new OBDLink cable to check for continuity between sensor ground and battery ground, and that one is the same as the old one, so apparently that's a feature, not a bug.

 

Great news! The issue is fixed. My dumbass should have looked at the trigger reference wire from the beginning lol. And I should have done better on this wiring in the first place. I'm not sure why it didn't cause issues from the very beginning, but for whatever reason, apparently it started making contact with the shielding at some point. I did three WOT pulls tonight and never had a hiccup. Perfect timing too because we're supposed to get our first real snow tonight, and it was dusting while I was driving, hoping that the roads weren't cold enough yet for me to lose traction, but no issues there.

It also makes me wonder if that's the cause of all the other things dropping out, maybe all of those things are on sensor ground.

Here is a pic of the CAS connector, and you can see the copper wires.

 

I tested the cranking amps on the RX-8 2kw starter tonight. I have a 0 gauge cable from the battery behind the passenger seat and it's going straight to the starter. It pulls around 240-245 amps during cranking. So I guess I'll be sticking with a 300a breaker, or MAYBE trying a 250a, but I'm not sure there's enough wiggle room.

 

The sizing of your main breaker sounds like you are taking a bit of a risk. 0 ga wire does not support 300 amps at any wire length. There is a possibility that the wire can fail before the breaker would trip. I will attach Waytek's amp guideline table. I suggest you reduce the size of the breaker to conform to the maximum amperage rating of a 0 gauge wire at the length of the conductor your using. The inrush amperage you are seeing during the starting cycle should not effect the breaker as it is just momentary. I have a 200 amp main breaker, with about 7' of 1/0 ga servicing my starter and I have zero issues with breaker tripping, even though I'm sure the inrush current is greater than 200 amps.

 

Interesting. My current 300a breaker will trip if I try to start the car for more than about 8-10 seconds, and it won't let me close it again for about 30 seconds, which is hell when you're sitting in heavy traffic and you're holding everyone up lol. Although that's a rare occasion.

Maybe I'll try the 200a breaker first and see how it goes. I didn't test what the draw is once the car is running.

Where do you have your battery, in the same place? I don't know exactly how long my cable is but it's probably about the same as yours.

 

It sounds like there is some wiring that is under sized between the battery and starter lug. I just recently got my car running on brand new, full custom wiring on the entire chassis. During the initial attempts to start the motor the first time I was on the starter for 15+ seconds over and over for like 10 cycles in a row. No issues with breakers/circuits at all. It sounds like something is getting hot and getting the breaker to trip.

 

It's been doing that for over 10 years now too. I don't have any wire smaller than 0 gauge going all the way to the starter. It does go through a bulkhead near the gas pedal and straight up from the starter, but it's a sizeable bolt (I don't remember the size off the top of my head), and it's completely isolated from the chassis, obviously.

I went looking for pics but this is all I could find, and of course I didn't get all my pics pulled from their site before they closed so it has the watermark lol. I had a pre-made bulkhead installed originally, but I never could keep it tightened/secured, so I made my own. The smaller bulkhead was for the ground cable, which is also 0 gauge straight from the battery to the transmission, and the larger one is what I used for the battery.

 

As it turns out, all the cranking issues associated with the 300a breaker are due to the breaker itself. I installed the new 200a breaker and it cranked for at least 15 seconds with no issues, I haven't tried cranking longer yet. I counted on the old one and it cranked for 6 seconds before popping. I will say I've had it for probably 15 years and it's a cheap POS, and the new one seems to be quality.

 

Wow you're on a roll fixing things! What brand is the new circuit breaker?

 

Yeah it's about time I fix things instead of making them worse lol.

I bought this Bussman.


And apparently this is the old one I bought back in August of 2012. So I guess it isn't quite 15 years old.