Der_Idiot

iTrader: (2)

Does anyone happen to know what this might be? I seem to get it between 2500-3500 mostly, it's the engine as well as the tach. Not sure what to think of it. I went almost all night without it tonight, but got it quite a bit earlier on around 5pm or so.

Der_Idiot

iTrader: (2)

Issue is persisting and much worse, I'm pulling my hair out trying to isolate this issue. I'm thinking it might be a ground issue, besides the engine to heater core area ground and the one under the brake booster, are there any other grounds that might cause this issue?

Symptoms:
Ignition breakup around 2500-3500 (can happen above that but not as often)
I am using Toyota COPs with capacitors; could this be a COP going out or the caps dying?
I also did recently install a Hall sensor for my 36-2 wheel; but the car would die if that was an issue I'd think.
Tach reflects a drop in RPM at the same time as the car lurches forward (thus my conclusion: ignition breakup)
Hydra logging shows a drop/increase in RPM as the car lurches from the cut out, nothing else on the datalog showed anything indicating something obvious.
While this can happen in boost, the overwhelming majority of it happens while I'm cruising. I could handle not being able to boost, but not being able to drive at all is something I can't let slide.

Here's a clip I made tonight, it's been particularly bad tonight.


Edit: I just remembered I have spare COPs, I'll give those a shot tomorrow.

fooger03

iTrader: (2)

I had cutting issues that I couldn't sort for the longest time. Bought an eBay COP and started switching them out - Cylinder 1, no luck. Cylinder 2, problem completely solved.

I've also previously been able to solve cutting problems by drying out the spark plug holes, which can be an issue for cops after an engine bay rinse or heavy rain since they don't seal like stock plug wires

Der_Idiot

iTrader: (2)

That actually reminds me of before I swapped to COPs, I had water/oil in the #3 well.. I'll pull my COPs and plugs tonight. Here's hoping this is the issue.

I'm also trying to figure out how to add another ground or two to clear this issue in the future.

Der_Idiot

iTrader: (2)

Cleaned the hell out of the ground strap under the brake booster, and made sure the engine ground was secure. Took the car for a spin and made it all of 2 blocks before I got a big ol' F-U from the car. Luckily for me I was prepared and had the trigger test open (since I can't log Igniter, CAS or CrAS trigger events. The first few trigger tests didn't see anything and then it refreshed and showed this:



Interesting behavior. Trigger events show several missed fire cycles. I zoomed in to get more detail and saw this:



Strange, so the COPs aren't firing and the Crank Angle Sensor isn't reporting properly. Which one's the culprit? I ended up pulling the plugs (which are amazingly clean for how rich I was running a while back) to verify I had no leaking fluid around the threads - Nothing there. I then swapped out the COPs with a spare set I had laying around. I took the car for a spin for a good 30 minutes and not a single cut out happened.

I'm skeptical to say it's fixed, however so far the behavior is promising. I have read a few threads that mention the Hall effect sensor can act up and not report properly when the engine is heat soaked. If I find it behaving like that again I think I'll revert back to CAS only and see if that fixes the issue. I am hoping for my sake when I overheated I fried one or more COPs or one of them was on the way out.

Der_Idiot

iTrader: (2)

COPs were swapped out and while it idles better it's still doing the cut-out, which lead me to think it was the Crank sensor so I swapped that for a new one. Still doing the cut out. Gave up for the season on using the crank sensor so I unplugged it and reverted the cut white wire on the CAS back to plugged in and switched the ECU to CAS only.

So here's the kicker, I haven't had a cut out yet while driving but now I have no gauges (except tach) and my turn signals don't work (4ways and running lights do though)....

Edit; Think it might be the meter fuse but I'm definitely not going back out there tonight, I'm about ready to start taking it apart for a partout

Chiburbian

iTrader: (1)

Check out these ground points. I had a similar problem and once I added grounds at these points directly to the MS the problems went away.
https://www.miataturbo.net/build-thr...6/#post1017483

Der_Idiot

iTrader: (2)

Looks like the METER 15A fuse popped. Replaced that and now the gauges work, but I'm still getting some of the same ignition issues, but now it bucks back and forth like I'm letting on/off the throttle over and over. I talked to some friends and one of them mentioned his TPS was going bad on his car and at some RPMs (or throttle range) it would consistently make the same intermittent cut out/bucking that my car is doing now. It can vary, sometimes it's mild and you almost think it's just a bumpy road, other times it's like I'm lugging it in second... only it's in any gear and between 2 and 3500 rpm.

Der_Idiot

iTrader: (2)

Not sure where to go from here, everything I spliced for the crank sensor conversion is soldered and the crank sensor is disconnected, but it still persists. It's not dropping RPM and resuming again anymore, but now it struggles to get from 2k to above 3250. And when it does occasionally the car will rock forward and backward as it gains and loses power. Letting off/on the throttle seems to fix it temporarily until it decides to happen again.

Now what I've found so far for options to fix this is rather broad. It could be the TPS, small dead spots on the sensor's range. Another suggestion has been ground issues, so I cleaned all the grounds and ran a few wires from the engine to the firewall just as a precaution. It was also suggested as I could have a bad harness connector/wires for the CAM sensor or the CAM sensor could be bad. And another thread suggested the fuel pump, but really? Would it cut out only between 2 and 3k and be perfect under boost?

Lost and confused, any help appreciated.

Chiburbian

iTrader: (1)

Not to beat a dead horse, but have you run wires from the megasquirt directly to the ground points I posted above? I had what sounds like a similar problem and once I just bit the bullet and ran fresh grounds directly to the engine ground points everything started to work great. Grounding the engine to the firewall isn't the same thing. Your sensors work best with a dedicated true engine ground.

If you have already tried this, disregard.

Der_Idiot

iTrader: (2)

I've cleaned all the existing ground points however I still get the issue. I have a Hydra though, not a MS. The weird thing is I've never had this issue before. I'm thinking of picking up a spare CAS and engine harness to eliminate both factors, but the car will be out of commission until I get a new softtop.

fooger03

iTrader: (2)

Are you running sequential spark or batch?

My Hydra had issues running Toyota COPS in batch, took a few starts before the problem surfaced.

Gryff

iTrader: (6)

I had a similar issue before, and genesplicer also had this issue, he can attest to either the cas being bad, or the signal from the cas being intermittent for one reason or another. im my case it was a bad cas, swapped cas for another one at it worked great. in genesplicers case it was faulty wiring coming loose at the connector to his cas. Hope this helps!

Der_Idiot

iTrader: (2)

Yeah I'm thinking I need a harness for the engine+CAS and if that fails I'll try a different CAS to switch to; I spliced into the CAS harness per FMs directions for the Crank sensor and that's when I started getting this issue. I'm wondering if I damaged a wire somehow. I've reverted the setup but it continues (less noticeably)

I'm running sequential spark as well as injection.