[RocktimusPryme]

I have been chasing an intermittent issue for a while now. We all love those. It’s driving me nuts. I don’t know if it’s a tune issue or a hardware issue.

Basically once in a while the car will go lean and start running almost like it’s missing. Picture making a motorboat sound with your mouth, that’s what it’s like. Then it will just snap out of it and throw you back in the seat as all the power comes back.

Now if I didn’t have the o2 I would say this was a spark issue all day. But why would he lean out if it’s not firing? Wouldn’t that show rich?

I changed all my plugs, and plug wires. Looked for any electrical connection that might be shorting out somewhere.

You can usually see it coming because when you are idling around a corner or something it will super lean out. That’s almost always a sign that when I put my foot back in it there will be the motorboat.

I also think I can hear faint light pinging too when it’s doing this. Maybe one of the injectors is intermittent not firing?

Sometimes it goes days without doing it. Idk. It’s dumb.

I’m going to send EFI systems pros the log and global but I wanted to see what you guys thought. I can upload the files here too. The tune is basically just the factory tune from the initial upload with whatever self learning there is.

[JLMounce]

Check your fuel pressure and fuel pump.

This is similar to what I just went through with my car. I had three items that were in the process of failing.

Fuel pressure regulator
Fuel pump
Coil

[RocktimusPryme]

Coil is a new hyper spark unit. Could be that I suppose bad out of the box.

The fuel pressure is always on display and I’ve never seen it drop below 60. The regulator is remote in the rear but the sensor is right at the inlet and it lives around 62-63 all the time. It will come up to 64-65 at a stop light but I don’t think I’ve ever seen it drop below 60.

Going to pull it out in the dark tonight and crank it up. See if I can see any sparks jumping anywhere in low light.

[krisr]

Need to see logs.

[ID67goat]

Sounds like the problem that I had with RF interference. What kind of plugs and plug wires are you using?

Once I swapped the plug wires I never saw the issue again.

[RocktimusPryme]

I think the plugs are ngk resistor plugs but I can look. I had MSD street fires on it but I went to a Taylor wire I had laying around just to eliminate it.

I have a terminator though with the ecu inside the car. From what I understand RFI is pretty much non existent on these.


I’m going to buy a new coil because that’s an easy check. I’ll post up the logs later today.

[RocktimusPryme]

So I changed the coil. Unfortunately didnt solve the issue.

Edit: It wont let me attach the Logs. Says its an invalid file, but if someone thinks they can help or just wants to see, I can email them to you. Just PM me your email.

Posting up logs. And Im adding the email I sent to EFI systems pros if anyone wants to take a stab at this. Some of this will be a repeat but it might make it easier. Im going to send the same to Holley's Customer Service.

---------------------------------------------------
I added a Hyperspark last year.* It finished the year running great, but after I brought it out of winter slumber Ive been fighting an intermittent issue.* I dont*know what else to try.* I dont*know if this is a tune issue, or a simple parts failure somewhere.* Either the hyperspark or maybe an injector issue.

The car is a 67 Firebird with a Terminator X Stealth.* 461 Pontiac, Mild Roller and an Edelbrock RPM intake.* Makes about 580 HP. Tune is the basically the stock Terminator X tune with whatever self learning is added over time.* The Terminator went on in 2021, but the Hyperspark setup is less than a year old.
Im going*to try and be thorough here to give you the most information I can.*
*
The Issue:**

I have this intermittent issue that if this was a carbed car I would say is 100% a spark issue.* It seems like it starts missing.* But when it does it I get lean AFR signals, I feel like if a cylinder wasnt*firing I would be getting rich readings from fuel not being burned.* Basically it will go from running perfectly normal and smooth to feeling like its on 7 and running rough.* Then it will suddenly come back to normal and throw you back in the seat as all the power comes back.* I know this is rudimentary, but picture making a motorboat noise with your mouth and thats what its like when its running bad.

It will sometimes go days without doing it.* Sometimes cycling the key helps. It will do it hot, cold, just started, or been driving fine for miles and suddenly do it.* Sometimes it will do it once and go away, others it will run terrible all the way home.* Im afraid*I am going to hurt the motor.**

The only precursor I can give is sometimes when Im coasting instead of the ARF readings staying stable, it will start flashing in the yellow/red lean on the*HUD. Thats usually a pretty good indication that when I put my foot back in it all will not be well.* *

Things I have tried:

1. Changed all my plugs and wires.* I had MSD street fires, now it has some Taylor wires I had laying around.**
2.* Changed the O2 sensor (I started with a reset base tune after this)
3.* Looked at all my wiring to see if I had any loose connections.
4.* Took it out in the dark and ran it at night to see if I could see any spark jumping anywhere.
5.* Inspected for vacuum leaks.
6.* Changed to a new Hyperspark Coil.
7.* Checked*Static Timing.

The Logs:

Im attaching*3 logs and my downloaded Global File.* This is all from Today.* I drove to the gym which is about a 10 minute drive.* Started fine then went bad about halfway there.* Logs 1 and 2 are from that.* After the gym it ran perfectly all the way home.* Log 3 is from the ride home.* Global is pulled from today.

Log 1.* This log is with the engine running poorly, then at about the 16 second mark you can see the RPM jump.* This is me just holding down the throttle (Partial not WOT) and the engine starts running normal again.* Like I said earlier it will throw you back in the seat as it smooths out and all the power comes back.

Log 2.* Is a short clip of it just running bad as I go from coast idle to applied throttle.* It goes lean, and then the AFR comes down but its still running bad.* This is normal when its doing the bad thing.* Applied throttle will lean spike for a second.

Log 3.* This is a clip for comparison of the car running normally.

Let me know if I can provide any more information.