Fuel cut feel like total loss of power, it sounds like it might be a boost leak

Should get worse with more load( higher gear) if it was fuel cut

Yeah sounds like a boost leak. also sometimes it causes like this if you are using a AFC to adjust the AFR such as MAF-T, S-AFC or so, should check if it is adjusted properly.

Ok. So it's not fuel cut.

We have done a boost leak test. Had 2 minor leaks that we fixed. The issue has continued, it is a fresh engine but a used turbo. System holds pressure up to 20psi ( we did not surpass 20 during the leak test) motor has 360 miles on it since rebuild and the issue has been present since drive #1.

Also, if it was a turbo issue or a boost leak issue wouldn't it persist through all gears at the same psi? It is only 1st gear regardless of the load I put on. As soon as I hit 10 psi it stutters/cuts but will progress boost if i continue. My afr does not change during this incident either.

DSMPT said:

Yeah sounds like a boost leak. also sometimes it causes like this if you are using a AFC to adjust the AFR such as MAF-T, S-AFC or so, should check if it is adjusted properly.

Click to expand...

Just verified with my husband, we do not have any type of afc. We are just monitoring what the ratio is.

Could be knock (real or phantom).

Mauispyder said:

Could be knock (real or phantom).

Click to expand...

Elaborate please. How do I check/find it and how do I fix it?

Are you using a internal wastegate actuator? I had some very similar situations with my customer's cars.
The one was very similar to your issue but it was just one cut (was not like stutters, was like one little explosion), that happened only in 1st gear at 10 psi. This case was solved when I replaced the wastegate actuator.
The other one was happening only in 3rd and 4th gear and was caused by electric boost controller setting (the gain number was too high).

Yes to an Internal wastegate. And I really feel it's more like a stutter, power sputters and then picks right back up. Hmmm, now to find an actuator for cheap to try this.

As for the boost controller issue, this issue was present before I purchased and installed a manual controller.

It could be related to the ignition timing issue you are having, if you are to far advanced it can cause knock, the ecu then pulls timing to try to stop the knocking. Test your wastegate before just replacing it, though I personally doubt the wastegate is the issue.

The car came with a few random parts when I purchased it, a spare actuator was among them. So we can replace it fairly easy and the no cost to test the potential fix.

With the flip of the cas, we are now running decent timing numbers. There is just zero change to the feel of how it drives.

Still having late spools, the odd issue at 10 psi in first gear and the general slow feel of the car. I do not feel like it climbs the way it should. However, I will try the actuator swap and see if that fixes the issue in first gear. If it doesnt, I shall be posting again.

Could be a fuel regulator problem. Check the fuel pressure to know hows the fueling system doing.