Down on power L67?

[rcLord510]

My 03 GTP is having a weird issue, had it for about a year now and one day while going 70 I accelerated up to about 75 and it was down on power, burning coolant. So I changed the LIM gakeets(completely forgot to when I got it) and it fixed the coolant consumption but now it struggles under boost and any more throttle than 1/4, I have to feather into it and even then it struggles. On the accel if I do too quickly it makes a nasty sound that sounds blower related, but im not sure, tried plugs, maf sensor cleaned, iat cleaned, and it’s still having the issue, which comes and goes. During scanning, I noticed when it does this, it pulls timing, almost like traction control is sensing slip and removing timing, but I know I’m not slipping, and traction control hasn’t worked on my car since I got it anyways, im out of ideas guys, do any of you have any?

[rcLord510]

Oddly, filling it with a full tank fixed it, despite the issue sometimes occurring at over half a tank, it’s fixed for now but not sure if it’ll stay that way

[Schurkey]

Reduced timing advance can be a result of knock sensor activity, not just traction control.

The scan tool tells all.

[rcLord510]

9 hours ago, Schurkey said:

Reduced timing advance can be a result of knock sensor activity, not just traction control.

The scan tool tells all.

Should’ve said this. My bad, there’s no knock, well maybe .1kr at wide open, very minimal, so knock isn’t the issue 

[55trucker]

Perhaps not the source of your issue....the L67 engine is a premium fuel eng only, what are you running in the tank?

[rcLord510]

Just now, 55trucker said:

Perhaps not the source of your issue....the L67 engine is a premium fuel eng only, what are you running in the tank?

Premium of course. 93. My brother 3 or so weeks back apparently didn’t see the sticker on the gas cap and put like $5 of 87 in there, but then the rest was filled with 93, and since then only 93

[Black92GS]

17 hours ago, rcLord510 said:

Oddly, filling it with a full tank fixed it, despite the issue sometimes occurring at over half a tank, it’s fixed for now but not sure if it’ll stay that way

If it regularly occurs below a specific fuel level, I'd start suspecting an issue with the fuel pickup inside the tank.  Perhaps a cracked suction line that once you drop below a certain fuel level, it begins sucking air and isn't able to supply as much fuel as required?

I’d expect something like that to show up on live data as reduced fuel pressure and a lean condition, but being intermittent, there might not be codes stored.

 

Edited November 22, 2024 by Black92GS

[rcLord510]

6 hours ago, Black92GS said:

If it regularly occurs below a specific fuel level, I'd start suspecting an issue with the fuel pickup inside the tank.  Perhaps a cracked suction line that once you drop below a certain fuel level, it begins sucking air and isn't able to supply as much fuel as required?

I’d expect something like that to show up on live data as reduced fuel pressure and a lean condition, but being intermittent, there might not be codes stored.

 

I would expect that too, im gonna look over the scan again, but if I recall it had no such condition, it was just pulling timing, but I gotta look again at the scan and see if I missed something the first time

and good call on the pickup thing, may drop the tank at some point if the problem is consistently when the tank gets to that level

Edited November 23, 2024 by rcLord510