Need help gst running very rich all of a sudden

[Epicind]

Hey guys, I'm officially new here but have been lurking around on here for a few years now. I've encountered my first problem that has me truly stumped and could really use some help. My problem is this, I took the car for a spirited drive in the mountains one weekend and it ran great, however the next day I went to drive it and it started up but was running very rough. Please help me diagnose this problem

300rpm idle
wideband shows afr of 10:1 at idle only pulling 8 inches of vaccum
Smells very rich
Drivable, but runs bad and fouls plugs

Here's what I've done so far
Check iacv
Check maf
Check ect
New plugs (.029) gap
New wires
New coil pack
Boost leak test
Timing check (lined up at 10 degrees btdc)
Verified fuel pressure at 46psi
Verified Karmen signal with safc2
Replaced ect sensor

Here's the mod list for the car
95 gst
Safc2
550 rc injectors
Agp 50 trim
Hks 38mm Watergate
Walbro 255
B and m fuel pressure regulator
Forced performance intake
Greddy bov
3" turbo back ex
Full emissions delete

 

[Lou98GSX]

You might have to play with your low fuel settings on the afc

 

[Epicind]

Thanks for the reply. I did try that as well. Right after New plugs and wires I adjusted the afc all the way lean for the idle and lower rpm setting and didn't see any change on the wideband...also worth noting, the afc was tuned by wingz perfomance in Phoenix and the car was running great the day before

 

[jukebois]

Check the fuel regulator for a leaky diaphragm.

 

[Epicind]

Thanks, I'll check that today after work and report back

 

[Dsmkauai]

Did you do a boost leak test? How high did you test it if so?

 

[Epicind]

Yes I did, the turbo to the throttle body is is good and leaks very little up to 20psi. I only tested to 20 because I run 18psi. When pressure testing all the charge piping and into the motor it doesn't hold pressure as well, if I take it up the 20psi it'll leak down to 0 in about 4 or 5 seconds...I figured it was leaking past the pistons

 

[Epicind]

Ok, I removed the fuel pressure regulator, dismantled the adjustable cover and pressure tested the part with the diaphram to 50psi and it held, so I don't think the diaphram is torn

 

[steve]

Timing check (lined up at 10 degrees btdc)

Please explain.

 

[Epicind]

When checking the engine timing. The cam alignment markings were lined up facing each other perfectly and the crank marking was at 10 degrees btdc, if I lined up the crank to tdc the cam markings would be slightly mis alligned by about 3/16 of an inch

 

[Lou98GSX]

It looks like your timing jumped . When you put your crank mark at top dead center your valve timing marks should line up .

 

[Epicind]

Thanks, I'll check it again and take some pics to show. If the Timing jumped 1 tooth would it cause my symptoms?

 

[Lou98GSX]

yes

 

[steve]

When checking the engine timing. The cam alignment markings were lined up facing each other perfectly and the crank marking was at 10 degrees btdc, if I lined up the crank to tdc the cam markings would be slightly mis alligned by about 3/16 of an inch

This is why I asked.

I assume you used the harmonic dampener mark so you also need to verify that the outer ring on the dampener hasn't shifted/slipped. The easiest way I know is to remove the #1 spark plug and make sure the piston is at TDC when the mark is at TDC.

Where both cam sprocket dowels at 12 o'clock when you lined their marks up?

WRT the B&M fuel pressure regulator. If it's one of those attachments that modifies the factory regulator they can't lower the fuel pressure and since they reuse the factory regular suffer from fuel pressure overrun like the stock one.

 

[Epicind]

Great info, thanks...I did verify tdc to the dampner with a screwdriver through the spark plug hole, but I did not verify the dowels being at 12o'clock...I'll recheck it this evening and verify my results

 

[Epicind]

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Ok, so with the crank at tdc this is where the cams are

 

[steve]

Hard to say from the angle (can't be sure that the exhaust cam timing mark is aligned with the top of the block) but it looks like the intake cam has jumped a tooth.

 

[Dsmkauai]

Time to get a oem timing kit! Jnz has a nice one if your on a budget uses gates but has the oem tensioner which is the most important piece and why your timing jumped mine did that same thing years ago got so so lucky on that one!