Is this a sign of a vacuum leak?

[kev0]

Rough start and rough idle. Sometimes the RPMs dip below 500 and sounds like it's dying to stay alive. Eventually, it does die though and I would have to start it back up. Newly boosted with the Sprintex 210 kit and tuned with @Xero-Limit. I haven't even gotten a chance to drive the car yet.

P0300 (went away after clearing) P0304 and C1288 codes. The Check engine light blinks and sometimes stays solid.

Does this sound like your typical vacuum leak? I did a smoke test and soapy water test. I found two leaks with that and have since fixed it. Problems still persists. Is it likely that it could be the hoses under the intake manifold?

https://datazap.me/u/kev0/p0304

[steve99]

Alaways clamp all manifold vaccuum hoses when going boosted they will blow off under boost.


Check you di computer is bolted to engine with all three mount bolts, thats its Earth.


Manifold pressure at idle semms high at about 7-8 psi should be lower like arround 4 or 5, possible slight vaccuum leak.


Also fuel trims are wayg positive 35% and afr is still way lean, at 17 to 18. Check you dont have exhaust leak near or vefore first 02 sensor

[mrha]

The hoses under the manifold come off very easily. I was tempted to not clamp mine because I have a 2013 and pretty much every hose on top takes a lot of effort to remove. However I decided not to be lazy and took off my manifold to do it. Those hoses came off with a flick of the wrist. I put worm drive clamps on all of them.

Also I had a problem with my supercharged car stalling when coming to a stop. I thought it was the tune but after some research I found out it was a dirty throttle body. I bought some throttle body cleaner and spent 30 minutes spraying and cleaning. Drives like a champ now.

[kev0]

@steve99 Will a bad spark plug make the car run lean? Because my data shows that I have insanely high fuel trims and misfiring in Cyl 4 which leads me to believe that the intake manifold gasket in cylinder 4 has gone bad. The manifold did have oil and crud on it, so I believe it is the manifold gasket.

[BigTuna]

You could try testing for vacuum leaks. I made a smoke tester out of a transfer pump, cigar, and a pipe cap. I followed this video:

[ame]https://www.youtube.com/watch?v=GOhl4r0GSiE[/ame]

[maslin]

Originally Posted by kev0

@steve99 Will a bad spark plug make the car run lean? Because my data shows that I have insanely high fuel trims and misfiring in Cyl 4 which leads me to believe that the intake manifold gasket in cylinder 4 has gone bad. The manifold did have oil and crud on it, so I believe it is the manifold gasket.

Lean means too much air. Bad spark would go rich, too much fuel.

Lean is almost always a vacuum leak, could be injector, 2 sensor or ?? but vacuum leak is the first place to go.

[kev0]

Originally Posted by maslin

Lean means too much air. Bad spark would go rich, too much fuel.

Lean is almost always a vacuum leak, could be injector, 2 sensor or ?? but vacuum leak is the first place to go.

omg thank god!! I was afraid of my spark plugs going bad. I'm sure its the seals on my intake manifold going bad then.

[steve99]

Originally Posted by kev0

@steve99 Will a bad spark plug make the car run lean? Because my data shows that I have insanely high fuel trims and misfiring in Cyl 4 which leads me to believe that the intake manifold gasket in cylinder 4 has gone bad. The manifold did have oil and crud on it, so I believe it is the manifold gasket.

Bad spark plug ie no fuel burn would tend to make ecu think its rich

[Soloside]

running into the same issue. Flashed a new tune and the abs/trac light comes on. The previous tune did not have the issue, I even reflashed back to the previous and the light's still on.

https://datazap.me/u/soloside/log-15....02&tmax=20.33

Here's 2 logs. One is right after the flash driving. The other was me waiting about 3 hours and the car actually shut off.