Misfires after boost tap install, give me peace of mind please.

[It's Sam]

Good evening,

I just finished installing APR's boost tap and gauge (of which the gauge was a major pain, for a number of reasons I'm blaming APR for). I had a little issue.

Intake was completely removed, battery was completely removed. Followed APR's written instructions very closely. Allowed car to warm up fully (roughly 200F oil temp) before installing. Hole was punctured in manifold while manifold was warm-ish.

Everything installed normally, everything was put back together, everything was in its original place that was there before.


I go to start the car up, and I get a CEL and a very rough idle after start. Idled as such for about 10 seconds, dipped, and shut off. Again, started, seemed normal for about 3 seconds, then began to dip and shut off.

Third time, started a little rough, then picked up and held steady. No issues. Drove around the block with no issues. I cycled the engine about 4 times when I returned, no issues.


Using the Accessport, I read 4 codes: One for random misfire, One for Cylinder 1 misfire, one for Cylinder 4 misfire, and, for some odd reason, one for an inefficient catalytic converter (which I haven't gotten before. Input would help!).


I'm assuming a little plastic got into the manifold from when I punched the hole, and that caused little misfire or some skittishness when it made its way into the engine. I really have no clue. There's nothing else that I know of that can explain this in a reasonable way.

If you have anything you think it may be, please let me know. Otherwise, give me peace of mind in knowing it was just a little hiccup.

 

[Twist1]

I don't think they would be related. Unless a piece of plastic got in or you forgot to put the viton o rings on? Maybe it's more from you resetting ecu/disconnecting battery?

I've done three of those taps and they have all been flawless. The best kit on the market imho. You just gotta do it when it's warm or heat it up with a gun for a few and it's ez pz.

 

[It's Sam]

I don't think they would be related. Unless a piece of plastic got in or you forgot to put the viton o rings on? Maybe it's more from you resetting ecu/disconnecting battery?

I've done three of those taps and they have all been flawless. The best kit on the market imho. You just gotta do it when it's warm or heat it up with a gun for a few and it's ez pz.

I agree with you, I'm just trying to narrow it down. The ECU being a little jittery after reconnecting the battery makes the most logical sense. It's not a huge hole that the punch makes, so any plastic would probably either melt or just find its way out right away.

Also, APR's tap is awesome, and pretty easy to install. It's their gauge "kit" that's a little too jumbled for my preference.

 

[Twist1]

I agree with you, I'm just trying to narrow it down. The ECU being a little jittery after reconnecting the battery makes the most logical sense. It's not a huge hole that the punch makes, so any plastic would probably either melt or just find its way out right away.

Also, APR's tap is awesome, and pretty easy to install. It's their gauge "kit" that's a little too jumbled for my preference.

Check the viton rings on the Tap. They did NOT come pre installed on my last purchase but my first two they were already on there.

 

[It's Sam]

Check the viton rings on the Tap. They did NOT come pre installed on my last purchase but my first two they were already on there.

Mine weren't preinstalled either, but I definitely put them on.

 

[acorazza]

I have the tap too and have to say I don't have any issues with mine. It sounds like a vacuum leak with the rough idle. Ever try pulling the dipstick when the engine is on? I have once and it started stumbling. Make sure you check the connection between the gauge too, I'm not familiar with how it connects to the tap. Otherwise maybe check the hose from the boost tap itself and make sure there are no cracks or leaks in the hose.

 

[Redmk7gti16]

You may of cracked the intake manifold when using the tap.

 

[gti925]

It sounds like you have a vacuum leak assuming that this didn't clear up. Spray carb cleaner in the questionable areas. If the engine RPM rises, you have a leak in that area.

 

[It's Sam]

Thank you everyone for all of the responses, I appreciate the input.

I'm thinking along the lines of what Twist mentioned, in that the battery disconnect and the tune didn't agree with each other initially. I did 4 engine cycles (on/wait/off) with no issues after I let the car sit for a few minutes, and today I drove ~20 miles with no major issues. The rough start and idle are seemingly gone for good.

I still have a CEL for a weak catalyst, So I wonder if some of the stored values were lost when the power was disconnected. The trip odometer and clock reset, as expected, so I wonder if the tune has some values that are stored similarly. (This sounds more and more stupid when I see it written out)

I want to try to reflash the tune this week to see if it clears the CEL, since clearing all codes didn't get rid of it. If it does, that may be the reason for the issues I had at first.

 

[anotero]

O ring? Interesting, mine came without an O ring and everything runs fine.