[trb1]

3rd gear shift at 7k. Mhd/jb4 with meth. Intake/meth backfire. At least my logs looked great right before.....

Car was mint. Now the hood is totally fucked. also took out the engine cover. Beware of meth with plastic intake.

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[Fallenangel123]

OP is this you?

[Kevin39]

Same thing happened to BMS awhile back

[blown07]

How much boost, how much meth, and W/M ratio?
Never heard of this.

[trb1]

Originally Posted by blown07

How much boost, how much meth, and W/M ratio?
Never heard of this.

Blew when the NLS kicked on. 100% meth, 18 psi. It was meth backfire. I’m spraying too much.

IATs are substantially lower with the cold weather so my trims are now negative. FOL is too high, or meth is flowing too much.

Don’t give a shit about the intake, I’m passed about my hood though.

[nicky dj]

Originally Posted by trb1

Blew when the NLS kicked on. 100% meth, 18 psi. It was meth backfire. I'm spraying too much.

IATs are substantially lower with the cold weather so my trims are now negative. FOL is too high, or meth is flowing too much.

Don't give a shit about the intake, I'm passed about my hood though.

Time to get a Seibon carbon fiber hood. Think I got mine for $900 or something like that, aside from the weight reduction and better look - my overall oil temps are 5-10 degrees cooler

[mike@x-ph.com]

[V8bait]

Common on 6mt.

1) Very common on 6mt with NLS using meth or PI, you flow fuel/meth through the shift and get backfires from overlap events and unburnt fuel mixing with burning. If you catch a coil charging with NLS you will definitely flare up. Seen this happen many times especially at events.

2) Less common on 6mt with PI and without NLS. Happens on fast shifts racing, you let off the pedal and the throttle closes. TMAP is pre-throttle and sees a boost spike before BOV opens, this injects a nice bolus of excess fuel into the manifold, which is under vacuum with the throttle closed. Any incomplete combustion will easily be drawn into the intake manifold backwards (EGR effect in a way) and may ignite the excess fuel, especially if there was a misfire during the pull causing a cylinder to shut off since that air is fresh. Seen it maybe twice.

Fixes:
1) Stop using NLS, especially the kind implemented by jb4 or wotbox.

2) Use a boost reference for PI based off manifold readings instead of charge pipe.

[Fuel-It!]

It's happened before but not that common. If the JB4 is controlling meth it cuts it as soon as the throttle closes but if the nozzles are large enough you still might have some in the intake.

The good news is there are replacement stronger manifolds available: https://www.burgertuning.com/product...nifold-for-bmw

[trb1]

I'll just be turning off the NLS for now. $60 plastic manifold on ebay, cheap quick fix.

I'll buy a metal manifold this spring when i buy a new hood. What a disaster. I shipped this car across the country because of how clean it was. I hate body work. Ah well, pay to play I suppose.

[trb1]

Have a question now guys. Replaced intake, noticed my fuel tank breather valve for damaged in the process of the intake blowing up (one that connects to the right of the throttle body).

I capped it for now, and have a valve on order. No vacuum leaks, car pulls hard as hell with no smoke, and my logs look great, but I have pretty bad idle misfire.. cyl 4/random misfire codes have popped up a few times. Valve is plugged in, and like I said, no leaks on the engine... Could this valve not being connected cause a random idle misfire? Want to get some insight. If not, I’ll be leakdown/compression testing this weekend. Hard to imagine an intake backfire caused valve or piston damage

[trb1]

If not the tank vent, or an injector, what could cause cold/warm idle misfire but solid logs besides a valve that got a little toasted?

[weehe126]

I doubt the fuel vent tube is causing this. Did you pull plugs to see their condition after the explosion?

[trb1]

Saturday I’m doing that with a leak down + compression test. Have an injector on order too. I have a feeling I tweaked a valve because it misses only at idle and only on cyl 4. Still pulls hard and strong. Shit.

[Mike@N54Tuning.com]

Wow.. That sucks!

Mike

[trb1]

Fixed. Cyl 4 spark plug electrode gap was reduced to zero by the backfire. No contact with anything. No compression issues. Plugs fixed my issue.

I have no idea how my misfire was only at idle and not in boost, but I’m not asking questions at this point.

[trb1]

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[b92]

Wow, can't believe that didn't cause larger issues than misfires at idle

[trb1]

Originally Posted by b92

Wow, can't believe that didn't cause larger issues than misfires at idle

Zero idea...my logs looked phenomenal with the plug like that too. Just a bad miss at idle

[chadjones99]

ya I always heard people say to stay away from meth ...... next thing you know you are stating up all night chasing that HIGH