Trouble with BOV after MAFT install

[alex99gst]

I just recently installed my new froun mount intercooler and MAFT setup and after driving around for a while I noticed that while the turbo is spooling up, I can hear the BOV sound like its opening a little bit. Its as if it is partially open and then when I let off the throttle it then acts normal. I was wondering if any of you guys running the MAFT setup had this happen and its normal or if I have a leaking BOV (the little flapper thing inside is ed somewhat). It feels like the car spools slower than it used to.

Another unrelated problem is with my datalogger. It works for things like knock, timing, rpm, etc... , but when it comes to O2 volts and fuel trims, they dont seem to change at all. Whenever I was driving around tonight the O2 volts never changed from 0.04-0.06v and the fuel trims didn't change at all until I was adjusting the idle knob and it said that the high trims went up to 199%. Does anyone know what is going on?

 

[Cool Mr Steve]

Have you done a boost leak test yet? That seems like the only way you'd be able to find out for sure if you have a leaky BOV, and it does sound like that could be the issue. If you just installed your MAFT and are now venting, your leaking BOV would be more audible. What exactly do you mean it "feels" like it spools slower? Does it start spooling/hit peak boost at a later RPM, or does your car just generally feel slower? If it simply feels slower, that could be another indication that your BOV is leaking, or possibly that your new MAFT isn't properly setup for your injectors (or other tuning issues...).

As far as your o2 and fuel trims, your o2 sensor could be failing. Is it cycling properly?

 

[Mr4G]

It sounds like your bov is leaking.or it isnt strong enough to hold in all your boost. try crusing the top of it and then if you still have the problem you need to replace your bov.

 

[alex99gst]

Whenever the car starts to build boost I can hear the BOV opening and letting some of it off before it reaches full boost (only 13psi right now). The car does feel slower in general, but I'm going to take it out later today when it is warmer. I tried to tune it last night in 15* ice cold weather. I have not been able to do a boost leak test yet because I don't have access to an air compressor and whenever I try a bike pump the boost gauge doesn't move. I just replaced the oxygen sensor with a denso one not even 100 miles ago. Am I supposed to let it idle for a while and let the engine heat up and then it will cycle? The MAFT instructions said I should let it idle and it would enter closed loop in about a minute.

 

[Cool Mr Steve]

Whenever the car starts to build boost I can hear the BOV opening and letting some of it off before it reaches full boost (only 13psi right now). The car does feel slower in general, but I'm going to take it out later today when it is warmer. I tried to tune it last night in 15* ice cold weather. I have not been able to do a boost leak test yet because I don't have access to an air compressor and whenever I try a bike pump the boost gauge doesn't move. I just replaced the oxygen sensor with a denso one not even 100 miles ago. Am I supposed to let it idle for a while and let the engine heat up and then it will cycle? The MAFT instructions said I should let it idle and it would enter closed loop in about a minute.

Eh, it will enter into closed loop whenever it's warm enough. I'd give it at least a few minutes, but you should just check it while cruising. The bike pump is not going to do you a bit of good for a boost leak test. Just wait until you have access to an air compressor. It does sound like your BOV is leaking though. Don't bother trying to tune it right now with a boost leak like that. Your just going to have to re-tune it after you get that leak patched. Are you still on the stock BOV? What kind of boost are you running? If you find out the problem is a leaky BOV (assuming your still on the stock BOV) you could either crush it, or do the Dodge Garage method found here. Good luck

 

[alex99gst]

Right now the boost is set low around 13psi. It rained all day after school so I couldn't go try to visually check for anything leaky and then test drive. Hopefully we will get out tomorrow and I can work on it for a while. I don't want to mess up my BOV, so maybe not the dodge garage mod, but crushing the BOV might be an option. I always hear about crushing the BOV, but I've never heard how/why it works and how its done.

 

[Cool Mr Steve]

Generally I believe the 1g bov should be good for about 18psi, so don't go crushing it before you know what the problem is. Make sure you research crushing the bov thoroughly before you attempt it. If you crush it too much it won't open under low boost and may cause compressor surge under higher boost. Basically it's crushing it to increase the pressure resistance so it requires more boost to open.

 

[alex99gst]

I fixed a cracked coupler tonight that I was sure could potentially cause a problem, but I just wante to get it to run first. Fixed that and eliminated the slight knock I was getting. Now the BOV sounds like its leaking even more than before. It still sounds like it is partially opening before full boost and I can hear some of the air leaking out still. I might just pick up another BOV and see what happens.

 

[Cool Mr Steve]

Looks like there was air escaping from your bov and the coupler. Since the air isn't escaping out of the coupler anymore, theres more air pressure to escape out of your bov. Thats what it seems like anyway. If your planning on getting a new bov, you might as well try crushing the one you have first.

 

[oldman]

1. You need to get to an air compressor ASAP so you can complete the fmic installation, boost leaks needs to be taken more seriously, you wouldn't be driving your car with a flat because you have no access to a new tire would you? This really isn't a choice.

2. Which mbc and where is it tapped to, the BOV line?

 

[alex99gst]

I am working on getting an air compressor shortly. I have my boost controller hooked up the way that you aren't really a fan of. Where the BOV line is T'ed off with the intake manifold and the controller and then a line going to the wastegate actuator. The only reason I hesitated running it like you like to is because I figured any boost leak would throw off the accuracy of the whole setup. I know the way you like to run it is a line from the BOV directly to the intake manifold, and then I assume the other lines would run from the wastegate actuator and then one to the turbo outlet elbow (no spot to tap in there). Could I run it like you suggest but instead of a line from a niple somewhere could I run that to the intake manifold as well even though that would be my setup now minus the T? Sorry if that is confusing

 

[oldman]

I am working on getting an air compressor shortly.

Good deal.

I have my boost controller hooked up the way that you aren't really a fan of. Where the BOV line is T'ed off with the intake manifold and the controller and then a line going to the wastegate actuator.

It's not about what I prefer, there are serious conseqences when tapping off the BOV line, one of them happens to be BOV openning prematurely/slightly under boost.

The only reason I hesitated running it like you like to is because I figured any boost leak would throw off the accuracy of the whole setup.

It's the opposite, boost leak is exactly why you want to tap off the compressor/licp rather than the BOV line.

Could I run it like you suggest but instead of a line from a niple somewhere could I run that to the intake manifold as well even though that would be my setup now minus the T?

Where would you take this source from? Taking another manifold pressure source other than the BOV line will eliminate the possible BOV problems but still isn't the best option.

I know the way you like to run it is a line from the BOV directly to the intake manifold, and then I assume the other lines would run from the wastegate actuator and then one to the turbo outlet elbow (no spot to tap in there).

So tap one yourself, not exactly rocket science. This thread explains everything I just posted, read through it carefully and ask follow up questions here.