ISSUE RESOLVED: CHECK POST #60

Hey all,

Not trying to double-post, so the question here is a bit different that my other post regarding no vacuum and the Forge BOV here: https://www.northamericanmotoring.co...ff-sounds.html

Basically, I'm trying to get an idea of why I have no vacuum... I'm measuring at the MAP, and I have boost, but I have little to no vacuum at idle, decel, or anywhere.

After reading hundreds of threads over the last 24 hours, I can assume that our N18 engines certainly have vacuum at idle and decel, but I have zilch.

Does anyone have any idea of why I wouldn't have vacuum? That sounds funky, and I have literally gone over everything I can think of. Searched back to the start of the R56 for info or similar situations, but I'm stumped...

Very stumped...

 

what are you reading with?

 

I'm using the MAP tap that comes with the Forge BOV with the MAP sensor bolted in.

Direct hose off of the tap into an Autometer 4401. Bought another 4401 in case that one was defective, same thing.

Attached a new 1' hose directly to the tap, and just used my thumb to feel for vacuum at idle, nothing.

I think that's all I can try from that MAP port.

 

Hmmm,

You should still be getting vacuum, no cels or harsh idle? try un plugging the pcv and see if you feel vacuum with your hand. This is gonna be a tricky one.

 

No CELs ever, thankfully. Idle is... erm... sort of diesel-y. But this is my first Cooper, and they all seem to run like that after driving a handful of N18 cars. Idle is pretty consistent, though. No jumping/spiking on the tach, so I think we're good on that.

Not to make you read the other thread, but could this have anything to do with installing the Forge BOV? I was too stupid to think about taking pressure reading before upgrading the diverter valve.

That being said, since I'm measuring right off the MAP, I'm taking the BOV out of the equation, I believe, since that uses the MAP tap that goes to the solenoid, and then goes to the BOV. Perhaps I'm a bit mistaken, but I think the MAP is the best shot at getting a clear reading regardless of the BOV/RCV used.

Is it "safe" to remove the PCV hose and check like that at idle? You can tell I know nothing of these engines yet.

 

Yeah,

A vacuum hose is a vacuum hose, your just introducing a leak. Make sure nothing gets sucked up. if you unplug the hose and the engine stumbles you should be feeling vacuum. If left leaking for a while youl get a check sum cel that will go away once replugged for a couple of cycles.

is your gauge mechanical or electrical? autometer doesnt make any impressive stuff so if it is a basic mechanical you could have a pinched line. that wouldnt explain why you feel no suction because you should.

As far as the map, it is the closest source so it is good but any part of the system will experience the same amount of vacuum. Try the pcv, since it is a bigger hose you will feel more vacuum to verify.

 

Okay, I'm going outside to try that right now. I see what you're saying.

AutoMeter isn't the most impressive hardware, which is why I ordered a second gauge, and then just didn't trust either of them. But when I'm measuring right off the MAP and there's no vacuum... It's kind of depressing.

That's when I just went to the old 'feel test' and realized that there's nothing sucking at the MAP. I'll go check at the PCV right now and report back in a few minutes!

 

k im at work so ill be here.... is that bad haha

 

Same here... Nothing wrong with that.

 

PS cold start n14 is at 20hg n18 shouldnt be that far off.

 

Uploading the videos now. In all seriousness, the iPhone 4S takes great pics and video, but Jesus the files are big now.

 

Here's the first one:

http://www.youtube.com/watch?v=Yr8c-qSsZ1g

Engine doesn't even sputter.

 

Here's the next one. Permission to raise my Whiskey Tango Foxtrot flag, sir.

http://www.youtube.com/watch?v=AFchemwixLc

Now I magically have vac pressure. What... the... hell...

 

Wrong location, Lets try this unplug the hose going to the nipple to the map sensor, does that give you and vacuum to feel?

 

nm saw the vid now you do.

Issue solved, pinched line or bad orientation


Focus on the bpv now

 

You know, I think the boost tap wasn't on correctly... If I had to guess.

Thank you for the help with round 1. Over to the other thread we go.

 

I don't know if I should cry now or later, but I should probably schedule it for some time tonight.

I went to take that drive and get a sound clip for you guys. Guess what? No vacuum. Grr. Tried everything I could think of, no vacuum.

Went out and bought a new, better O-ring for the Forge boost port. Fits much better, still no vacuum. Made sure the MAP was sealed to the boost tap. No vacuum. Even made sure nothing around there/holes/gremilns were causing a vac leak - nothing.

So I'm back to having like -4 at idle, same as before this whole mess. Didn't make any changes since the last video I uploaded here.

I mean... am I cursed? Is there anything that could explain this? Boost gauge was directly on the tap (1ft) with no kinking, etc. The old finger suck test was just like before - nearly nothing.

Here's a video of the same problem happening yet again: http://www.youtube.com/watch?v=QOdFvm0ox7c

 

I just did a bunch more testing, and quite a few conclusions, but no answer.

I can guarantee I have vacuum BEFORE THE MAP SENSOR. Or, before the boost tap, what have you. The hole is sucking hard, and it stalls the engine if I unplug the MAP sensor. So, we have that much at least.

Here is a video to show that the engine is still sucking at full vacuum when the MAP sensor is unplugged (no boost tap). I almost stalled the engine with this, and it was sucking like crazy. So, we know the car, itself, has vacuum.

http://www.youtube.com/watch?v=I_HIuKPjJCk

 

On to the assumptions/conclusions:

Bought new O-Rings for the Forge boost tap. No change.
Switched out hose to/from tap. No change.
Re-installed factory MAP sensor ONLY, unknown change (we do know it sucks when removed).
Installed Forge tap w/ MAP Sensor - if I unplug the MAP sensor, hole sucks, car stalls.
Re-tightened Forge tap side screw - why they put that there is beyond me. Checked tap for leaks, none found.

At this point, I'm kind of leaning toward a bad boost tap. I wonder if I should get a NM tap or something to test out before yelling at Forge about this.

If everything else checks out, I have no idea why it worked for exactly one crank today, and hasn't worked since there for 25 or so cranks. That makes no sense when nothing has changed.

The crappy part is that I can't really drive it until I get a working tap, since the BOV uses that vacuum/boost to actuate.

 

Well, I've spent another full night on this, and it's driving me batty.

The only conclusion I can come to is that the boost tap is busted. That's the only explanation, seeing as how everything else is working fine.

That would also explain the brief fluke of it working - it simply got moved around until it made a seal, then no longer had it upon turning off / back on.

I'll PM Way, and hopefully he can get me a replacement from Forge. That, or I'll have to overnight an NM tap or something. Can't drive it until the tap works thanks to the solenoid control on the BPV.

 

Well the boost tap is just a "riser" to say to allow vacuum past the sensor.

With the sensor inserted to the tap, try blowing past the openings, could be that the map is fitting too far into the tap blocking the passage.

You have vacuum, just getting it to the "new system"(from the tap to the valve etc.) seems to be the issue.

Ok heres a thought,

Other than the blow test fit the tap and map sensor with out the set screw, it's not necessary as the system is in vacuum and is there to avoid dislodging due to vibrations and bumps.

While at idle , use the gauge alone* connected to the tap, gently move around the map sensor, kind of wiggling it to see if your readings change. I have a hunch that if its too far down the design may "choke" the passage way.

 

Here's the diagram of how it sits normally. Please ignore the crudeness...

 

And here's the diagram of what I tried last night with using O-rings to space the nipples out in case they were blocking flow, etc.



Excellent thought, though. That was my assumption until it didn't work to add the spacing.

 

Try moving it manually, the spacing may be off or not enough.

 

Sorry to keep adding messages, but I wanted to keep the thought line clear.

As for the other steps, I've tried:

1) Not using the set screw, placing the tap and MAP sensor in, and wiggling, turning, twisting the two pieces in there. No change.

2) Used the gauge directly (I think it might have been in that one video a few back) using the above scenario, and still the same result.