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Rev drop when braking

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Only noticed this since fitting the FMIC.

The revs will drop to about 500rpm if I pump the brake at idle, wont stall but comes close!

I can't seem to find any sort of leak, I'm assuming that's probably the culprit though.

Its driving me insane, anyone got an ideas?
 
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Does it hold boost when driving? I doubt it's a leak but will be if it's not been mapped as now the air pressure and volume is different to the stock levels. Does it do it if you put the ac on too? Doubt it's anything bad
 
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Not been mapped since I fitted the FMIC but the brakes are also very spongy, but that could be due to lack of use.

Not sure if it does it with the AC on will try that as soon as I I find my charger! :) I think there may be a leak from the pipe below the BOV, Will have a fiddle at that now and hopefully that will stop it!
 
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OK guys,

Seems it happens with air con on, after playing around a bit it seems not as bad, however under acceleration it sputters and hesitates badly. I might get a smoke test see if that can indentify a leak
 
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Now that does sound like a leak lol. Have all your pipe work got rolled ends? I'd go and tighten all your clamps up too
 
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I've checked everything on the intake side of the engine and that seems fine, If its dry later this evening I'll go out there with a few torches and check the other side.

I think all the pipeworks got rolled ends anyway, it was the Autobahn FMIC I fitted.

Will update soon, hopefully I'll have fixed it tonight.
 
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checked and everything seems to be very tight and I can't find any splits in the vacuum hoses.

I don't know what else to do, I can definitely hear the boost leak when giving it full throttle and then it sputters and jumps around at about 5000rpm.

Brakes severely drop the revs still, I'm lost.:(
 

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BOV leaking maybe? Can you tell where the leak you can hear is coming from? which side even? Deffo sounds like a leak, might be worth checking joins especially around the pressure lines that go to the turbo actuator etc.

Do you have a boost controller? Still got the OEM dump valve? Just wondering what's modified - usually the last thing you fiddled with is where to look! Sometimes cracks at vac/boost hoses that were too small or old, or even just lines you've forgotten to reattach, look where the boost gauge take off is etc.

if it weren't spluttering I'd say adjust the idle but you need to sort the leak first.
 
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FMIC was the last thing modified, I have a HKS SSBV, no boost controller.

It sounds like its coming from the compressor side near the turbo, but I have to be driving the car hard to hear it so I can't be certain!

Every clip on the intercooler seems to be nice and tight and secure, Will have another look tomorrow night hopefully.
 

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You'll probably be right about where it's coming from, you just gotta go through methodically. If it's spluttering it'll be a hose totally disconnected imo. I had similar once where I left the take off on the plastic inter cooler pipe with no hose on at all and just didn't notice even though I was looking right at it.

Does the the problem happen since doing the FMIC?

best of luck fella!
 
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Kind of the same problem here. Rev slightly drops when braking to a stop, and it idles at 700~ish rpm, but gets back to ~800 if I push the throttle just a bit. Also it sometimes makes a funny sound when cold, like that of a musical whistle, it gradually goes away while driving...I thought it might be some leak in the brake booster circuit?


Maybe someone has experienced the same problem as mine?
 
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sibbers

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Sounds like you are probably right. The whistle is air getting away, although you can adjust the idle if it turns out to be unrelated. The link dread has shared is very helpful so you could give that a try but it won't show leaks in the brake servo lines so inspect them by hand/eye. I've not known them to go personally, but maybe someone else can offer suggestions if they've had similar?
 
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I can't hear any air escaping from mine unless its under load, and I'm driving it then so can't really inspect!

I've heard the brake booster can be a cause, I've tried inspecting the 1 pipe I can see connected to the servo, not sure where else I could check for that.
 
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ok, Got a smoke test done and the boost problem has been resolved! no more brakes dropping and car feels a lot better.

but this has shined light on another issue, When I've got my foot flat the car still stutters at about 4 5k, the motorsport company said its likely down to the plugs gapping, I change re gapped my plugs to 7 (NGK 7's)
This has not solved the issue, it'll have the odd hic up when idleing as well.

its driving me insane.

what else could likely be causing this?
 
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That sounds like it! Could that also contribute to my lumpy idle then?

Just cleaned maf and that didn't help.
 

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Yep, deffo. It'll get worse as it wears/gets colder/gets more damp in the air. You can probably get around for a good while though. Pretty sure you need S15 coilpacks though, so don't go shopping for S14 ones and I've heard that some aftermarket ones aren't all that great so probably worth seeking advice on that. Coilpacks seem to fail a lot on our cars, I really don't know why.
 
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Yeah, I have been reading up on them.
I don't want to splash out £300 for splitfires either haha.

Noticed my revs still drop on a rare occasions when braking and my belts are squealing with my foot on the brake which is intermittent, its also clicking when pushing the pedal down past a certain point.

I feel like cutting my wrists with this car lately.

one problem at a time though!

If anyones got a good set of coils for sale, let me know!
 
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