I’m going to post this on here because truthfully, I’m tired of hearing the same answers on dsmtuners-boost leak boost leak :stfu
Here’s the situation. My car has been overboosting. It shoots up to 14psi and then the car acts like it just hit a brick wall. I’ve had spikes up to 20psi. When this condition happens, the car is blowing out gas rich black smoke and the BOV is open the entire time purging the air.
I’ve replaced the wastegate with a known working one. Replaced the solenoid with a MBC (which was set to 10psi and held consistently before this). The MBC is routed from the wastegate nipple to the J pipe nipple. Replaced my PCV and all vac lines.
Boost leak test results: pressurized to 15psi and lost 2 psi over 45 secs.
Compression or leakdown test is one thing I haven’t done yet, will try to do it this weekend.
Here’s the kicker. If I hold the wastegate open with vice grips, the car drives fine. It just doesn’t hit full boost. Take the grips off and the condition comes back.
Oh and I do have a CEL for front bank 02, but I don’t think that would have anything to do with this?
You need a new wga (I think). I had the same problem on my Evo. It’s common on the Evo 4g63…not so common on your car. I had the problem a second time (doh) and it ended up being the lame Forge MBC the 2nd time around. Hope this helps miss :banana
fix that problem… The BOV should never be open venting boost(unless you’re like me an build/tune a system to do so). If it’s open under boos, your venting metered air before it hits the motor. PCM has compensated for this metered air by adding extra fuel, however since the motor is not seeing the required air for the fuel metered out, the car will run STUPID rich. Hence, hitting a brick wall and blowing black smoke out the pipe. I’d check the bypass valve first thing…What model DSM are we talking here? I’ve built more 4g63’s that most have ever seen in their lifetime.
That is the first complete answer I’ve gotten on any forum! :bowdown I’m still learning the ins and outs of a turbo system and by explaining it, it helps tremendously instead of just saying ok you have a leak somewhere. I hate vagueness.
Anyway, it’s a 95 TSi AWD. I’ve heard the BOVs are not up to par, but not once did someone point out that.
This condition typically happens around 3k RPMs. With my foot still on the throttle you can hear the pshhhhhhhhhhhhhhhhhhhhhhhhhhh the entire time until I let off. If I stay under that threshold, the car will drive. It just takes an insanely long time to get to highway speed and forget putting it under load, i.e. going uphill from a slow start. With the vice grips holding the wastegate fairly open, I have no driveability issues-the car just isn’t using it’s full potential.
The BOV is puking. Why the hell didn’t the other forums pick that up?
Basically, metered air is leaving through the BOV while the engine is under load. This is causing your car to run rich as the ECU has no idea air has escaped.
So, replace your BOV. The 1G DSM crushed BOV is a nice mod too.
Oh yeah, get rid of that plastic POS bypass valve and install either a decent aftermarket valve, or buy a stock Evo MR valve and retrofit that in. MUST STAY recirculatory unless you retune the car to operate off the MAF(waste of time right now at the cars current setup). It sounds like the diaphram in the top chamber popped and the reference boost signal is leaking internally, whioch means that the boost pressure in your charge piping is pushing the vavel open. Spring in the stock 2g bypass valve is about 11lbs and will start to blow open around 10psi on the gauge. Personally, if you have the money to buy it, get the Synapse Syncronic valve(this is NOT the Synapse here locally). www.synapseenginnering.com The absolute BEST bypass valve I’ve ever used anywhere and I’ve used damn near all of them out there. Contact Jon(JVG) to get it, that’s where I picked up the one I installed on Erics Evo 8 to remedy the issue those cars face(long story)
DSM’s and the 4G63/420a are where I started in this “tuner” end of my business. Ask me anything you need to know about those cars. '95 Talon was my favorite of all the DSM’s too Owned a '91 TSi for a long time as a beater car.
It’s because of these cars that I learned how to wrench myself. Got tired of paying labor fees out the ass LOL. Not to mention, not many shops here are familiar with their quirks and forget the dealer, nearest Mitsu is 30 miles away. Chrysler won’t even deal with it. I love the car though.
I just want to get all the little things squared away before I start upgrading it in a couple of months. After I get this and the 02 fixed I have the timing belt next and then I’ll start working on it.
I’m a budget tuner though. A lot of stuff I make, buy secondhand, or look towards Ebay. Right now I’m spending a lot of time researching lower end products (price wise). Sure, I want to save a buck, but not at the expense of my engine.
Owned a '91 TSi for a long time as a beater car.
