yuichiror

iTrader: (1)

Right after I fixed my last boost leak, I noticed I was boosting up to 13psi. I figured I just needed a boost controller, so I bought one, but havn't installed it yet. Then a couple of weeks ago, my friend and I were working on the FD when I noticed that the vac line to the WG Controller wasn't connected. It looked like it had NEVER been connected. The vac line going to the solenoid was too short to reach the metal tube and that tube had no broken line connected to it. So we cut a new vac line and connect the soleniod. Voila, overboost issue resolved.

Fast forward 2 weeks, I trade my butt ugly sideskirts to another friend for a vac hose replacement job. Nice blue silicone hoses. During the line replacement we find that the nipple to the double throttle solenoid is broke, so we replace the solenoid. Then we take a moment to adjust the idle down to 1k rpm. After we finish, I take my car around the block to see how she runs, I boost lightly, everything seems good. BTW, we only replaced the lines on top of the engine.

So last weekend I'm driving and as I get onto the highway, I look around and everything is clear, I really hit the throttle. I'm watching my boost gauge and as soon as I hit 12+psi, I let go of the gas. Normally, I drive like an old man, but lately I've been driving harder and I've noticed that if I'm driving harder and I shift from 2nd to 3rd, I'll suddenly boost and I'll have let go of the gas, I never noticed this before the vac line job(or maybe this is normal and it's a result of me driving faster).

So now what's wrong. I took a moment and looked at the vac lines from the TPC and WGC solenoids and they seem correct. As far as I know, switching the wiring on those two soleniods will only let you boost up to 6psi. The friend that did the hose job suggested my overboosting is an attribute of having a ported engine, I'm not so sure on that. I also find it hard to believe that my solenoid just suddenly went bad, but as soon as I find the solenoid check procedures, I'll go ahead an check it and make sure the vac line is attched to the wastegate actuator.

Anyone have any other suggestions on what I should check, could the overboost be caused by fixing the double throttle control vac line and having a ported engine? Someone also suggested it MIGHT be due to the cold weather, though unlikely. I did a search and found that Dale Clark had spiking during transistion after his dp and catback install, which seems similiar to my problem, but what's the diff between a spike and just overboosting, length of time?

For what's it's worth, here's couple of links to the hose job pictures with the UIM on.
http://i31.photobucket.com/albums/c3...s/IMG_1509.jpg
http://i31.photobucket.com/albums/c3...e%20Pics/2.jpg

BTW, my only mods are catback, ported engine and dp. Though I wouldn't be surprised if I found more, the previous owner didn't know alot about the car.

Thanks guys!

Recentlyconverted

I'm having the same issue dude, I've only got a catback and a dp too. What you're seeing is that it is getting colder, so you're getting denser air through the system and therefore a higher instance of boost spiking. lay off the gas until you get the boost controller in there, it'll take care of things until you open up the exhaust more. i spiked to 14psi once while racing an acura and almost pissed myself. my engine is fine, runs smooth and power is good, and still running -18mmHg at idle., but now i know i've gotta lay off the gas too till i get a proper boost controller in there or it gets warmer.

yuichiror

iTrader: (1)

Thanks dude. I did some more searching and I found alot of people have similiar issues with a dp and catback. Another thing I recently noticed is that when I'm in fifth gear and I lightly push on the gas, the boost gauge jumps. The harder I push the throttle the the higher the gauge jumps. Not sure how it was before the hose job. Is that normal, another attribute of the mods plus cold air, or another indicator to a wastegate issue.

Kento

A spike is an immediate and very quick jump in boost, either during the transition or when you suddenly jump on the throttle at higher rpms. It should only last for a second or so, and then drop to "normal" boost numbers. If you gradually open the throttle and the boost levels rise to above what the mods on your engine (are you sure you don't have a hi-flow cat on there? Or a gutted stock cat?) should dictate, then you may have an overboost problem (I say "may", because every car is different. Spiking to 13 psi can easily occur with just a DP and CB, but generally, unless the stock airbox has been modified or a hi-flow cat is in place, just those two mods shouldn't push you above 10 psi.)

yuichiror

iTrader: (1)

Thanks for the info. Like I said, the previous owner didn't know alot about the FD. Like his boost leaks, oil leak, upgraded suspension..... I know the muffler is aftermarket, but no idea what brand/model(some say it looks like the RB single tip before they started putting their logo on it). And I know nothing about the current cat. What should I look for in a visual inspection of the cat, brand markings?

Kento

The stock cat has thin metal heat shielding surrounding much of it, and has a squarish-looking appearance compared to hi-flow cats. It'll probably be looking pretty weathered compared to a hi-flow as well.

dgeesaman

iTrader: (7)

I don't have any magic bullet answers, but here are a couple possibilities:

1) The pills in the lines might be switched. The wastegate controls peak boost on both primary and secondary, and if you put the precontrol pill in the wastegate line, the smaller orifice will increase boost. But I'm not sure how large an effect it will have.

2) Cold air makes better boost. You might be seeing the effects of the recent weather change.

3) Your boost gauge could be wrong.

Dave