vincentrx7

iTrader: (2)

I just got boost gage installed and it looks like the boost at times is more like 12-10-12 instead of 10-8-10. I also had a AF ratio meter installed and it is sitting almost midrange in the rich area throughout the boost sequence. Should I be worried about anything with the boost higher than 10psi? The only mod is a HKS catback. The gauges are electronic autometer cobalt series.
I tried searching for this question but had no luck. Sorry if this is a dup.

Recentlyconverted

how long have you had the car, and where did you get it from. the stock ecu is only set up for 10, and will "creep" to 11-12 mostly if you have you have a leak in the exhaust or have a catback, intake, and exhaust. you sure it's only a catback you have? I'd also check to make sure you've got the stock ecu and not an aftermarket one. It is possible that the person that sold it to you had all sorts of mods on the car before they sold it and an ecu set to 12psi and then before they sold it put all of the stock parts back on except for the ecu. If the car is solidly hitting 12 psi, I'd check the ecu first. The problem with the 12psi is that if you have a stock pre-cat and not a downpipe you are probably causing all sorts of backpressure on the exhaust ports of the car, which, correct me on this if I'm wrong guys, but is not good for the engine in the long run. You might also want to take the car into a known rotary shop that has good ratings and have them take a look at your vacumn lines.

Also, one other thing you might want to take a look at is in the engine bay, right where the engine drive pulley is suppoed to be (it's the biggest pulley in the front of the engine bay, located pretty much in the center of the engine bay in the front. there is a cut out circular disk behind that pulley. (don't pull anything off if you can't see it, if you can't see it from the engine bay, try what I'm gonna say next). If you can see that circular disk with the square cutouts, there are two cylindrical probe looking things that will stick out horizontally from the engine block, if that disk is in direct contact with those probes I'd guess that might be part of the problem. There is suppoed to be about a dime's workth of clearance between the probes and the disk. I had that problem and along with a whole load of other problems, had random boost spiking kind of like what you're talking about.

Also, turn the car on, warm the car up, then let the car sit at idle, then press the clutch in. does the boost meter change vacumn levels when you press the clutch? Like, does it go from 20mmHg to 18mmHg or from 18 to 16 or anything like that. Also, when you press the clutch in, does the engine change sound (a sudden scrapping sound begins to happen when you pres the clutch in) If that is the case, that is also a definite hint that the circular disk is hitting the probes.

Let me know what you find.

zullo

Whoa, relax. 12-10-12 is not unusual when you start opening up the exhaust. Don't go looking for problems where there aren't any. If you're consistently pushing 12 psi you might search on manual boost controllers; one can effectively quicken your wastegate response.

Recentlyconverted

yeah, I guess so, but 12psi for just a cb? no dp or anything? I'm runnin only a dp and cb and still consistently boost to 10, well after the car's front half of the engine got overhauled.

Recentlyconverted

yeah, I guess a boost controller should be fine I guess. just curious as to what could be causin it though.

vincentrx7

iTrader: (2)

Thanks for the help. I really appreciate you taking the time for such a thorough explanation. I'll check the things that were suggested. I haven't had the car but about 2 months. I don't think there were any other mods to the car. It seemed to be well taken care of and not driven hard. The guys Dad was the original owner and he had if for a year or so. In fact, the guy had 60 series tires on it to help the ride. Those are coming off soon. My plans are to go with a DP and intake in addition to the existing CB, but before I got too carried away, I wanted to understand the car's performance and condition as it is. The times I was getting 12 psi, it was fairly cold outside...I'm guessing <40F. Might that contribute to the high boost or does the ECU control it regardless? Also, you seem like a pretty good guy so I'll ask the dumb question...how would I tell if the ECU is the stock unit? Again, thanks for the help.

Gamezilla

Get rid of those junk gauges. I know for sure that AF gauge is lying. Unless you have a wideband O2 sensor. But Im betting its wired to the stock one, so its always gonna say you're running rich.

alberto_mg

Very wise approach. However if you are already hitting 12 psi with only a cat back, you will want to do a boost controller if you start seeing spikes over 12 psi. The more you decrease restriction to the intake and exhaust, the more boost you will produce.

That could contribute. Turbos like cold air and you will likely run a little more boost in the cold with the stock boost controller.

Pull off the passenger side kick panel and check out the stickers on the unit. Why would you think it is not stock?

Also, spend some time reading the sticky with the FAQs. The moderators have spent a lot of time putting that list together and they are very informative and very relevant. Lots of your initial ownership questions have been covered multiple times already so use the search button and get your answers.

Good luck.