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Misfiring and Crummy Idle After BOV Replacement on a Turbocharged Car

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miked17

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Discussion starter · #1 ·
When I bought this car it came with an aftermarket BOV like this:
Image

Today I replaced it with the OEM recirc valve thinking that it may fix the issue of it running like general poo. It made some improvement, like now I can hear the turbo spooling up more and its making about 7-8 psi. But it still has a crummy idle and is misfiring. I plan to change the plugs/oil tomorrow but I cant figure out why the car idles and bounces on the idle at 1100-1500 rpm. Any help would be great, thanks.

Some of the mods done to the car before I got it include:
550cc injectors
255pl fuel pump
2 in. charge piping with new FMIC
K&N filter

When I thnk about it, they put a new timing belt on it also, is it possible they didnt put it on right and screwed up the timing?
 
Discussion starter · #4 ·
No fuel control/tune.

I have a Apexi Neo in my Aveo I can prolly swap in, but I have read that using a Neo without a data logger can be dangerous. But I have thought about it and if I do put it in I would only cut the fuel back 5-7%.

I was doing a search and stumbled upon this and it describes my problem.

http://www.dsm.org/how-tos/tttt/tttt3.html

"Q: So what, exactly, is idle surge?
A: Idle surge is the condition that occurs when something in the ECU idle speed feedback loop fails to operate as expected. Since the ECU is not quite as smart as you are and has a very microscopic view of its world, its behavior may seem very strange to you, but seem perfectly normal to the computer. The result is an idle speed that oscillates from ~1200-1500 RPM about 2 times a second and no error codes are ever displayed."

Not exactly sure how to correct this as Im not a mechanic nor do I know a whole lot about these cars.
 
Discussion starter · #7 · (Edited)
Well tomorrow Im going to hook my Neo and give it a try and also look into FPRs. Are FPRs a universal thing or are there DSM specific ones?

Edit: What should I look for in a FPR kit? Im very new to this so be easy on me please. Thanks.
 
Discussion starter · #10 ·
I installed my neo today and now my car wont rev past 2000 rpm and is misfiring like a mofo. Also the CEL wont go off.

I followed the How-To from VFAQ to the "t" and triple checked my work as I went, you know checkin the connections and what not.

Plus side: The idle no longer surges. :-/

Here is a vid I made quick to show ya:
http://www.youtube.com/watch?v=49TDg6dnn9E

Please help.
 
Discussion starter · #12 · (Edited)
No FPR yet, It was running like poo initially, but now its way worse after neo install. Was hoping it would make it better as i could cut the fuel back a bit but that is to no avail at this point.

Not to sure how to check their work.
 
Discussion starter · #13 ·
http://www.amsperformance.com/cart/Fuelab-Fuel-Pressure-Regulator-Amsperformance.com.html
Im thinkin about getting a FPR since the neo is not working out. Would this be what I need? Please help me figure out what I need as I am very new to turboed vehicles and DSMs. IE hoses and fittings and what not.

I also have a friend who has smaller injectors for the 1G that would be willing to trade with me. Seeing as how I just want the car to run smooth and on the cheap I will start with the injector swap, then if that dont work, the FPR. Sound right?
 
#14 ·
Just get the stock 450's in there and throw that Neo against a wall. (Or put it back in the Aveo) In the DSMing world the Neo isn't as good as a SAFC I or II. I think it has something to do with not being able to read Karman intaked vehicles right. If you want to use your injectors and do it right your looking at AT LEAST a better SAFC and a AFPR. There is alot of tuning to be done with these cars when your messing with injectors on an SAFC tune only. Especially when you dont even have a logger and you can't tell whats going on in your engine! Hope this helps you out some.

EDIT:Yes, a Fuellab or Aeromotive would be a good choice of fuel pressure regulator.
 
Discussion starter · #15 ·
Im going to try to get them stockers from my guy first seeing as its a more economical route. I dont have to worry much about the fuel pump do I? (255 pl)

Ill prolly just put the neo for sale seeing as I dont really need it in the Aveo and its no good in the Talon. I got some other shit to sell anyways.
 
#16 ·
There is some good info here, but some is hit and miss. As for the NEO being a poor management chioce, many people will agree. It was not made for the DSM application, and gives many people many problems. As previously stated, a SAFC I or II would be ideal for starters, but those are just piggyback management systems, and really aren't the best choice overall. For now, get a SAFC II and save for something like DSMlink if you plan on making larger power numbers.

As for your injectors, I'd personally try and keep the 550's. Don't move backward unless necessary, just get the SAFC. Right now, without any engine management, the ECU essentially thinks your car still has the stock injectors, so its planning on giving the fuel for stockers. Those 550's dump a bit more, so there is a problem with fuel there. If you had a SAFC you would be able to "fool" the ECU into running correctly with those 550's.

Adding more problems to your fuel situation is your larger fuel pump and stock regulator. Just like the injector problems, your bigger pump is pushing way more than your stock one, and you've got a stock regulator trying to compensate. The stocker typically wont' be able to bleed off enough excess fuel, so it goes to the injectors. I would at minimum get some sort of fuel pressure reading to see where your at, and then decide where to go from there. Some can get away without a AFPR and a 190, I doubt a 255 is ok...

The odd thing here, to me, is that your having an idle surge problem. Typically that isn't associated with having to much fuel, its usually an air problem, such as a boost leak or bad MAF. I'd be curious to see if you've got any boost leaks. Boost leaks are super common and the leak tester can be made for less than $15.

To check timing belt work you'll have to pull off the timing covers and make sure the timing marks line up. Check your haynes or chilton repair guide if you've got one, or try vfaq.com.

If you've got a CEL going, don't be foolish. Get a code reader or get to an auto parts store and borrow one. Find out what code is being thrown, they are there for a reason. It would be even easier on a 1g because all you need is an analog volt meter. Vfaq.com should have the 'how to' on that as well, or check your haynes or chilton repair guide.


What turbo do you have on your car??
 
#17 ·
Please just get a datalogger. Correct me if I am wrong 93 GSX, but doesn't a logger have the ability to read and reset codes as well? If you are tuning with a SAFC it should be manditory. Especially assuming you have no wideband or anything else to see whats going on with the engine.
 
#18 ·
I'm not 100% sure if every logger can read and reset codes, some can read, I don't think any can reset them. As far as I know DSMlink was the only system available to do so (leaving out stand alone for obvious reasons). Most loggers I've seen are all just non-specific palm pilots or PDA's that have DSM specific cords attached. I'm also sure 1g and 2g will have differences, as OBDII is typically easier.

I do agree with picking up a logger, but that won't fix anything. It will make things easier, and it should be purchased by any serious modder, but these cars have been around long enough, if you have a base of parts, you really don't need a logger. If its a daily driver, nothing special, a logger may be overkill, esp for someone who is good with tuning. The OP may not be experianced, so it may be a good idea to get one anyway. Either way, we all know what happens to our cars when you toss in big pumps, big injectors, and do nothing to compensate. Therefore it should be really easy to just pick up the few needed parts and go from there.

I guess I'm just saying the the OP needs to figure a few budget and car-goal related things, and decide his path. If he doesn't, he's probably going to waste money on a few parts that aren't needed.
 
Discussion starter · #19 ·
My goal is to have a running fun car. I dont want to put phenomenal numbers down at the track or on the dyno, if thats any clue as to where Im going with this car. If I remember right there is a how to on vfaq for building a boost leak checking tool. And Im not overly experienced when it comes to cars, for instance Im pretty confident working on my Aveo but only because Ive had it for a while and was actually working to boost it. Im not claiming to know everything about it, but you know what Im saying. As for the Talon, I know squat so hence my hesitation to work on it until I have all the knowledge I need to work on whatever particular system needs working on (thank you VFAQ!).

So for me to go backwards on the injector size is ok with me as long as it is was fixes my car and makes me not eat fuel like a mofo. And seeing as how my budget is super tight downsizing for free and having possible fix is ok with me. I can always upgrade later if I feel the need. But I just want to clean up the car, have it run good, and overall look good. Thanks for the heads up on the boost leak idea, will try it either tomorrow or this week early.

Hope this offers a better understanding of where I am coming from.

Thanks for the advice guys and not being to hard on me as a newbie!
 
#20 ·
Hey, we may have a new member who *doesn't* have his head up his ass!!

If that is the case, man, get those stock injectors back in, save the 550's for later. That pump, however, is probably going to stay in as its a bit more difficult, and I don't imagine you've got that stocker sitting around. If that is indeed the case, seriously look into a AFPR, even a used one from the classifieds as soon as your able...
 
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miked17
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