Loss of power after MODS

[SpaceGhost711]

Yeah...

I feel like I am getting closer. My SES light came back on so I headed straight to AutoZone. Posted 3 codes. P0100 (M.A.P.), P0110 (MAF), and P0420(CAT). I check my MAF sensor and there is no damage to the honey comb insert inside. No exhaust leaks that I could detect. I think that my ECU can't handle the setup so it's posting codes. Now do you think I should start tuning? I just won a used working S-AFC 1 for 160.00 shipped. Got a cam gear on the way. Anyone know who else besides Vision Imports sells cams for the 4g64?

[DOHCstunr]

the ecu sees airflow, it makes adjustments based on it. the stock ecu can be turbocharged without posting a code.
you have something wrong.

[peanotation]

you should cross reference the codes and see what they mean. you still have a problem there. still don't think you should start tuning untill the problems are fixed. my ECU still hasn't triggered the CEL light, and i've 5spd swapped...nitrous....turbocharger....

[TJC]

I'd honestly chalk it up to your piping. I4 w/o FI should never go to 2.5" or bigger AND definitely should never change sizes throughout from beginning to end. That just causes turbulence and drop in torque. Their are members here that have changed many different size diameter axleback's numberous times and they can attest that going to a larger diameter degrades their performance. Regardless of your future upgrades, you should get your exhaust pipe sizing down to one size. And if you are throwing check engine lights, that should be diagnosed first and taken card of before everything else. Getting more upgrades will increase performance but it will never be at it's full potential with other problems still there. Baby steps and do it right! goodluck.

[Agent|THC]

Just asked this on my tranny swap thread.

but according to most and Peano thank u very much, your ECU is throwing "performance" based codes and is in limp home mode, which will kill your performance! Correct me if im wrong here guys

Definately get those codes sorted out!

[peanotation]

P0100 (M.A.P.), P0110 (MAF), and P0420(CAT).

checked your codes over at galantspeed....
P0100 Mass or Volume Air Flow Circuit Malfunction
P0110 Intake Air Temperature Circuit Malfunction
P0420 Catalyst System Efficiency Below Threshold (Bank 1)

the first two i believe are directly related to your MAS. i would buy a new one. try to see if you can get one from local junk yards, ebay, mitsu graveyard, etc etc. third code is your cat i think? yeah. so the items that were suspect are the ones to blame.

throwing an afc on there with a bad mas is like trying to tune a fat kid for performance in a dodgeball competition

[DOHCstunr]

i think your 2.5" exhaust is fine, however, i would definatly replace that 3" resonator w/ a 2.5 inch resonator.
you can run an o2 simulator to eliminate your post cat o2. can't rememeber where the directions are. think they are on vfaq.com

is your rear o2 installed. did they make a bung for it when you made your exhaust?

[SpaceGhost711]

Thanks for all the input. I am going to replace the resenator with a 2.5" one. Is there any kind of after market MAF sensor available, one that might handle these upgrades differently? I have seen the O2 sims out for like $20 but I don't care if my car runs right.

[SpaceGhost711]

Thanks to peanotation for researching those codes

[SpaceGhost711]

Ok so I went to my mechanic today and we scanned the ECU. Found out that my MAF sensor is working fine. My fuel trim is way off and he seems to think it is because my front O2 sensor is too far back. When we were lookat the the tool, he was showing me a line graph that was flat at idle and should have gone up when you give it gas. It went down and he said tht was the fuel trim. Also, the front O2 sensor is responding slow. What do you guys think about that conslusion?

[DOHCstunr]

if your o2 was slow, then you just need a new o2
quite posible that the heater on it has failed and its not getting hot enough to get a reading (they need to be 900+ degrees
i still doubt that your o2 would cause any stalling.

[SpaceGhost711]

Yeah I might just get a new one, do you think moving the new one closer to the header would help?

Check out my 8G.
http://pg.photos.yahoo.com/ph/pcmaintenanc...lbum?.dir=/c988

[DOHCstunr]

o god are you a 4 cylinder 8g?
check your intake manifold near the throttle body.
are there any cracks in any of the welds?
look very closely

[SpaceGhost711]

"Oh God"!? Is that a bad thing that I have an 8G? I understand it's not the best platform but still... Are cracked manifolds common on these? They're plastic right? I did not see any but I can't look all the way around it.

[DOHCstunr]

"Oh God"!? Is that a bad thing that I have an 8G? I understand it's not the best platform but still... Are cracked manifolds common on these? They're plastic right? I did not see any but I can't look all the way around it.

no no no, the 8g is a great platform.
the 4 cylindsers has very thin tubular intake amanifolds and its quite common for the welds to break when an aftermarket intake is installed
just wanted to rule that out.

[SpaceGhost711]

Cool! I don't believe it is cracked. I didn't force anything while installing the CIA system. Where is a good place to order O2 sensors?

[peanotation]

i just bought mine from these guys. free shipping if over $50

http://www.oxygensensorwholesale.com/

[SpaceGhost711]

Just got a SAFC. How many other ppl have one on a NA engine? What kind of Hz do you get on the Karman sensor? I'm getting 1071 at WOT and 6350 RPM. Going to get a EGT guage and guage to see the O2 sensor voltage adn try to tune myself but probably end up on the dyno with someone who knows more about this stuff. Pulleys and cam gear on the way

[SpaceGhost711]

UPDATE:

The culprit the whole time was a faulty O2 sensor. It was giving bad readings and from what I understand, .04 - .08 volts off can make a big difference. I guess I will get a wide-band soon and a scan tool so I can really see whats going on. I love the S-AFC II. I think it should be at the top of anyones list of mods. I have seen that some of you have a BATT reading on yours. Mine doesn't have that but it also doesn't have that kewl dial either. When I get the cam gear installed I doing to have someone tune it for me. I am going to attempt the pulleys myself. Thanks again for all your input and I am glad I found TGC. I wish there were more ppl with Gs here in Oklahoma. I guess I will have to start going down to TX more often.

[seth98esT]

You must have an SAFC not an SAFCII