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Top swap issue

Enzo354

Enzo354

New member
Well Ive replaced the MAF, front 02, vac lines, everything I could think of and it still is idling bad and cutting out under heavy load. The idle is jumpy around 600-800 rpm. Its been tuned with all the basics, and now its been smoked for leaks too.
The o2 is reading lean, about 100 and the fuel trims are all very positive, about 16+. Any suggestions on this?
 




You could scan Idle air counts anything lower then 45 on a warm engine idle in park is going to be a vac leak
 
The guy who tuned his car on a local forum says its near impossible since he has 20 in hg on his boost gauge.
 
Funny Ive read around 20 even with a vac leak. Like we said +16.4LFT is a vac leak.
 
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I don't think you can just say is a VAC leak and that is the only possibility. Obviously that has been checked already. I would recheck your VAC routing and how you did it with the North*. If you have your MAP plugged in I would unplug that and try to run just off the MAF and tuning of the MAF. I would venture to guess is has something more to do with VAC routing than a VAC leak.
 
Enzo said in another thread that once he unhooked the MAF sensor it idled normally.

He also said his fans are constantly on, if that matters.
 


Well if the mafs been unhooked and it runs fine then obviously theres an issue. max fueling 99.99 percent of the time its a vac leak. Maf's usually toss off there own codes, as well as 02's. The post also gives no indications as to the mods on the car. So we gotta assume its a basically stock car. But if this issue was started after a top swap and a tune Id think it could be the IFR table, Or the possibility of the car being a 2001 plus and and having no rear 02 sensor.
 
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I agree enzo should have included more detail in here...Ik he has headers, ported SC, smoothed heads, and EGR delete.
 
Ok Ill get a bit more specific. Its got headers, ported SC and LIM, just gasket matched heads, N*, EGR delete, and thats about it. 3.8 pulley.
I bypassed the BBV, by leaving open the bottom nipple,

LQ4 MAF with tables transferred on. Its a 2000 and has had the front 02 replaced.
 


Why would you hook the BBV back up? Enzo with that LQ4 do you just have your normal wiring going to it?

Or are you using this:

ZZ Performance

I am running the TAC on my setup and its working fine.

You are running basically the same setup as me other than me having a Gen V. You should take a picture of your vac line routing and PCV routing. I am not saying you did it wrong but I just wanna see what you did and how you did it.
 
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I have a used N* kit from zzp, Its just the normal wiring from what I can tell.
Ill get the vac lines up here soon.
 
Vacuum routing.
vaclines.jpg
 
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