hello Everyone, THIS IS LONG! SORRY!
I'm obviously having some problems with my car. I just did a heads/headers/intake/TB/cam swap, and then took it to a reputable shop (one of our sponsors) for a dyno tune! They did a great job on that respect, and they worked really really hard to fix the driving issues, but couldn't do it. My cam is 228/236 .612/.582 114+2, and they said it was the cam that was causing the problems. Frankly, I highly doubt it. So, I took my predator tuner and checked for any codes (cause I think they turned off all error reporting) cause it then showed that my H02S sensors bank 1 sensor 1 and bank2 sensor 1 (P1133 and P1153) had Insufficient Switching. What does that mean? Does it mean that my O2 sensors are bad and I need to replace them?

Also, it said that my Idle Control System, RPM's Higher then Expected showed up as well...(can't remember the code at the moment). What does this mean? Did my Idle control module go bad? Do I need to replace it?

Here are the problems I'm having.
- When I first pull out of my spot, i let the clutch out, and the car decels and bogs down all the way to 200-300 rpms and sometimes stalls, and if it doesn't stall, the rpms will jump back up to 1500 and then it'll surge up and down until it finds idle at like 880-900 rpms. This is after the car has warmed up and has sat idling at 880-890 for a little while. This will also happen while driving.... coming to a light, let clutch out, then bogs or stalls
- AND, when i'm driving and coming to a light, the car will stick at idle at like 1800 rpms and then i'll rev the engine and it may fall lower, but sometimes won't, and then randomly it'll fall back down to idle, or sometimes it won't. Its random.

Now, for a little backround,

-Have the FAST 90 tb that does stick, but I installed check springs, and it never sticks anymore. I can guarantee that because when the car is idleing really high, i'll make sure the blade is not sticking, and it isn't.
-I have the rear 02's deleted, and I asked them to tune them out, and I don't have any 02 sims on them, so it should just be alright because they tuned them out right? They're showing a steady voltage of 445-450 mv through my predator tuner...is this correct?

The place I took it to worked a lot a time trying to correct it, but its still acting up real bad. What do you guys think? What do i need to do? What could be causing this...its driving ( ) me crazy!!!

Thanks a lot!!
Haans

 

did they charge you for it? if they couldnt tune it and it be to your satisfaction, then you shouldnt have been charged....maybe just for dyno time, but not for the tune.

 

Most likely the headers are the cause of the insufficient
switching codes. The O2s won't boogie until they get heated
up. If you reused old ones they are probably not up to the
job in the new cooler environment.

The cam is large but it's tunable. The cam has whacked
your low end air pumping, the VE table needs to be trued
up. That's not something you do on the dyno. It's something
you could do in the parking lot for the most part. Though
with the O2s whacked it gets more difficult. Poor idle mixture
makes idle operation unstable. So does lack of useful O2
feedback. I'd start with the O2s ('vette rears, try) and
see how much of it clears up.

The high idle I would suspect a vacuum leak from all the
intake messing-around, since you are certain that the TB
itself is not to blame. Why that's intermittent / "sticky",
I dunno. The FAST TB will need some idle air massaging
just because it's physically different from the stocker.

 

I will change out my 02 sensors to the rear vette ones tomorrow....see how that helps, I'll also check out all of my vacuum hoses and make sure everything is alright.

Also, these symptoms look very much like my IAC valve is going bad and would be a good explanation for the idle "sticking" situation, and idle bogging issues with high idle conditions. The guys that tuned my vehicle also did a whole bunch of driving tuning, and even tuned on the fly while driving the vehicle. So, i'm sure they got the VE tables tuned in properly.

Also, what is low end air pumping?

Thanks!
Adrian

 

Engine being an air pump with a bang in the
middle. Cam overlap kills the pumping at low
speeds, both valves open too long together.

The IAC loop to me seems to get unstable when
any other slow / laggy, sensor / actuator element
starts to fall behind. Unstable trimming from lame
O2s is one such. Gummy IAC, mismodeled idle
air effective area in the tune, too much dependence
on idle loop trimming (like RPM not consistent with
idle airflow needs), I bet there are plenty more.

Anyway, those were concepts you ought to put
to your tuner and see what you get. Let the dude
drive it maybe. If it pukes on cue there'll be no
denying.

 

Yea, they did drive it, and I'm SURE they had the same problems and just couldn't fix it. There is also 4 degrees of overlap...is that too much? I'll check my sensor....its located on the throttlebody right? Plus, replacing the 02 sensors....which ones should I get? Are the Bosch ones for the rear corvette ones good? I should be able to get them from Autozone or such.

 

Also, what should the rear 02 sensor mv be at? Because with my tuner, it appears they set it at a constent 445-450 mv.

Thanks!

 

Well, I replaced the 02 sensors with the corvette rears and its still being retarted...although my code is no longer there which is good, so that means that the 02's weren't the problem. I'm just going to get the NW90 and be done with it. I'm tired of ******* with that damn FAst 90 tb.

Another question, using my predator tuner and checking to see what DTC's are not run, it showed 49!!!! Does this mean that my tuners turned off all trouble code detection?! Isn't that not a good thing?

Plus, that P0507 code showed up again, so, i'm thikning i'm also going to replace my IAC valve.

Can someone give me a run down of all the vacuum connections I should check?

Thanks!
Adrian

 

Anyone got a rundown of what to check for vacuum leaks? I really want to get this mess fixed!!

I also replaced my valley cover with an LS6 one, and instead of using a 5/16" ID tubing for it, I used a 3/8" ID because thats what I had on hand, would that make a difference? I also replaced my PCV valve as well, with no luck.

The thing that is driving me crazy is that its random!! I just don't get it. The only thing I can think of that would make it random would be the IAC valve. I did check it, and there was some play to it, and it looked as if it was completely open, but it was clean, and I also sprayed some electrical connector cleaner on it and wiped it off and let it dry. Reinstalled and still had the random issues.
I also set my throttlebody plate to 2% open, and then zeroed it in this position. Only thing this accomplished was a little higher idle haha.

Anymore help would be awesome!
Adrian

 

so its running rich possibly because, yes you have an air leak and the computer is over compensating for the extra air and throwing more fuel which could be your answer. Is that the same thing on the left and right side? if so, then its an intake leak. Make sure that the manifold gaskets are intalled, the injectors are seated, the MAF and TB are sealed. im running a 230/232 +4 112 and its very tuneable. Its not your cam that cant be tuned, its the tuner cant tune Do you have your own tuning software or scanning software or know someone who has hptuners that can log your idle and cruising so you can email it to us to take a look at it?

 

Hey Nino,
Sadly, I don't have or know of anyone who has any tuning software. I do have the predator tuner which is capable of doing some monitoring, but thats it.
What do you mean by being the same thing for both the left and right side?

Here is what i've found. my headers have welded on collectors, so they are not welded completely around each primary because you can't get the welder inside there, which could be a source of an exhaust leak...I tried using some high temp RTV to cover the rest of the primaries/collector before i installed them, so its possible the headers are leaking at the collectors...which could allow more oxygen into the exhaust and throwing off the 02 sensors. Maybe thats why i just got the same codes as before...(insufficient switching on both sensors bank1) after i swapped them with new sensors, but it could also be because of the random idle issues. Not really sure if thats likely, its just a thought.
Checked all my vacuums and I can't find any mishaps with that, all hoses are connected, nothing open or hanging. I removed my AIR and made sure everything was sealed up from that too.
The intake seals are a possiblity, but wouldn't a leak cause an air loss, and not too much air entering? I could see that if the manifold always had negative pressure, but its always under pressure which would mean a intake leak would cause a loss of air. But i'm going to replace the seals anyways.
Lastly, it it possible that my IAC valve is wacked out. So, i'm going to replace that next and see what happens. Hopefully it'll fix the problem, if not, then well, this sucks haha.
Nino, I really wish I had something to send you, i'm curious to see what my tuners did. Also, while i was monitoring my spark at WOT it was at 22.X according to my predator.

I do have a laptop with EFILive v7, but I don't have the hardware to hook it up.

What do you think?
Thanks!
Adrian

 

first things first, your going to have to get the headers fixed or your not going to be able to get a good tune, PERIOD. your max spark seems a little low...i would think it would be around 25-26* Get the NW TB in there quick also. now i dont think it could be the intake manifold after you telling me about the headers. What i meant by both sides was , are both your o2 sensors reading the same or are they different? if they're doing the same thing, then its usually and intake leak if just one bank, then its the exhasut side. or just specific to that side of the house.

 

Alright, i'm going to have to fix up all of my exhaust leaks then, before I do anything else...

Will using a brazing rod be sufficient? Thats the only way I can see I can get it fixed at this point, cause I can't get the headers out without lifting the engine...as i don't want to do that haha. Otherwise I can try and get some more hightemp rtv around there to seal it.

Thanks,
Adrian

 

i dont think the brazing is going to work. your going to have to remove the headers and take them to an exhaust shop or see if they can do it with them on the car, but it has to be welded. hightemp rtv should not even be a thought! What are all your mods? what headers are your running and who did your installs?

 

I did all of my installs. I'm running the following

Volant CAI
FAST 90 intake
FAST 90 tb
ARE Stage 3 heads flow 327cfm at .6 lift 61cc chambers
Patriot Gold Dual Spring kit
Chromoly Pushrods 7.275 (I measured with an adjustable pushrod length checker)
Morel Lifters with ~.03" cold preload
Ed Custom Cam 228/236 .612/.590 114+2
Edelbrock Victory Race Stepped 1 3/8 to 1 7/8 with slip on 3.5 in to 3 in collectors
ORY
3.72 gears with detroit trutrac in stock 10bolt.
Textralia clutch with steel billet roselock flywheel

When I put in the headers i didn't pay attention too much to the weld, but upon further inspection, they're not welded completely. I figured they were alright because they were used headers that i bought and the last person didn't have any issues....stupid me. Amazingly these part of the headers don't even get hot enough to burn off the High-temp RTV, because they came with a little bit on them so I left it like that. I'm going to take it to a muffler shop and see what they can do for me first, and if they can't do anything, i'll try the brazing rod.

Thanks!
Adrian

 

is it daily driver? if not, then id call edlebrock and send them back to them and see if they can do something about it, but then again, im not sure if the collectors were welded to begin with. Another thing is welding may ruin the hitemp coat in the area around where it was welded. Since you also did your own installs, Id look at the intake if the collectors werent the problem, but it sounds like they are.

 

yea, its a daily driver, I'm going to look at the intake as well, and i'm going to take it to a muffler shop today and see if they can fix it. If not, then that sucks.

 

good luck with it. why not just get a set of pacesetters and be content? im running them and they're great.

 

Reason is I can't get my ones I have on right now off without having to pull my heads/intake and lifting my engine, so they're staying haha. I fixed the leaks, took a little easy engineering with some tin cans and hose clamps haha, but the problem still exsists without any change. Plus I'm still throwing the O2 codes, which now is most likely because of the idle issue.

Next is to change the IAC valve, and if that doesn't work, then the intake seals...if that doesn't work, i dunno wtf.

Just an observation...I have a powerbond 25% UD pulley installed, and it seems that the bogging is worse if I'm turning the steering wheel and, when driving, my steering wheel has slop in it. How would I go about fixing the slop? Is it possible that the UD pulley is throwing something else off?

Thanks!
Adrian

 

you know im glad you mentioned that about the pulley, when i turn hard right, my car boggs big time. i think the bolt may be loose. How can u not take the headers off w/o taking the heads and intake??