Badbowtie247 Posted January 4, 2014 Report Share Posted January 4, 2014 So justin has tuned it bout 5 times and has changed and dial in the AFR every time I'm starting to think its a vacuum issue bc it wants to stall after small revs, turning the wheel, and after braking also pedal feels stiff and somewhat hard to stop any input? Brake booster maybe ? I sprayed the intake down and no leaks. Idle is set at 850 and MAP sensor when the truck is running is at 6-7 psi.. Quote Link to comment Share on other sites More sharing options...
AKSSS Posted January 5, 2014 Report Share Posted January 5, 2014 (edited) Idle is set at 850 and MAP sensor when the truck is running is at 6-7 psi.. I am no expert by any MEANS. But your map or your vacuum is showing 6-7? Your map in kpa should be around 40-50 with a stock setup. Your vacuum should show about 19-21 of vacuum. You have a stock cam? Edit- I am on my phone and tapatalk doesn't show sig mods. I'm guessing that you are f/I if you have a vacuum gauge? Edited January 5, 2014 by Aksss (see edit history) Quote Link to comment Share on other sites More sharing options...
Badbowtie247 Posted January 5, 2014 Author Report Share Posted January 5, 2014 No it's comp cam 224/230 .581/.591 114lsa Quote Link to comment Share on other sites More sharing options...
AKSSS Posted January 5, 2014 Report Share Posted January 5, 2014 (edited) Once again I'm no expert. Hopefully one of the other guys will chime in. If you have zero vacuum leaks then it is probably a tuning issue. I am an amateur tuner so don't go off what is say, but I'm guessing that your idle air is off or something along those lines. Are you doing logs for blackbear to read after you load your tune? Also, I don't know how much vacuum it takes to run the brake booster, but if you are only getting 7# of vacuum( or whatever it is called "hg"), it is probably not enough vacuum and your probably going to have to do a hydro boost brake conversion to make things function properly. Edited January 5, 2014 by Aksss (see edit history) Quote Link to comment Share on other sites More sharing options...
canadianVRss Posted January 5, 2014 Report Share Posted January 5, 2014 I think he means he's running 6-7 psi of boost. I have a very similar cam (224/228 581 588 114) and run 14.5-15 inches of Hg of vacuum at idle NA. Here's what I'm thinking, just a theory though but now you've got me curious. Your intake manifold is basically a vacuum chamber right, pulling vacuum that your brake booster needs. But now you're pressuring the intake manifold up, so there's less vacuum in the intake manifold for your brake booster to feed on. Anyone else running a similar set up with this problem?? I'm extremely curious. Subscribed. Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted January 5, 2014 Report Share Posted January 5, 2014 I had a stalling issue when my cam first went in a few years ago, particularly in reverse and with the AC on. From what I remember, it was something in the tune that had to be adjusted, the motor wasn't getting enough air(I don't remember what table it was). Is it a live tune or a mail order tune?? Quote Link to comment Share on other sites More sharing options...
RockHead Posted January 5, 2014 Report Share Posted January 5, 2014 (edited) Is it a live tune or a mail order tune ?????? Sent from my SCH-I545 using Tapatalk Edited January 5, 2014 by RockHead (see edit history) Quote Link to comment Share on other sites More sharing options...
Badbowtie247 Posted January 5, 2014 Author Report Share Posted January 5, 2014 Yes mail order I'm doing the logs with my V2 scanner Quote Link to comment Share on other sites More sharing options...
Downeast Johnny Posted January 5, 2014 Report Share Posted January 5, 2014 I'm curious too. Good luck. Quote Link to comment Share on other sites More sharing options...
Brentd Posted January 5, 2014 Report Share Posted January 5, 2014 (edited) Saw this on my friends truck...it would stall when he would cut the a/c on and surge at 55 if you cut it on. Couldnt find a vacuum leak in it, changed the plugs...didnt change. Swapped the iac from his old throttle body into his fast 90mm throttle body, pulled the iac out and confirmed it was working by plugging it in and turning the key to on and then off and verified it was extending and retracting, but it was sticking slightly so used throttle body cleaner and a soft brush to get gunk off of it and cleaned out the hole that it sits in. Problem went away. Pretty sure it was the idle air controller. Clean it up, if it still has issues have it checked or just replace it. Edited January 5, 2014 by Brentd (see edit history) Quote Link to comment Share on other sites More sharing options...
Badbowtie247 Posted January 5, 2014 Author Report Share Posted January 5, 2014 Not to sound stupid but I have a 90mm throttle body ls3 being drive by wire it just has the tps there's no idle air controller? Quote Link to comment Share on other sites More sharing options...
Brentd Posted January 5, 2014 Report Share Posted January 5, 2014 Not to sound stupid but I have a 90mm throttle body ls3 being drive by wire it just has the tps there's no idle air controller? Computer controls it, cable driven has a plunger style tps. Quote Link to comment Share on other sites More sharing options...
Brentd Posted January 5, 2014 Report Share Posted January 5, 2014 Here is some useful info I dug up on Google for those that wonder how it all works http://www.agcoauto.com/content/news/p2_articleid/215 Quote Link to comment Share on other sites More sharing options...
Badbowtie247 Posted January 5, 2014 Author Report Share Posted January 5, 2014 Ok that's what I thought so the tuner can control it and adjust it then but again why would the brakes stiff up and pedal feel hard going back to the vacuum issue I'm thinking that I can't figure out.. Quote Link to comment Share on other sites More sharing options...
AKSSS Posted January 5, 2014 Report Share Posted January 5, 2014 Not to sound stupid but I have a 90mm throttle body ls3 being drive by wire it just has the tps there's no idle air controller? The idle air I was talking about is a table in the ECM. Quote Link to comment Share on other sites More sharing options...
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