Basetune/stock tune idle issues after SC & other goodies install
I finished installing a Vortech T-Trim on my 2004 Z06. I also added a ported throttle body & FAST intake (stock 78mm size) along with Black Magic fuel rails, longtube headers, NO cats & x-pipe. I also installed a new base tune to get the car running decently before going for a dynotune. She started up but idled at 4,000-4,500 RPM so I immediately shut her down worrying about running that high on cold internals.
First, I checked the TB to make sure nothing was clogging up the intake. Nothing was there blocking the intake but with the MAF & the plumbing from the intercooler removed, I noticed that the plate in the TB was NOT closed all the way when the engine was off. Is this normal to let a little air in or with the plate being slightly open, is there too much air from the forced injection? My thought was that there is just TOO MUCH AIR coming in & possibly causing the high idle? Though the plate was slightly opened at rest, I was able to close it all the way by pushing it back with my fingers which showed me the company that did the porting did not remove too much material from the bore nor that the plate was stuck (it moved easily & smoothly). So I thought about trying to reset the TB sensor so the plate would be closed at rest.
I did the "idle relearn procedure"...ignition On and pull fuses #16 and 23 in the engine bay, then ignition off & put back fuses. With the original stock tune in place (versus the new basetune modified for the SC), I started it up and it ran at 2,000-2,500 RPM (better/slower than before but still far from being right) so I let it run or a few minutes (2-3 minutes) to try to let her warm up but then the idle started to creep up to 3,000 RPM so I shut her down before reaching operating temps. Then I tried something I read about on the Forum to reset the TB sensor. Attempting to get the TB plate to close all the way at idle I did the following procedure -- ignition On, disconnect harness to TB sensor on passenger side, ignition Off & reconnect harness then start her up & clear codes. I did this reloading the SC "base tune" since she was now almost up to operating temp but the idle shot up again to 4,500 RPM with some sputters and small backfires.
What else can I try before replacing the ported TB with a stock unit (it was suggested that the ported TB could be the problem)? It seems that between the stock tune running at 2,000-2,5000 RPM and the new base tune running at 4,500, the problem is an airflow issue. Can I calibrate airflow to compensate (I am new to HPTuners)? I get scared starting her up and having the engine rev up to 4,500 being semi-cold. Also, running her rich with the stock tune, will I have to R&R the sparkplugs since they might be fouled because of the rich A/F ratio?
Don't mess with the T-Body---YES it is completely normal for the t-body to stay open when the engine is OFF--It is similar to a carb. "unloader valve " sytem--when the engine is 1st cranked it will stay open briefly to allow it to start--then immediately it will close--
Seems like you have a whole host of issues that need to be addressed---The Superchips tune provided with the SC usually addreses all the neccesary tables to make it run properly--however you have made too many other mods all at once to make it run correctly--
Just off the top the headers are the greatest issue--because the 02 bungs are futher back then they were with stock manifolds your 02's are giving erroneous readings in closed loop
Next the ported t-body always requires additional tuning for things like idle etc.
I would 1st though start with the commanded AFR in " open loop"--this table sets the AFR at start up in both cold and warm starts--generally you have to lean these #'s down a bit--The "hanging idle" is caused ususlly by adjusting the "desired airflow " table--there are 2--one for P/N and one for in gear-- a hanging idle would suggest they added too much of a % to these tables---Next you can adjust the "throttle follower table" Seems like they subtraced too much of a % to create a hanging idle---
Make sure 1st you do NOT have any vacuum leaks-The suggestions made are for tuning--but a vacuum leak is a mechaical problem that has to be checked 1st---with a FAST intake you have to make sure that the Valley cover bolts under the manifold have plenty of clearance--this is a common problem wit a FAST and smaller headed bolts such as button head allens or some bolt head grinding is often the only cure---If the bolt heads are touching the manifold it will not seal correctly and will cause a major vacuum leak--worst case senerio is that it will crack the manifold beyond reapair--
Start here and get back to us---
Yes, I will test vacuum tonight but I did use FAST's "button" allen heads bolts for their clearance/low profile.
Here is the link to my stock as well as supercharger base tune files but they're done in HPTuner's Beta (2.23) version so I don't know how many folks can open them to look... http://www.hptuners.com/forum/showthread.php?t=25470
Tonight I reloaded the stock tune (don't know how many times I can reprogram my PCM before it craps-out), hooked up my MityVac gauge to a "T" off the brake booster. Started her up and wow, she idled at 1,500 RPM.....better but weird. Why different from the last time I had the stock programming loaded where she was at 2,500 RPM? Anyway, the MityVac only registered 8 in. Hg of vacuum (actually, it was bumping around between 7-8 in Hg).....shouldn't it be around 20? After a few minutes, her idle started to slow so I shut her down....thinking about it now, I should've let her continue to run. I tried starting her again after a minute and she gruntled, backfired and died. On the third attempt she wouldn't even start so I stopped trying.
I went out to the hardware store to get what some of you suggested....a pipe end & clamp along with a tire valve so I can seal off the manifold (planning on doing it in front of the MAF since it's easiest). Then I'll either track down the hissing noise or spray some soapy water around the intake to look for bubbles. By the time I got home, it was too late so I'll continue tomorrow. Just wanted to post the latest.
By the way, I check the two hoses and the sensor on the back of the manifold and they are all on solid. I also used the low-profile "button-head" bolts when installing the manifold along with new seals so there wouldn't be any leaks.....how ironic! I checked the lines running from the valley-PCV to my catch can and back to the throttle body...all are on good. Didn't check my BOV yet because the car wouldn't restart.
Believe it is not programming anymore but a vacuum leak that's causing my dilemma. Suggestions on tracking down a vacuum leak/most probable places to look would be appreciate (yes, I know, besides the TB).
Finally, I had reset the DTCs tonight and this is what she threw after the 2-minute warm up session -- P0101C (again), P0106C (again), P0300C (new one), and then on the last group BO-RFA she threw U1000HC.
--I've had the best results by using "starting fluid"-- Spray it all around any suspicious connections sealing surfaces etc--(while the engines running)-make sure you spray around the T-body flange--If i remember correctly my 78 was a bitch to get on--the bolts have to be exactly the rite length or they will not fit--If they are too long you will crack the flange and could ruin the manifold---If a leak is present the motor will flare up---When dry the starting fluid will flash bone dry like brake-clean so there is no mess---Some guys use wd-40 but it is a holy mess----Some guys use brakeclean but again that makes the engine die rather than flare and it is hard to use---
I would be afraid of using compressed air and soap--If you make a mistake and over pressurize the engine you could blow all the gaskets out--pan--valve covers--etc
Ok, thanks tblu92. Will try a couple of things tonight....keep everyone posted. I also received a stock LS6 throttle body to replace the ported one I have in there now.
First, since the car has sat for 24 hours, I tried restarting her with the stock tune. She started right up and idled roughly around 1500 RPM so I jumped outta the car, grabbed the starter fluid and started shooting it around the manifold and TB looking for a leak but the engine died. Not from the starter fluid (which should have made the engine surge) but just as she did yesterday, her idle first slowed & then she died. And just like yesterday, when I tried to restart after stalling, she would just turn over but not catch.
Next, I tried the pressure test but to no avail.....plastic cap on the front of the throttle body with a new tire valve stem sticking out. Put a clamp around the cap and also put tape around the stem just to make sure of no leaks. Pumped it up carefully and .......... nothing. ??? No hiss, no leak, no nothing. And then when I tried to the relieve pressure in the manifold by pressing the valve on the tire stem, again, nothing. I must've done something wrong so I will retry tonight.
And now for some good news, I received the stock LS6 TB from Andy to replace my ported unit. This will go in tonight.
And 2 important revelations:
1) As per the FAST intake instructions, I only torqued the 10 manifold bolts to 50 inch/lbs (my GM manual states 89 inch/lbs) but I followed the FAST instructions as I believed they knew what they were talking about with their own polymer intake...I didn't want to over-tighten & crack the FAST intake. But maybe that's my source of the leak and why she didn't hold air with the aforementioned pressure test. NEEDS TO BE TORQUED IN TWO STAGES....44 inch/lbs and then 89 inch/lbs. Maybe the 50 inch/lbs that FAST instructs is just not enough!
2) I have done research and found enlightening info that probably would have made me steer clear of the FAST intake if I knew about this before purchasing it. Appartently, it is noted that FAST intakes along with "big" TBs have a lot of reports of excess idle air. My TB being ported & polished, I consider it big even though its the stock 78mm size. Here's a quote I took off of HPTuners Forum (link is attached),
"The FAST intakes and big TBs seem to have a lot of reports of excess idle air. Whether it's manifold seating/ sealing (button-head valley bolts?) or just the greaterblade periphery / leakage, seems to be more air gettingby and messing with peoples' throttle cracker and idleairflow. IAC effective area should not change at the lower range (dominated by IAC plunger & seating circle) but might deviate at higher, where casting runnerdifferences might show. My epoxied TB was way off at counts above maybe 200 or so until I drilledit (IAC port) bigger.I'd shoot some propane at the base of each runnerjust to see if any sealing issues, and check out theblade-stop, light-check the blade seal circle etc."
from.....http://www.hptuners.com/forum/showthread.php?t=21461
Also, on Z06Vette.com, "Yes, there do appear to be tuning issues with the FAST intake + 90mm TB (at least, with MY FAST & TB ). I'm not positive on the details but from what I'm being told, there appears to be a discrepancy between what air flow the computer believes is coming in and the actual amount flowing. If you are hearing about fitment problems that too might explain the discrepancy."
from........http://www.z06vette.com/forums/f5/in...427-c5r-59215/
And by the way, yes, I did replace the stock valley cover bolts with the button head allen bolts that FAST provides to give you the additional clearance needed for their manifold.
Tonight I will retorque the manifold to 89 inch/lbs and then install the stock TB. I will also try pressure testing one more time with the stock TB in place. If she starts up and sounds ok, I will reload the supercharger basetune and then do one final check for leaks by spraying starter fluid around the manifold while she is running. IF NONE OF THIS WORKS, THE MANIFOLD IS COMING OFF. I'm open to other suggestions as well................
....... I retorqued the 10 manifold bolts to 89 in/lbs instead of the 50 in/lbs that was on the FAST intake instructions. I AM HOPING THIS WAS THE SOURCE OF MY HUGE VACUUM LEAK. Then I removed the ported TB and put on the stock LS6 unit that Andy sent me and ............. now the car won't start. I am so frustrated!!!
The last time I started the engine two days ago (with stock tune), she started up right away & ran for a minute at 1,500 RPM and then slowed & died. I was out of the car spraying starter fluid around the manifold trying to find my vacuum leak when this happened, otherwise I would have given her some gas to see if that kept her running. Well, I tried to restart her a few times but to no avail. She only threw DTC code P0101.
Last night was a continuation from the other day....no change. She cranked over fine but would not catch. She sputtered a little. I tried cranking her three times & then decided to research the no-start issue.
I haven't posted in a few days in order to regain my sanity.
Here's what has happened since my last post on Friday...
I did retorque the FAST manifold to GM specs of 89 in/lbs (not the 50 in/lbs as listed in the FAST instructions). This seemed to clear up the vacuum leak. The spark plugs got fouled since I was switching between stock tune and the supercharger basetune; when running with the stock tune, she was running very rich which fouled the plugs and was the cause of her not starting last week. So that issue was straightened out.
After cleaning & reinstalling the plugs and retorquing the manifold, I removed the ported throttle body and installed a stock unit. I also tried the "pressurization test" some of you recommended at the beginning of this post but it still didn't pressurize.....wouldn't the air (hence, the pressure) leak out of an open exhaust valve???? Anyway, this didn't deter me too much. Figured it's time to try starting her again since a stock TB is now in, the manifold has been retorqued, the plugs are clean & I am running the tune set for my injector flowrate. Well, she started right up and
* immediately went to about 3,500 rpm ,
* vacuum was a steady 17 in Hgs ,
* and when shooting starter fluid around the manifold and throttle body, there were NO variations in engine speed...there were before I retorqued the manifold and vacuum then was ONLY 7-8 in Hgs. SEEMS THE ELUSIVE LEAK HAS BEEN FIXED (unless vacuum should be highly since it is running at 3,500 rpm versus idling at 900 rpm).
So the problem seems to be in the tune. I know some of you wanted me to pull the manifold and put the stock unit back on but I wanted to try everything possible before doing this as I also spent $ and considerable time wrapping the manifold in gold reflective foil.....hate to waste all that, not to mention the coast of the FAST intake itself!
So, after researching the high idle issue pertaining to FAST intakes with ported or enlarged TBs, here's what I have found either on this forum, other forums or what some of you suggested I look at as being the source of the ULTRA-HIGH idle speed:
1) The FAST intakes and big TBs seem to have a lot of reports of excess idle air. Whether it's manifold seating/ sealing (button-head valley bolts?) or just the greater blade periphery / leakage, seems to be more air getting by and messing with peoples' throttle cracker and idle airflow. IAC effective area should not change at the lower range (dominated by IAC plunger & seating circle) but might deviate at higher, where casting runner differences might show. My epoxied TB was way off at counts above maybe 200 or so until I drilledit (IAC port) bigger.I'd shoot some propane at the base of each runner just to see if any sealing issues, and check out the blade-stop, light-check the blade seal circle etc.
2) Yes, there do appear to be tuning issues with the FAST intake + bigger bore 90mm or ported TB. I'm not positive on the details but from what I'm being told, there appears to be a discrepancy between what air flow the computer believes is coming in and the actual amount flowing. If you are hearing about fitment problems that too might explain the discrepancy.
3) If it settles down, it's in the tune and not a vacuum leak. Throttle cracker & follower tables can turn into cruise control if the values are too high
4) Mine car was doing the same thing after my Kenne Bell install......Tuner fixed it the next day and told me it was the throttle crack stuff.
5) Mine did that same thing with the FAST90 but not that high, only shot up to 2k at cold start. Doug@ECS re-adjusted the parameters for air friction or something? I dont remember the exact terms but it wasnt just a simple idle setting. He mentioned mine was turned down below even factory setting but you have to give what the motor is asking for. Now it starts up cold just fine and idles at 950 RPM.
6) Just off the top the headers are the greatest issue--because the 02 bungs are futher back then they were with stock manifolds your 02's are giving erroneous readings in closed loop
Next the ported t-body always requires additional tuning for things like idle etc. I would 1st though start with the commanded AFR in " open loop"--this table sets the AFR at start up in both cold and warm starts--generally you have to lean these #'s down a bit--The "hanging idle" is caused ususlly by adjusting the "desired airflow " table--there are 2--one for P/N and one for in gear-- a hanging idle would suggest they added too much of a % to these tables---Next you can adjust the "throttle follower table" Seems like they subtraced too much of a % to create a hanging idle---
Being new to HPTuners, can some offer a detailed set of steps for me to run through to see if it is in the tune. I would like to try different adjustments to the tune before going back to 'square-one' and removing the FAST to put back the stock manifold. Thanks!
The cause of the high idle was a Burst panel in the bottom of the FAST intake that popped. Don't know how it happened or what caused it but when I pulled it off and put on the stock LS6 intake, the idle dropped to around 900 rpm but now I am getting misfires.
The DIC states misfire code P0300. When I put a scanner on the car, it says P0301 so I pulled plug#1 and it looked fine (light brown with no fuel or oil), checked the sparkplug wire and tested the coil (with a timing/strobe light)....all are fine. Please note when I first started getting the misfire code (after I found the cause of the high idle was a blown burst panel in the FAST intake), I replaced ALL plugs & wires. Since then, I have tested all the coils with a timing light and all coils seem to be fine.
So I started thinking about the last time I scanned the car. Please note that every time I scan the car, the car is not actually being driven since it is still on jacks in my garage. I rarely run the engine (due to all the problems) past the point of warm-up, if it even gets that far. SO I GUESS I AM ALWAYS RUNNING IN "OPEN LOOP." So getting back to the scan, I noticed that Bank1 and Bank2 were WAY-DIFFERENT from each other even though this was in open-loop running off the MAF & tables. I still thought that Bank2 looked "weak" and was maybe giving a false low-voltage reading to the PCM, thereby dumping fuel and was the cause of the heavy fuel smell I was getting. But then again, maybe not since it was in open-loop, the O2 wouldn't be making any adjustments and the fuel smell could be from the misfirings & unburnt fuel coming out of the exhaust. I know the O2 sensors hadn't heated up yet but the readings were so far off that I decided to replace Bank2's O2 sensor anyway.
After replacing Bank2's O2 sensor, I started the car again and this time she ran with more pronounced misses (misfiring) and then she started to stumble and threw out a P0336 (crankshaft position sensor fault - circuit performance) error code....hope it's just due to all the misfiring. Anyway, still trying to diagnose the misfires -- MAYBE A BAD GROUND? MAYBE BURNT O2 SENSOR WIRES ON BANK2 (passenger side)?....I heard you can not splice O2 wires because it will give false readings?????
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Basetune/stock tune idle issues after SC & other goodies install
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