So, I've recently put together a 5.3LS engine for a '69 GTO Rag top (Triple black car) and I'm having issues getting the base running air flow nailed down. Everything I've done so far is not working. This morning I attempted to do an idle config to get the #'s for BRAF and it's all fubarred.. The data I'm getting is bogus. So, I'm doing something wrong. Can you guys look at the tune, and the log and tell me what I've screwed up so bad that the idle config won't work? In the past I've used a wide band O2 sensor to do the idle config and that way seemed to work.. Is it not possible to use the factory narrowband O2 sensors for the idle config?

2nd problem.. My timing is saw toothing all over the place! What do I need to do to calm the timing down? Thanks for any and all help and advise.

 

Here is the tune I started with this morning, at least the RAF #'s I started with. Car started, but died instantly.. I was logging and saw that it populated a 23 in the 90 degree field in the short time the engine ran, so I went back and put in the 23 in the 90 deg field and interpolated over to the 198 field. I knew from running the engine yesterday that the 198 field was CORRECT so I left it alone.. Car did start, run, and idle all the way through to full operating temperature with the #'s that are in the tune in the post above P/N #'s ONLY... But.. I know it's not right... any help?

 

KWB, I could not see the tune, because of version conflict. What I think I see in your log, I cannot confirm. Please add TPS voltage and TPS % to the channels. I am assuming a cable throttle based on the IAC position channel being present.

It looks to me as though the blade closed very far and needs to be cracked open further, and possibly the blade needs a hole drilled in it or the existing hole enlarged. This is based on the IAC counts not dropping below 200 fully warmed up.

What I would recommend is after you add the TPS voltage, key on and start recording on the scanner. Set throttle blade to 0.65 volts on the scanner via the set screw. Then key off, unplug tps, key on for one minute, key off, plug tps back in. This will rezero the tps. If your warm IAC counts drop to zero, then slowly close the blade until your idle stabilizes with 30-60 IAC counts. Once this is done, key off and do the TPS rezero again. At that point you should be good. If your warm counts are still very high, then you will need to drill a small hole in the throttle blade, getting progressively larger until your counts come down.

I think after you do those things you will find your idle trims do not go very high like you are seeing.

As to the timing sawtooth look -- after you get your counts right, this will likely improve. if it does not, then look to your spark page. The idle overspeed and underspeed spark tables. Make them less aggressive. Do this slowly, as that adaptive spark helps control idle speed.

 

Darth, thanks for the reply. I will work on those things immediately, and will post a new log with the TPS voltage, and %, added in. You are correct it is a DBC T/B from a 5.7L LS1 in a GTO (2003 or '04-not positive of the year as I bought the T/B separate from the car)... I have already opened up the throttle blade set screw a little bit because the idle air counts were right at 300 before. I will crank the set screw open a little more, do the TPS re-set, and then log a start an idle session. This car has the Comp Cams XR275-HR-12 in. It is SMALLER in specs than the cam in my truck, but my truck was much easier to tune.

 

Non problem. That cam should really not be a pita to tune. Wish I could look at the tune but I cannot upgrade versions on my work computer.

 

is the computer out of a 2004 gto also?

like said above, try to get the car to at least stay running with opening the throttle blade. I like to start with opening the blade first to get it running. the hole in the blade should already be decent sized enough. if it idles too high, start backing it down. I try to get 50 iac steps at idle in neutral. my voltage is set at .49

once you get it to idle decent then your braf will need to be done (well after the ve is done). I'd set the base timing at 18-20 degrees. Take a few degrees of correction out both ways. that will tame it.

Do realize that your ve table having big differences in numbers next to each other in the idle area, can/will cause it to surge. Having the timing too high at idle will cause a surge. I like to start low with my timing and use the scanner to add a degree in at a time until you tell it doesnt like it and cant control it well, then take a few back out. Man I could type for and hour on idle tuning. Its the hardest thing to nail and I aim to get mine perfect, it takes lots of time.

your BRAF is important, but I usually get that in the ballpark first, get ve, timing, throttle blade, timing correction done first. then get your base running air flow, then dial in all your adders for return to idle, coast down etc.

 

Thanks guys for the information and help.

No, the computer is a typical 411. I tried unsuccessfully to get at that set screw and could not make it happen. Looks like I will need to remove the TB to get to it. Anybody know what size the torx bit is for that set screw? I'm running an LS1 intake, with truck accessories, and truck water pump, and truck harmonic balancer and pulley. Very tight fit at the set screw location. I can barely get a finger tip up in there. I will get the screw adjusted, do the TPS re-set, and start a log in the AM logging TPS % and voltage. Thanks again for the help.

 

I opened up the set screw a little bit more today and ran another RAF log with the scanner. I'm slowly whittling it down. I got the IAC counts down to 160-180 today at operating temp (205), I forgot to log TPS %, and voltage. I have to adjust the set screw more and do another RAF log later today after the engine is dead cold again. I will add those channels and then post that log up. I know I need to get the IAC counts down to 60-80 when hot, at operating temperature. At least at this point I have numbers that will allow the engine to start, and idle, from dead cold to hot. I also upped the idle spark advance in P and GEAR, and reduced the engine over-speed #'s, and messed with the underspeed #'s. The timing line on the log from this morning is still saw tooth, but it does not have the exaggerated swings my logs from yesterday had. Today, it's rising and falling in a much smaller window with a max swing of about 8 degrees between the highest high, and the lowest low. Yesterday it was swinging VERY wildly with a max swing of about 20 degrees or more as evidenced in the log posted above.

 

if you get to 0.65 volts ont he set screw, you might need to get out your drill

 

You are wasting your time running BAF logs. You need to get the tps voltage (you may need to cut the tab off and slot the holes) in the correct range, get your fueling, timing and throttle blade set. THEN you work on running airflow. Doing it backwards like you are is counterproductive.

 

KFX-I'm honestly just trying to get the engine to idle well enough that I can move it around the shop without having to power-pedal and brake pedal it simultaneously. Once I get it to a point where it will start and idle on it's own-both in gear, and in P/N, then I can start driving it to do the VE table. I do have a Wide Band O2 sensor and will be datalogging to get the fueling correct..... I also need to repair a minor engine oil leak, bleed the brakes, and some other stuff... I just have to have a car that will start and idle on it's own before I can dive into the other stuff. I just looked at the log I did earlier today-it shows now with the FINAL set screw adjustment that I was in the 80's on IAC counts.. See the next post for that log.. I have to get on my lap top to post the log.

 

You can see from the log that the TPS voltage was at .88, and the TPS % was 2.4... I forgot to do the TPS re-learn before I started the log.. IAC counts were in the mid 80's at the end of the log... At this point, I'm leaving the set screw alone, and now will focus on getting the TPS percentage to 0, and the voltage to .65. I will do the TPS relearn first thing in the morning before running another log and see where the voltage is sitting after doing the re-learn, and before starting the car and running another RAF log.

 

that’s why I’m telling you what I’m telling you. The throttle blade opening, fueling and timing play a much larger part than your braf. Let me ask you this. If you open the throttle blade up to where its idling at 1500-2000 rpm. You iac counts are 0. So you reduce the braf, Is that going to make a difference? No. What about the other way around? You close the blade and try and rely on the braf and iac counts to make it idle. Your gonna have a tough time to get it it idle, if it even will. I’m just trying to help you. I can’t make you do it the way I’m telling you, but you need to.
I always use the throttle blade to get it to idle with little to no iac counts, at least at 500-600rpm. That way if you let off the throttle suddenly, and your iac counts are very low, then everything won’t have to work to catch it from stalling. You realize that when you press the throttle, your idle desired airflow goes to 0? Then it has to ramp back up quickly when you let off the throttle. That’s why it’s not going to fix it on its own.

 

Very likely this means you will need to drill. Once you get the set screw much higher than 0.67, it won't reset. It's not always a hard fast number. I saw one ECU take 0.76 volts, some take 0.69. But point it, if you're at 0.88 and still at 80 counts, you're going to have to drill a hole in the blade. If you go too big, you can close the set screw some.

 

im 99.9% positive that when he does a tps reset, the voltage won’t change but the % will go back to 0%

i would slot the holes in the tps and cut the nub off first before drilling. Then turn the key on, initialize the scanner. Bring with you under the hood, watch the tps voltage in your channels and set it around .55v. Crank it. Won’t idle. Add a little more throttle blade. Or drill the hole very very slightly larger. Try again till it wants to idle. HOWEVER. if your fueling is too lean or too rich, it’s not going to idle till you get that close.

 

Btw. I could go change the fueling only in a good tune, crank, die. Crank, die. So please understand all these things intertwine with each other.

 

Okay, I did the TPS relearn this morning, and using my laptop under the hood (convenient because that's where I put the OBD2 port!) voltage after the TPS & IAC relearn are the same-.88V, and 2.4%. Car still will not idle. starts, dies instantly. If KFX guy is right, and it's the VE table (fueling) being off too far that the engine just won't run at lower engine speeds, then maybe I need to go into the tables for the idle areas and just whack a bunch of fuel out of that section. *IF* the car would idle, I could put my wide band on it and get some actual readings to go on.. But... we all know.. It will NOT idle. Further, it seems I'm going to have to enlarge the already drilled hole that is there in the throttle blade. I can measure the diameter of the hole that is there, but then how much should I open it up? Should I simply go next drill size, and then start testing again? It seems to me that drilling the hole incrementally larger is a better idea than messing with the TPS. If the TPS goes bad later and has to be changed, the new TPS will have to be modified to work. Better that I make the changes on the actual throttle body (at least this would be my preference). I'll pull the throttle body and enlarge the hole just a wee bit. I'll also look at the VE table for my truck and see what kind of numbers I have in the idle areas and copy them over if they are leaner than what is in the VE table for the GTO. I know from yesterdays log that the STFT was pulling upwards of 10% of fuel (negative numbers) during the BRAF log attempt. KFX is right.. The fueling in the idle areas of the VE table are off... Next question, and probably the most important question... If I fix the fueling FIRST, will that negate having to drill the throttle blade? OR, is the fact that my TPS is at 2.4% and .88 voltage, and my IAC counts are STILL in the 80-87 range indicative of the need to do BOTH correct the fueling, and still slightly enlarge the air bleed hole in the TB? You guys have been a big help and I really appreciate your time. Virtual beers won't get you drunk, but I'm sending them anyways!

 

Dont drill the hole yet. Get the fueling right/close. You should not have to crack the throttle blade much. I spotted my tps, I had to replace it last week, so I just slotted them again. I prefer to mod the tps vs the throttle body. Chances are your main issue is fueling. Basically you gotta kinda ballpark timing, ballpark braf and get the fuel, tps and throttle blade in line, then address the other areas.

 

The TPS reset will not work at 0.88 volts. That's why it won't idle. You're going to either have to drop the set screw to .67 or slot the holes and twist the TPS until it drops the volts so you can zero it. I prefer to drill vs slotting the TPS holes and risk them coming loose and the TPS going wherever it wants. Unless you're in SD, idle runs off the maf-only anyway, IIRC. Getting your fueling right will obviously help. Sounds like you're rich at idle, which will sometimes cause return to idle surge issues.

My bet is you'll end up doing both - correct the fueling and then I'm betting you'll end up enlarging the hole.

 

Thanks again guys for the information. I checked my TRUCK tune (6.0L bored .030" to a 370), with an ELGIN E-1839-P cam, and it is MUCH LEANER in the idle areas than the GT-NNNOOOO!!!!! is... So... I copied those tables over from my truck tune. Tomorrow morning I will pull the throttle body off the intake, open the air bleed hole a smidge, and then close the blade until I'm on top of .65 voltage.. I already figured out that with the throttle body unbolted from the intake that I can plug the TPS back in, and then hook up HP Tuners, and watch the voltage in the scanner while I adjust the set screw. Wish me luck with this next round of "ger-er-done's!".. I will post back with my results so that anyone else struggling with a similar situation can actually see what finally got everything back on track. I'm just excited about being able to DRIVE this car.. With the top down... This weekend! Yes! Yes! YES! It WILL happen!!!!!