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Im still feeling my way around this tuning thing. So the car idles fine in park and neutral but as soon as i get into gear the rpms die off and i have to get on the gas quick or it will die. doesnt seem to change even after the car warms up. my IAC count is steady pegged at 140 and my idle set crew is all the way extended. TPS is right where is should be. Its a 383 with a pretty big cam. is there something im missing in tunerpro? why is my IAC count pegged?
So the car idles fine in park and neutral but as soon as i get into gear the rpms die off and i have to get on the gas quick or it will die. doesnt seem to change even after the car warms up. my IAC count is steady pegged at 140 and my idle set crew is all the way extended. TPS is right where is should be. Its a 383 with a pretty big cam. is there something im missing in tunerpro? why is my IAC count pegged?
If I am reading this part correctly, then your VE table is completely off, as well as your TPS setting. It sounds as if you're saying the engine idles good in Park/Neutral, but lousy in gear with the idle set screw extended all the way out in both cases. As already mentioned, first make sure your timing is set correctly for your application before you even get started. Make sure your base timing by hand matches your spark reference. Idle state should be somewhere around 24'ish during idle RPM, and make sure your IAC idle RPM isn't set too low in relation with the bin you are using, as most larger cams won't idle well at 600-RPM in gear which is what some of the bins come with from the getgo. Shoot for 25 - 35 IAC steps at idle with no more than 800-RPM in gear with the proper TPS voltage at key on before hand (be sure to program 800-RPM in gear, don't just turn the set screw to obtain it, that is old school). Once obtained, do not open the idle set screw any further than that. Once you go into gear after that, and during idle, you'll notice the VE move, and when it does, if your idle steps start escalating, that is telling you it is too rich in that particular area and the IAC is compensating by opening as much as it can. Start adding or pulling fuel in that particular area in increments until you observe the IAC steps making their way back to where you want or need them to be. Once the idle portion is taken care of in Park and Gear, the VE Learns will handle the rest...
- Rob
Last edited by Street Lethal; 04-07-2020 at 05:22 PM.
It does smell rich at idle. It so weird though, I've pulled so much fuel out of the low speed VE table already. comparing it to the 3005 bin.... Ive cut it by more than half across the board. Ill keep pulling and see what happens. Timing is good. i have a 2800 stall converter. TPS voltage is at 0.5 key on engine off. Thanks
Ok... I tried pulling fuel a little at a time until I starved it and it didnt help. I'm beginning to think I need a bigger stall? Any recommendations? It's currently 2800. Again TPS is correct as well as timing. The idle speed parameters in the bin are set around 1000. Which is right where it idles in park or neutral. IAC is still pegged though. RPMs drop down to about 650 in gear and will die if I dont open the throttle. SA is steady 24 give or take 1 at idle in park and in gear. I cant even begin to run the idle set screw back in. The wierd thing about the VE is it smells rich and I get horrible mileage but everytime I run a learn it wants to keep adding fuel. I'm an idiot but does this maybe mean I need to crank up SA a bit?
I just have a mild cam but it idles best at 28* @ 750rpms. Bigger cams can use more advance. I found my idle sweet spot by turning the distributor to find the best idle, then reading the advance with a timing light. Then I reset the base timing and adjusted my timing table. Also it will not idle smooth in closed loop. Even though it smelled rich idling at 14.7 AFR it wants about 13 -14 AFR for a smooth idle. And the exhaust isn't stinky rich smelling any more. Bigger cams work better with open loop idle. The 02 sensor can give you a false reading at low rpm's. With a lean miss fire the o2 sensor will read it as rich and take out even more fuel.
I don't think it is your stall speed. My small block was idling at 65 to 70kpa (very big cam), 850-RPM, with higher than normal IAC steps, with the stock stall at one point, and it never stalled or even hiccuped when placed into gear. It's got to be in the tuning somewhere. Why not post up the bin that your running so we can take a look...
Attached is the bin Im currently running. Ive tried to tweak a few things back and forth but nothing seems to help. I also tried to upload a datalog file to show exactly what its doing but i guess its not an accepted attachment file type in here. I would appreciate any input.
Last edited by edixon24; 04-13-2020 at 10:32 AM.
Reason: fatfinger
Dixon, you're injectors and engine size are correct, 32# injectors and 383 cubic inches...
However, your Initial Timing is wrong. It is the same as your Idle State. Your Initial Timing should match your base timing by hand, so wherever your base timing is set (6*, 8*, 10* or 12*), that is what your Initial should reflect. Your current Initial is 23.91* which is the same as your Idle State. Fix the Initial SA from 23.91* to match your Base Timing by hand (see image)....
Also, your programmed Idle is off. Try to lower it a little to a more feasible 900-RPM in Park/Neutral, and 800-RPM in Drive when you are in your operating temperature range (see image)...
Thanks Rob, Ill mess around with that. yes my injectors are 32#. Yeah i was figuring the IAC idle speed was set a little too high I kept creeping them up hoping it would help and to see what my IAC was doing. Without being able to provide a datalog file to show you... my MAP stays between 50 and 55 KPa in park and neutral. It jumps up to about 75 KPa when i put it into gear just before it dies at about 600RPM. Please let me know if there is any other useful information I can provide from the datalog
First thing to do is correct the Initial SA to match your base timing that was set by hand because your timing is completely off. Then bring your idle speed screw back to where it needs to be... with the butterflies closed so that the IAC itself is the only thing drawing in air during idle. Correct your IAC Idle Speed in the bin so that you're idling at 900-RPM in P/N and 800-RPM in Drive (both during operating temperature), so target 56/68 Celsius and higher. Once the idle is taken care of, the rest will be a breeze...
The Initial SA being off is the culprit with what we are seeing in the datalog (pegged IAC). The length of the log is in Open Loop too, so I can't see what the narrow band is averaging. One thing I noticed is that the Gear Selector seems off, as you mentioned 55-kpa in P/N and 75-kpa when you put it into Gear (1/2), but then it stalls out. Looks like it is reading 1/2 during what should reflect as P/N.
Once the Initial SA has been corrected to reflect your base timing by hand, just turn the idle set screw back in (clockwise) to where the butterflies are "just" opening, but then take it a tad back. Then just leave it alone. You'll then want to fix the IAC Idle Settings during P/N and Drive, as if they are over 1000-RPM in P/N then other parameters are being triggered involuntarily.
I now would question any VE Learns that were done if the Initial SA was like that during them. I would feel more comfortable if you started from the beginning with a brand new bin, albeit with the proper changes being made ahead of time. I'm also not too crazy about the Spark Map in that bin being used with your engine setup.
Im going to start from scratch with timing. seems like Ive been struggling with that since the beginning. I did notice the gear selector remaining at 0 in the WUD but searching some older posts in here, I read that the indicator is for manual transmissions anyway. (must be true if its on the internet) I changed my IAC idle speeds and will flash those in ASAP. VE was an issue at first because all the recommendations i was getting were WAAY to high so i kept bringing them down until i got it driveable. Would the incorrect timing explain that? ill get to the bottom of this timing situation and start over with the 3005 bin. Thats the one i started with but again.. i had to lower my VE drastically across the board just to get it started. The spark map i think i got off of an LT1 bin somewhere along the lines and seemed to get me going. ive never felt like the engine was at its full potential but i was down for a few months replacing the tranny and ive been chasing this idle issue ever since.
Go with the 3004 (LB9) Spark Map, it is a tad more aggressive. So use the 3005 L98 bin as your base, but cut and paste the 3004 SA Main Tables (include the extended) into it. Just be sure to smooth out your SA Main table Idle Area (kpa area when running) with your Idle state setting (23.91) so it is nice and smooth, and doesn't deviate. Also adjust your fan settings, right now the primary is being triggered at 224* degrees, which is kind of up there. If you're running a low temp thermostat like a 160* degree one, then bring down that primary trigger closer to 200, maybe even a tad under. So long as they are switched on and off above your thermostat setting, you're fine. Mine is set at 190* degrees for what it is worth...
Got to the bottom of my timing issue. Turns out my distributor was clocked a tooth off. Fixed that and set my base timing. I flashed in a new bin with the correct timing. Car will now idle on it's own while in gear but barely. It's almost painful to listen to it try and stay afloat. My IAC is now reading around 60 instead of pegged out. My RPMs still dont match what's set in the bin but at least it stays running. So... progress. I'm thinking this is all related but let me know if I should start a new thread. Playing around with the bin I found that if I put my base timing at 8* and idle state at 32*.. it seemed to like that and that's where I finally got it to stay running when I put it in gear. I adjusted the 3004 sa map to reflect. So test driving... if I stab the throttle from a stop it's very sluggish up to about 3500 RPM but beyond that... acceleration exceeds my expectations bigtime. Are these problems related? In the mean time I'll get some VE learns in and get a closed loop data log.
Don't keep it at 32* because that is practically full timing at idle.Your RPM speed is simply too low to have that much timing down there. You want full timing to almost come in closer to your stall speed, or tad above. Entirely full by 3000-RPM. Not sure where your new RPM settings are, but keep them higher than the stock bin, as they are way too low. To reiterate, you want 24* at idle (SA - Idle State), check your engine with a vacuum gauge for any leaks (or just go by your current kPa at idle), and if all is well, let the VE Learns dial in your IAC and your VE. Might take a few times, so hold the gas with your foot in P/N so it doesn't stall while it Learns, then do the same in Gear while holding the brake as well. Did you fix the Gear indicator on the WUD yet, because that too is contributing to your stalling issue because the ECM thinks you're in gear when you're not...
Will do. So what should the kpa be at idle? I havnt figured out the gear indication thing in the WUD. How do I fix that? Or is it likely a wiring issue I should be chasing somewhere with the new transmission?
I think I figured it out. My preferences were set to manual transmission. Havnt drove it yet to see but if that's it I guess my only question is... without having a vac gauge... how do I determine my kpa is acceptable and not indicating a vac leak?
That more than likely is the culprit (the preferences), but if it isn't, then try readjusting your neutral safety switch slider. If you don't have access to a vacuum gauge, just use a conversion chart for kPa to Hg, so for example using the chart below; 46 kPa at idle is equivalent to 13.6" of vacuum...
KPA at idle depends on many things, Spark advance , Idle speed, cam duration. And your first post you said you have a "pretty big cam". If you post your cam specs someone with a similar cam may give you a good idea of what to expect for KPA.
Ok so I didnt notice the map hi 33 malf so I changed that to 90. It's still showing that malf light. With the P/N switch... everything looks good with my neutral safety switch if that's what you are talking about. However, when I figured out the preferences (switching it from manual to auto) it now shows 1/2 instead of P/N even when I'm in park. Not sure if its suppose to say R when I'm in reverse because it always show 1/2 until I hit OD. Then it changes to OD. I feel like I'm getting close...
The ECM resets after five start attempts. It will go away. Or you can just disconnect the battery if you have no patience. As for the 1/2, that is the EBL telling you that you're halfway there, so don't give up lol (kidding). Loosen the Neutral Safety Switch while you're in Park, and with the EBL WUD screen up (key on), start to gently slide the switch backwards until you see the EBL show P/N, then tighten.
Alright... malf code is gone like you said. Now.... lol. So I have a b&m megashifter, pulled it apart and found there is no sliding adjustment for the switch on that. It is stationary with 2 machine screws and nuts on the mounting plate for the shifter. That being said, I cant remember what the stock setup looks like, but I'm trying to find the logic in that.... seems like that switch is a simple open and close circuit type switch. Like it either gets the required voltage or it doesnt. Like there is no variable signal to send to the ECU? Maybe it's just a particular switch for the b&m? On the upside. I'm driving the car daily so it is running pretty good. It's still idling too low in gear and the IAC varies high, from 50 to 150 or so. But I'm gathering that this neutral safety thing and the 1/2 gear indicator is combined and directly related to the idle/IAC problem. Until I get that fixed I'm afraid to do any more VE learns because it wants to keep adding fuel and it already smells rich
Alright... malf code is gone like you said. Now.... lol. So I have a b&m megashifter, pulled it apart and found there is no sliding adjustment for the switch on that. It is stationary with 2 machine screws and nuts on the mounting plate for the shifter. That being said, I cant remember
The switch to the ECM is either open (+12 PU from ECM) for drive. Or grounded for P/N. IIRC, by '90 it is a multi-purpose switch, also providing back up lights and a P/N safety to the stater solenoid.
The O/D indication is from the high-gear pressure switch in the transmission. It activates once the trans is in 4th gear (OD). If there was a 3rd gear switch that too would also be reported. But there are far and few (ever?) in the 700R4 transmission.
* Just want to verify that your base timing by hand is 8* BTDC w/EST disconnected, correct...?
Your Idle State SA is set to 24*, which is good, but your SA Main Table in the area you are idling is off (between 50-60 kPa at 800 to 1000 RPM). Smooth out that area in the SA Main Table so that it averages closer to 24*, as some cells are showing 26* to 29*. This will stop your SA from jumping up during idle...
Now, I noticed that this was a warm start, but Closed Loop was MIA during idle until you accelerated and got some heat in it. Thought for sure you had Open Loop Idle set, but you don't, so this may imply your O2 sensor isn't getting hot enough. Unless you are running a heated O2, or wideband? Just confirm either or on that...
The IAC steps, yes, they escalate up to 200 in some cases for no reason at all. How old is the IAC (might be sticky)? Can you pull it and maybe clean out the pintle if it's an older one, then try again?
Yes, base timing is 8 by hand. The engine seemed to like it a little better than 6.
Will smooth out the SA table.
Yea that was a warm start. I left it in gear at idle for a little bit right there at the end before shutdown so I could get some closed loop data on it for you. I do not have a heated or a wideband O2. In fact I think it may be my old O2 sensor from before I built this engine about 1500 miles ago.
As far as the IAC goes... I'm fairly certain it came brand new from Holley with the stealth ram setup I installed during the build. However the first 200 or so miles was pretty rough on things while I was trying work out some kinks in the tune. Ill try to pull it and clean it and see if that helps.
With the given info and data, do you think it would be worth it just to put in a new O2 and IAC? Could the O2 temp problem be because its old? I figured it would throw an SES light of some sort if it needed to be changed. Also could it be the engine just doesn't like the semi-conservative timing? Sorry if that's a stupid question. Apparently I can build an engine from the ground up but I need you guys as a crutch when it comes to basic dumb questions when it comes to the computer type of stuff.
You guys helped me quite a bit in another thread where I stated the build specifics but engine build is as follows
Gen I small block
383 ci
aluminum trickflow 195 super 23 heads 72 cc chambers
roller cam
2500-6000 RPM range
duration at 050 lift: 236 int.//242 exh.
advertised: 288 int./294 exh.
valve lift: .520 int./.540 exh.
lobe sep: 110
grind # CS XR288HR-10
Holley stealth ram intake
32# injectors
shorty headers
calculation says 10.5/1 compression
also i live at a fairly high elevation (around 5000 feet) here in utah
That is a very healthy engine combination. I'd like to see you upload the LT1 SA Main Table in that bin, you'll be grinning ear to ear, but first straighten out that idle issue. It doesn't hurt to install new components, buy why not shoot for a heated O2 sensor. You would be glad that you did in the long run. The IAC, you can always try to clean it if it is dirty, it's no biggie. Disconnecting the O2 will throw a code, but a cold O2 won't, you'll just stay n OL until it reaches operating temperature.
So do you think that a heated o2 might solve my problem? I'll get one on order but is there something else I can be trying in the mean time? Besides the IAC?
Your engine will run a lot better with a three wire heated O2 sensor, a one wire is so prehistoric. As far as everything else, I would need to see a cold start datalog as well without you touching the throttle. Just start it up cold, let it warm up on its' own, and watch the sensor readings indicate what they are supposed to be indicating as she enters into Closed Loop....
O2 sensor is in the mail. I got a cold start datalog for ya. For some reason it never went into closed loop after about 20 minutes. I normally dont have an issue getting it into closed loop but ive never let it idle for that long without being on the throttle at some point. also... my fans are on toggle switches... thats a long story but thats why they dont kick on once it starts getting hot. Im not sure why SA starts out in the 30's and works its way down as temp comes up. ive attached the bin that shows at that rpm and kpa it should be 24. maybe some type of SA temp compensation setting?
Okay, your IAC is fine. It is showing 200 steps because it is trying to keep the engine from stalling, with the engine doing exactly that the first few starting attempts. The engine is being restricted in RPM during cold start, and/or cold temperature despite targeting a particular RPM when cold. IAC steps return to normal when engine is warmed up some. First thing you will want to do is this;
BLM - Idle Cell RPM Threshold; change this from the stock 800-RPM to 1200-RPM
Now, with the changes you made to the engine and bin, you will need to update your cranking fuel. This is why you are stalling during cold start, the engine isn't getting enough fuel;
Crank - Prime PW; change your cold settings in the 8° Celsius through the 44° Celsius range. You will want to add to the mSec values accordingly, but lighten the number as temperature increases. So for example change 8° Celsius from 13.93 to 16.00, and work your way to 44° Celsius. When the engine stops stalling and maintains proper RPM, you're good...
Yes, there is a Spark Advance compensation that you are seeing when cold;
SA - Coolant Comp Spark Advance; if you want to zero out this table, fill in every cell with 9.84, it is synonymous with 0.
Twenty minutes for Closed Loop is a tad too long to wait for, don't ya think...
The O2 sensor isn't getting hot enough, the heated O2 will make a world of difference.
So I'll be installing the O2 tomorrow and see what happens. I changed those parameters but it made it slightly worse. Not much worse but it still takes a few cranks to get it up and running without any throttle. And I feel like the idle rpms dropped a touch while in gear. Not enough to kill it though. What is happening in the motor with those parameters? I assume the one is adding more fuel for cranking so should I up that one a little more until I can get a cold start on the first crank? After searching the depths of google I couldn't find actually what is happening by changing the threshold on the other one from 800 to 1200 RPM? Is there a tunerpro for dummies book or something lol. I feel like I would be better at tuning if I knew exactly what I am changing
Dixon, I am driving home as I am writing this, voice text actually. Do not worry about the BLM adjustment from 800 to 1200 RPM. That is for later, when you were actually able to get into closed loop. The cranking fuel parameters needed to be uppedd anyway, But it looks like your throttle at Idle is not set up properly. When you do a coldstart, watch the data log, live of course, and slowly open the throttle until you see the IAC steps decreasing. Don’t open it too much, just enough so that your target RPM at that specific temperature is met. Do you understand? When I get home I can give you a demonstration with mine, but I have another 45 minutes to go.
I think I understand. So once I get it up and running cold. Depress the pedal until my target rpms are hit and then record the TPS reading? Also I set the "crank-prime pw" to 16 msec @ 8 degrees, 11 msec @ 20 degrees, 6 @ 32, and 3 @ 44. .. celcius of course. Should I up those numbers a bit or leave them until I get you the results of the throttle situation.
No no, do this. Set your WUD screen up at key on near the engine bay somewhere. From a completely cold start (50 to 60 degrees Fahrenheit, going by the weather here), start the engine. It may take a couple of starts to keep it idling because of its' current setup, but once it can idle on its' own while still cold, and with no assistance from the floor pedal, just go by the engine bay and observe the WUD screen. You will see your IAC steps way higher than they should be. Now, using a torx screwdriver, slowly (slowly) turn the fast idle screw clockwise to open the throttle a little. Keep watching the WUD as you are doing this. You will see the IAC steps go downward, and the RPM begin to stabilize as well as rise. So, lets say you targeted 1100-RPM at 70 degrees, okay? You will look at the WUD, and when you see 70 degrees on your coolant temperature, observe where your RPM is, and where your steps are. If the steps are too high, and RPM too low and erratic, you are struggling for air. Keep opening the throttle blades until you see the IAC settle lower, and the RPM go where it is programmed to be, not to mention more steady. The engine is obviously getting warmer relatively quick, so you need to do this kinda quickly. get it as close as you can. If by chance you missed the lower temperatures because the engine heated up too fast, just shut it off and do it again tomorrow during a cold start. But understand that whatever you do today will help tremendously, as you are helping the IAC in getting back to their respected ranges because the engine can't breath.
04-06-2020, 02:39 PM
