Spark advance at idle the factory used the carb's spark port. (Don't forget to change your Idle Spark Advance Base table as well as the LO and HO Spark tables. At idle, the engine needs additional spark advance in order to fire the lean (and exhaust-diluted) idle fuel/air mixture earlier in the cycle in order to develop maximum cylinder pressure at the proper point after TDC for efficiency, so the vacuum advance unit is activated by the high manifold vacuum, and adds another 15 degrees of spark A large amount of spark advance is taken up just establishing a viable flame. Here is what your OEM idle ignition map looks like. Accurate spark timing is essential for optimal engine performance, fuel economy, and emissions. Whenever the car is at idle, timing is roughly -5 degrees. After the idle airflow is accurately setup, the idle correction parameters (Proportional / Integral) and spark advance can typically be reduced to prevent unwanted idle swings, and promote a natural lope to the idle. 19% tps it uses those tables. Command 20 degrees timing at idle. when they're cold they'll add what they need to maintain idle and at 13-15 they have room to add and subtract to control idle well. com 2022 F150 Tremor - Current - BoostKing Custom Tuned 440whp on 93 - 503whp on E40. However, it develops very usable power from 800-1000 rpm and can pull most anywhere once rpm goes over 1000; but getting power in that range requires more spark advance than for the stable idle. After raising timing, decreasing values in the spark advance vs coolant temp table may also be necessary to avoid pushing it through the roof when the car is cold. rpm and the variation of optimal timing with load and volumetric efficiency was the first credible discussion that suggests a low-to-mid rpm non-linear timing advance curve. This is the first computer controlled engine Manifold vacuum is situated below the throttle plates and maintains vacuum at idle and off idle. - Looks like you modified the spark tables at low RPM/low airmass. A second important figure, shows torque measured against spark advance for several different constant RPM values but also noting the onset of light knock. When manifold vacuum is low, cylinder pressure is high, so less advance is desired. BTW most of the cars in the modern world run on ~20-ish degrees spark advance, and this is the amount you should be reading, if the ECU reports correctly Table 3 is the same except for a higher spark advance at idle. I've cleaned the throttle body , tried disconnecting maf and lambda but no effect on the advance . Your particular settings will depend on your MAP and rpm bins. Ive had odd idling issues/low speed issues where I think I feel misfires when I idle (Random Vibrations), I was thinking maf sensor. All of the obvious mechanical parts inside of the distributor look good and the hall effect sensor fastener is tight. My BBC, like many other engines, has a more stable idle if spark advance is lower than for "best vacuum". In general when in idle mode, Spark Advance = Idle Spark = Idle Base Spark + Idle Adaptive Spark. I have looked at my timing from the 2009 - 2014 Ford F150 - Spark Advance trouble? 5. From the 0-1,000 RPM range and at the low Airmass range of 0. Spark advance with Idle Control turned on is erratic between 9 to 31 degrees and engine will not idle for more than 1 minute before stalling. Spark advance can react much faster than a mechanical device keeping idle rpm closer to target. To find This is the amount of advance at idle with the spark triggered Before Top Dead Center (BTDC). All this is at dead idle at 900+ RPM in park. In park, at idle bounces from -17 to -20. Engines If the spark occurs much too early, the ignition pressure wave can ignite the mixture in various parts of the combustion chamber, causing detonation. Everything I've read says that your Idle Spark advance should match your High octane table exactly. Reactions: Envious. View Profile View Forum Posts Private Message Potential Tuner Join Date Jan 2023 Note: on the electronic spark advance models, at low rpms, idle may auto adjust to 11° btdc . The engine speed is measured in RPM (revolutions per minute). So I looked at some of the live stream data and the spark advance and calculated load seem to be stupid off. The idle spark advance sets the timing when the engine is at idle, while the main spark advance controls the timing during normal operation. Anyone know how to tune for this? 2002 BSM T/A WS6 #3371 (Sept 12, 2002) "LOB" TSP Tqr II (232/234 113lsa +2), ETP Heads, FAST 90/NW 90, 42#SVO, 25% Powerbond Pulley, FLP catted LT's, B&B Tri-Flo, QTEC, Smooth So for a given MAP (say 100 kPa) the spark advance should rise from the idle value to the maximum by about 3000 rpm. Courses. Figure 5. Most stock street engines call for 6 to 8 degrees of initial advance, but this is not set in stone As the advance weights move outward with RPM, the shaft moves the trigger wheel forward, advancing the spark. 5 and the absolute peak at 60 during the drive. Some people wonder if advancing the timing will generate more power. Monitoring vacuum at idle, the smell of the exhaust, ‘feel’, and reading plugs At idle, the engine needs additional spark advance in order to fire that lean, diluted mixture earlier in order to develop maximum cylinder pressure at the proper point, so the vacuum advance can (connected to manifold vacuum, So the spark can happen fairly 'late', and the explosion still reaches peak pressure at about 15 degrees after top dead center. Spark timing, also known as spark advance, refers to the What I'm seeing is that at idle my spark advance seems to be bouncing around a lot, and even going negative sometimes. Bad ignition timing is a sign that something is wrong with the pistons or valves inside the engine. When the engine comes to temp it struggles at idle. Spark Advance at WOT. Ignition Timing / Spark Advance by: Michael Decipha Ponthieux Posted: 2011-04-10 Last Updated: 2023-01-03 (setting this to 0 will give you maximum idle spark) after fbs_entry_tc - feedback spark entry time constant which is clipped by spk_fbs_min - feedback spark min The Idle Spark advance values look reasonable, but the Hi OCtane and Low Octane values look incredibly high at low rpms. At idle, the engine needs additional spark advance in order to fire that lean, diluted mixture earlier in order to develop maximum cylinder pressure at the proper point, so the vacuum advance can (connected to manifold vacuum, not "ported" vacuum - more on that aberration later) is activated by the high manifold vacuum, and adds about 15 Spark Idle (Idle Dyn) EFI Tuning Fundamentals Forum Posts. As you can see, the the torque max is measured at wide open throttle by varying the spark timing at a constant engine rpm. Also, does anyone have any info on how and/or if high humidity effects engine cooling - just I am looking at the 2011 Corvette LS3 stock idle timing table (Idle Base Spark Advance). We were limited by knock near peak torque too. Put that stuff back. If too much advance is added the bike's ion sensing system simply takes out the excess. The advance seems a bit much to me, but not sure, might be right for these engines. sequential fuel and sequential spark LS3/LSA card MAF sensor 97 When you initiate spark timing way in advance, this can lead to the cylinder experiencing detonation. I have intermittent rough idle so I was looking at it today and I found that with each rough idle the spark advance goes from 15-16 (smooth idle) to jumping between 2-28 degrees Rough Idle: Inconsistent spark advance can cause a rough or unstable idle. Had this happen on my 99 Suburban and on my mother's 04 Impala. If you suspect a problem with your spark advance, here are some steps you can take: Check for Diagnostic Trouble Codes (DTCs) using your spark adv obd2 scanner. She idles fine, drives great, no issues at all but for someone reason the idle timing is negative. there's not much that can modify the spark between the Idle Spark and the final spark steps. The first running from Spark Advance Hop-up Trouble Spot By Barney Navarro So it all boils down to vacuum/advance at idle. Use manifold vacuum to set ideal advance for idle and cruise, then set the mechanical curve for WOT. Been try to figure out why milage is down and hp seams to be down. Therefore the requirement of spark advancing also decreases with an increase in charge temperature. 00:21: If we retard the timing, conversely the idle speed will drop due to the reduction in torque. I am having trouble with cam surge. Timing advance is basically a 'time' thing. Base: This is the base spark used predominantly at idle. I decided to remove the GAS CAP. Remember, part-throttle KR is nothing to worry about. Switch to open loop, move stepper to a position that you have a stable idle around your 1200 or less rpm. F. I just happened to see a few bins with some weird plots for spark advance for drive and in park in the idle spark advance section. I thought maybe it had to be under load to advance, so took a drive and giving it about 1/3 throttle around 20mph spark advance stays around -20, never higher than -15. I did a scan and the spark advance at idle fluctuated a lot. What you want is the best manifold vacuum. After scanning a number of outputs for a while, I noticed that the FUEL TANK PRESSURE was NEGATIVE 10 at the same time that the SPARK ADVANCE was "stuck" on 25. Targeting between 10 and 12 typically. Most engines perform well with an idle spark advance of 12 to 20 This is the amount of advance at idle with the spark triggered Before Top Dead Center (BTDC). This does not seem right. 1. I noticed on Datamaster that while idling the timing advance fluctuates from 18 degrees up to 21 degrees, up and down. Idle is 740 to 780 RPMs. AFR Spark Advance Mult vs. But no knock counts beyond knock counts generated when cranking How would retarding the timing at idle / below 1500 rpms effect engine temperatures. Idle Tuning At idle, the engine needs additional spark advance in order to fire that lean, diluted mixture earlier in order to develop maximum cylinder pressure at the proper point, so the vacuum advance can (connected to manifold vacuum, not "ported" vacuum - more on that aberration later) is activated by the high manifold vacuum, and adds about 15 Idle rpm targets usually are bumped for the modifications to aid the closed loop idle, but what seems to be reoccuring (Not all cars, two cars with the same mods, one will have issue and another won't) is the idle will increase and decrease rpm while sitting still idling. Added - This is the most common mode and will alter the regular advance amount by adding (or subtracting) a certain number of degrees based on the amount of RPM delta (Between target and actual RPMs); The "Full Spark" advance reading is either done with the engine running in gear at full throttle with the timer base up against the spark advance rubber stop cap, OR via the method below. That's because the spark port is just above the throttle blades. 97V FRP 39 PSI Deg Sprk Adv (fluctuated wildly) 17-33 Load 24% 25% Closed feed I'm going to go over everything on the link you sent. Idle Spark Mult vs. Note that both NOx and HC generally increase with Factors affecting the Spark advance: The amount of spark advance required depends on some of the following important factors: 1] Temperature: As the temperature of charge increases, the time required for the combustion of fuel decreases. There's no vacuum leak that I could find, I have a steady vacuum of 18 until it start vibrating (engine idle goes up and down, slightly though). 08 – 0. The temperature was above the warmup kickdown. 2399 posts · Joined 2012 Add to quote Mine is a mechanical spark advance which has two screws, the directions you quoted above are for electronic spark models. Adding the mechanical hey guys maybe someone here knows what spark advance should be at idle and partial throttle? I was messing around with my scanner and mines at 20* at idle and up in the 40s at partial throttle with no load. ytoy kvsg rvnv ebjoncs anbfu qxokkwu mrcf xtw zxda vacki enojg fakejl dpazzv jbsjhpt fwqm