I did some further checking, and I was a little off in the previous statement I made. The ECU can detect even very slight engine speed changes by monitoring the frequency of the Crank Position sensor, not through the knock sensors. I have posted the relevant information below, but there are specific areas that stand out in your particular case, and I have listed those with discussion first. Several of these point to worn components which I know is not the case for your engine, but it is the components it mentions that are of interest because a modified engine will be out of “specification” in some of these areas, so they are worth looking at from that perspective as they give indication that those areas of the CMR tune may need adjustment. - Binding Engine-Driven accessories: A/C Compressor, P/S Pump, Water pump. - Misalignment of the Water pump, P/S Pump and A/C Compressor pulleys With a new engine, observe the rotating components to make sure there is no wobble and that the belt is aligned properly and not off a groove on any of the components. I recall in some cases where people had issues with the way the oil pump to crank pulley interface was chamfered. - Corroded PCM power and ground circuits. This would just be a sanity check, if an ECU ground reference is left off, it will cause havoc with the ECU operation. - Improper CKP, CMP, MAP, and TP Sensor mounting - Poor connector/terminal to component connection. i.e., CKP sensor, Fuel Injector, Ign coil, etc. Again, a sanity check to make sure all connections are seated. However, this also points to an issue others have seen, and well worth checking on a new engine, pull the crank position sensor and check to see if it shows any signs of touching the tone ring. If it is, then you will get random misfires all over the place. - Gap size out of specifications If your sparkplug gap is really tight, you might try opening it up some and see if this has any effect, sometimes a really tight gap causes misfires. - Vacuum leaks - Restricted Air Induction system or Exhaust system. - ENGINE VACUUM - must be at least 13 inches in neutral - ENGINE VALVE TIMING - must be within specifications - CAM LOBES - must not be worn excessively - VALVE SPRINGS - cannot be weak or broken I know this is a new engine, so some of the above are listed as to the area of concern they point to. In this case, they are all pointing to what could be categorized as out of specification airflow and vacuum levels. You already made mention that you have very low vacuum at idle, and I have seen all kinds of issues with out of specification vacuum readings. This can also point toward the MAP sensor scaling as well. If you are running a non stock MAP sensor while you are essentially still an NA combination, I would switch to a stock 1 BAR sensor and rescale the tune accordingly to see if the issue goes away. Keep in mind that all MAP sensors regardless of BAR rating operate on a 0-5 volt range. The higher the BAR rating, the more compressed the voltage span becomes, making tuning and drivability increasingly difficult as the BAR rating goes up. Even when scaled properly, the rate of voltage change increases dramatically as the BAR rating increases, the ECU sees faster and faster voltage changes, and this can cause all kinds of issues from misfires to drivability concerns. This also points to a possible issue with the airflow settings in the tune, you have a lot going on in this engine, so if this is the area causing the issue, it will take some tweaking to get it to a point where the ECU is happy. I would try to resist, at least for now, from simply changing the misfire threshold and making the issue artificially go away, as this may be the first indication that things need to be dialed in related to airflow, and it will likely show up again if not addressed now where you have a good indicator of when you get it right (the misfires go away). - TORQUE CONVERTER STALL SPEED - must be within specifications I am not familiar with what settings are related to this in the CMR, but this is another potential area of concern, due to the high stall, and the fact that it is an aftermarket converter. I know for a fact that if the crank ring is left out on a torque converter install, you will get random misfires from hell and they will never go away. Also, while unlikely, don’t dismiss the possibility of an actual issue with the torque converter. Remember, anything that can affect the engine speed as read by the ECU through the crank position sensor is a likely culprit. One of the other areas mentioned is the ASD (Auto Shutdown Relay) system in the electrical harness. If you have ANY electrical accessories tied into any of the ASD circuits, move them to a non ASD circuit. I have found over the years that the ECU becomes very unhappy and does all sorts of stupid things when something other than a single 12volt relay coil trigger is attached to these circuits. Hopefully this will help you to rundown and eliminate some of the potential causes so you can zero in on the issue. Possible Causes (F42), (A15) ASD RELAY OUTPUT CIRCUIT INJECTOR CONTROL CIRCUIT COIL CONTROL CIRCUIT IGNITION WIRE SPARK PLUG IGNITION COIL FUEL PUMP INLET STRAINER PLUGGED RESTRICTED FUEL SUPPLY LINE FUEL PUMP MODULE FUEL PRESSURE LEAK DOWN FUEL INJECTOR ENGINE MECHANICAL PCM NOTE: Anything that affects the speed of the crankshaft can cause a misfire DTC. NOTE: When a Misfire is detected for a particular cylinder, the PCM will shut down that cylinders Injector Control circuit. - Visually inspect the engine for any of the following conditions. - Worn serpentine belt - Binding Engine-Driven accessories: A/C Compressor, P/S Pump, Water pump. - Misalignment of the Water pump, P/S Pump and A/C Compressor pulleys - Corroded PCM power and ground circuits. - Improper CKP, CMP, MAP, and TP Sensor mounting - Poor connector/terminal to component connection. i.e., CKP sensor, Fuel Injector, Ign coil, etc. - Vacuum leaks - Restricted Air Induction system or Exhaust system. - Internal engine component failures. 5. SPARK PLUG Turn the ignition off. Remove the Spark Plug. Inspect the Spark Plug for the following conditions. - Cracks - Carbon Tracking - Foreign Material - Gap size out of specifications - Loose or broke electrode 9. ENGINE MECHANICAL Check for any of the following conditions/mechanical problems. ENGINE VACUUM - must be at least 13 inches in neutral ENGINE VALVE TIMING - must be within specifications ENGINE COMPRESSION - must be within specifications ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks. ENGINE PCV SYSTEM - must flow freely TORQUE CONVERTER STALL SPEED - must be within specifications POWER BRAKE BOOSTER - no internal vacuum leaks FUEL - must be free of contamination CAM LOBES - must not be worn excessively CYLINDER LEAKAGE TEST - must be within specifications VALVE SPRINGS - cannot be weak or broken
Okay, I found the information I was reading, it is from Autoenginuity. Understanding Misfires A misfire is an incomplete combustion event that will cause an increase in emissions or catalyst damage. There are two types of misfires: 1) Type A - Catalyst Damaging; and, 2) Type B - Emissions Threatening. The difference between the two is only the frequency at which the misfire occurs. The OBD-II standard has gotten progressively more stringent on what are considered Type A and Type B misfires. A misfire can be in an individual cylinder or multiple cylin¬ders. Some vehicles do not have the ability to differentiate between individual cylinder misfire and multiple misfires and may consider them a random misfire. Detecting a misfire is a very complex process. A very common technique is to monitor crankshaft rotation. The crankshaft vibrates slightly when each cylinder fires. If a misfire occurs, the crankshaft rotation speed changes rapidly. The ECM monitors the crankshaft rotation speed based on the output pulses from the crankshaft posi¬tion sensor. By monitoring changes in the crankshaft rotation speed, the ECM counts the number of misfires and attempts to determine which cylinder is misfiring. Since the normal rotational frequency of a motor is known by the ECM, it only has to detect subtle varia¬tions. Since a lot of things can influence the crankshaft rotational frequency, the ECM must have a way to ignore false misfires. Therefore, the enabling conditions to run the misfire monitor are chosen specifically to mitigate the detection of a false misfire. Common enabling conditions are sufficient fuel (at least 10 - 15%), a learned crank position sensor (GM), no accessories running, vehicle at operating temperature, and the crankshaft rotating at so many RPMs. Several notable reasons why the misfire monitor will be tem¬porarily disabled are: 1) fuel delivery issues such as fuel starvation and sloshing of the fuel; 2) rough road conditions or deceleration which causes the crankshaft to vibrate or be driven from the driv¬etrain; 3) accessories driven off the accessory belt (A/C systems); and, 4) fuel delivery changes such as wide-open throttle or heavy acceleration. Because of the complexity of detecting misfires with such low resolution systems, manufacturers are constantly changing their detection algorithms. The need to check for TSBs in the case of a misfire code is imperative to prevent wasted time tracking down false misfire detection. A scan tool is one of many tools that you’ll need to track down a misfire. We recommend starting with examining the Freeze Frame data if your vehicle provides it. The context of the misfire is a great place to get an idea of the driving conditions the vehicle was under when it detected the misfire. (Don’t forget Freeze Frame information is slow-updating on most vehicles and can have a full second between the first stored sensor value and the last.) Isolate fuel delivery issues by examining the Freeze Frame fuel trims and the fuel trims at idle. Don’t forget to check fuel trims across the fuel banks if you have a multiple bank vehicle. You can reproduce the conditions by taking the vehicle for a test drive and putting the vehicle in fuel enrichment mode by going wide-open throttle. To find out if its spark related, check the condition of the sparkplugs. Look for oil, carbonizing, or cracks. Also, if your vehicle uses coil packs, try relocating them and see if the misfire relocates.
Excellent post. I didn't come across any of this information when I was looking a year ago. GREAT JOB!
Andy it's my bday and I. Think this build would be a great gift. Feel free to send it to me I guess I would drive it haahsha. Sick build make those turbos work and I am in for a kit
Andy, It was my B-Day on the 28th and I would like to thank you for the fuzzy .030 slippers. Raising my BR from 4.2 Beers/P/Hour to 4.8 Beers/P/Hour was a genius idea on your part. Oh, and thanks for the pics of your brown/yellow toenail issue...it was genuine of you to share that with me but I actually didn't have an issue...I forgot I was at the beach yesterday. Thanks. Love you. Jon
Here is a video of what is happening when the misfire code pops up and blinks at me. I did not give it any gas, I only down-shifted to bring the rpms up. Everytime I go over 3500rpm or so, the code is triggered. Trying a new map sensor on Monday.
Rest of the kit came in today. I must that that it was packaged extremely well and I cant wait to get this thing installed.
Well since I got my hands on those 5 aluminum blocks, I had Mr. Norms stop what they were doing so I could build an Aluminum 440 to put in its place. In addition to that, we are doing a new Pro-charger 1300hp intercooler, an n2o kit, and a 9" IRS with 3.55 gears and a spool.
PM me the info. I have a vedor subscription that will be ending on another forum that I wont be renewing.
I can understand the motor/block change, but what prompted the mode of induction? Has anyone been successful with the Hellion TT kit yet? Forgive my ignorance, but why is it so difficult? Tell us more about the 9" IRS...why a spool? Track only car?
Im not sure I understand your question Kyle. Are you asking why I am using the Hellion over a supercharger?
Shit...my bad, i misunderstood your last statement...I thought you ditched the TT's and switched to a Pro-Charger SC instead...After reread, you are just using that intercooler....Good call, and my bad. Rear end stuff???
