One of the biggest sources of frustration and additional tuning costs we see is cars showing up without any preparation for the big day. Avoid disappointment and extra charges by performing the following checks listed in order of how often we see them ruin the day.
#1. Spark plugs and wires / boots should be NEW and should be gapped accordingly. Even if you are quite sure they are ok. A misfire will often only show up under heavy load half way through the tuning process and its likely your car will be making more power and more load than it ever has before. Not to mention it takes very little untuned or badly tuned runtime to kill spark plugs.
#2. Verify your front oxygen sensor / sensors are functional. This is REQUIRED. We do not do open loop tunes. Period. Call us if you are not sure. Every narrowband o2 sensor needs to be bouncing from below .45v to above .45v constantly as shown below. Wideband sensors need to be reporting something other than full rich (~10:1) / full lean (~18:1). Closed loop status on the scantool needs to be “Yes” or “Closed Loop” not open loop. Short and long term Fuel trims should not be stuck at 0% they should be moving and have a number other than 0%. You should have no codes for front (B1S1 or B2S1) o2 sensors or the related o2 heater circuits. If you do end up replacing O2 sensors they should be name brand parts. NTK, Bosch, Delphi, Ect. White box Chinese sensors are a great way to have problems and blow stuff up. See #20.
#3 If you have done an engine swap with a stock ecu and you got your harness from ebay or amazon it likely is going to have issues. Very common is non functional o2 sensors and MAF. A good rule of thumb for LSx engines is that if the harness cost less than $500 without the computers you are going to spend 4x what you saved in troubleshooting time. We condemn roughly 50% of ebay harnesses before they even make it onto the dyno. Best bet is to order a quality replacement and reschedule. Or even better just buy an aftermarket ecu and harness whenever doing swaps so you can avoid all of the stock ECU hassles.
#4 STOCK ECUS. Essentially all stock ECUs expect a wheel speed signal. If you are hooking up a manual or non electronic trans you need to find a way to generate this signal. LSx ecus in particular get unhappy and have a tendency to stall without it. I can typically make it work without but its far from ideal. Once again. Its often better just buy an aftermarket ecu and harness for swaps so you can avoid all of the stock ECU hassles.
#5 If you are substantially modifying the exhaust system (big single turbo for example) with a stock ecu the o2 sensors need to measure the same cylinders they measured BEFORE doing the turbo kit. And not a mix of all of the cylinders unless they did that originally. You cant put one in the crossover and one in the turbo downpipe for example or any other shenanigans.
#6. No exhaust leaks before and 18″ after the oxygen sensor / sensors. This means you actually need a minimum of 18″ of exhaust system. Without this the sensor cant work properly.
#7. Injector data is REQUIRED. You need to know EXACTLY what injectors are in your car and injector data MUST be available for them. By proxy this means no knockoff injectors. Its nearly impossible to clone an injector and have it work exactly the same and match the data. So no “Its an ID injector sold before it gets to ID”. Thats not a thing. A good rule of thumb is that good injectors have plug and play tuning data (not just a flow chart) for your exact platform available and published clearly online that has lots of numbers like this.
If you show up the day of the tune and we have to “email for injector data” we are at a standstill until it shows up. We do not tune decapped or no data injectors. Period. When in doubt contact us and ask.
#8. Size your injectors appropriately. Putting Bosch 210lb injectors in to everything just because they are cheap does not make them a good choice for your 450hp v8 setup that could easily run 50lb injectors that cost substantially less than even the Bosch 210s. Especially on stock computers since they often require huge compromises to make these giant injectors work. Your car WILL run better with a reasonably sized injector. If you show up with giant injectors on a build that does not need them there’s a chance I am going to send you back to get the correct injectors.
#9. Scan for codes / errors BEFORE you show up even if your car is not yet running. Then contact us with the list so we can help you figure out what matters and what doesn’t. There are many misconceptions about what is ok and what isnt. Please ask us.
#10. A fresh battery. We cant start your car if the battery is dead and it takes valuable time to charge.
#11. Fix major electrical / mechanical issues before you show up. They all affect the tuning process including brakes and tires that are unsafe or a transmission that is acting up. We understand your car is a work in progress but changes made after tuning will mess up the tune and require rework. This includes the cooling system. If it gets hot driving around its going to get even hotter on the dyno. Cheap electric fans are notorious for this. If they draw less than 10 amps each when checked with an amp clamp or you can hear them over the sound of your engine they probably will not keep your vehicle cool.
#12. Have the correct fuel in the tank and make sure there is plenty of it. If you bring your car with 87 in it we are tuning it on 87. If it has E85 in it we are tuning it on E85. Only exception is flex fuel tunes. Generally those go best when the tank is 1/4 full of the gas of your choosing. Then bring 10 gallons of e85 for us to add once we get to that stage. If you show up without a reasonable amount of fuel in the tank we charge whatever the pump price is x2 to fill it.
#13. GM ONLY. Beware of the xlink throttlebody adapter for 00-07 GM truck setups. WE CAN NOT TUNE OUT ELECTRICAL TB FAULTS. Sometimes they work. Sometimes they dont. We have seen 50% failure rate on them. We have spent many hours troubleshooting them. Its a very touchy system and a very touchy way of fooling it. Best option is to follow our guide on How to upgrade your drive by wire throttlebody on your 2000-2006 / 2007 GM Truck or SUV or use an upgraded housing with the stock electronics like the BBK 1757.
#14. GM ONLY. If you are doing a 00-07 “LS” standalone harness and dont want to be stuck with the truck throttlebody make sure you order a corvette or 00-02 truck TAC module / harness and OEM ls2 silverblade throttlebody (preferred) or ls3 throttlebody (less preferred).
#15. Clean your MAF and throttlebody. If I set your idle and MAF calibration when they are dirty its going to no longer be correct if you later clean these.
#16. Knock sensors are your friend. They are on essentially every single factory vehicle for a reason. They should be on yours too with the exception of some aftermarket computers and some racecars. Also a note for “LS” setups. The knock sensors must match the computer. Gen 3 knock sensors with a gen 3 computer. Gen 4 with a gen 4 computer. No there is not a way to enable the use of gen 4 sensors on a gen 3 computer. The trick you read about does not work.
#17. Please do not bring in your car / truck filled with mud and dirt. I will ask you to go to a car wash first to avoid filling the dyno with mud.
#18. If you have a Holly sniper system it is worth every penny to either install the sniper distributor to get timing control or one of the many stock computer controlled distributors that Holly sells adapters for. Computer timing control is 50% of the magic of fuel injection.
#19. Ford applications. Your engine computers are NOT friendly to modifications like other platforms. I need EXACT PART NUMBERS for any throttle bodies, intakes, mass airflow sensors, or injectors put on your vehicles. You cant swap intakes, throttle bodies, or anything computer related without tuning. Some years have adjustable DBW throttle bodies. These NEED the manufacturers voltage set procedure done before they show up because it requires the original throttlebody be installed to get readings off of it. If your vehicle has a supercharger or turbo kit it is REQUIRED that you have the handheld tuner with the base map for that application. It is nearly impossible to make some ford applications go into boost without the custom modified operating system from the vendor. If any of this is missing and not signed off by us beforehand its a full stop to the tuning process.
#20. Sensors are critical and should be name brand. We see a nearly 100% failure rate of off brand manifold pressure sensors, crank sensors, cam sensors, o2 sensors, and DBW throttle-bodies. Quality parts are critical when it comes to these systems. We saw two race engines blown up in one year because the off brand o2 sensor would read a false rich condition at wide open and caused everything to go lean.
#21. There needs to be at minimum a bolted down drivers seat. Its not safe to sit on the floor in case a driveshaft fails and its nearly impossible to operate a clutch without a seat. Not to mention we cant test drive it on the street without one.
#22. The dyno is 2wd. It should go without saying that if your vehicle has AWD or 4WD it needs to be able to be easily and safely disabled. Some can be disabled by pulling a fuse. Many part time AWD systems can not be fully disabled by pulling a fuse and require that the front driveshaft be removed. It must be removed before the vehicle is dropped off or you will be billed to remove it.
#23. When installing new calibrated sensors like map sensors or temp sensors on stock ecus or any non factory sensor on a standalone / aftermarket ecu we need to know the exact part number that was installed. In the case of additional sensors added to standalone ecus we need to know what pin they are installed on. Please have this ready. You will be billed troubleshooting time if we need to figure out what you installed and where you wired it.
#24. Similar to #23. If you have wired in additional relays or buttons into your standalone ecu we need to know how they were wired (Pull up or pull down) as well as what pins they are wired to. You will be billed troubleshooting time if we need to figure out how and where you wired it.
#25. Cars with distributors or adjustable timing systems MUST HAVE A TIMING POINTER and at least a 0 degree mark on the balancer. It also must be visible so we can verify it with a timing light.
Thank you for taking the time to go through this list. It will make everything go much smoother, save you money, and make your setup work better in the long run.