The engine's wiring harness should not have any exposed wires. NO wires should be twisted together and taped! Make sure all wire connections are soldered and heat shrinked together. This ensures that you have good continuity in the wire, as well as adequate shielding. Some of the most common wiring issues are injector clips being twisted together (huge no-no), improperly installed resistor packs, dis-installed VAFC controller wiring exposed and not being taped.
2. Check engine lights
If you are using a stock ecu (i.e. hondata, neptune, uberdata) and have a check engine light, you need to find out the codes that are tripped. Depending on what codes are tripped, it can make it virtually impossible for a tuner to tune your car. In order to see what codes are being thrown, you need jump the service connector. The service connector is located above the factory ecu. Its a two wire plug, located in a green boot. You have to pull the plug out the green boot. Once its out, in order to "jump" the connector you need to use a paper clip or piece of wire. You simply put both ends of the wire or paper clip into service connector, completeing the circuit. If you have a complete circuit, the check engine light will now start to blink. It will be a series of long and short blinks. For example, two long blinks and two short blinks. The long blinks would represent 2x. The two short blinks would represent x2. Putting both together you would get a code 22, which would be vtec oil pressure switch. Now if you jump the service connector, and you dont get the CEL to blink at all, there is an issue with the stock ecu. If you are using a chipped ecu, there is something wrong with either the chip, or the external chip circuit that was installed into the ecu. A list of obd-1 ecu codes:
1 Primary Oxygen Sensor (HO2S).
3 Manifold Absolute Pressure Sensor (MAP).
4 Crankshaft Position Sensor (CKP).
6 Engine Coolant Temperature (ECT Sensor).
7 Throttle Position Sensor.
8 Top Dead Center Position Sensor (TDC).
9 No. 1 Cylinder Position Sensor (CYP).
10 Intake Air Temperature (IAT) Sensor.
13 Barometric Pressure (BARO) Sensor.
14 Idle Air Control (IAC) Valve.
15 Ignition Output Signal.
16 Fuel injector.
17 Vehicle Speed Sensor (VSS).
20 Electric load detector.
21 VTEC Solenoid Valve.
22 VTEC Pressure switch.
30 A/T FI signal A.
31 A/T FI signal B.
41 Oxygen sensor heater.
43 Fuel supply system.
I have experienced many tuning appointments that were cut short due to failing alternators or weak batteries. Before a tuning appointment you should verify that your alternator is in good working condition. An easy way to verify that your alternator is in working condition is multimeter the battery and make sure that the voltage is staying around 12-13 volts. If over time at idle it starts to drop below 12 volts, and gets progressively worse your alternator is going bad. If your engine cranking is weak on engine start-up, your battery is weak. You can do one of two things. One, check each cell on a "wet cell" battery to make sure the distilled water level is up to full. If not fill it, and put a deep cycle battery charger on it to bring it back up. Two, just get a new battery! MAKE SURE THE BATTERY CABLES ARE TIGHT TO THE BATTERY TERMNALS, I GAIN 50WHP BY JUST TIGHTING THE CABLES
4. Fuel pump
This is somewhat related to electrical aspect since its part of the electrical system. If you are replacing your stock fuel pump with an aftermarket fuel pump, while you have the gas tank open make sure there is no rust or sediment in the tank. I have several customers car that have had dirt, rust and other debris in the tank, and have caused fuel starvation during a tuning appointment. If rust is present, replace the tank! Do not install the new fuel pump, you'll ruin the seals pumping the rust through it. If dirt is present, drop the tank and clean it out with alcohol.
The internal combustion engine is a very complicated machine. Due to this nature, before a tuning appointment its neccessary to check the engine vitals to ensure that the engine is in a healthy state. This includes doing a compression and leakdown test. Listed below is a estimated engine static compression vs compression test results that you should see:
8:1~8.5:1 compression: 150-170 psi per cylinder
8.5:1~9.5:1 compression: 170-210 psi per cylinder
9.5:1~11:1 compression: 210-275 psi per cylinder
11:1+ compression: 250+ per cylinder (highly depends on cams being used)
This is an estimate. What the goal is to have no more than 20 psi variances between each cylinder. Ideally you want to see as close of compression between cylinders as possible. If you see a large variance in one of the cylinders (more than 20psi+), there are a few more steps that should be taken:
a. Put a cap full of oil down the spark plug hole. Redo the compression test. If the compression goes up more than 15-20psi, your rings arent sealing and need to be replaced. The oil temporarily seals the damaged part of the ring, and gives higher compression.
b. Do a leak down test. While doing the leak down test keep your radiator cap off of the radiator. Get each cylinder up to TDC at the piston, as well as TDC at the valves. The firing order is 1-3-4-2. Its easiest to check what cylinder is at TDC with a long rod touching the top of the piston, at the peak of its travel you are at TDC on either 1 and 4, or 2 and 3. With the leakdown test you should see less than 10%. If you are seeing more than 10%, listen to where the air pressure is escaping. Put your finger over the oil dipstick hole on the block. If the rings are shot, or you have a hole in the piston the dipstick hole will get pressurized, and you'll feel the pressure on your finger tip covering the hole. Watch the coolant with the radiator cap off. If while doing the leak down test you see bubbling on a specific cylinder, the headgasket is tore or the sleeve sunk in that cylinder (those with sleeved blocks). The air pressure is getting past the headgasket and pressurizing the coolant jacket, causing the bubbling.
If you getting white smoke it indicates you are burning coolant. This can happen with a bad headgasket, sinking sleeve or cracked sleeve. The leak down test should confirm this by the bubbling in the radiator. If you are getting blue smoke you are burning oil, this can be from worn rings, bad valve guides or valve stem seals, or turbo seals are shot (if you are turbo). If you are getting black smoke you are running rich. You should be able to smell a rich condition if you are getting black smoke.
Valve lash on the engine should be set before the tuning appointment. Its a good idea to check the last every 20,000 miles with a stock engine, and even more with a higher revving modified engine, espeically with aftermarket camshafts installed. If you are using OEM camshafts, set the valve lash to stock with the engine bone cold. If you do it while the engine is hot, the metal expansion rate is much different, and you are set the valves to loose. If you are using aftermarket camshafts, set the valve lash to the manufactuers suggestion. This is typically a little looser than OEM settings. I have seen pretty drastic power gains with forced inductions engines having the valvelash not being set properly.
2. Turbo system
Some of the more common issues that occur with turbo components are the following:
a. Piping blowing off during the tuning session. Make sure that you have the ends of the intercooler/charge piping with a ridge so that the clamps can bite into coupler material. I prefer to use t-bolt clamps. These provide a much higher and more even clamping force over the entire piping area. Having piping blow-off during the tuning session will make it impossible for the tuner to tune the car.
b. Exhaust manifold bolts being loose. One of the most critical aspects that is often overlooked is loose exhaust manifold bolts. If you have loose exhaust manfolds bolts, exhaust pressure is getting bleed off. This does two things:
1. Causes slower spool depending on how bad its leaking.
2. Causes power loss due to lack of exhaust pressure in the exhaust manifold. Turbines apply work to the compressor through the exhaust pressure. Having a lack of the pressure makes the compressor less efficient, and therefoe a powerloss. I have measured 10-30whp gains by fixing leaks and tightening exhaust bolts down.
Other things to check are the wastegate bolts, as well as the turbo to manifold bolts. Any leaks will cause a pressure loss in the manifold, and therefore a power loss.
c. O2 sensor hole not being open up enough for the wider/larger bosch sensors common with PLX/AEM/Tech Edge/etc widebands. This seems lika a no brainer, but i have had to uninstall many customers downpipes and headers to dremel out the hole larger. This takes 1-2 hours out of the tuning appointment to take out the material. When installing your downpipe, feel with your finger to make sure there is no extra metal flashing inside of the o2 bung hole. If there is, dremel it out as it will most likely cause an issue with your tuners wideband sensor.
d. Make sure your blow off valve is tight enough. Most aftermarket bov's have an adjustment screw on them. You want to tighten down the adjustment screw so that you can hear the bov working, but no loose enough that its going off prematurely out of boost. Its easiest to watch your boost gauge. If you in vacuum, and the bov goes off its too loose. You want the bov to open up coming out of boost pressure only.
e. Oil feed and return lines. With the oil feed lines, use a -3 A.N feed or restrictor fitting if at all possible. The goal is to make sure that you dont get to much oil pressure built up against the turbo seals. With the return line you want to make sure that the fitting is welded high up on the oil pan to ensure proper drain. The line should descend downwards to the pan. It should not be level, or go uphill. If it does you risk improper drainback, and getting to much oil pressure built up agaisnt the oil seals and blowing them out. Typical symptoms are blown turbo seals is alot of blue smoke from the exhaust with a healthy engine. Check the return/feed lines.
f. Turbo shaft play. Before the tuning appointment check the turbo shaft play. You should not be able to move the turbo shaft more than 1/16" in any direction. If you can, your turbo thrust bearings are probably shot and you need a rebuild. Tuning the car with shaft play will give very poor power production since turbine/compressor efficiency goes way down.
OBD-2 to OBD-1 Conversion:
1. What you'll need to go from obd-2 to obd-1 are the following:
a. OBD-2 to OBD-1 conversion harness
b. OBD-1 ecu such as p28/p30/p72/p75/p06/etc
c. OBD-1 injector clips if going with aftermarket fuel injectors (peak and hold injectors need peak and hold clips (to be plug and play)
Essentially its plug and play. I have had many tuning appointments end before they even begin from customers not realizing they need obd-1 injector clips for their aftermarket fuel injectors. Often overlooked, but defiently very important!
Some miscellanous things that i would like to add are the following:
1. If you have locking wheel lugs, make sure you bring the wheel lug key to the tuning appointment! This is critical for me since you have to take the wheels off of the car with the dynapack dyno. Its a good idea to bring the locking wheel key to the appointment if you are using a roller type dyno, just incase something happens.
2. Bring extra spark plugs! This is so overlooked, but very very important. Bringing a set of spark plugs is just insurance in case something happens to the current set in the engine, or the tuner feels they need to be replaced. I personally like a fresh set of plugs in the engine when i tune. It allows me to accurately read the plugs since they are super clean.
3. Make sure coolant and oil levels are full! I have seen customers ruin their engines from lack of oil, and engines overheat due to lack of coolant.
4. Bleed your coolant system before the tuning appointment! If you are having overheating issues, its possible that you have an air pocket in the radiator/coolant system. The easiest way to bleed the coolant system is to start the car with the radiator cap off. Let the engine idle for 10-20 minutes with the heater motor on full blast, and the heater control setting to high. You should see bubbling coming from the radiator cap opeing for awhile if you have an air pocket. Until the thermostat opens you wont see bubbling typically. If the air pocket is in the coolant jacket, this will get rid of it.
5. Make sure your braking system is up to par for your power level, as well as your suspension system. Most tuners street tune before or after the dyno tuning. If you are going fast, you need to stop just as fast. Its safety for the tuner and yourself.
Thanks to Jeff Evans for letting me use this.
tryna tune my car how i do i get in contact with u its me n my boi