Please make sure your vehicle is ready for a tune!

Please make sure your vehicle is ready for a tune!

We see a ton of different vehicles. Some from private owners and some from either tuning dealers or dyno shops. Most of the vehicles we see seem to have one thing in common: mechanical issues.

No matter who builds the engines or looks over the vehicle, there always seem to be issues. Rare is the vehicle anymore where everything is 100%. It does happen, but those vehicles are the exception.

The #1 issue we see are vacuum leaks. If we had a dollar for each time a person assured us there were no vacuum leaks, only to do a smoke test later and find one or more, we’d be rich. Even some of the shops we tune for where they do a great job putting a combo together have this issue from time to time. It even happens to us! So before you get a tune, the least you can do is to run a smoke test on your vehicle. Trust us, you will probably find leaks. You do not need a $1000 Snap On smoke test machine, though they work fine. You can take it to a repair shop or make a cheap DIY smoke test machine. You Tube has a ton of videos on how to make one, like here or here or here plus many more. Don’t waste your time by spraying carb cleaner or brake cleaner around the motor, you can miss too many that way, plus you have to inhale nasty fumes.

Other issues include bank to bank fueling disagreements for V8’s and V6’s. The short term fuel trims bank 1 and bank 2 fuel trims must agree within about 5 points. This could be caused by an exhaust leak ahead of the 02 sensors, a vacuum leak on one side, a bad spark plug or other ignition component, a bad injector, bad 02 sensor or wiring, cams in wrong or a few more things. The bad injector could be really bad, because you will destroy one cylinder. It could not be firing or stuck open. Either is bad. 90% of the time it is an exhaust leak, even a tiny pinpoint will do that - but they tend to go away as the revs increase. If they stay the same or get worse, look for something else. Check for exhaust leaks, have it smoke tested for vacuum leaks, check the plugs to make sure none are cracked, check ignition components. For injectors, record fuel trims for bank 1 & 2, then swap injectors side to side - record fuel trims again - if the fuel trims follow the swap, you have a bad injector and should get them flow tested or replaced. Fords do NOT have adjustable fueling bank to bank in the tune, so it has to be a mechanical issue. We have seen a number of OHC vehicles with the cams put in the wrong position relative to the other bank.

Low battery volts is another issue we see from time to time. It may be a bad battery, bad alternator, slipping belt or wiring issue. The battery terminals may need to be cleaned. They may look clean but a very thin coating of oxidation will cause resistance, so clean them. Clean all grounds and make sure all are solidly attached with no corrosion. Have the alternator tested. Have the battery tested. Nothing in the tune will increase battery volts, this is a mechanical issue. On a normally operating vehicle, volts tend to run in the low 13 range. It HAS to be fixed or it will affect everything about the vehicle and be untuneable.

The first rule of tuning a vehicle is: The vehicle needs to be in 100% perfect mechanical condition. If your vehicle is running poorly, you may think it needs a tune. A tune will maybe sometimes mask a mechanical issue, but often times will just make it worse. So check the vehicles out before getting a tune to save yourself time, money and aggravation!