#1945 - 08/18/0702:30 PMCommon results with the wrong choices
Joined: Dec 2000 Posts: 5,240teamzr1 Owner - Pays the bills
teamzr1 Owner - Pays the bills Lives in Engine Bay
Joined: Dec 2000
The owner of this 1998 C5 coupe with A4 trannie had several mods done that included LG headers, CAM, larger injectors, etc
Since these mods were installed the owner says the car was not running well.
Common issues - bad idle, too rich at idle and worst is being in Ca the car just failed the EPA I/M 240 threadmill tests at both 15 an 25 MPH.
He has had this tuned by 2 other so called custom tuners and paid as much as $600 for just one so called dyno tune
Owner met up with one of our teammates and they did a test drive using the Ease scanner in record mode and then emailed it to me asking if I'd analyze it.
For the mods it has and all these custom tunes the end results are quite lousy.
Notice in the raw PCM data results highlighted in yellow.
1. even with a 165 deg Tstat the water temps were as high as 215 deg. 2. Part throttle the new O2s reported only 300 mVolts when it should be around 450 mVolts so reporting way lean 3. Yet at idle fuel trims were -5% too rich. 5. Recall this has a A4 trannie and at idle timing was up at 24 degrees !
6. Constant engine knock but worse when getting on the gas pedal also had misfires !
7. Due to lousy LG header design, having no rear O2s and not even using sims ( allowing O2 wiring connector not terminated can pick up EFI/RFI noise) causing front O2s to not report correctly)
8. WOT timing too low and engine at maximum load only was digesting 497 CFM air ( Stock MAF supports 750 CFM)
9.Review the snapshots of the OBD-II data clearly would have told those PCM tuners not only was their tune off but also the fuel trims from left and right heads are not balanced.
10. Instead of proper tuning they moved the IAT sensor from the airbridge to inside the aircleaner to try and fool the PCM as to true air temps.
11. Stock engine idle would be around 35 KPA MAP and now this engine idles at 60 KPA MAP meaning loss of low end vaccum !
12. Using wrong sparkplugs and gap
13. in the end with all the mods and the tuning was done the HP and torque are no better then stock