| and they were all contributing to the overall poor running condition that was not just at idle. 1) There were several leaks and improperly connected vacuum lines. The EGR lines were mixed around, which was adding to the idle problem. There were two significant boost leaks; one at the driver's turbo outlet pipe (which I replaced the hose/coupler as the original was bad), another leak at the hardpipe, and one of the used RFL BOVs had two scratches in the valve. I had to dismantle the BOV and use lapping compound to repair it. The spring also wasn't tight enough and the BOVs would crack open when the idle surged, which further exacerbated the idle problem. 2) The car was fitted with a dual-mas setup using an Apexi AFC, and it wasn't configured properly. There were also wiring issues with how the AFC was connected to the second MAS - fixed those. 3) The car had the wrong plugs in it - I believe they were autolite non-projected plugs - we put in the NGKs gapped to 0.030". Fuel pressure test showed proper fuel pressure.
Compression test showed good compression on all cylinders.
Conzult diags was throwing a MAF code, but that was an old code that was corrected when the AFC wiring was fixed. The car would finally idle smooth at this point, but, even after ALL of this work, it still didn't run right under boost. I pulled both MAS units and thoroughly flushed the hotwire with brake parts cleaner and compressed air - it ran a little better, but still had hesitation on the top end. The filters Vince used on the MAS units were not the standard POP charger intake as with his custom-built FMIC there is no room for the K&N filter. I found that the foam filter elements he had connected to the end of the MAS units was causing cignificant turbulence in the flow of air through the sensor, and it was causing the sensor to give very high readings and making the mixture go pig rich. So I modified the filter elements so that they were no longer against the face of the wiremesh screen at the front of the MAS, and it finally corrected the issue. It took about 3 hours to figure this one out, and I learned something new in the process - something that I feel confident in saying that no one here has ever seen before. Even after all of this, the boost would only go up to about 1bar. So I had to make my infamous "turbo actuator adjustment tool" and climb under the car with a gauge and compressed air to tighten up both actuators on the turbochargers. After doing this, the car was boosting up to 21.5psi (peak) at 80% duty cycle and spinning all through first and second. You should have seen Vince's face when we took it out after doing that and I had him punch it - it was a look of disbelief, and I was happy for him. So we tidied everything up - ziptied all the vacuum lines and did a once-over to make sure all ducks were in a row, and called it a 12 hour workday. In many cases, there is not just one single problem that creates the symptom. As you can see in the description above, there were several key faults that all contributed to the observed problem, and it is never the same between two cars.. Good luck to you though and be sure to let us know what you end up finding!
[ ashspecz.com ]
[ agpowers@bellsouth.net ] Enthusiasts soon understand each other. --W. Irving.
Are you an enthusiast? If you are out to describe the truth, leave elegance to the tailor.
Albert Einstein
|
15:59:35 10/02/05
