1994 FD - weak transition and secondary boost
03-25-16, 03:17 PM
#1
1994 FD - weak transition and secondary boost
Hey everyone,
I recently became a FD owner and it's been a blast so far. I haven't noticed any issues until just this past week with the transition and secondary boost pressure.
Here's a little bit of info of the engine related on the car:
Pettit Racing ECU
PFS downpipe, high flow cat, and PFF 3" exhaust
PFS intake and intercooler
AEM water/meth injection set to activate after 10psi
I flew to AZ and drove the car back to the bay area with no trouble. The boost pattern in 3rd gear followed a "12-10-12" sort of format. Last week, I found a crack in the ABV inlet hose. As a quick fix until I can find a replacement hose, I cut cracked section off and vented the ABV to atmosphere. Since I've read that the ABV spring is weak and may suck in air at idle, I pulled a blitz BOV off an old, abandoned HS car project and installed that at the end of the now-chopped hose.
During the test drive immediately after, I noticed that my LED (indicating the meth injection was active) was not lighting up in the upper RPM. Upon inspection, I noticed that the boost pattern is now 12 - 7.5 - 9. I've checked my hose clamps and made sure to put all of the zipties I removed back in place (e.g., vac line to the ABV). I also tried swapping back the factory ABV and venting that, but I still see the same issue, ruling out the BOV as the cause.
Any ideas on how I can track down the issue? Low RPMs, it's a solid 12 psi consistently. During and after transition, it's been a bit less consistent. Sometimes it's 12-7-9, other times it's 12-6-9.5. Maybe there's still a hairline crack in the ABV hose that I missed? Would that cause the low secondary issue...?
I recently became a FD owner and it's been a blast so far. I haven't noticed any issues until just this past week with the transition and secondary boost pressure.
Here's a little bit of info of the engine related on the car:
Pettit Racing ECU
PFS downpipe, high flow cat, and PFF 3" exhaust
PFS intake and intercooler
AEM water/meth injection set to activate after 10psi
I flew to AZ and drove the car back to the bay area with no trouble. The boost pattern in 3rd gear followed a "12-10-12" sort of format. Last week, I found a crack in the ABV inlet hose. As a quick fix until I can find a replacement hose, I cut cracked section off and vented the ABV to atmosphere. Since I've read that the ABV spring is weak and may suck in air at idle, I pulled a blitz BOV off an old, abandoned HS car project and installed that at the end of the now-chopped hose.
During the test drive immediately after, I noticed that my LED (indicating the meth injection was active) was not lighting up in the upper RPM. Upon inspection, I noticed that the boost pattern is now 12 - 7.5 - 9. I've checked my hose clamps and made sure to put all of the zipties I removed back in place (e.g., vac line to the ABV). I also tried swapping back the factory ABV and venting that, but I still see the same issue, ruling out the BOV as the cause.
Any ideas on how I can track down the issue? Low RPMs, it's a solid 12 psi consistently. During and after transition, it's been a bit less consistent. Sometimes it's 12-7-9, other times it's 12-6-9.5. Maybe there's still a hairline crack in the ABV hose that I missed? Would that cause the low secondary issue...?
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