Engine - Hesitation During Warm-Up When Cold
88vw09SUBJECT:
Hesitation (under hard acceleration) during engine warm-up at cold ambient temperatures
GROUP
25
NUMBER
88-03 August 29, 1988
MODEL(S):
Cabriolet/Scirocco, Golf/Jetta w/CIS-OXS all m.y.
Cause:
Engine over-enrichment when cold can cause power loss (hesitation) during hard acceleration.
Service solution:
Over-enrichment reduction can be achieved by installing a manifold vacuum switch to interrupt the OXS temperature switch during hard acceleration.
This system was installed in production as a running change starting May 1987. The production version of this system (on imported vehicles) deviates slightly from this field fix by including an additional relay to override the lean out function during engine cranking when starting.
Installing
^ insert vacuum switch A (P/N: 171 919 825 B) between existing manifold vacuum line and new vacuum line (P/N: N 020 281 1)
^ connect two pin connectors (from new wiring harness) to vacuum switch A
route wiring harness (P/N: 176 971 134) in parallel with production harness from vacuum switch A to OXS temperature switch B tie-wrap harnesses together disconnect harness connector from OXS temperature switch B and connect to male connector on new harness connect female connector on new harness to OXS temperature switch B
Parts required:
(1) wiring harness, P/N: 176 971 134
(1) vacuum switch, P/N: 171 919 825 B
(1) vacuum hose, P/N: N 020 281 1
CAUTION
Part numbers are for reference only. Always check with your Parts Department for latest information.