Date:         Sat, 15 May 2021 01:18:20 +0000
Reply-To:     Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject:      Vanagon syndrome
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Reply was blocked for this tread also.



If all this effort was billed by the hour the GoWesty engine management system could have been a cost saving investment. Of course that would only be true if the engine management system is actually the problem.



Since it starts and runs OK cold most things are close enough to run. So part of the diagnose is to look at tings that change after warm up. If truly going rich after warm up the next steps I take are to look at the temp 2 circuit and O2 Sensor circuit. On the 1.9L the O2 sensor is not as reactive as the 2.1L but still it can cause some grief. The temps 2 and O2 sensor inputs relay heavily on proper ground reference. Check for stray voltages on the O2 sensor wire outer sheath and the ground side of the temp 2 sensor. Also make sure the inner signal wire for the O2 sensor is not grounded. Be prepared that you can have broken wires inside the insulation and defects in the harness.



Resist the temptation to just clean all the grounds. The more you blindly touch the more broken wires and failed connections you can have. Diagnose as much as possible in place. For aggressivle cleaning or sanding terminals consider that all quality terminals have a surface finish to maximize contact and some type of coating or plating to control corrosion. They also were not designed for 4 decades of service. If needed carefully replace with quality stuff, sealed connections to stop further corrosion of the wire and good crimping tools.



While probably not the cause of shut down situations the poor engine health can be a contributing factor. The fuel management relies on a number of assumptions. Bad intake valves and worn guides present the same problems as vacuum leaks with the addition of burning combustion gasses. Think of stuck EGR valves on other vehicles. This combination can give faulty reading to the O2 sensor and cause it to way out either rich or lean. Same for leaking valve covers. Also make sure the exhaust is tight. If exhaust is getting out then outside air is getting in. Fresh air in the exhaust, drive the engine richer. Back firing, the fuel is igniting in the exhaust, not the cylinders.



Some of the parts choices are also questionable. For spark plugs you want to only use plugs that are nickel plated. The black oxide ones will at some point take the threads out of the heads. Distributor cap and rotor, Bosch only.



Dennis