SureTrack Community Fix: Rich Honda

Sometimes assuming something is not the cause of your problem leads to doing a lot of extra work just to end up in the same place. SureTrack community member perkins1987 had a Honda Ridgeline in their shop that was running rich and had the check engine light on. They posed the question to the community, and with the help of fellow community member ericsautomotive and others, they were able to resolve the issue.

The following Real Fix summarizes the interaction between them in the community that led to the solution.

Vehicle
2007 Honda Ridgeline RT 3.5L

Title
Runs Rich, P0172 and P0175, adjusted valves.

Complaint
Customer complains that check engine light is on.

Diagnostic Steps Performed/Parts Replaced
Engine running rich. After it is hot, codes P0172 and P0175 set. Checked fuel pressure at idle and it is 55-60psi. Replaced all fuel injectors. Did check for intake leaks and no leaks found with smoke test. Checked EGR valve. Checked and replace MAP sensor. Checked valve timing and it was good. Valves do not make noise so I do not think is out of adjustment. Updated ECM and also tried replacing with used one. LTB1 and LTB2 stay at 0.87v but when increasing RPM it will drop below 0.50v. Same with STB1 and STB2 at idle 0.89v and after revving engine and idle will drop 0.50v. Did replace both air fuel sensors upstream both sides. I am giving up on this any ideas?

Best Answer from Community Member Ericsautomotive
Valves don’t have to make noise to be out of adjustment. What the MAP sensor reading at idle with the engine at operating temp? Readings should be 0.9v or less. 1.0v or over would indicate the valves are in need of adjustment.

Cause
Found valves over adjusted.

Correction
Performed valve adjustment to specs and engine no longer runs rich and codes did not return.