running on 3
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3mta3
Hello Max. We just moved to CO, Glenwood Springs, elevation 5400'. I have heard that carbed cars may suffer @ elevation but I didn't think this would affect my FI, am I mistaken? Also do you think this could be caused by throttle valve switch defect? Mine doesn't click until far R side of scale, I thought it should be more in the middle. Thanks, Rob
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Max Welton
- Posts: 3026
- Joined: Mon Jun 03, 2002 12:01 am
High altitude will affect both carbed and FIed engines.
A carbed engine becomes progressively richer as more and more air is removed from the equation. Depending on the carb, smaller main and idle jets or possibly larger air correction jets can be used to counteract altitude.
A modern engine management FI system will be closed-loop and able to maintain the optimum A/F mixture by constantly monitoring a host of parameters including the actual O2 content of the exhaust. It shouldn't go rich like a carb will, but it can't replace the missing air. Only a forced-induction system (I.E. turbo) can do that. Even my wife's Subaru performs better at sea level.
I am pretty sure the D-Jetronic system is not closed loop. But there may be an adjustor for making the mixture slightly richer or leaner. I don't know much about the D-Jetronic system specifically, though. Although I do have the components of two FI engines out in the barn.
Max
A carbed engine becomes progressively richer as more and more air is removed from the equation. Depending on the carb, smaller main and idle jets or possibly larger air correction jets can be used to counteract altitude.
A modern engine management FI system will be closed-loop and able to maintain the optimum A/F mixture by constantly monitoring a host of parameters including the actual O2 content of the exhaust. It shouldn't go rich like a carb will, but it can't replace the missing air. Only a forced-induction system (I.E. turbo) can do that. Even my wife's Subaru performs better at sea level.
I am pretty sure the D-Jetronic system is not closed loop. But there may be an adjustor for making the mixture slightly richer or leaner. I don't know much about the D-Jetronic system specifically, though. Although I do have the components of two FI engines out in the barn.
Max
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3mta3
Hi, have waited for something else, so far no one has been able to help me...I know you guys can. Still same probs... what about TVS? Or does D-Jet Max spoke of offer a culprit? Car in storage til this can be fixed, please help me figure this out! If you think this is D-Jet prob I will shoot it over to that forum, thanks Rob.