I’m sorry to report that my first and only experience with your company has not been satisfactory.
I originally brought my 928 to you to solve the immediate problem of why the engine is running in the limp home mode. The car has been running perfectly, but after shutting the engine down for only 60 seconds it restarted in the limp home mode. The question then becomes what could have happened in that short time, or on engine start, to cause this problem? I’m sure a 24 year old car will have other issues, but there is only one malfunction that is causing this limp home problem, and that is the only issue I specified to be fixed. Since I did not want to drive the car in that condition I had it towed to your facility.
You checked the spark plugs and found that the gap on three plugs was closed. The gaps were readjusted and the car was taken for a test drive during which time it performed perfectly for 15 minutes before again going into the limp home mode. Since the engine needs spark, fuel and compression, and the engine ran perfectly for 15 minutes with only work to the spark plugs, we can therefore rule out fuel and compression as causing this problem. I also sent Ryan an e-mail with several possible malfunctions that I found on the Internet that could cause this problem. These included exhaust temperature sensors, the M A F and the ignition protection circuit. However, I do not know if these items have been checked and/or the outcome of that inspection.
Your next plan was to borescope the engine and install new sparkplugs. The borescope was clean and new sparkplugs were installed, but this did not solve the problem.
The next thing I knew the engine was given a compression test although compression is not a variable that could cause this immediate problem, especially since the engine ran perfectly for me and during the test drive.
The bottom line is I found myself in a position of having new sparkplugs, a borescope, a compression test, several hours of labor, with a bill of several hundred dollars, and still there was no idea of how to solve the limp home problem. I therefore had no choice but to remove my car and take it to a different repair facility.
I am certainly not a mechanic, but if I had to tackle this problem I would find out why Porsche built-in this limp home mode, and what specific malfunctions would cause it to activate? There can only be a certain number of malfunctions that would cause the engine to enter this mode. I would make a list of all those potential malfunctions, and since working on the sparkplugs seemed to solve the problem, I would put all electrical malfunctions at the top of the list. The immediate problem of having the engine in the limp home mode has to come from a failure of one of the items on this list. However, I don’t know whether such a list has been made and investigated.
In closing, I would like to say that Ryan represents your company very well and was certainly trying to solve the problem. However, in this case I think he was misguided to check engine compression to solve the limp home problem when the car ran perfectly for me and for 15 minutes during the test drive.
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