Questions and Answers
Ratty Running Thunderbird
Q. Vincent, I have a 1989 Thunderbird SC. I bought new in 1989 and have had very few problems.
Details:
1989 Ford Thunderbird SC
3.8 liter, 5-speed
Port Fuel Injection
ABS, P/S, A/C, Cruise Control
110,000 milesI have an intermittent ignition or fuel injection problem. There is a complete loss of spark or fuel at a rate related to the RPM's. It is a complete cutout of all cylinders for a few revs then on for a few revs. The off and on will continue for maybe 30 seconds to 3 minutes. As you increase the RPM's the cutouts increase at the same rate. Under load it feels like someone is tapping a kill switch. At idle the engine will lope much like a big block with a high lift cam.
It is thermal related, it usually occurs only in the winter months (Seattle, 20-40 degrees in the morning), only at cold start (overnight). It always starts okay, it happens between 3 and 10 minutes of driving. After complete warm up it has never happened. However it did happen this week in the warmer weather. Last winter I left it with a mechanic overnight but of course it did not happen. There are no codes left in the ECC. One time I did get it to an independent mechanic while it was happening, he manage to hook up his analyzer before it stop. Nothing! No codes, no errors, nothing! The "Check Engine light has never been on.
A secondary symptom is that sometimes the tach does not function. Sometimes during the cutouts and sometimes when the engine is running fine. It can stop functioning during the cutouts and start functioning before the cutouts stop. Any idea what might be wrong?
Thanks,
CraigA. First thing I would try is cleaning the Air By-pass Valve. They are good for getting dirty. clogging up and causing this problem. Two different types of air by-pass valves have been released for use on 3.8 liter EFI-SC engines. One type of valve has a silver metal housing and the other type has a black plastic housing. Both of the valves function in the same manner. Air by-pass valves that have a black plastic housing cannot be cleaned, they must be replaced. Valves that have silver metal housings can be cleaned.
Additional Information provided courtesy of ALLDATA
