SL/R129: '94 SL500 - Floppy throttle pedal and cuts out.
04-03-2017, 04:06 AM
#1
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'94 SL500 - Floppy throttle pedal and cuts out.
The car is a 1994 SL500 (old four-speed hydraulic transmission). I just fitted a rewired throttle body, but it hasn't cured the problem.
Operating the TB manually before fitting it, it would move a fair way before the actual throttle butterfly moved, and the butterfly did not open more than about half-way. Is this some sort of limp mode, and can it be reset?
Fired up, the car still idles, with a fair few misfires, at around 1100-1200 rpm, and the throttle pedal has no effect for the first couple of inches of movement, though it then revs OK (in neutral and stationary). Once the coolant temp reaches just under 80 degrees, it cuts out, and will not restart until it's cooled down again.
I've fitted new plugs, leads, and distributor caps and rotors. The engine harness and the TB have both been rewired. I've almost reached the point where I want to fix it, permanently, with a gallon of petrol and a match.
Is it time to give up on the horrible heap? It's easily the least reliable car I've ever owned, and I wonder if I've now reached the point of throwing good money after bad. Should I just throw it away and get something that actually works properly for more than two minutes?
Operating the TB manually before fitting it, it would move a fair way before the actual throttle butterfly moved, and the butterfly did not open more than about half-way. Is this some sort of limp mode, and can it be reset?
Fired up, the car still idles, with a fair few misfires, at around 1100-1200 rpm, and the throttle pedal has no effect for the first couple of inches of movement, though it then revs OK (in neutral and stationary). Once the coolant temp reaches just under 80 degrees, it cuts out, and will not restart until it's cooled down again.
I've fitted new plugs, leads, and distributor caps and rotors. The engine harness and the TB have both been rewired. I've almost reached the point where I want to fix it, permanently, with a gallon of petrol and a match.
Is it time to give up on the horrible heap? It's easily the least reliable car I've ever owned, and I wonder if I've now reached the point of throwing good money after bad. Should I just throw it away and get something that actually works properly for more than two minutes?
Last edited by E55BOF; 04-03-2017 at 04:08 AM.
04-17-2017, 08:46 PM
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94 SL 600, 98 993, 89 XJS Conv., 85 Daimlier Princess 16 Hybrid Lincoln 16 Chevy crewcab
While I have owned and enjoyed several R 129. I have learned not to add parts until the blink tester has directed me or the mechanic in the problem solving direction.
The temp of engine has never been the start of the problems, but the LIMP Home mode has several aspects of what you describe. If memory serves the 8 cylinder and 12 cylinder only uses on side of the piston block in LM.
In 94 the OBD has two systems so the blink tester is the start but not the only test needed. Again I just pay the mechanic and hand him things when asked. The other world has lots of stickies to consult before the petrol and match method!
Where in the world are you?
The temp of engine has never been the start of the problems, but the LIMP Home mode has several aspects of what you describe. If memory serves the 8 cylinder and 12 cylinder only uses on side of the piston block in LM.
In 94 the OBD has two systems so the blink tester is the start but not the only test needed. Again I just pay the mechanic and hand him things when asked. The other world has lots of stickies to consult before the petrol and match method!
Where in the world are you?
