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nsargeant |
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#1
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Newbie ![]() Group: Members Posts: 12 Joined: 27-August 17 From: Vincennes, In Member No.: 21,381 Region Association: Upper MidWest ![]() |
In the quest for a perfect running 914 im getting oh so close. In the past I have replaced the tps with a new one that fixed the severe bucking/hesitation. The car ran so much better after that. What I am trying to figure out now is a random hesitation/hiccup that happens mostly during steady throttle when I am cruising on a highway. If I drive 30 miles it might happen once or twice. It seems pretty minor compared to the bucking I was having with the old tps. If I recall it has had this hesitation since I have owned the car for the last 3 years. I know the distributor does have a pertronix module in it. Ive recently changed replaced a few things listed below but still have that little hiccup. What would you guys investigate next?
Replaced: Fuel pump/filter Installed SS lines plugs, wires, rotor, (cap still looked new) tps sensor |
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BeatNavy |
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#2
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Certified Professional Scapegoat ![]() ![]() ![]() ![]() Group: Members Posts: 2,924 Joined: 26-February 14 From: Easton, MD Member No.: 17,042 Region Association: MidAtlantic Region ![]() ![]() |
Finding the root cause on this symptom can be tough, particularly if you don't have a wideband O2 sensor. To Bleyseng's point, it would probably show you running (or suddenly going) lean when the bucking starts. Lean meaning Air/Fuel ratio of 15 or more as he mentions.
But, it can also be ignition related (dizzy, etc.). To break it down, the root cause can fall into one of two categories: 1. Fuel Delivery interruption, which can be caused by many things including: a. dirty fuel filter, sock in tank, or other obstruction in lines b. dirty or clogged injectors c. poor ground connections on FI harness d. bad, dirty or misaligned trigger points e. worn TPS f. poorly adjusted or malfunctioning MPS g. fuel injector connections loose etc. etc. 2. Ignition interruption a. issues with dizzy (sticking advance), cracked rotor or cap, etc. b. cracked or poorly connected spark plug wires etc. etc. I'm sure I'm missing some ideas here. You need to start methodically eliminating these off your list (you've already replaced a bunch of parts, so a lot of this list should already be checked). If you had the O2 sensor you could probably eliminate either fuel or ignition (if it goes lean, it's something on the fuel side, if not, something on the ignition side). In any event, I would check all your grounds and other FI connections to make sure they are secure. I know it's annoying. Good luck! |
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