QuestionWe just baught a 87 new yorker 2.5l fuel injected,when we go to put it into reverse it acts like it wants to die. same when we go to put it in drive or come to a stop. i have to put it up in nuetral to keep it running. it runs fine while in park. we have changed air filter, rotor cap spark plugs and wires. here latly the power loss light keeps coming on and going off and i drove it tonight and the speedometer didnt work. when i turn the key the the power loss light blinks 2 times then 4 times, there is a longer pause, then it blinks 5 times twice. i figure it came up with 24, and 55 but im no mechanic. what do those mean and what could be causing the other problems?
AnswerHi Holly,
Good work in getting the trouble code, 24 (the 55 means "end of readout"). That code says the throttle position sensor signal is not in the correct voltage range. A couple of things to check: the sensor is on the passenger side of the throttle body. Remove the air cleaner lid (three hand turned plastic knobs);then begin the process of removing the rest of the air cleaner housing: notice the large inlet air hose (remove that) then notice the heated air inlet hose coming up from underneath the housing from the exhaust manifold area (remove that), then notice a small hose on the underside, on the passenger side (pull that off), then notice the rubber hose on the front from the pcv valve (remove that); then lift off theair cleaner housing (I think I remember all the fittings, but check it out so you don't overlook an attachment, you'll want to make sure you get them all back on the housing without any damage to the fittings).
Once you have that off you can see the throttle body. On the passenger side there is one item that has a three wire plug; that is the throttle position sensor. Make sure that it was plugged in tightly, and then trace its wires from the plug back to the harness from which the wires begin to emerge, make sure the wires are in good condition and not melted together due to the heat from the underlying exhaust manifold. If the wires all look good, then remove the plug from the sensor. If you have a volt-ohmmeter you can use the ohmmmeter function to test the sensor. If you place the leads of the meter between the middle pin and either side pin of the 3 wire plug and observe the resistance reading as you open and close the throttle (lever on the driver side of the throttle body) the resistance should vary smoothly from near 0 to some maximum value. If you change the side lead from one side position to the other side position, the resistance will similarly change, only inversely to the first measurement. If you place the leads on the end terminals only, it will read the maximum resistance and it will be constant no matter how you move the throttle. Make sure the resistance varies smoothly in the first two configurations of the test. If it is discontinuous or jumpy or doesn't vary at all (except when the leads are on the ends position of the socket) then the sensor is bad. Ideally something will prove flakey about the sensor. If not, then the issue is whether to try a new sensor nonetheless, or trace the wires from the sensor socket to the plug-in at the engine control unit. That is a separate instruction I can give you later if necessary.
So check out that sensor. It would be a pretty likely reason for the engine running problem you are having. To replace it, you just have to remove the 2 screws on either side of the plug and pull it out of the throttle body. Get a new one from a dealer or a reliable parts store.
The no speedo reading (if the odometer is also not working) means the distance sensor is not getting its signal to the engine control unit (either the sensor went bad, or the plug into the sensor is loose). I would begin first by checking the codes again now to see if you have both a 15 code and a 24 code; sometimes we make an error in counting!
The 15 says the speed sensor signal is missing in action. If the odometer still works, then you won't get a 15 code and then it is the speedo unit in the instrument cluster that is bad, not the sensor. If you get the 15 code, look for a wire that goes down behind the engine on the drivers side dropping toward the top of the tansaxle housing (the box out of which the two half shafts that drive the wheels proturudes. That wire has a plug and it then ends at the housing where the sensor is located held in place by a single bolt (10 mm head). The plug could be loose or dirty, so open that up to check, or the gear on the sensor could be damaged (that happens if a mechanic pulls the passenger side half shaft out of the housing using brute force, because to safely do that you first should remove the sensor or its gear will be damaged). Enough details, have a look!
Roland
