Question-------------------------
Followup To
Question -
Dear Roland - I have a 95 2.5 Jeep Wrangler with 122k, with no spark. I have replaced the crank sensor and cam sensor in the distributor. I also had the coil checked at auto zone and is fine. I also replaced the spark plugs cap and rotor. The asd clicks and vibrates koeo,when I pull it out the fuel pump pressurizes. When I put a test light on the negative battery post and touch the other end to the connector that plugs in to the coil and then go koeo the light is very dim, when I crank it over the light goes bright for 2 seconds and goes out. Can you Help?
Answer -
Hi Jon,
I can only help with Jeep engine problems if I can relate them to identical setups on Chrysler/Dodge/Plymouth models because I don't have any manuals for the Jeep line. But from what you describe, the fact that there is 12v at the + post of the coil for only 2 seconds is telling me that for some reason the engine controller is not getting a signal from the crank sensor because that is what will happen in the absence of such a signal in most Chrysler engines of that time period. Can you tell me if you have a 4 cyl or a V-6 2.5L engine because both were available in the 90's on the Chrysler line? If I can figure out which engine and electronic controls you have I can better help you out. Are the cam and crank sensors inside the distributor? Does the engine have Turbo? What does "koeo" mean, I haven't heard of that term before? So please tell me more and in the meantime I suspect that there may be a wiring problem between one of the sensors and the engine control module that is causing your no spark since the sensors are new.
Also, have you tried turning the ignition switch:"on-off-on-off-on" and leaving it "on" and then watching the check engine light to flash,pause,flash, pause, etc.? Do that key switching quickly, less than 5 seconds. Count the number of flashes before each pause, group the numbers in pairs to form two digit fault codes. The last code should be 55, two groups of 5 flashed each. Then tell me what other codes came out. That is the self-read technique for Chrysler engines up to about 1997.
Roland
Roland
Mr. Finston, Thank you for responding. I already sent a follow up through the Thank and Rate but am unsure if you received my question. To answer your questions it is a 2.5 4cyl, the cam sensor is in the distributor, the crank sensor is near the bell housing, the engine does not have turbo, the term koeo means key on engine off, the check engine light stays on when the ads relay is in and when I take it out the light goes off, but when the relay is out I cannot read trouble codes. I put a ohm meter on the wires coming out of the cam sensor and cranked the engine and I do get read outs. I will be banging my head on the wall till I hear from you.
Thank You,
Jon
AnswerHi Jon,
I hope the wall has not gotten damaged yet ;)
Unfortunately I am not familiar with the Jeep 2.5 with a crank sensor on the bell housing. It apparently is not an engine that Chrysler uses in it automobile lines. When you say that you get readout when you crank the engine, that is from the cam sensor only so far. How about the crank sensor? because that is the sensor that prompts the spark (while the cam sensor synchronizes the location of the spark and the fuel injector pulses to the proper cylinder). You should be able to put a voltmeter on the crank sensor signal wire and while turning the engine by hand using a wrench on the crankshaft end bolt see if the voltage pulses from 5 to 0.3 volts, with the ignition switch in the run position of course. When you put in the new sensor did you leave the paper spacer on the tip and then touch the tip to the flywheel surface when you tightened it down? It is a spacer that "self-destructs", but it assures the proper separation distance to get a good signal from the hall effect crystal.
Also I don't know the coil design, but verify that you are getting 12V on the primary input wire while you are cranking, or alternatively put the voltmeter on the Fuel pump and see if it is getting 12V. If not, then the ASD is somehow not getting the message from the controller to stay 'on' which implies that the controller is not getting the crank and the cam signals. That is what the ASD is for, so that the fuel and spark will shut down in the case of an accident when the engine is no longer rotating.
Those are my suggestions. They are based on general design principles not specifics to that engine set up.
Roland
