CRANK POSITION SENSOR HOW TO TEST ?

I replaced the A518 trans in my 93 Ramcharger 318 2WD. Afterwards the engine would turnover, but not run. I checked and found no spark. I figured I may have damaged the crank position sensor. I changed it and still no spark. According to the shop manual you test accross terminals B and C with an ohm meter, and should get an open circuit. If you get a low ohm reading, the sensor is bad. Both the new and old sensors when tested, show open when the ohm meter leads are hooked up one way, but when you reverse the leads, it shows 660 ohms on the old sensor, and about 450 on the new one. I don't know if the sensors are good or bad, as the shop manual doesn't mention a difference in readings according to polarity. If the sensors are good, I am not sure what the problem is. I checked all connections, and I have the original flexplate on the engine. Anyone know how to test the sensor? Any suggestions on what may have gone out of whack. I t was running fine a week before I changed the trans. Thanks !

Come on guys ! Any Magnum knowledge here ?

There is alot more knowledge available about the GM and Ford products ! You know what I will buy next .........

Doctor Mopar,thats a great screen name! Yep maybe it's time for a chebby. LOL

well I looked it up in all data, and it says nothing different then your manual.

I do have to ask, are you sure your meter is any good. There should be no difference in how that circuit works no matter which way you plug in the connectors.

Engine will still start with bad crank sensor,just won't run above 3000-3500.Check the cam sensor wires leaving the distr/cam sensor housing.They like to crack there.

Did the flex plate get bent?
I know what a pain those dipstick tube brackets can be and the sensor is right there. Did you man handle it at all?

If you have a Snap On MT 2500 Scanner you can find out real easy if that Crank Sensor is bad! Just a thought...maybe the "new" crank sensor is bad. Aftermarket are made overseas and are cheap. Is it a factory Mopar one?
I had a Buick Riviera - Supercharged 1995 with 3800 motor. I went through a crank sensor every 2-3 years. Then replaced it with a factory GM one and never replaced one again!

Well Thanks for some effort guys ! The flexplate is not bent. I used a trans jack. My meter is good,and I beleive it reads in one direction because of the type of sensor this is. I believe the manual is wrong. I have used many Chrysler shop manuals, and many of the GM manuals, and have found the Chrysler manuals to be weaker in there diagnosis information.I have been a fan of the Chrysler musclecars since I was a kid in the sixties. I have owned and restored many of the Chrysler musclecars. As for the Chrysler products since the seventies, I am not as much a fan. I look at things realisticly ! For my bread and butter daily drivers I have had more difficulty with my Chrysler products. The reason I mentioned the possibility of my next automobile being other than Chrysler is just as simple as the reliability, expense, and of course knowledge and information to repair, which I find to be weak. I am hoping to be proven wrong, but even in my local area the information from the people I know with shops, and info from mechanics with the dealerships is weak. I hope that I get some real insite from this site! I don't need to get the doctor chebby comments,Prove ne wrong by information, or prove me right by a lack of it !I am really trying to repair my Ramcharger ! I have done mechanic work for over 40 years ! Every once in a while, I have something that stumps me ! I have ver7y little time off from my regular job, and I was just in hope of some help. Checking the cam position sensor is my next step planned. Anyone with more insite, let me know ! Thanks, Ron

Fastfrankie, The sensor I bought is a Borgwarner and made in the USA. I was going to get an OEM one at the dealer, but the parts man sounded confused on the phone, and told me there were several ones listed for it and he needed a number off the old one after I pulled it. He said none of them were in stock, and he would have to order it. None of this works for my time frame to work, and I don't believe his competance, as I have had nothing but trubble with them in the past. The reason I started my post here was to make sure how to test the sensors off the vehicle, so I could determine if I got a bad part. I don't have a scanner, and my friends don't have the adapters for their scanners on my vehicle. I still have a couple things to do before I give up and tow it to a shop that can scan it and fix it. Thanks

I'll assume battery voltage and connections are good,very important. Have you checked for fault codes? Simple and can often lead to the problem. I don't see how swapping the leads during your testing could show the results you got,I just went to the garage and picked up a good CPS and couldn't get anything but infinite resistance no matter which way the leads are connected. Yes even NEW DEALER CPS can be bad out of the box,it does happen and I have first hand knowledge of this. You may want to double check the distributor cap if the back of the engine was lowered during your swap,they have been dislodged enough to cause a no start or very rough running engine and some

Your magnetic CPS has to have 50thou clearance at the flywheel trigger. Turn the key on and rotate the crank by the crank bolt. Pierce the wires and check for voltage/signal, 4 times per 1 rpm as I remember. Measure your OEM sensor mounting depth length to the new one.

Check the wires that lead into the distributor for the hall effect trigger. Mine went bad right where they go into the hall effect trigger itself. I moved the wires and the truck ran.

Something else to check at least.

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Engine will still start with bad crank sensor,just won't run above 3000-3500.

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Absolutely unbelievable....If you don`t know the system..DON`T give incorrect advice!!!!