Author Topic: Engine wont turn over.  (Read 334 times)

Offline smallblock

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Engine wont turn over.
« on: July 12, 2017 - 08:28:38 am »
My 74 challenger always started fine until a month ago, now all the lights and radio work but there is absolutely nothing when I turn the key. I have power at the coil when turning the key and power at the starter relay when turning the key, both a little over 12 volts. I can jump the starter relay with a screwdriver and the car turns over. Battery is new and charged. Ive checked the neutral safety switch and its clean and plugged in. Ive tried putting the car in neutral and starting and still nothing. Ive checked for good grounds and broken wires and everything looks good. I ordered a new starter relay and put it on and still nothing. Im going nuts at this point. Anyone know of more checks I can do to try and narrow this down? Thanks.




Offline solarguy

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Re: Engine wont turn over.
« Reply #1 on: July 12, 2017 - 08:36:26 am »
With the car in park, temporally ground the post on the starter relay that goes to the NSS.  If it cranks, the problem is at the NSS, (bad or not grounding)  or the wire to it.  You said you already checked power to the yellow when cranking?  Be careful doing this test as the car will start in gear so make sure you're in park, brake on. 
« Last Edit: July 12, 2017 - 08:44:32 am by solarguy »

Offline smallblock

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Re: Engine wont turn over.
« Reply #2 on: July 12, 2017 - 09:39:21 am »
If the NSS is bad wouldn't it start in neutral?


Offline burdar

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Re: Engine wont turn over.
« Reply #3 on: July 12, 2017 - 11:24:16 am »
Quote
With the car in park, temporally ground the post on the starter relay that goes to the NSS.  If it cranks, the problem is at the NSS, (bad or not grounding)  or the wire to it.

 :iagree:  If grounding that post doesn't change anything, you have a starter relay problem.  Both are easy to replace.  Just have a drain pan handy when you remove the NSS. 

Offline smallblock

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Re: Engine wont turn over.
« Reply #4 on: July 12, 2017 - 11:45:57 am »
I replaced the starter relay with a new one yesterday and nothing changed. Could have gotten a bad relay I guess.

Offline solarguy

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Re: Engine wont turn over.
« Reply #5 on: July 12, 2017 - 12:05:17 pm »
I replaced the starter relay with a new one yesterday and nothing changed. Could have gotten a bad relay I guess.

You could have but do the test above to rule out the NSS or the wire to it.  No, it will not start in neutral with an bad nss. 

Offline burdar

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Re: Engine wont turn over.
« Reply #6 on: July 12, 2017 - 12:26:47 pm »
It's also possible that you have an issue with the "rooster comb" inside the trans.  That's what rides on the NSS and moves when you change gears.

Offline smallblock

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Re: Engine wont turn over.
« Reply #7 on: July 13, 2017 - 08:14:57 pm »
Put a temporary ground wire on the starter relay and engine cranks over so it's the nss or wire. Shouldnt be to hard to fix now. Thanks for all the help again!

Offline solarguy

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Re: Engine wont turn over.
« Reply #8 on: July 14, 2017 - 12:15:42 pm »
Put a temporary ground wire on the starter relay and engine cranks over so it's the nss or wire. Shouldnt be to hard to fix now. Thanks for all the help again!

the shifter linkage could be out of adjustment and not allowing the grounding of the nss when in park or neutral. 

Offline HP2

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Re: Engine wont turn over.
« Reply #9 on: July 17, 2017 - 12:42:58 pm »
'74s have the seat belt interlock relay that will do this. Have you checked that system or bypassed that relay?

Offline burdar

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Re: Engine wont turn over.
« Reply #10 on: July 17, 2017 - 12:52:49 pm »
Good call. I completely missed the fact that its a 74.  I think there is a button on the control box that bypasses the system for a couple start cycles.