Intermittent no crank.

[zeeman]

Hello, I am hoping someone here can help me diagnose my no crank issue. I have a 94 lt1. I have replaced the starter with a new one. It has good battery. I attempted to do the security resistor bypass, and found it has already been done.
When I go to start it sometimes it will crank and other times it will not. When it doesnt crank it does not draw power from the battery. I check this by turning on the headlights and turning the key, the lights do not flicker or dim, they do nothing when it wont crank. I may have to play with the key a few times or wait for a minute or so then it will crank up like nothing is wrong. I have tried it in neutral and in park, makes no difference. The security light is not on other than when the key is turned initially for 5 seconds or so.
to "test" the neutral safety switch, when it wont start, I hold the key over to start and move the gear selector in and out of park, or neutral, each time I can hear a relay click. I am assuming that it is the theft deterrent relay I am hearing. So, quick and dirty, the ignition switch, neutral safety switch and the theft deterrent relay all seem to be functioning. Which leaves me with the theft deterrent module. I cant find one at the local parts suppliers, is this a dealer item? How can I test it for function? and if it is malfunctioning why isnt my security light coming on?

[TB2]

Sounds like it could be a bad ground. Check where the ground attatches to the block that it is clean and in good condition. Also check the body ground(s)

[Fox Slaughter]

Go under the how to. I posted a page on how to Diagnose a LT1.

[zeeman]

ok grounds are all good and solid, clean. I will look in the how to section thanks.

[1BADAIR]

I wouldn't rule out the neutral safety switch. Jump the wires

[zeeman]

Well I probably will if I have to go back in to the console. I picked up a anti theft system relay on the way home tonight.
I dont think its the module, the fuel pump is working when it does this no start thing. I am pretty sure if the module was bad it would lock out the fuel pump along with the starter. So the relay was only $15.00 so what the heck.

[zeeman]

Go under the how to. I posted a page on how to Diagnose a LT1.

sure, where is the how to section again?


Found it, but none of that relates to my non starting issue. My starter no spinny. fuel pump works, I can hear it everything else is normal as soon as the starter engages. I just cant always get the starter to engage.

[zeeman]

I almost hate to admit this here. So, I replaced the anti theft relay to no avail. As I was laying under the car cleaning the engine ground, it hit me like a lightning bolt. Put a jumper on the small signal wire on the starter and connect that to my test light. Turn key, if it doesnt light the light when I crank it and hit the key its a bad anti theft module. But it lit the light when the starter didnt crank. I have a brand new bad starter with the exact same problem as my old starter. What are the chances of that? FML.

[1BADAIR]

Probably nothing wrong with the starter. Solenoid

[zeeman]

Probably nothing wrong with the starter. Solenoid

Yep, prolly. No one local sells just the solenoid though. The place I bought it from is just sending me an entire new one. Internet sale. Auto parts warehouse. I put the old one back in for now.. now its working just fine.

[zeeman]

Update. Auto parts warehouse is completely out of starters for the 5.7. None of the listed brands are in stock except for the $300.00 dollar one. So I had to order it from another online vendor. Hope they have one in stock.

[JoeliusZ28]

Before i even read your resolution i was going to say not to rule out another bad starter (solenoid). Glad u got it figured out.

[zeeman]

yeah, never overlook the obvious.