danno Posted June 17, 2011 Share Posted June 17, 2011 Hi New to Jeeps, spent the last 4 years with Toyotas. Got tired of the lack of power! So far I love this truck, a 90 4.0 AX15 4X4. Power, style, utility, parts availability, and much better mileage than my V6 4runner. Just completed the external slave conversion to my AX15 and am loving it. This site has helped me tremendously. It had a leaking MC when I got it. Replaced MC, removed the fuse block and cleaned with an entire bottle of electrical contact cleaner and replaced all the fuses. Checked for rust as well. NONE! Gotta love the southwest. On to the problem When starting, if I turn the key directly to "start", there is about a one second pause before the starter engages. If I turn the key to "run" and leave it there for one second then turn the key to "start", the starter engages immediately. Whats going on here? Or is just something that these things do? Any help would be appreciated! Dan Link to comment Share on other sites More sharing options...
zagscrawler Posted June 17, 2011 Share Posted June 17, 2011 I'm new to jeeps as well so this may happen to me without warning as well. Mine does not lag when i hit the start possition with my ign. switch, not to say there is not a relay that gives power to the trigger lead on the starter solaniod. I would take a multi-meter of sorts and connect it to the trigger input pole, or stud, on the starter itself. Its usually the one with only one wire and is smaller than the rest in size visually. Have your meter set to volts dc (usually -- lines vs a sidewase s) and put the meter in the window and check the timing between when you turn the key and when your meter gets 10+volts. If there is a delay at all i would say there is a relay in place and its acking up, if you get proper volts and then there is a delay i would say grab a new solinoid and give it a shot. If its not the soliniod i would check the wear on the teeth on your flywheel and make sure things engage mechanicaly like they should. Good luck friend. :wrench: After rereading this i guess a sticky or gunky ignition switch can act this way as well but i would still start there. Link to comment Share on other sites More sharing options...
zagscrawler Posted June 17, 2011 Share Posted June 17, 2011 Also don't mean to rant but in a fuel injected vehicle you should, imo, always give it a solid second or three to let the fuel pump prime before you start it anyway. Just good practice if you ask me good luck. Link to comment Share on other sites More sharing options...
danno Posted June 19, 2011 Author Share Posted June 19, 2011 Testing the starter solenoid signal wire shows zero voltage when going straight to start then voltage after one second of holding start. Turning ign to run and letting sit one second shows voltage immediately when turned to start. WTF? :redX: Link to comment Share on other sites More sharing options...
zagscrawler Posted June 19, 2011 Share Posted June 19, 2011 I'm headed out to tinker around with my MJ in a few. ill double check that my truck starts immediately like i think. There is a starter relay i believe on one of the fenders. If you can determine which one it is you can use your multi-meter again to check where the lag is coming from. I'm not sure which wires are what but with some time i think you could figure it out. Good luck and ill look around on the net for some diagrams and whatnot and give any help i can. Link to comment Share on other sites More sharing options...
zagscrawler Posted June 19, 2011 Share Posted June 19, 2011 Well mine turns over soon as i hit start on my ignition switch. Mine is an 88 4.0L 2x4 and I'm not sure if the starting system changed in between the years. Anyone else have any info on the location of the starter relay in a 90 4.0L and also if it is triggered by the ecu or the ignition switch directly? Link to comment Share on other sites More sharing options...
danno Posted June 19, 2011 Author Share Posted June 19, 2011 Awesome thanks alot man! Link to comment Share on other sites More sharing options...
danno Posted June 23, 2011 Author Share Posted June 23, 2011 Alright found the problem The neutral safety switch wire (blk/wht) to the starter relay had burned up at some point and had extremely high resistance. Ran a new wire and cleaned up the relay connections and problem solved! Any ideas as to what may have caused this? The wire casing was completely gone from the relay to the connector that leads down to the trans and NSS. Link to comment Share on other sites More sharing options...
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