95 Q45 intermittant starting problem

[jelvin]

OK this one has me completely stumped.

Over the past two weeks my Q would not start 3 times. I get the typical humming but no cranking each time.

The first time it did it, I waited about 20 mins and it started right up.

Second time, I towed it home (1/2 mile away), I decided to go after the starter (I could not for the life of me get the bolts out) and decided for the hell of it to start it and low and behold it started right up! go figure!

Third time, my wife drove it around on various errands when she got home about an hour later we went to leave and it would not start, no cranking, just the hum of the pump. So after taking another car we came home and tried to start it and it fired right up (about an hour had elapsed).

I am stumped. I have tried to recreate the problem but no luck. I can not figure out why it starts sometimes and not others. When it does start I have no idea why it starts.

I cleaned the battery terminals, put a meter on it (12.7v). The cranking seems normal (not slow cranking). I tried putting it in neutral to see if it was the neutral switch, nothing! I have also tried different keys and even jiggling the key in the switch (nothing!)

I am inclined to replace the starter (if I knew how to get to the bolts!). I am not sure if it is the starter. I will try the following, switching the battery and the starter relay.

Any thoughts?

[Q45tech]

The first thing one tries on a 12 year old car is to replace the starter relay.

[Q451990]

I'm not sure that you can exchange the starter relay with anything else... I would locate it and tap it the next time it fails. It should be blue and located by itself near the firewall on the right side of the engine bay. You might narrow things down. If you don't have your FSM (Factory Service Manual) download a .pdf copy at http://www.phatg20.net - then google for the freeware that decompresses the .rar file. You should be able to check at that relay with your meter to see if voltage is going to your starter.

Starter failures are pretty rare on the Q45 - but we have heard of a few, typically on the later years of the series. The relay failure is much more common.

Good luck!

Heath

[jelvin]

Update: I changed out the starter relay and even tried a different battery, no change. I will meter the other points to see if juice is flowing to the starter.

Someone had even mentioned a module at the ignition switch, what is this and could it also be a source for the problem?

[Q451990]

It sounds like you're on the right track. I think the next step is what you mentioned - check the input and output sides of the starter relay and see where you have voltage. Were you able to download the FSM? That will really help you see how the anti-theft system is interconnected as well...

Good luck!

Heath

[jelvin]

I did get the manual and found the wiring diagram in it. Thank you for the link.

This may be premature but just in case I do have to pull the starter do you know what tool/method to use? The manual does not give that info and when I tried to pull it earlier I had trouble, it is a very confined space. You can not use a standard wrench (no room to turn it), and the impact wrench and socket did not work either.

[aaronl]

search for starter in the infiniti forums. there is a post some were of Q45 starter replacement with pics of the tools used.

[qsiguy]

If you can verify the crank wire is getting 12V at the starter when you try and crank it then the problem has to be with the starter/solenoid. So when/if it does it again try and get to the starter where the crank wire is connected (coming from the starter relay under the hood) and check the voltage. While you are down there have someone hold the key in the crank position while you "malletize" the starter (hit it with a hammer ) and if it's a sticky solenoid it will usually crank right over. **DISCLAIMER: keep your hands and other appendages out of moving parts if you try this!!**

I've used this procedure hundreds of times to diagnose sticky solenoids...no exaggeration.

[jelvin]

thank you, I will try it this evening and see what I get.

I am not ruling out a problem with the ignition yet either. Last night before replacing the starter relay and battery I tried to start it. It fired right up, I turned it off and immediately tried to start it and nothing! So I replaced the relay, tried it, nothing, swapped the battery out, nothing, I then took the cover off the steering column, tried it and the car fired right up, turned it off, restart, dead again. I looked and poked around a bit around the ignition (don't know what to look for), never could get the car to start after that. Of course this could all be a fluke!

I will crawl under the car this evening to see if spark is getting to the starter or if the solenoid is sticking. If it is the solenoid I will still have to remove the starter to get to that (correct?). I will do a search for starter removal.

Thanks for the advice everybody.

[Q45tech]

In 12 years of working on 90-95Q we've probably replaced only 8 starter in 2000 different Qs. We've replaced ten [10] times that number on LS400.

Roughly we replace 30 times more starter relays than starters.

[jelvin]

And to think that I almost bought an LS400!! Well at least their starters are probably easier to get to?

Trust me, I have no desire to mess with my starter, but I did replace my relay with no luck. If it is my starter I guess you can add it to your stats (9 out of 2000?) ...oh well ... at this point I just want to get it fixed.

[Q451990]

And to think that I almost bought an LS400!! Well at least their starters are probably easier to get to?

Actually, if I remember correctly - the LS400's starter is located in the valley under the intake. If that's anything like the Q's to remove - that's no picnic either!

Heath

[jelvin]

Checked the voltage at the solenoid/starter, read 12v, I had my wife turn the key many times to make sure the voltage was consistant which it was, I even used a hammer to persuade the solenoid, that worked too so after cursing my bad luck I went to work on pulling the starter.

I followed the procedure I found for the starter removal found under the Online Mechanic link. That helped a lot but I will add a few tid-bits to the procedure/link to help someone else down the line.

For those reading this post, if you ever have to replace your starter, make sure you get the exact match (outer body) or just have your starter rebuilt. More info on that detailed in the link I mentioned above (search Online mechanic, keyword "starter").

here's the link --> zerothread?id=120220

[Q45tech]

Obviously way too many start up per mile as my 17 year old 315,000 mile Q still has oem as built starter.

I've had my oem spare standing by for the last 3 years.

[Q451990]

Obviously way too many start up per mile as my 17 year old 315,000 mile Q still has oem as built starter.

It almost makes you wonder if Infiniti decided to save a few pennies by making the brushes shorter in later years?

Anyway... glad to hear you're getting to the bottom of your difficulties Jelvin.

Heath

[jelvin]

I am glad that I was able to make the repair myself. Tedious work but managable with some patience. Now all I have to do is put the new one back in this evening.

Thanks for the advice Heath.

[qsiguy]

I thought that would be it. Glad you narrowed it down and that we could help.

[jelvin]

Final post on this thread.

I put the new starter in last night using the procedure found at this link --> zerothread?id=120220 . It went in a lot easier then when I took it out (of course). Works like a champ now.

Other vitals I should mention:

Reman. starter from Napa auto parts: $115.99 final cost after core. I also made sure the new starter matched exactly, very important! You may find a listing for 8 tooth and 10 tooth starter, mine and I suspect most others will be 8 tooth.

Miles on my 1995 Q45: 168,000 (starter should have lasted longer)

tools used: top bolt - 14mm curved box-end wrench (Craftsman - starter & manifold)bot bolt - 14mm socket with 2 - 6" ext with uni-jnt in middle (see link above)

I hope this helps those who might have a similar problem. This site was a great resource for me.

Modified by jelvin at 8:55 AM 7/26/2007
Modified by jelvin at 8:56 AM 7/26/2007

[Q451990]

Thanks for the update! Hope to see you hanging out here more... your signature line makes me think you would appreciate the preventative maintenence suggestions from Q45Tech and others!

Heath

[jelvin]

Yes, I will most definately be checking on this site for many things. I have already checked on Q45tech's postings and am blown away at the wealth of knowledge shared! Thanks again for all the support.