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Alberta_ZR1
07-04-2011, 10:45 PM
Hello Gang,

I've got a no start problem and I'm looking to see if anyone has any quick suggestion or common causes before I jump into the diagnostic charts in the FSM.

Here is the history....

My last big road trip down to Montana I was experiencing hard starting when the car was hot and driven for a lengthy period. Then on the second day, the car sudden stalled out and would not start, only turn over. I popped the hood, did some minor touching of connectors etc. After 10 minutes, the car started and ran fine. On the third day, waiting at the border crossing, the car has a hell of a time starting after shutting it off to talk with border services (at this point I'm thinking my new fuel regulator is giving me troubles).


Travel 4.5 hours at various speeds with no troubles. I pull into a small town for a soda and bam no start. Pushed it to a friend's house and played around with it. Popped the fuel lines, had pressure etc. Continued to play with it and finally after 45 minutes it started. I got it home (well almost) and then it quit again. It?s been in the garage since then and it won't start no matter what.


There is no CEL.

Due to a busy work schedule, I haven't had much time to thoroughly dig into it. I have check the basics and found that I have no spark. I've checked the connectors by the coils etc, all look good.

The plan is to get into over the next few evenings and hopefully figure out the cause. I know the crankshaft sensors suck in GM?s, so I was leaning towards maybe doing that.

Any suggestions would be greatly appreciated!!

PS - I tried running a search for similar topics, but some of the words are too small or too common, so they don't bring back any results. For example "no start"

Thanks again

Tyler

sammy
07-04-2011, 11:28 PM
just a thought but how old are your coils ????

Alberta_ZR1
07-05-2011, 12:38 AM
just a thought but how old are your coils ????

I basically did a complete over haul this winter on ignition and fuel systems (new plugs, coils, wires, injectors, fuel filter, and regulator)

That's why I was so disappointed to have it quit on me :(

Alberta_ZR1
07-06-2011, 01:24 AM
Did some diagnostics's tonight and it appears that I have an open circuit between the ignition module and the crankshaft position sensor.

I crawled underneath and the wiring looks good, so now I just need to get access to it so I can check the resistance of the sensor.

Any suggestions on where to buy a new crankshaft sensor? I'm going to try GM tomorrow.

Any suggestions on the removal of it? I see the exhaust heat shield should come down, but I have no clue how many more bolts are holding that thing in place.

Thanks for the help,

Tyler

Kevin
07-06-2011, 01:30 AM
have you bypassed to clutch safety switch

Alberta_ZR1
07-06-2011, 01:57 AM
have you bypassed to clutch safety switch

That's a good suggestion, but the car does turn over, it just won't fire. I think the clutch safety switch would cause the motor to not even turn over, but I could be mistaken. I haven't looked at that system very closely.

I checked the resistance on the crankshaft position sensor circuit at the ignition module and I'm getting an open circuit. The FSM says I should have a reading of somewhere between 800-1200ohms. It says that anything under 800 is a faulty sensor. So I want to at least check the sensor on its own to see what it has for a reading and then check the continuity of the wiring.

HADI-ZR1
07-06-2011, 08:50 AM
Tyler
Did you washed your engine before that issue?!
:neutral:

Kevin
07-06-2011, 11:13 AM
you're right but it never hurts to do the cheap thing first

Alberta_ZR1
07-06-2011, 11:29 AM
Tyler
Did you washed your engine before that issue?!
:neutral:

Nope it just started happening while I was on a 1200km road trip. Then at the end of the trip it died permanently.

Alberta_ZR1
07-30-2011, 03:48 AM
FINALLY! The LT5 is alive and well.

As suspected it was the crankshaft sensor. So I tried to remove the sensor for inspection and the top of it literally fell out in my hand (explains the open circuit I was seeing).

So after spending 2.5 days trying to dig the rest of the sensor out, I finally decided to order up an oil pan gasket from Jerry and go in from the bottom. The gasket arrived late this week and it took me 35 mintues to force the old sensor out with a hammer and punch.

http://i279.photobucket.com/albums/kk135/tbishup/IMG00983-20110726-2253.jpg

PS - A positive was that NAPA had this sensor in stock...:dancing

sammy
07-30-2011, 10:33 PM
what was the napa part number,please??/

Alberta_ZR1
08-02-2011, 02:08 AM
The Napa part number for the crank sensor is -- CSS109.

I also did a quick write up this evening on my troubleshooting adventures for the crankshaft sensor. You can find it here.

http://www.zr1.net/forum/showthread.php?p=120267#post120267