Sudden Issue - Starts, Runs Rough, Dies - 96 RoadMaster

Hey Guys!

I am a bit stumped here... I drained and re-filled the coolant in the car couple days ago. Been taking short 2-3 mile trips in the car to work air out of the system.

Today I drove it to the store about 5 miles. Drove home, no issues. Let it sit in the driveway idling to see if it held temp. Noticed it was getting a bit warm so figured there must still be air in system. Shut car off and let it cool 30 mins. Started it up and cracked the bleeder screw, coolant comes out slowly and the car starts to idle REALLY Rough and soon dies. Started the car 4-5 more times and same thing - starts and runs rough for a few second and dies. What happened?? Not getting any check engine lights or anything...

Is it maybe a battery issue? I'm thinking the alternator is bad and maybe I have been driving on battery only the last couple days on short trips, now battery is low enough it won't run - but why does it start? I threw the charger on it anyway. I just have a trickle charger with me at moment - says battery is taking charge.

Hope to suggestions. Seems really weird to me that opening the bleeder screw on coolant system would make car run rough and die.

Thanks everyone!
Eric

Yonkerse wrote:

Hey Guys!

Seems really weird to me that opening the bleeder screw on coolant system would make car run rough and die.

Not weird at all. Unless your bleed screw has a drain tube, to drain the coolant away from the OPTI or you diverted the coolant away from it; you probably have got water inside the OPTI.........not good.  That's why your car is running rough and dying.  You may be able to dry the OPTI and cap with a hair dryer and hope for the best.  Most likely you're going to need wires and a cap (at minimum).

Tom

silverfox103 wrote:

Yonkerse wrote:

Hey Guys!

Seems really weird to me that opening the bleeder screw on coolant system would make car run rough and die.

Not weird at all.  Unless your bleed screw has a drain tube, to drain the coolant away from the OPTI or you diverted the coolant away from it; you probably have got water inside the OPTI.........not good.  That's why your car is running rough and dying.  You may be able to dry the OPTI and cap with a hair dryer and hope for the best.  Most likely you're going to need wires and a cap (at minimum).

Tom

Thanks SilverFox! That must be located directly below the bleeder screw? Why would they do that??? haha. Will let it dry out overnight and will try getting some heat to it tomorrow!

Yonkerse wrote:

Thanks SilverFox! That must be located directly below the bleeder screw? Why would they do that??? haha. Will let it dry out overnight and will try getting some heat to it tomorrow!

You are correct on location. Why they would do that, is beyond me. You are not the first to have this issue. Let it dry overnight and try the hair dryer.

Tom

Little update here - was able to locate a new OPTI locally and put it in. Car still not starting. When replacing it, I noticed the Crank Position Sensor had a fair amount of moisture in it, I dried it out good and let it air-dry for a day, could that be the problem?

I'm planning to pick up some plug wires today and swap those in. I have submerged various off road toys which plug wires get wet. Let them dry good and they always work fine. Are these cars a bit more sensitive if water gets in the plug wires?

Thanks for the help!

I would try replacing the distributor 4-wire harness. I have seen those fail. Also, the coil and ICM are wear items as well and are worth it to replace.

Are you getting trouble codes?

I checked the 4 wire harness going into the OPTI and I'm getting voltage across the pins - between 6 and 12 Volts depending on which pins I check. (some variations result in 0V) Also getting voltage across the CrankShaft Position Sensor.

When I first checked the codes, I was getting the P0300 - Random / Multiple Misfire code. Totally agree with it based on how the car ran before it stalled and now won't start. I cleared the code and not getting any codes now - although the car won't run so most of the sensors, etc probably aren't enabled until car is running.

Local parts store is getting a new CrankPosition Sensor in the morning. I pulled the old one out. Not sure how to check to see if it is good / bad. I'm didn't replace plug wires yet - I don't think they are the problem.

Thanks for the input! Greatly appreciate it!

obviously I'm over the hill. OPTI? ICM? P0300? the Crankshaft position sensor, I get that one. Random misfire usually high tension side, plug, wire, dist. cap., rotor.

Alright guys - I'm at a loss on this one....

Replaced the Coil and checked for spark on a drivers side spark plug. Getting spark but seems to be weak to me....maybe that is normal for these cars? Car was still not starting.

Took the ICM to O'Reilly's as they offer free checks. They said it "failed" the test so I bought a new one. Swapped it in - car still won't start.

I read a post from an old thread saying the Crank Shaft Position Sensor would not keep the car from starting...is that true? I have not replaced that. I also have not replaced the spark plugs / wires. Seems odd that enough would go bad while the car was running. Remember the car stalled out when I was bleeding the coolant system.

I have replaced OptiSpark box / Distributor which I mentioned above.

I'm at a loss. Getting a little frustrated with it now. Not getting any codes from my Code Reader - I cleared them after it wouldn't start and car hasn't ran since to even trigger code.

Open to suggestions. You guys are great. Thanks for being patient and helping a LT1 Rookie!

I have to ask, have you checked the fuel system? I know that's walking away from what you HAVE been messing with, but I had to do the fuel pressure regulator on my 96 wagon a couple years back after it had similar issues. Has run like a watch since!

-Mike

Yonkerse wrote:

I read a post from an old thread saying the Crank Shaft Position Sensor would not keep the car from starting...is that true? I have not replaced that. I also have not replaced the spark plugs / wires. Seems odd that enough would go bad while the car was running. Remember the car stalled out when I was bleeding the coolant system.

The CPS is not like on the later cars.  It should not prevent the car from starting but it can mess up the opti signal in rare cases.  You shouldn't focus your diagnostics on the CPS.  It's there to be able to give the misfire codes.

A failed ICM will cause no start.  Is the new ICM the proper OBD2 (1996) ICM ?  Did you reinstall the new ICM with the heatsink paste (should have at least started once)?  It would not be the 1st time someone has received the wrong/faulty electronic item out of the box at a chain store.  This goes for the new opti as well.  (hope you did the opti seals at the same time). Make sure all the plug wires are at the correct location on the opti and DOUBLE CLICKED in (I like to mark the plug wires with 1,2,3 or 4 dots of liquid paper when doing the opti and not wires).

Like mike said, ensure the fuel pump is working ok.  You'd be pretty unlucky to have an opti and fuel pump failure within a few days of each other, but the fuel pump is known to just kick the bucket at any point.  Put a fuel pressure gauge on to measure the pressure with the key on engine off.

don't you just hate when you do some big maintenance and then something different takes a crap?!
When i did a coolant flush/refill on my wagon at first i couldn't figure out why it was getting hot (didn't realize i had the bleeder screw to deal with) - that solved it - i DID get coolant spillage down on the opti - but nothing happened. It might be because i had a new acdelco opti installed?
My understanding that i read is certain if not all new optis - MSD, acdelco, and others have been redesigned to solve the water intrusion major failure issue.
If the car is cranking then starter is good, battery should be good... then it's usually fuel (fuel pump issue is one possibility) or spark.
also, if my memory serves me if you don't have the air cleaner or intake sealed up right it can also cause the car to not run for more than a few seconds - I recall that happening to me when i had been working on the engine and didn't put everything back together.

jasonlachapelle wrote:

Yonkerse wrote:

I read a post from an old thread saying the Crank Shaft Position Sensor would not keep the car from starting...is that true? I have not replaced that. I also have not replaced the spark plugs / wires. Seems odd that enough would go bad while the car was running. Remember the car stalled out when I was bleeding the coolant system.

The CPS is not like on the later cars.  It should not prevent the car from starting but it can mess up the opti signal in rare cases.  You shouldn't focus your diagnostics on the CPS.  It's there to be able to give the misfire codes.

A failed ICM will cause no start.  Is the new ICM the proper OBD2 (1996) ICM ?  Did you reinstall the new ICM with the heatsink paste (should have at least started once)?  It would not be the 1st time someone has received the wrong/faulty electronic item out of the box at a chain store.  This goes for the new opti as well.  (hope you did the opti seals at the same time).  Make sure all the plug wires are at the correct location on the opti and DOUBLE CLICKED in (I like to mark the plug wires with 1,2,3 or 4 dots of liquid paper when doing the opti and not wires).

Like mike said, ensure the fuel pump is working ok.  You'd be pretty unlucky to have an opti and fuel pump failure within a few days of each other, but the fuel pump is known to just kick the bucket at any point.  Put a fuel pressure gauge on to measure the pressure with the key on engine off.

I know about the fuel pumps, I was driving my 94 rmw and it was running fine no problems at all, then the next morning go to start it up to go to work and she would just sit and crank. a bit of advice if you get a new pump, watch out for the small piece of hose between the pump itself and the top of the sending unit, thos are known to fail, I had three fail on me within a couple months, shop finally just put a chunk of submersible fuel rated hose on in place of the factory hose and no problems with that since. But I would cycle the key a couple of times then use something to push down the pin on the relief valve at the back of the intake for the fuel rails, if you get fuel coming out good, if nothing comes out, best case might be a bad fuel pressure regulator which is right there.

But I've bled the coolant on my buick without rerouting or diverting it away from the opti while the car was running and have never had a problem with it, but I'm not completely certain if my car is still running the original opti or not