Help! Anyone ever had this happen to their car before?

[Go Fast For Life]

I had not driven the viper in about a month so I thought it might be a good idea to back it out of the garage and let it idle for a few minutes to bring the motor and oil up to operating temperature.

The car started fine and idled for about 10 minutes. I heard the radiator fan motor come on so I knew the engine was at operating temperature. I was going to shut it of in a few more minutes when suddenly, it died. No sputtering, just running fine one minute then dead the next.

Now if I turn the ignition on, the radiator fan motor starts running-- even though the car has completely cooled back down. The starter cranks the motor but will not start.

Anyone ever had this problem before? Could my PCM have gone bad?

 

[Joseph Dell]

totally normal. don't be alarmed. this will happen with a low battery as well. turning on the AC would make this happen too. car needs to re-learn idle. it may do it one or two more times but it'll fix itself on its own. PCM is fine... don't panic on this one. might need to replace the battery if it is 2yrs + old, though...

JD

 

[ArlyDude]

Maybe you ran out of gas...lol.

 

[BDZ1984]

Dont be alarmed but had something to this effect happen to my shop car and the PCM had a short in it and had to be replaced.

 

[Go Fast For Life]

Joseph Dell: Thanks for the tip. I disconnected the PCM. Let it sit for 10 minutes. Reconnected PCM. Same problem. Fan runs on high with ignition on but car still will not start. I did this two more times with no success. I'm going to try to leave the PCM disconnected overnight.

ArlyDude: I thought about that too, but gas tank is half full (or half empty) LOL.

bdz1984: Thanks for the info. I have a spare PCM. If leaving the PCM disconnected overnight doesn't fix the problem. I'll swap out the other PCM and see if it starts.

Thanks for all the help guys.

Ron

 

[Warfang]

let us know what happens

 

[Joseph Dell]

oh yeah... darn alarm problem. i hate those too. i didn't realize that the car died and ddn't re-start. could be the trottle-body re-sync thing too...

definitely sounds like it could be alarm related now...

 

[Steve-Indy]

Ron, give me a call.

 

[Go Fast For Life]

Ok, here is where I'm at. And let me say a big thank you to Steve-Indy who has been helping me by phone all afternoon.

Had PCM unplugged all night. Re-installed PCM. With the ignition on, radiator fans run full speed and dash-mounted alarm LED comes on. The engine cranks but will not start.

Swapped in spare PCM. Same exact thing.

Switched the starter motor relay with the radiator fan relay (thinking the relay was stuck) no change.

Cleaned the temperature sensor connector-- no change.

I noticed that my dash-mounted volt meter falls to about 8v when I crank the engine. When I only have the ignition on and am not cranking the motor, the volt meter reads 12-13 volts. Could a low voltage battery be keeping the engine from firing? And why is the dash-mounted alarm LED lit when my ignition is on?

Tomorrow, I may try to talk my local dodge dealer to send a tech with a DB3 over to my house and see if he can pull some codes.

Any thoughts would be appreciated.

 

[santo]

I don't have a Viper but I have had something similar happen before in a different car; twice. Check for loose battery cables attached to the battery or corrosion around the terminals. Simply taking them off, cleaning up the battery terminals and putting them back on may help.

Just a thought but it sounds like it's a PITA to get to the battery in a Viper, unfortunately.

Santo

 

[Ulysses]

Could a low voltage battery be keeping the engine from firing?

Yes.

And why is the dash-mounted alarm LED lit when my ignition is on?

Because the low voltage messes with the alarm module as well.

 

[ArlyDude]

O man, I made fun of you about checking for gas. I went to start my Viper today and she started right up and then 2 seconds later she shut off. I immediately thought about what I typed here last night about no gas! Anyways, I try for about a minute off and on to start her and she'll crank and act like she's starting, but still nothing. I was mad. I knew it was fuel related. I opened the door to get out and I see a huge puddle of gas on the garage floor!!

THe [******] who put my fuel filter on about a month ago didn't secure the filter to the chassis and it vibrated the top line from the filter. I fixed her and she's good now.

 

[Go Fast For Life]

ArlyDude: My condolences. I think I'm going to check on a new battery tomorrow.

 

[Viper Specialty]

What you are describing sounds like something is back-feeding the electrical system. My first notion to a problem like that would be to inspect all of the ground wires that you can find. A broken/loose ground wire could be feeding back through the fan and other parts of the electrical system, causing them to run. I will pull out a schematic and see what I can find.

PS- Check the fan relay to make sure it isnt stuck closed while I check this out.

 

[Viper Specialty]

Just looked through the schematics. The ground location for the PCM is the stud on the front of the driver side outer frame rail, about a foot in front of the PCM itself, right next to the sill. The Electronic Entry Module ground if located in the passenger side footwell, under the dash, around the knee bolster. Check them both, as it appears that a ground fault at either could cause your condition. If the PCM lacked a ground signal, it may be trying to aquire one by backfeeding another crcuit on the board, which happens to be tripping the relays, in turn kicking the fan on. By doing this, it also would not be able to control engine functions, hence No-Start. the starter itself is a different circuit. The Entry Module, though less likely, I suppose could do the above by grounding back through the Speed Signal wire to the PCM.

 

[Vic]

*DELETED*

 

[Joseph Dell]

i still think alarm... had this happen too many times. replace that battery (if it is 18 months old or older) and then hit the RESET button on the remotes. these darn alarms do lots of crazy things...

JD

 

[v10sloboy]

I had a problem like this also disconnect the alarm module under the dash on the driver side. All you have to do is remove the panel below the steering wheel. Let it sit for a few minutes, reconnect the line and disarm the alarm. Make sure the remote batterys are good they do go bad.

 

[carguy07]

Sounds similar to a problem I had that traced back to a loose connection on the positive remote battery terminal. Every time it would wiggle the voltage would dip on the gauge. It was intermittently setting the alarm. I would start with a new fully charged battery and go from there.



My Problem

 

[Cal Cobra]

I had a similar issue. I ended up replacing my battery, although I suspect the battery was ok to start with, and the alarm kept arming itself automatically, and then it would set off, and I think it just killed the battery as a result. After replacing the battery I also found out that the remote keyfob was defective. Ordered a replacement from Tators.

Cal

 

[viper spray]

I need to get a new battery , mine is not as strong as it used to be. What is a god choice , other than the Optima?

 

[Russ M]

I dont think anyone is right here, your car would not turn over if the voltage was too low for the car to start.

Sounds like you have a fuel delivery problem. When you put the key in the on position but dont start the car do you hear your fuel pump? It is very obvious if it primes.

Check this first before you do anything else.

If you hear nothing then check the fuel pump relay, its in the trunk next to the amp.

 

[Viper Specialty]

RUSS- While that issue would be the most obvious, it doesnt address his fan issues, or the alarm light being on. If he has a grounding or shorting issue, that could also cause the fuel pump relay not to kick on, and lead him in the wrong direction as to the culprit.

If it comes down to the relay, check the relay with a 9V battery for operation, then short accross the N.O. circuit and see if it turns the pump on while shorted. That will tell you it is UPSTREAM on the relay, as it would be working properly.

PS- you dont happen to be running an Optima Red-Top battery with shaved posts...?

 

[Go Fast For Life]

Wow! Thanks for all the help guys. I finally tracked down the problem.

Remember, the car was idling for several minutes (mabye 10) before it died. I finally realized that the auto shut-down ASD relay fuse was opened (burned out). And as soon as I replaced it with another, it would open (burn out) again. I checked the ASD output resistance (to ground) at the PCM connector and found < 0.1 ohms! I checked the service manual and started tracking all connections leading from the ASD relay output. The ignition coils were okay, as were the injector drivers. But when I started testing the O2 sensors, three of them measured > 1 meg ohms and the fourth, the upstream left O2 sensor lead measured < 0.1 ohms to ground. I started searching the leads and found that just below my headers, the lead for the left O2 sensor had melted and the power lead was shorted to ground. (I guess this happened while the car was idling.) While I did not have a spare O2 sensor and lead, I'm 99% sure this is the cause of the problem. I'll try to get a replacement tomorrow and report back.

Does anyone know if a dealer normally stocks these? Is this the same O2 sensor used on all the DC vehicles?

A big thank you to all of you who gave advice and especially to Indy-Steve and Ron F. for helping with the finer details. You guys make the Indy-Kentucky Viper Club one of a kind. Thanks for your help.

Ron

 

[Joseph Dell]

you can get an O2 sensor at Autozone... standard part. or a dealer.

glad you found the issue! congrats!

JD