Got A Puzzler.........Need Some Help

[Don Hiltz]

Approximately 3 weeks ago, my Viper began to sound labored on start up and would not attain idle speed until I gave it some gas. It's gotten worse, to the point that it now coughs out exhaust (unburned gas)and sets off the security system for a blast or two.

My Viper tech, in whom I have a lot of confidence, feels that it may be a bad injector. However, identifying the culprit is next to impossible. The check engine light has not come on, so there are no codes.

I've tried a can of fuel injector cleaner, but it may be too soon to see any positive results.

I guess it's anybody's guess as to why the alarm system is set off.

What's finally going to happen is that, in the not too distant future, it will simply fail to start. I only hope that when it happens I not too far out in the boonies.

Any ideas..........they would sure be appreciated.

Don

 

[Bill B]

My guess is the battery.

 

[Don Hiltz]

Bill,

I would have thought that too, but I had a new battery installed less than a year ago. I guess if all else fails, I may try that route.

Thanks....

Don

 

[PRVT JET]

is it only during cold starts? could be a fuel pump

 

[Qualitywires.com]

Don,

You sure your dog didn't *** in the gas tank?


I bet you the reason why your alarm goes off is due to the long time it takes to turn over your car? My 1994 did the same.

I don't know, but maybe bad O2's or clogged IAC valve?

It could be a faulty battery or the terminals not being tight on the car. Take it to autozone and have them hook it up to their machine and have them put a load on it....it will show real easy if it's a bad battery.

 

[Joseph Houss]

I agree with checking the battery. Idle sensors (I believe?) are controlled by 12 volt .... and do tend to cause stalling when voltage levels aren't 100%

 

[Tom F&L GoR]

During cranking, the system is still in open loop, so the O2 signal doesn't matter.

The idle air control valve is a dry system (i.e. no fuel ever gets to it) so it could have deposits but the injector cleaner isn't going to get to it to clean it. You can remove the IAC valve and clean it with spray stuff.

Even though no light comes on, you can still have a code. Try the key on-off-on-off-on and after all the usual lights go off, the yellow light will start blinking. If it has more than the 55 signal, there's another code to look into.

 

[Jack B]

A dead injector gives the car a unique and characteristic sound. The exhaust tone takes on a flat note. You can also use a stethoscope to listen to the injector. A major difference in the solenoid actuation is obvious.

Tom is correct the car runs a permanent preset map cycle in the warm up and the O2's are not used. Check the vacuum, it might give you a clue. Does the problem exist after the warm up cycle. The "service engine" code is typically enviromentally related there are many soft codes set that go unnoticed. The use of a scan tool could also show some old codes that may not be present via the key method.