mountain

[Viala]

Hello

Pontiac 3.8 in the mountain ; I am back from holidays
in Alpes (south of France). It was the first time for me , my transmission is new, and i was surprised to be overtake by all the cars
it was not possible for me to accelarate much .
I presume this car is not built for moutain roads or may be my engine is weak but on flat roads and motor ways it doesn't seems to be tired

Who as already used is car in such conditions?

Thank's

Paul

[cdru]

Lack of power can be any one of a bunch of different things. Bad plugs, poor ignition system, dirty filters, clogged catalytic converter, etc. Do you preform routine maintenance or do you just fix things when they break?

[Viala]

Yes sometimes I just fix things when they break, but since I have a new transmission , I take care more than before , and now all the filters
air , oil , gasoline are new , camshaft detection too. I have been learning much with the forum and feel more in confidence with the car.
When I bought it in 1999 I was scared when I opened the hood to see the engine with a special equipement of LPG , now the car has 170.000 miles, and hope it will run even more.


How could I know if the catalytic converter is clogged

Thank's

Paul

[cdru]

There are a variety of ways that I've heard of. If you have the converter off, pouring water through it will tell you if it's plugged. The water should run out with some resistance, but not a lot. However, usually getting it off is 1/2 the battle to begin with.

If it's still on, there are still ways to tell. From another post in a different forum: "On my wife's 2001 Impala LS, we found the CAT was clogged by running a vacuum test with a standard automotive vaccum gauge (0 - 30 in. hg). On the Series II 3800 you can tee into the fuel pressure regulator or purge solenoid vacuum lines. On the 3.4L, there are plenty of vaccum lines to tap into on the intake manifold. Normal vaccum in inches is around 15 or green area. To checked for a clogged CAT or excessive exhaust backpressure, you run the rpms up to around 2000 - 2500 and hold steady. Observe the gauge. If rpms (ed: I think he means vacuum) drop towards zero or into yellow or red zones then there is a high probability its the CAT." However this doesn't guarantee it.

A better way, but it takes some additional work, is to unscrew the pre-O2 sensor and in it's place put an adapter that hooks up to a vacuum/pressure gauge. Run the engine for a short period and 2-3000 rpms taking note of the pressure (or lack of). Replace the sensor. Then move to the post-converter and take the same measurement. If the difference is more then 1, you have a plugged cat.

I've also heard of other ways that shops can tell, using infrared sensors and the like but I don't know much about those.

All this is with a conventional engine. Things may be different in your case since you've converted to LPG. Donno. An exhaust shop may be able to help you out with some preliminary diagnostics.

[Viala]

Thank you for your answer.
of course when I run with LPG the engine is less powerfull, but even cheaper than gasoline. Her one one US gallon ( 3.785 liters) of gasoline is about 6 dollars and one gallon of LPG is half price.


Bye

Paul