PLEASE.... someone help! i dont know whts wrong!

start
trucks
van
chevrolet

#1

My 2002 chevy van has been running horrible, it wont accelerate, it backfires, and now it wont start. We have changed the fuel pump, rotary cap, spark plugs, wires. the fuel filter, air filter are both fine. I have no idea what else to check, any ideas?


#2

Why did you put up a whole second post?

Is the check engine light on?

Did you check the actual fuel pressure? Do that. Are you smelling raw fuel anywhere? Pull the vacuum hose from the fuel pressure regulator and look for fuel in it.

Are the spark plugs actually making spark? Pull the plugs out and see if they are wet with fuel. Are the fuel injectors actually getting power and spitting fuel?

You may want to check the compression. How many miles are on this van?


#3

sorry i didnt see it on there. so the fuel pressure was fineand no raw fuel everything was ok but the guy thats been working on it said something about the cataylic converter. its actually a box truck but its listed as a van on the title it has aboutl 110,000 miles


#4

It is possible that your mechanic suspects a clogged catalytic converter. That could certainly explain the symptoms.


#5

It certainly could. This is a very easy thing to check. Has “the guy thats been working on it” actually checked it? I’m not a mechanic and I could tell you in about 10 minutes.


#6

would i have to replace the catalytic converter or could it be uncloged ??


#7

this has been going on for over a week we dont want to take it back to the same guy. how do we check to see if its clogged?


#8

Unscrew the 02 sensor(s) before the suspected clogged catalytic converter(s). Take a small test drive. If power output is very improved, then the exhaust is clogged, probably at the converter.


#9

how do i get it unclogged?? or do i have to replace the catalytic converter??


#10

The backfiring has me thinking of a different problem. Could be the timing chain slipped.


#11

Is the backfire through the intake manifold, or is it out the exhaust pipe.
When it doesn’t start, what does it do? Does it crank at normal speed? Does it backfire during crank?
Have you CHANGED the fuel filter?
Has somebody been turning the distributor (it has a distributor, doesn’t it?)? Someone misadjusting the timing will cause the engine to backfire – either forward or backward. Has someone CHECKED the timing with a timing light (when it was running)?


#12

I think that you should see the comments below about checking the timing.

As for the cat, as far as I know the only way to unclog one (if it is clogged) is the not so legal way of busting out its guts.

Aftermarket cats can be had for reasonable amounts of money. But don’t do anything w/ $$ until you get straight on the actual problem.


#13

Any converter problem can easily be checked with the use of a vacuum gauge; if you can find a mechancic who will actually use one and knows how to read it.
It’s a bone simple, fast process.

So has anyone checked for any codes during all of this or has it all been one of those throw mud against the wall and see what sticks kind of deals?


#14

im not sure about the timing chain tht was the first time i heard that. We also just learned that the manifold has a crack init could that cause all those problems? And sometimes it starts and some times it wont it will just crank. and at first we ran it for codes and it came up with two things for the mass air flow sensor, but we replace it and now there are no more codes but its still having tons of problems


#15

A crack in the intake manifold could allow enough air into the engine cylinders that it could upset combustion. Perhaps, you could put a piece of tape, or use a sealant, on the crack? Then, see how the engine runs. The tape, or sealant, would just be a temporary measure, of course.


#16

i think its the exhaust manifold though, will that make a difference?