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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29427
Experience:  GM Grand Master Technician 2007. 14 years experience.
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2002 chevy astro: driven..the replacement distributor..rotor..cap

Customer Question

Looking for CAM. 2002 chevy astro van Previous distributor bad as it would move while vehicle being driven. niece to lazy to get the replacement distributor so she kept changing out the rotor and cap. Finally the van got pissed off and upon driving down the 15 south (CA) it quit. Towed to yard and now we are trying to fix the beast.


van would not start got it running put van on scanner. it told me P101 Mass sensor bad changed that then threw a P300 random misfire changed the plugs changed the MAP sensor changed out the fuel filter, new plugs, new air filter. changed out the fuel body ($300 + big ones) van idles great no misses van cuts bogs down when trying to accelerate no power the above mentioned codes were gone and are now back. Could this problem be the ECM? Again looking for CAM
Submitted: 5 years ago.
Category: Chevy
Expert:  GM Tech (Cam) replied 5 years ago.

GM Tech (Cam) :

Hello, I'm Cam. Please include all the details about your issue so I can accurately advise you. I cannot see your vehicle so please be detailed.

GM Tech (Cam) :

How about the exhaust, did you check the cats for restrictions?

Customer :

Hi Cam, had to look for you as you were the one to figure out the problem with that 97 Pontiac Grand Am, remember? Have not check out the cats. Could this be the problem as vehicle was running great, had tuneup and such? OBD11 scanner keeps going back to Mass and Map sensors?

GM Tech (Cam) :

IF the cats are plugged it will lower MAF and MAP readings.

GM Tech (Cam) :

Take the front oxygen sensors and use a pressure gauge there.

Customer :

What kind of range on the pressure gauge do I need?

GM Tech (Cam) :

up to 5 psi, max is 1 psi

GM Tech (Cam) :

that is 1 psi at any time.

Customer :

I've been told that this van has 3 oxygen sensor, do I do all three

Customer :

on the exhaust?

GM Tech (Cam) :

just the ones on each side close to the engine so one on each side.

Customer :

the exhaust flow is very strong per husband, concerning the exhaust pipe. No misses, backfires, unit idles great, but upon acceleration, it bogs down.

GM Tech (Cam) :

OK, did he test as we outlined?

GM Tech (Cam) :

also did he test the fuel pressure?

GM Tech (Cam) :

The other option is low fuel pressure if the pump is weak.

GM Tech (Cam) :

This will almost be a new van when done.

Customer :

we changed out the fuel body as a unit with injectors, fuel filter, checked the fuel system for blockage, changed out the MASS, MAP, new plugs, new air filter, new distributor, rotor and cap. Fuel pressure is 55 as the book calls for. still have not done 02 sensors, yet. Have new ECM on order. New fuel pump

Customer :

keeps throwing the same codes P101 and P300

GM Tech (Cam) :

I doubt ECM

Customer :

why

GM Tech (Cam) :

Then rarely cause this sort of issue.

GM Tech (Cam) :

Did you check the fuel pressure when this is happening.

Customer :

yes

GM Tech (Cam) :

and it stayed above 55?

Customer :

acts like it is starving for gas and we know it is getting plenty. then if you try to accelerate with van in park, it starts out good and then runs rough and then stalls out. Doesn't want to restart but if you wait a moment or two, it will start

Customer :

yes

GM Tech (Cam) :

Did it run better if you unplugged the MAF?

Customer :

it ran but it still bogged down

GM Tech (Cam) :

Ok, plug the maf in and unplug the MAP, what happens?

Customer :

same thing, still bogging

GM Tech (Cam) :

Ok, then test the back pressure. simple test is to remove them.

Customer :

doesn't make sense? what back pressure, these are new items on van

GM Tech (Cam) :

The exhaust is new?

Customer :

no, no leaks or anything wrong with exhaust

Customer :

air flow is very good, thought that if 02 sensor is bad, it should show a code, obd scanner is new

GM Tech (Cam) :

but unless he pulled the sensors out and looked/tested it could be plugged not allowing the air to flow and causing.

Customer :

could he run the van without the sensors installed to see if the engine bogs down?

GM Tech (Cam) :

sure, for a short time.

Customer :

with as slow as the husband is, how much is a short time?

GM Tech (Cam) :

a couple miles.

GM Tech (Cam) :

just enough to see if the issue is gone or not

Customer :

at this time unable to get van out of yard, would it be easier to remove one sensor see if engine runs ok, put that sensor back in and then move on to next sensor?

GM Tech (Cam) :

sure.

Customer :

of course, would have to see what happens upon acceleration

GM Tech (Cam) :

yes

Customer :

will have to check this out, are you on line tomorrow?

GM Tech (Cam) :

yes I will be around tomorrow.

Customer :

don't want to keep you hanging, the ecm is out of the van and we will have to put it back in, and he is so frustrated, I honestly, don't need the arguement

GM Tech (Cam) :

I can understand.

Customer :

can we continue tomorrow?

GM Tech (Cam) :

bookmark this.

GM Tech (Cam) :

sure.

Customer :

how do i bookmark this area?

Customer :

save and exit?

GM Tech (Cam) :

CTRL D

Customer :

got it, thanks, talk tomorrow,

GM Tech (Cam) :

ok