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Discussion Starter #1
My car is a GMC Savana 5,7 model2001, 160000 miles
Trouble with stalling frequently, I can drive 5-6 tmiles and again stalling, I have changed plugs, fuel pump, spider system, PCM, ignion details etc. Every time I take an new spare part it starts
MAIN PROBLLEM NOW is misfire, very hard ones not like misfire of one or two plugs , feel like fullstop for some turns, like it would die all the time, you have difficulties itting in the seat if seat belt not fitted!!!
It starts up normally and after 5-10 miles it starts misfiring, if I stop for about half an hour and start again evrything is OK, if I go on without stop it jump and misfire for the whole ride ( have drove for over 200 miles but it does not stop jumping)
No influense of ambient temperature is found, cold or warm it starts misfiring
I have tried high and low octan fuel no change
I had code for lambda trouble but I chanded rigt from left without result
 

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Ok, stop driving it, you will destroy the cats.

You probably saw O2 codes because the mixture is too rich.

I would say when changing plugs you damaged the plugs, or the plug wires.

Are you saying you do not see any mis-fire codes?
 

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Ok, stop driving it, you will destroy the cats.

You probably saw O2 codes because the mixture is too rich.

I would say when changing plugs you damaged the plugs, or the plug wires.

Are you saying you do not see any mis-fire codes?

thanks for the answer

I have changed the plug wires too
have for several times checked the plugs and they are goo looking so the mixture is not too rich I suppose
But can be something with the mixture because when I start it is at first ok perhaps due to the fact that it will ge more
fuel in the beginning and when PCM later starts decriesing fuel it starts misfiring
sometimes I got misfire codes have not checked now, have to do it

perhaps the cats where destroied allreadi when I bought the car five years ago I have used it for about 40 000 miles
and all the time with trouble
I have had problems with the "authority exam" every year( hard pollution demands in my country!!!!)
 

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Discussion Starter #5
What is your fuel pressure when at idle and 2000 RPM?

I check the preassure several times when it did not start and remember it was OK somthing like 50
and the preassure did not drop for 10-15 minutes
should be ok

I have a new pump in the tank but think that the old was also ok
 

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What I was saying about the cats seeing too much fuel was in reference to the misfire, if a cylinder does not burn the fuel, it gets dumped into the exhaust and raw fuel is not good for cats.

If your seeing misfire codes, post up the codes.
 

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What I was saying about the cats seeing too much fuel was in reference to the misfire, if a cylinder does not burn the fuel, it gets dumped into the exhaust and raw fuel is not good for cats.

If your seeing misfire codes, post up the codes.


yes
you are right
As I said the spark plugs look fine and I say that the fuel consuption is about normal
so thats why I suppose no abnorm rich mixture
now I checked the code and the only onen is P 1345 , the camshaft sensor
I have changed that sensor but perhaps it is broken again, I bought a STANDARD
I have to buy an new
 

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Ok, stop driving it, you will destroy the cats.

You probably saw O2 codes because the mixture is too rich.

I would say when changing plugs you damaged the plugs, or the plug wires.

Are you saying you do not see any mis-fire codes?

jes
the only code is camshaft sensor P 1345
and that one is quit new

not good at all
 

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What I was saying about the cats seeing too much fuel was in reference to the misfire, if a cylinder does not burn the fuel, it gets dumped into the exhaust and raw fuel is not good for cats.

If your seeing misfire codes, post up the codes.

I changed the camshaft sensor and the car is now ok
let's see for how long!!!
 

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This day is the independent day in my country Finnland

and I believe I have found the Villain in my car
when I changed the camshaft sensor ( I had 1345 code)some weeks ago I also cleande the distributor and as may times before noticed that it was very dirty, full off white smog on the contact surfaces
I thing the problem is right here in the distributor
but why does it go dirty
a year ago I had a brand new...from Taiwan I think...and it was running properly for many miles
WHAT CAN BE THE REASON why the distributor goes bad
Can this also have resulted in all the other failures with ignion amplifier etc that I have been going trough
 

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That white stuff is probably dried residue from moisture and since it is in a high voltage area it deposits everywhere there is an electrical discharge especially the contacts. I have seen dist caps that looked good but actually had a thin invisible film on the inside of the cap which allowed occasional crossfire. There is no substitute for quality ignition parts concerning a dist cap and rotor etc. Do not use cheap parts for this.
 

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AGAIN THE SAME PROBLEM
when starting no big problem but idling with some misfire
when driving it starts dropping out due to misfire but after driving for about half an hour better again
especially if I stop and turn off the motor for a while and start again everything is OK
sometimes when starting it is shooting loudly in the exhaust
when it finally stopped in summer 2019 after 1000 miles on the road the ignition position had changed so when I got ignition in position again it started and worked well but now again....
 

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The ignition position should not change. You could have a timing chain problem that skipped a tooth or your distributor is bad. Backfire thru the exhaust means the timing is off.
 

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The ignition position should not change. You could have a timing chain problem that skipped a tooth or your distributor is bad. Backfire thru the exhaust means the timing is off.

thanks for the answer

I know that the ignition should stay firmly but can there be somewhere else the position might change. When it stopped last summer the position was completely wrong but the mecguy said the chain was OK. I have not yet changed the distributor it is still made in china but it has been good for many miles
 
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