97 Blazer
kopo0001
10-01-2003, 10:57 PM
I have a 97 Blazer with a 4.3L Vortec V6.
It has been starting very hard, idling rough when cold and hot, and hesitating when trying to accelerate. I pulled a code out of the computer that said 'Random Engine Misfire'. A few people have told me it may be the fuel pressure regulator. Is there an easy way to test this part, and also how difficult is the replacement/have any tips or hints?
Thanks
It has been starting very hard, idling rough when cold and hot, and hesitating when trying to accelerate. I pulled a code out of the computer that said 'Random Engine Misfire'. A few people have told me it may be the fuel pressure regulator. Is there an easy way to test this part, and also how difficult is the replacement/have any tips or hints?
Thanks
GMMerlin
10-02-2003, 12:35 PM
It may be that the injector poppets are stopped up.
The poppets cannot be cleaned by conventional means (injector cleaner and additives).
GM has a special procedure and tool to unstick and clean the poppets.
I have done many of these unstick procedures with great sucess.
You can test the fuel pressure regulator by installing a fuel pressure gage and watch for fuel pressure drop when the engine is turned off.
The poppets cannot be cleaned by conventional means (injector cleaner and additives).
GM has a special procedure and tool to unstick and clean the poppets.
I have done many of these unstick procedures with great sucess.
You can test the fuel pressure regulator by installing a fuel pressure gage and watch for fuel pressure drop when the engine is turned off.
Mr Clean
10-10-2003, 01:54 AM
This excerpt is from my brother who warned me about this problem before I bought my Blazer.
"4.3 vortec engines with CIS injection are prone to a peculiar problem. Most commonly the complaint will begin with the vehicle running poorly followed by excessive fuel consumption and the smell of an acutely rich exhaust. The problem is a leaking fuel pressure regulator inside the upper intake plenum.You can verify the priblem by attaching a fuel pressure gauge to the valve at the rear of the intake on the driver's side and checking for pressure loss with the engine off. When you key on pressure will go between 60-70 pounds, after a minute or so it should maintain at least 50 psi. Unfortunately the regulator is part of the injector assembly and is quite expensive. Also don't count on your local shop to figure it out until after they have sold you a tune-up, MAP sensor, MAF sensr, fuel pump, oxygen sensor and any number of other parts. I used to go to other shops after they pulled their hair out they would call me and then they were really pissed when it takes five minutes to identify the problem. This one used to throw a lot of people off, way off."
Hope this helps dude.
"4.3 vortec engines with CIS injection are prone to a peculiar problem. Most commonly the complaint will begin with the vehicle running poorly followed by excessive fuel consumption and the smell of an acutely rich exhaust. The problem is a leaking fuel pressure regulator inside the upper intake plenum.You can verify the priblem by attaching a fuel pressure gauge to the valve at the rear of the intake on the driver's side and checking for pressure loss with the engine off. When you key on pressure will go between 60-70 pounds, after a minute or so it should maintain at least 50 psi. Unfortunately the regulator is part of the injector assembly and is quite expensive. Also don't count on your local shop to figure it out until after they have sold you a tune-up, MAP sensor, MAF sensr, fuel pump, oxygen sensor and any number of other parts. I used to go to other shops after they pulled their hair out they would call me and then they were really pissed when it takes five minutes to identify the problem. This one used to throw a lot of people off, way off."
Hope this helps dude.
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