Help Please

[stlysmack]

I have a 1995 Chevy Blazer, it has been running very rough , really bad gas smell, shaking and Check engine light is on and sometimes flashes. and it is running rich. Got a printout of codes from Autozone. random misfire, MAP sensor, temp sensor, . Mechanic changed the cap & rotor, the plugs and wires, the coil pack, the MAP sensor , the temp sensor, and then he said that the fuel injector needed to be changed because it was leaking . So now after all this has been done, it is running exactly the same. He said that the there is a short in the wires some where and that is why the truck is running so badly. How do you find out where a short is and does this even sound right. I dont know anything about cars except for what I try to do research on. i am already out over $500 between parts and paying him. I am a single mom and need to know where to proceed from here. Thanks sorry if some stuff doesnt sound right I tried to write everything dowm.

[j cAT]

you must give vehicle details as I asked before. engine type, throttle body injection or fuel injection ?

go to another recommended repair shop that is familiar with your type vehicle.


the fuel pressure test must be done as I described earlier. running rich with missfires can very well be the fuel delivery system and this requires a pressure test .

DO NOT GO BACK TO THE SAME REPAIR SHOP.

WITH PROPER TESTING THIS IS NOT EXPENSIVE TO FIX .

MECHANICS GUESSING AT YOUR EXPENSE IS YOUR FAULT.

tell them no fix no pay !

[stlysmack]

Originally Posted by j cAT

with fuel injectors you read the fuel pressure with a pressure guage engine running to see if it is at the correct pressure. then you shut down the engine and wait and see if it holds pressure. if it drops pressure fast ,this can mean the injectors are leaking.

the injectors always have 12 volts to them. they are turned on by the pcm grounding out the ground/return side of the injector coil.

you may need new injectors. also check the fuel pressure regulator for proper operation .

he did this work backwards. though the MAP could cause rich running. he also charged you too much for that work.

post what engine, miles etc..

Hi, He put a new fuel injector in the truck, and all the other parts I already mentioned , but the truck isn't running any better than when he first started. He said the computer was bad, and then he said it isnt, but there must be a short in a wire that is causing the truck to run so rich. Sorry I dont understand much of what you were saying about the volts etc. I forgot to mention that I am a single mom and dont know much about vehicles. I have been buffing up on learinig the mechanical stuff, because I kind of get the impression that my mechanic might not be sure of what he is doing, Anyway, the check engine light is still on and I still get the random misfire code. How would I be able to tell if it really is a wiring issue or if it is something that he may have missed? thanks

[stlysmack]

I have the code that comes up P0300 cylinder misfire detected

Probable Causes
Ignition system fault (coil, plugs, wires Etc)
vacuum leak
injector fault
high or low fuel pressure

So I have basically addressed all of these probable causes
have replaced the plugs, wires, coil , cap , rotor, injector and regulator, also a MAP sensor

My question is could there have been an error in installing the injector (could it have been damaged or installed wrong) or does this sould electrical like my "mechanic"said

[NHRA]

since when does a 1995 use OBD-II P0300 thats is a OBD-II code

[stlysmack]

Originally Posted by NHRA

since when does a 1995 use OBD-II P0300 thats is a OBD-II code

It is a late model 1995 so it uses the OBDII

[Tech II]

Have to agree with Jcat....guy was obviously in over his head........

First of all, a good scan tool would isolate WHICH CYLINDER IS MISFIRING?

From there, you check spark, compression, and test the injector.....

Something very wronghere: cap/rotor, plugs and wires, coil, two sensors, and an injector and labor for $500? No freakin' way!

[stlysmack]

Originally Posted by Tech II

Have to agree with Jcat....guy was obviously in over his head........

First of all, a good scan tool would isolate WHICH CYLINDER IS MISFIRING?

From there, you check spark, compression, and test the injector.....

Something very wronghere: cap/rotor, plugs and wires, coil, two sensors, and an injector and labor for $500? No freakin' way!

I think I failed to mention that I did not take it to a shop to have it fixed, My mechanic has a garage he works out of , and I guess all the tools and machines required for repairing vehicles. I can't afford to take it to a shop. I bought all the parts from Autozone and NAPA ,, I paid close to $500 for the parts and he charged me to put all the parts on (the injector alone was $270) A shop wants an hourly rate and then they overcharge you for parts , i have three kids and two jobs and cant afford the rate a shop would charge me.