1995 Blazer missing badly / timing issue

Tiny
VIKEZFAN
  • MEMBER
  • 1995 CHEVROLET BLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 160,000 MILES
I have a 1995 Chevy S-10 Blazer 4x4. About a month ago it started acting up. It would seem to miss once in a while especially while accelerating between 20 and 50 MPH. It stayed this way for about a month and then it got progressively worse to the point where one day I walked out of a store to find it would just crank without firing. It eventually started but has not run right since. The only code I was receiving was a catalyst system code. The exhaust system was falling apart so I had it replaced from the catalytic converter on back. This got rid of the code but not the problem. I had replaced the EGR valve, plugs and plug wires a few months back for another problem. This time I noticed corrosion on the coil connection to the distributor so I replaced the coil and the coil wire. I have had the ignition module tested (good) and replaced the distributor cap and rotor. I got a fuel pressure tester and it read 60lbs when I first turn the key and it bleeds down to 52-56lbs. When I can get the motor running, the fuel pressure is 56lbs at idle and 60 when I give it some gas. So, back to the spark. When it is running, it runs smooth at idle, but when I give it a little gas it starts running really rough. I can not go past about half pedal or it will die. It will also backfire through the intake occasionally. This means timing. After replacing the distributor cap and rotor, I cleared the OBD2 codes. There are, at present, no codes. No matter how bad it runs, nothing is coding. I was suspecting the camshaft or crankshaft sensors, but I thought that they should code if bad.

Can anyone help me out on this? I am at a bit of a loss as to where to go next on it. I hate to just randomly replace parts.
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Thursday, June 26th, 2008 AT 9:43 AM

5 Replies

Tiny
DOCFIXIT
  • EXPERT
Hook up fuel pressure gauge and accelarate does pressure drop? Check timing pull dist cap get socket/breaker bar on crank. Roll motor clockwise note location of rotor and chalk mark dampner. Now turn engine counter cloclwise note when rotor starts to move if crank has moved more than 5 degrees. Then gears chain are worn.
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Thursday, June 26th, 2008 AT 9:53 AM
Tiny
VIKEZFAN
  • MEMBER
The fuel pressure does not drop when I accelerate. That is when it runs. It is back to not even starting again. It cranks but won't start. Spark looks good and fuel pressure is still up. No codes. Replaced O2 sensor because it looked old and badly fouled. Nothing.

Don't have time to do more tonight.
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Thursday, June 26th, 2008 AT 8:42 PM
Tiny
OBXAUTOMEDIC
  • EXPERT
Not to step on any toes here.

But, what color is the Spark. It should be a Bright Bluish/White. If it is Orange the spark is weak.

Have you checked the timing as docfixit suggested?
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Thursday, June 26th, 2008 AT 9:39 PM
Tiny
VIKEZFAN
  • MEMBER
I took off the plenum and took a couple of pictures. I was wondering if the amount of 'washing' shown in this picture is worth worrying about. As you can see it runs from the fuel pressure regulator down to the bolt below it. There was a tiny puddle by this bolt. You will also notice that the back of the regulator is clean.


http://www.2carpros.com/forum/automotive_pictures/53070_95cfi_1.jpg



I have not gotten my hands on a timing light yet. My friend is bringing one over later. Where is the wire to unplug to put it in basic timing mode? I have looked under the carpet by the passengers feet and on the distributor. I must be missing it somewhere.
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Friday, June 27th, 2008 AT 3:31 PM
Tiny
VIKEZFAN
  • MEMBER
I checked that the timing mark lined up close when I bumped the engine to number one cylinder and it lines up. So, I decided to go ahead and replace the fuel injector spider assembly. It runs great now.
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Sunday, June 29th, 2008 AT 11:31 AM

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