'93 S-10 Chevy Blazer 4x4 4.3 - Fuel Injector Related Problems???

[dknape]

This is my first attempt at posting my problems with my Blazer.

I have a '93 Chevy Blazer 4x4 w/ 4.3-L Vortec engine. I have had the truck since 69k miles. It is now at 140k miles.

Here are my symtpoms:
- Takes a long time for engine to start when cold, starts almost right up when hot/warm.
- Idles very rough
- Truck used to have "umph" when driving down the interstate, now when pressing it to the metal, I stay at same speed or slow down. (at least it seems this way)
- When running and sitting still on concrete, the concrete below the tailpipe exhaust will turn very black.
- When sitting still, there is a very strong fuel smell.
- Fuel milage is HORRIBLE. I get about 200 miles p/ tank right now.

I thought this might have been related to the EGR valve. I had it cleaned (it was very full of carbon build up). After having it cleaned, it started up quickly for about the next 4 or 5 starts. Now it is back to it's own horrible running self. :-(

This all started when my father in law helped me "tune-up" my vehicle 6 months ago. BTW, I am not a mechanic. He had me put 2 things of fuel injector cleaner into the fuel tank during the "tune-up". I informed him that I had an empty tank of fuel. He said, no problem. We did it anyways. He rev'd the engine from under the hood and blew out alot of black smoke (carbon???) from the tailpipe.

This is the only thing I can think of. Ever since this event, it has run horrible. I at first thought we had the plugs on wrong. Since then, we have replaced the starter, plugs, wires, and timed the vehicle.

I purchased a Fuel Injector from O'Reilly Auto Parts yesterday for $270.00. I did not purchase the nut kit I am seeing mentioned on here. Is this a problem?

Since purchasing the vehicle, I have not ever replaced the O2 sensor. Do you think this is part of my problem?

I am VERY low on funds right now and am getting ready for a 1,200-mile move on the 17th of this month and want to make sure that my truck makes it to my destination AND hopefully gets better gas mileage.

Any help is GREATLY appreciated.

[vballfun]

Those are almost the exact symptoms I'm experiencing right now.. (on my '95 Blazer (vin W))
right down to the 200 m/tank (used to get 300-330) and black marks on pavement behind exhaust.

I'd cleaned my EGR valve as well (majorly coked up and -stuck-).
I also ran some seafoam through my fuel/brakeboostervacuum line/oil
noticed a slight improvement for the next 30 minutes of engine runtime... then back to the smelly rough oscilating idle (from almost stalling to normal about every 2 seconds)

I took the truck to autozone (they will read your trucks diagnostic codes for free as opposed to the shop chargin ~$90 just to read codes) and had 'fuel too rich' and a 'random misfires' codes.
My SES (service engine soon) light has been solid for a few weeks.. So.. this week I'm planning on getting the same $270 part and nut kit everyone seems to mention on here and put it in (weather permitting.. calling for rain every day this week in VA)
before I went through the trouble of taking off the plenum I was considering replacing the O2 sensor (since it should be easier to get to) So.. I have the same quetion.. could these symptoms be from a faulty O2 sensor?

[joeval]

The oxygen sensor does control the fuel mixture but it operates after engine is warm. If it's giving the wrong signal, then it might be telling the computer to add fuel when it doesn't need it. There are other sensors that give the computer information. Make sure the gap was correct on the spark plugs. Also check the rotor and distributor cap for damage and check for any vacuum leaks.

[dknape]

My gap is correct on my plugs.

Vballfun
My engine too is doing the same oscilating idle / nearly die every 2-3 seconds. My bro-in-law is replacing my injector Tuesday. I will have Grease Monkey replace my O2 sensor this week when I take it in for oil change. I have been told by a guy who has done several of these changes that I do not need the nut kit. Perhaps this is why he has done several. Perhaps I should have asked if it was the same vehicle.

Let me know how yours goes.

joeval
I am curious. My engine light does not come on until about 5 - 10 minutes after a cold start and almost immediately from a warm/hot start. Do you think I should replace the O2 sensor before I do the injector?

Would a faulty O2 sensor cause it to nearly stall/die every 2 - 3 seconds as described above?

Thanks All!

[tomminajar]

I would wait with the O2 sensor till AFTER you have the Injector checked/fixed- If you run it while dumping fuel you could foul out the new O2-

The nut kit is up to you -BUT since you have it all apart once-it's not any more work- Few more $$ now could save a headache later... GL

[dknape]

Originally Posted by tomminajar

I would wait with the O2 sensor till AFTER you have the Injector checked/fixed- If you run it while dumping fuel you could foul out the new O2-

I idea was that perhaps my injector does not need to be replaced. What if all I need is to replace the O2 sensor. If that were the case, I can save $300 and just spend $50.

Does anyone think that it could possibly be the O2 sensor? Or do you think that mine is ruined based on the history given?

Thanks,
Dustin Knape

[tomminajar]

When you start the car the ECM doesn't even use the O2 sensor till the converter gets hot- A bad 02 shouldn't cause the truck to 'die' You can unplug it and it would still run- just set a code...

[hkdonfishn]

Take off the plenum and look. Look for the washing. If it is there is a guy who sells the parts on ebay there is a post on here that I put on. I ordered one from him and I have had no problems and they are way cheaper then dealer prices or auto parts stores. even if it is not with that year blazer you may want to replace it anyway as a precaution but I bet it is mine did the exact same thing and a new CPI fixed it. Good Luck.

[vballfun]

Ok.. well I went and got the injector from Autozone ($270) and the nut kit from local dealership (ranged from $77-$85 for the 4 dealerships in my area), and upper intake gasket ($11 at advance) And an Oxygen sensor ($51 from Advance).

Spent about an hour getting my plenum off (first time i'd done that) and sure enough the passenger side was a nice shiny golden color (as opposed to the nicely grimy black of the drivers side). So my fuel injector was leaking.



Oh also spent $30 on a fuel pressure guage (cause the 2 closest autozones didn't have any to rent grrrrr) and I was not keepin any pressure.

I think the hardest part for me was wrestling with the metal fuel lines going into the nut kit.. after moving them to get the old nut kit out, they didn't want to line up with the new nut kit and had helluva time getting them to even thread.

Anyway.. after putting new CPI and nut kit in I had fuel pressure that didn't dwindle away, and after running if for about an hour of test driving no SES light... and symptoms were gone (rough oscilating idle.. stinky exhuast)

So probably won't put the O2 sensor in.. take it back and save the ~$50..

Thanks for all the pointers everyone.

oh.. just a quick question.. what is this on drivers side of engine.. hooked together with vacuum lines

(The Arrow is just to show orientation.. it's pointing to the 'front')



Thanks

-VBallFun

[hkdonfishn]

Can you submit a picture of your EGR I need to see the wire plug.

[vballfun]

Originally Posted by hkdonfishn

Can you submit a picture of your EGR I need to see the wire plug.

This is the best shot I have, I only took about 10 pics (just a few before I disassembled everything so I knew where to put it all back at incase I forgot LOL)

Hope this is what your looking for. If I remember correctly it was an oval/oblong with 2 pins.

VBallFun

[hkdonfishn]

Originally Posted by vballfun

This is the best shot I have, I only took about 10 pics (just a few before I disassembled everything so I knew where to put it all back at incase I forgot LOL)

Hope this is what your looking for. If I remember correctly it was an oval/oblong with 2 pins.

VBallFun

Thanks for the picture. Wow the 93 setup is alot differant then the 94. I have the same vacume setup but it is behind the plenum and it looks a little differant. Thanks again.

[vballfun]

These pics are from a 95 not a 94.

[hkdonfishn]

Originally Posted by vballfun

These pics are from a 95 not a 94.

Gotcha.. i saw the top Post and it was for an 93. Well anyway it is allot differant.

[dknape]

Does the 95 have the same engine as the 93? I will be tackling my 93 on Friday. I will try to get some photos in.

vballfun: Did you clean out your EGR valve at all?