tracey1212

I'm new and I hope this is the right forum to ask this question:

The suburban has several codes: random misfire, bank one position 2 O2 showing heater malfunction, gas cap code.
Replaced wires, plugs and made sure all were just right. gap. .60. New distributor cap and rotor as well. Just got sensor in and will replace shortly.

Problem: Cant seem to stop misfire with all new items above. Fouling plugs for some reason. Checked wires to make sure they are on properly. Rechecked all gaps. Can't figure out the misfire issue. I am wondering if the O2 sensor is causing a super rich problem and is fouling the plugs.

What's your take on this?

5.7 engine 130000 miles. Was running fine then started having problems that seemed to be tuneup related.

Thanks for your help.

Tracey

johntaps

Hello and welcome to the Forum.
Have you checked that your fuel supply system working properly or not? Because most of the time the main reason behind the engine misfiring is due to the loss of fuel pressure, so check it once.

shamrock246

It might be some problems with the old spider injector assy poppets sticking, leaks etc,they make an upgrade http://www.amazon.com/Delphi-FJ10566...1997&carId=001

tracey1212

I looked at the comments on Amazon about the new Spider and the problems an old stuck up Spider creates. Sounds similar, I have to say, but here's the thing that might make a new fuel injection Spider the wrong road for me: When I replace all spark plugs, the truck has a slight misfire in one cylinder, but after a period of time, several other plugs get fouled and then they don't fire.

I would say maybe 100 miles later, the fouling takes place. When I look at the plugs that are fouled, the entire end of the plug that is exposed in the cylinder is darkened. Its not oil. Its unburned gasoline or improperly burned that has coated the plug.

This is driving me crazy. I have to fix this problem myself. The suburban is out of inspection, and I'm out of work, so very limited. My experience level is modest at best in doing engine level repair, so any and all ideas as to what might cause the dead cylinder problems is welcome. I hope its the O2 sensor which I will replace this week.

shamrock246

you could have multiple poppets starting to fail mine died on me overnite #5 poppet stuck closed change over is easier than it looks aside from the pressure regulator leaking which you have to go into the intake manifold to change that anyway thats the only way fuel is get to the engine,did you check the fuel pressure?did you try putting any of the original tune up parts that you replaced back in one at a time to see if that helps

tracey1212

I hate to ask, but since you've replaced the injector system, could you give an outline of what has to be done in order to replace the it?
If it turns out that I need to go this far, I will purchase the Delphi mentioned above from Amazon. Seems they make great stuff.
Just reading a few comments, it seems this is kind of hard to do...I'm still trying to figure out if I should tackle it.

Thanks!

shamrock246

1-disconnect the battery
2-remove the intake hose
3-disconnect any sensor connectors and move the wiring harness out of the way to be able just get the black plastic upper intake off
4-remove ignition coil mount and any vacuum hoses
5-you can leave the throttle body connected to the upper intake
6-disconnect the main injector connector in center of the upper intake and remove the two fuel lines
7-loosen the intake bolts i did mine evenly then remove them
8-the upper intake comes off yes the lower intake will look really dirty i just cleaned the injector ports so i could see the numbers to match them up with the new spider
9-remove old injector assy and wonder WTF was GM thinking
10-install new mount the bolt will tighten but the bracket will be loose i put some blue loctite on the threads
11-install new spider there will be numbers on the spider that will go to the corresponding cyl
12-install new o-ring on spider assy lubed with some engine oil
13-install upper intake manifold(get a haynes manual there is a specific torque procedure for the bolts)
14-reconnect the fuel lines,vacuum lines,electrical connectors
15-reconnect the battery and cycle the key a couple of times pausing for about 10 seconds between each cycle and check for fuel leaks
16-install intake tube and if done right it should start right up

I did this from memory from over a year ago i might of missed something

post up any questions you have