Misfiring 22re
 

About 3 days ago I put on an LCE header onto my 22re, I took it to the muffler shop for them to put an exhaust system on. I drove there with just the header so it was pretty loud and I expected it to shake a bit with low back pressure. When I got my truck back I noticed that it was still shaking and felt like it just wanted to die. With some experimenting I was pulling plug wires and it seems to run MUCH better with the 3rd cylinder not firing at all. When all the other ones are pulled it just makes it worse so I'm confident that the 3rd cylinder is not firing correctly. I also checked the timing and it was way off so I put it back to where it should be but it doesn't really run any different.



I have pulled the negative off the battery to restart the ECU if it needed to do any adjusting with the more free flowing exhaust. No results. My CEL is on and always has been since I bought it and it throws Code 21 which is the 02 sensor. I'm putting a new one in today but I highly doubt that will fix it....



Anyone have any clue as to whats is causing this? Because I am baffled.

Give the O2 thing a swap. Let us know afterwards.

What size pipe was exhaust make from??

I just put the O2 Sensor on and it runs the same with the CEL still on. I'm running through 44K(fuel treatment) to see if it makes a difference in anything.
The exhaust size is 2 1/4".

Is the O2 sensor in same location on exhaust. If it is moved too far downstream on exhaust it won't get hot enough to work. So a heated O2 sensor would be easiest answer.

The O2 sensor location is roughly in the same location, give or take an inch.

Does your's have a broadband O2??

Check all wires for continuity. Perhaps a wire broke when header was installed.

also use an ngk or denso sensor. all else is junk on our trucks.

double check all your gaskets. could have a breach or tear.

I put in Denso. All the gaskets are fine. I really do not believe it has anything to do with the O2 sensor because I've always had this problem, even when it was running great.

I checked that the chain had not slipped and the clearance on the valves checked out, and everything lines up at TDC. The only thing left would be injectors.

Thoughts?

Start with easy stuff. Swap that spark plug with another one and see if the misfire moves. Then try checking the plug wires. If neither of those solve the problem, start checking for a fuel problem.

I swapped all the spark plugs, switched around wires and replaced them. I checked all the injectors to see if they are in the ohm range, which they are. Checked all the valve springs to see if I had a broken spring. The cam seems to have normal wear, if any at all.

I took it to a mechanic yesterday and his only response was that the timing is jumping around and he couldn't figure it out.

I'm thinking that the ECU is not doing its job correctly. First, the CEL keeps throwing the code for O2 and TPS(Both replaced) and I have read that theres a certain circuit that can short out.

Could my ECU possibly not working correctly and not adjusting to the different back pressure with my more free-flowing exhaust?

Im sorry, I dont know much about troubleshooting an ECU. Have you tried checking the compression on that cylinder? I know you have done a visual but a compression test will summarize if you have a problem or not.

Also, see if there are any other tests you can do on the fuel injector. I had a problem with a skipping cylinder and it ended up being the fuel injector wire in the main harness. Over the years moisture accumulated in the harness and corroded a connection until it broke.

Maybe someone else with mores experience will chime in

absolutely. to the OP, stop throwing parts at it hoping it will solve your problem. diagnose and solve it, then replace parts that have failed.


what is your fuel pressure? if you don't know it, you will have difficulty diagnosing a whole host of potential problems that appear to be something else entirely. that's how you waste money on unneeded parts.

wally

The only thing I actually purchased was the rotor and cap, which was needed. The rest was already sitting around.

The compression on all the cylinder were in spec. I then checked the vacuum to see if I was leaking. It was far below where it should have been. After looking around the engine bay for an hour at hoses and scratching my head I had to step back.

After doing some random searching around, I ended up on 22rePerformance's website and their checklist for "misfires". I came about the EGR trick and decided to try it out.

I cut up some tin and blocked off the EGR that connects to the intake. Starts and runs like a champ. Not sure why a new header would have caused this; possibly different pressure of some sort.

Thanks to all who chimed and attempted to help.

Awesome man!! Congrats!

glad you solved it. doesn't explain the timing jumping around, though. i'd want to solve that, too.

also read up on blocking off the egr, and what it can do to your engine. could be a short term solution that leads to long term problems.