Ok, I need some ideas on where to start.. I basically picked the car up, drove it 15 hours home, and then started replacing stuff. I'm not sure if it was acting like this before or not.

92 305 TPI.
Replaced plugs, wires, coil, cap & rotor, o2 sensor.
Removed all emission stuff including the charcoal canister. (Plugged the vacuum line on the TB)
Removed all of the air intake stuff and just have a TB mounted filter.
Placed a breather filter in the valve cover and plugged the filtered air port on the TB.
Removed the heater control valve, plugged the vacuum line running to it, and re-ran the hoses to bypass it and the TB.
Relocated the MAP sensor to the firewall and extended the wires and the vacuum line (Using hard line and I've tested for leaks, line is about 10" long now).
There is still the hole in the CAT where the AIR pipe plugged in, haven't sealed that yet.

Problem: Once the engine is warm, it idles and runs pretty rough. You can feel it shaking the car at idle and it feels like it's loading up when you do WOT runs. I've rechecked plug gap and they're fine. Plugs had a very light gray almost white coating on them than can be rubbed off. Chart says I'm running rich/not enough spark. After a long highway drive (1 hour+), ECM will set a running rich code. I'm also getting crappy milage.

Just looking for things to check next. Besides checking the plugs, I've moved the MAP back with the shorter hose (no effect), tried a different coil (no effect), and checked everything for vacuum leaks. Could a small hole in the cat cause my problem? I wouldn't think so, but I'm not sure. Bad O2 out of the box? What would cause me to run rich that might not have anything to do with the stuff I've done (strange coincidence??)

Thanks for helping,

Kevin D.

 

I'm really not familiar with speed density, but if it wasn't doing it before you started working on it then it's something you did. SD cars are very sensitve to changes. I'm not sure how removing the AIR system will affect it, but it does inject air into the exhaust to completely burn and remaining fuel. So if you delete it and you aren't getting a good burn then it would show rich. As far as extending the MAP wiring, did you solder or use crimp connectors. a poor connection can really screw things up.

 

Can you burn you own Proms, If Not I would look into how to do it, the change in the air intake is enough to change the AFR on the car. Just a sugguestion.

my .02

 

I've been looking into getting the stuff do do my proms, guess it's a good excuse.. Does the ECM really learn different values? Maybe I'll try pulling the fuse for a while today. As far as the MAP wiring it is butt connecters, I'll switch to solder and heat shrink wrap.

As far as the AIR stuff, isn't the pump just running the manifolds at startup and then only injecting in the CAT for a complete burn there? The CAT is post O2, so it shouldn't effect the reading. The EGR is still there and functional.

Hmm.. I'll try and message the guy that has the explorer windshield washer bottle, he's removed all his air stuff and has a TB mounted filter. I'll see if he had to do anything special.

Thanks,

Kevin D.

 

Follow up..

It's not the hole in the cat
It's not the charcoal canister
It's not the timing
It's not the ecm needing to relearn

I've got a cable ordered and am checking out Tunerpro RT.. I'm positive that my crimps are good for the MAP wiring (I'm still planning on solder..), but I'm curious what effect different gauge wire would have? It's 16g that I ran, but I do have so GM wiring left over from my 93 part out. I'll be swapping out to the correct size wire when I redo the connection with solder..

Any other ideas to check before my cable gets here next week (hopefully I'll be able to see exactly whats failing)

Thanks,

Kevin D.

 

Your MAP sensor sends an electrical signal so any resistance in the wiring will affect what the computer see's. Bad wiring or bad connections could both cause that. You might also try going to a larger I.D. vacuum hose running to the MAP sensor since it is so long. As I said I'm not familiar with speed density. But if I understand it correctly then the MAP sensor the TPS are what realy affect the injector pulse. If the MAP is reading low then the computer thinks it needs more fuel because the TB blades are open more that would cause the rich condition. If nothing else I would put the MAP sensor back and see if that cures your problems. I really belive it is the source of your problems.