Bambam7

Well, I am not sure, but I think my host of problems may be caused by the ECU itself.
I checked the wiring- it seems OK, and I re-grounded everything.

I have a readout from the 02 sensor now, and It's pretty revealing.

The ONLY time my car is in closed loop is at about 1/4 throttle.
Idle- Steady at .95v. Criuse- Steady at .95v.
Whenever the throttle is almost closed it seems to go OUT(!?) of closed loop and locking into a full rich mode. The reading doesn't move around at all.
Full throttle is steady too. (That's fine)
The ONLY time I get the reading jumping around between .3v-.5v (indicator of closed loop) is accelerating giving it about 1/4 throttle. Tiny bit more or less and it locks into a very rich mode. (.95v)
I have a brand new 02 sensor.
Replaced TPS as well, and the TPS signal tests within specs at the ECU harness.
During my emmisions test it came out with HC 8x over the limit- they said it was running very rich.

My car gets around 10-12 Mpg (It has since I got it!)
Oh- also- The check engine light doesn't come on for around half the trouble codes, they only show up if you check the codes from the ECU. Just seems strange. (you can unplug the o2 sensor and the light won't come on, for example, but unplugging the TPS will! But there will be a code for the 02 sensor if you try and read the codes.)

I'm ready to cry.
Any opinions?
Anyone have a good ECU? 1990, with manual and A/C.

Bambam7

anyone have an opinion?

Scott 89t2

as I stated before, unplug the 02 sensor from the harness in the engine bay. then hook your voltmeter to the end of wire of the 02. do you still get .95v at idle?

have you tried reseting your ecu since these problems started?

Bambam7

Yep, I ran a new wire for the o2 sensor to the ECU just in case....
Not only is it stcuk at .95, but it doesn't jump around from being modulated by the ecu.... somethings amiss.

Scott 89t2

what codes do you get?

Bambam7

Codes 30,33, split air volave and ACV or something, because they've been removed.... Ocassionally I get fuel pump resistor relay.

Scott 89t2

Ya I am still a little confused on the relay since I only thought the turbos had them. so you say you have that metal box thing with the relay resistor behind you right headlight? pull up your rear carpet and measure your fuel pump voltage at idle. if you do have the resistor relay it should only be at 9 or so volts. if the relay was bad and giving you full 12v at idle. that would cause the richness at idle. but I'd get someone else to confirm that it should be 9v at idle on an N/A. It is on a turbo.

Bambam7

Ya, I've been thinking about that being the reason for rich running at idle. ....I will check the voltage soon...still doesn't explain why it isnt in closed loop at idle though.I am really getting pissed at my car.
I've got a little roughness/hesitation at very high rpm WOT too.. I always thought I was leaning out but the voltage reading stays at .9 or so uder full throttle. I have new plugs/wires, and an MSD. I am getting so sick of this- I just want it to run right!!

Scott 89t2

the voltage should be constant at idle. and move back and forth while light crusing. (I can never remember which way is open or closed.. )