Kennerz

Hi,

Been here since the start, but still learning. I'm trying to sort my car out to get it to pass smog.

(It's been in my garage for four years)

The maf was bad, (New richporter MA157 - looks just like a wells(Identical) Went over all the wiring and grounds.
Put in a new reman AC Delco computer
Fuel Pressure is good,

O2 sensor is swithching (100 to 900 mv)
Problem is once warm at cruise on the freeway, and WOT the BLMs got to 140, normally in other ranges they are at 128 +-4 or so.

The 140 is in BLM cell 15 usually the intergator is 128, the problem is it's failing Nox smog at 900or so ppm when it needs to be under 500. Passed cleanly on the other smog criteria. Just the Nox.

Just put on a new 3.5 in cat back and magnaflow converter.

Don't know if the fuel pump is weak, or if it needs to be retuned for the larger exhaust. Maybe the egr valve, could be injector (ford blue top 24 lb)

california MAF car with all smog in place.

At cruise the spark advance goes to 55 deg (seems real high, maybe the esc is bad?) Or I've heard that a bad torque converter lock up solenoid can wreak havock on the ECM. mine doesn't seem to be unlocking like it's supposed to. Any suggestions is good, really don't want to pull the runners appart to replace the egr yet, (AZS&M runners, need ot special order gaskets) but will tear it appart if I have to. everything else seems ok. Do you think I just need it tuned?

I don't have a lot of time and don't want to keep throwing parts and $ at it.
Experts, please help - I have to figure this out...

Vader

I'd begin by verifying the function of the EGR. I know it's not any fun at all to access the valve under the plenum, but the solenoid, vacuum lines, and control can be diagnosed externally, and even the temperature switch can be checked externally if the valve is operating.

FWIW, stock tuning on an '87 allows as much as 48° BTDC at cruise, and the '88 may have been more. Of course, base timing has an effect in the real world, but you're likely reading a data stream so you're getting only the reported advance adder.

Kennerz

Vader,

Thank You for chiming in, that is exactlly what I was looking for. I'll focus on testing the egr.