Readiness Monitors

[Turbo2g]

As some of you know, I picked up a 98 GST (manual trans) with a few issues. I fixed all the engine related problems first and have to pass smog to register. I have put over 100 miles on the car over three different cold starts over the past few days. I have not cleared one single readiness monitor! All of my data looks on point and no codes have returned. Usually at least Heated o2 and EGR clear in the first trip with EVAP and CAT taking the longest. Any idea why this thing is taking so long to clear? Fuel trims a good switching from +/- 1-3, rear o2 shows a good cat with steady low voltage, Front o2/ a/f sensor shows good voltage switching low to high. The fuel trims show there are no vacuum leaks, the o2 voltages that the cat is good, and the car goes into closed loop in a normal timely fashion. The MAF/IAT signals are plausible at a variety of speeds and rpms. The ECT reads anywhere from 190-205 as I'm driving around. Should be hot enough to run clean.

Do these cars just take a long time to clear, or is there anyone who has experienced this and can tell me if there was a issue or a fix.

 

[Turbo2g]

Okay I think I have this figured out. I hadn't had to fuel up since I bought the car. I did yesterday and the car cleared two of the monitors by the time I got home. I'm assuming the prior owned wasn't putting premium fuel in. A tank of Shell v-power may have done the trick!

 

[Turbo2g]

I still haven't cleared any more monitors. I don't like the data for the coolant temp (ECT) while cruising. The thermostat seems to be working, but I believe it is an aftermarket thermo that's way too low of a temp. The car sometimes sees 168ish going down the road. I know it isn't stuck open because the car warms up quickly. I'm thinking it has a 170* thermo some shuck though was an upgrade at one time. I believe this isn't allowing the car to run the rest of the monitors.

What is the stock temp thermostat supposed to be? And suggestions on what I should run? I saw someone say 195*. Thats a little too high for me.. Id probably do a 180.. what do you all think?

 

[2gGst98]

So first thing to start with is find out if your loosing the 12v constant to the ECU. I also have this issue right now. I have a 95 ECU with link v3 and cant get it to ready either as I don't have the 12v constant, so when you shut off the car the ECU resets itself. I have read that the 98 and 99 actually have a recall or problem with the 12v constant and people take it to the dealership and have them force ready the sensors then put the pipe up the butt. I have not yet done this as I want to find where I'm loosing me 12v. work and life takes priority though.

I ran hot also and smaller thermostat does not fix it. I a 190* just did my ducting around front mount and radiator, this pretty much took car of it. I also do not run an AC fan. Unless you run a 160*, a 180* and a 190* both start to open around the same temp. so if your having temp issues, a thermostat that is less is not going to stop it, it just will take longer to get to normal operating temp and will still run hot once warm.

hope this helps some, my issue just stated this year 2 months ago. So maybe someone who has fixed the issue can give more insight.

 

[Turbo2g]

Thanks for the advice. I'm not loosing the two monitors that I have already set, so I don't suspect a voltage issue. The ECM would rest those too if that was the case. I think for me its the 160s temps the car sees while cruising. The CAT monitor will never set unless the car is running hot enough to get a good 10-15 minutes at 55mph and see the right temp. I just need one more monitor to clear. 99 and older can have two monitors not ready. I have Three not ready right now. I'm gonna go with a hotter thermo and see what happens. My thought is so that the cruising temps don't go below 180. I think I have a faulty 170 thermo that's inaccurate enough to even allow it to go into the 160s.

Can anyone verify 180* is stock? The majority I see for sale are 180 and they say OEM temp.

 

[lasershark]

180* cracking temp
Fully open at 203*