Well, my "new" Bird is acting up again.

History: Bought a month ago with all sorts of minor problems. Replaced CTS, Some hosing, Radiator, reattached VSS, and replaced the air filter. Oil filter is new.

Problem History: Running Rich (Fixed, I think), Low MPG (5 before, now 13 on 91 octane), died randomly going to idle (Fixed, CTS). Vacuum leak at Climate Control (not fixed, I haven't had time to pull it out), Stumbling on cold idle, right after start (NOT FIXED). Code 13 (see below)

My main problem now seems to be the cold idle. It'll start up fine, and if the engine has been run in the past 8 hrs, it'll run good period. But if it has been sitting overnight, it has problems. I'll start it, and it'll catch fine. The RPM's will climb to 1200 or so as it starts, and then drop to idle. Almost instantly, they'll drop to 100-250 and the thing will shake like a beast. Engine stumbles, sometimes dies. If I do nothing, the RPM's will jump to 1700 or so after a few seconds, and then drop SLOWLY to idle, then fall rapidly to 250 again. This will repeat a few times, then as it starts to register temperature on the dash, it'll start to stabilize. It'll eventually come to idle at 750 or so, (plus 100 or minus 50). I can add throttle at any point and get power, and even drive, but there is BAD hesitation and funny sounds (thunks, might be detonation ??) untill the RPM's are above 1200 or so. If I drive it before it warms up, it will go fine (a bit low on power) untill it reaches normal operating temperature (210-220 in the city, 165 (YES YES!) on the highway, but it will have some hesitation before it fully warms up (between 100 and 160 degrees).

Recap: Cold idle rough and stumbles, extreme hesitation below 100 degrees, relatively bad hesitation between 100 and 160, excellant performance above 160 (normal, 175-220).

Now I just got the radiator installed, and everything is going fine (except for the above problem), and it throws me a Code 13 (TPS defective, open in O2 circut, defective ECM). I clear the code, and it hasn't come back in 40 mi.

So, I'm wondering, what would your guess as to the problem be? Would you believe the TPS is bad, or the O2 sensor? I personally have a feeling for the TPS, especially from the cold idle problems, but I could be wrong. Given the price for both at the local Autozone, I think I may just go ahead and replace both. All of the wiring seems ok from a basic check, but I haven't gotten serious about it yet. I know I need to get the vacuum leak fixed, but I'm not sure entirely if it is a vacuum leak, or the climate control is not hooked up (the last owner had a shop that messed the radio and CC wiring up a bit)


Sorry for the novel, and Thanks For ANY help

Later!

 

Anyone? Maybe I should have titled this "My Bird got fuxored by a Civic"...

 

A code '13' on your car is for a complete loss of signal from the oxygen sensor.

That problem may be completely different from the cold starting issues you are having. On a cold start, the oxygen sensor is not even used to determine fuel delivery. The ECM uses the BLM tables in the PROM to deliver fuel based only on the TPS, MAF or MAP, CTS, and engine RPM. Once the oxygen sensor becomes active, the CTS is above a given point, and the ECM has logged an appropriate time lapse, the ECM will enter closed loop mode and the fuel mixture is controlled based directly on feedback from the oxygen sensor.

Since your problems are apparently happening when the ECM is in open loop, you should verify correct fuel pressure, a correct TPS setting, and an accurate CTS indication. All of this also depends upon a reliable ignition system as well.