|Originally posted by 92wastheyear:|
I am curious about this too....mine 87 GT is very "cold blooded". When I start it in the morning it starts easily but hunts for idle and will almost always stall unless I fiddle with the gas pedal (to keep it running) for about a minute...after about a minute it will be able to idle....it also wants to stall when attempting take off from a stop sign until it is fully warmed up
Sounds just like how mine acts at cold idle, minus the stop sign issue. I have to catch it with the throttle twice, then it will be able to catch the stumbles by itself. As it warms up it gets stable.
When it started doing this, I noticed in WinALDL that the CTS was erratically reporting a very high temperature. It would read normal, and then suddenly say 300F. At the same moment, the engine would stumble. I think I was lucky to even see that happen, because the speed of the datalogging connection on this ECM is slow.
My electrical connector is completely rotted apart, so I'm going to replace that first. But the fact that it's temperature sensitive makes me think the problem is the sensor itself.
A high temperature reading comes from low resistance. So apparently my sensor, or something in the circuit, has an intermittent short when cold. Seems strange to me, I wonder if that's the typical failure mode?
My CTS is an aftermarket "BWD" that I erroneously bought about 1.5 years ago. There was nothing wrong with the old one, and now I wish I had kept it.
As far as the insert:
From what I've read, the original CTS used a "weatherpack" electrical connector. Later replacements use the "Metripack" connector. Some of these were sold in a kit that included the replacement connector. I wonder if the original CTS filled the larger opening, and the insert was added to fit the metripack sensors? That's just a guess. I've never seen the older style CTS.
From what I've seen happen to my metripack connector, I'm not exactly sold on it being an improvement. It's wrecked worse than any of the weatherpacks on the car, and that's saying something. The pins are also closer together, which doesn't help it's robustness any.
I think I really prefer weatherpack, and at minimum those connectors are easier to replace. But I guess the weatherpack sensors are unavailable so it's not an option.
The IAT can sometimes be fixed by cleaning. Mine was fixed after soaking in CLR, and has stayed accurate for about 2 years now (as seen in WinALDL).
Remove it from the car, check it's resistance and compare with a resistance vs temperature chart to see if it's working correctly. I think the same chart is used for the IAT, CTS, and the temperature gauge sender.
I've become cynical enough about the quality of modern aftermarket parts, that I would suggest not throwing away the old one until you try cleaning it. If it's factory, it's probably better made than the new one.