[SaturdaysSHO]

(Scenario, just fiddeling around while looking for the CPS sensor)
I disconnect a sensor, car wont start.
re-connect, car starts (sensor by some gear looking thing on lower passenger side)
I disconnect a sensor, car starts but idles at about 750.
re-connect, car starts and idles at 900. (IAC Sensor)
I disconnect a sensor, car STARTS

Hmm.. thats odd because it looks like the darn CPS sensor that the car was giving me a code for several months ago. The CEL light has since gone out and over the winter the car has not had a starting problem. Now Lately as it has gotten a little warmer once and a while the car decides after it has been shut off(at operating temp), to start idle like crap then stall, then try again and it does not start (cranks over but does not fire). But when the car is a little cooler it starts up like there is no problem. Last night I had left the sensor disconnected, and went for a road trip. Mind you I disconnected it before I started the car. While driving the only difference I have noted with it disconnected is that it seemed I had horrible throttle response from a rolling start, other then that the car drove fine (same at WOT too). So that now leads me to believe it is the TPS. This sensor was located somewhat under the throttle body but was hard to see. So I'm confused as to what sensor this is, and I am still looking for the CPS sensor. I think...

Nick Saturday

 

[SaturdaysSHO]

I found out that it is for sure the CPS Sensor.

 

[Guest]

The CPS controls injector firing and timing on your car. It's highly unlikely that this would cause idle issues, however you said the car threw a code a while back. Was it the CPS code? If so, did you repair it then?

With the CPS disconnected, the injectors may have been dumping way too much fuel in. This would cause hot hard starting, as well as a host of other issues. With the CPS disconnected, the car should misfire like a son of a gun. It should also set a CEL.

The gear looking thing that you unplugged the sensor harness from was the crank position sensor. The car will not start or run with that disconnected. That controls the spark timing and firing.

So I would guess the car still has the high idle?

 

[SaturdaysSHO]

Long Full Story-

I may have confused you Bob. I idle at about 900 but without the IAC connected I can idle at about 750. I just wanted to through that in there since that seems high to me and another member. This seems to be a qwerk that this car has had before I started to drive it so i dont know if it started on its own or it was "born" with that. I also have not had CEL from having that disconnected. About a few months back I was driving along, and felt what was like a "miss" at about 50. Soon after that the CEL light came on, so I figured that it was about time for new plugs, those were done, but it had a CEL still. I had it checked and it through I think P0340. Car had no ill effects as of yet, and continued driving it around with the CEL light on. Never repaired the CPS sensor yet. Eventually the light went out, then it came back, and did that 2 more times but stayed out up until now. When the CEL light was on it ran fine. One day I came home shut off the car, then about 5 minutes later I came back out to leave, started it, it started to get to idle then "chugged" stalled and wouldn't start. I let it sit for about an half a hour 45 minutes and it started like nothing happened, no CEL (In November). It did this about 5 more times since then. I went looking under the hood, and found the connector to the CPS Sensor. With the car off I disconnected it, then proceeded to start the car. Car started, so I drove it around and the only problem I seen with it disconnected mind you I had no CEL was a lag in throttle response. The only thing is that I doubt this problem cured itself, and with this no start condition sometimes who knows if the car will start when I need it to. During those months I had an encounter with a fellow Vulcan Gen 3, and actually raced him from about 35, and I had 4 more people then he did and I was pulling on him. He was not happy.

Answers to Bob's questions-

Was the CPS code, Never repaired CPS Sensor
Does not idle bad, missfire, or set a CEL.
CPS disconnected car starts, runs, idles fine, horrible throttle response.
CPS connected car starts, runs, idles fine, good throttle response.
Car still does have the high idle.

 

[SaturdaysSHO]

Anyone?

 

[Guest]

I think maybe you didn't disconnect the CPS, but something different. With the CPS disconnected, the car should run rough and backfire slightly.

For the high idle, I would suspect either an after-MAF vacuum leak (intake,EGR valve, hoses), faulty IAC motor, or someone has tampered with the idle adjustment screw on the throttle body.

 

[SaturdaysSHO]

I'll try and get a picture tomorrow of what I disconnected, but it sure looks like the CPS Sensor. How would I be able to check the idle adjustment screw on the throttlebody without screwing it up? I'll also look around for another IAC valve, wouldn't be too expensive would it? Checking for a vacuum leak could I spray throttle body cleaner around the EGR valve, hoses, and intake?

Thanks Bob!

-Nick

 

[Guest]

About the idle screw- has the car always idled this high? If it just started happening, it most likely isn't that.

Throttle body cleaner will work fine for the vacuum leak.

Forgot to ask, any other codes besides the CPS?

 

[SaturdaysSHO]

It has to my knowledge always idled this high, that would be minimum a 2 years. I'm the only one around here that notices qwerks in our family's cars. I'll try to get autozone to scan the car but usually they want the CEL light on.

I should be able to get a pic up in a few hours. Thanks

 

[SaturdaysSHO]

I have 2 pictures just need to find somewhere to host them. They are each 6**KB.