high idle that won't go away, need help

[2000StreetRod]

EGR valve gasket

Check the EGR valve gasket to make sure it is intact.

Another possibility is the coolant temperature sensor (the one that connects to the PCM) may not be functional. If there is an open connection the PCM may think the engine is cold and increase the richness.

You can disconnect the PCM connector and measure the resistance between pin 38 (LT GRN/RD) and pin 91 (GY/RD).

 

[Blackout51]

Check the EGR valve gasket to make sure it is intact.

Another possibility is the coolant temperature sensor (the one that connects to the PCM) may not be functional. If there is an open connection the PCM may think the engine is cold and increase the richness.
View attachment 80137
You can disconnect the PCM connector and measure the resistance between pin 38 (LT GRN/RD) and pin 91 (GY/RD).

I cannot find this info anywhere, which sensor goes to gauge and which goes to pcm? Which egr gasket?

 

[2000StreetRod]

which & where

The pins I posted are for the engine coolant temperature sensor for the PCM. The EGR valve gasket is between the EGR valve and the mount.

 

[Blackout51]

The pins I posted are for the engine coolant temperature sensor for the PCM. The EGR valve gasket is between the EGR valve and the mount.

Both sensors are brand new, and I don't have a way to test the resistance on them, I'll try abs get in to look at the writing and make sure it all still looks ok and isn't damaged

 

[2000StreetRod]

Vom

You can purchase a volt-ohm meter at Harbor Freight for about $6.
7 Function Digital Multimeter
Using the meter is much easier and effective than taking things apart to do a physical inspection.

 

[Blackout51]

You can purchase a volt-ohm meter at Harbor Freight for about $6.
7 Function Digital Multimeter
Using the meter is much easier and effective than taking things apart to do a physical inspection.

Just got the meter from harbor freight and tested then and both work good, now today when I started it up it idled around 2500 then dropped to 1500 in a few seconds and then tried to drop the idle down to 900s and the motor "chugged" and seemed almost like it was misfiring then it idled back up to 1500 and stayed there and I got the iacv over speed cel again

 

[Turdle]

key on engine off what is the TPS voltage at idle please.

reason I ask, is, I wonder if the throttle stop has been tampered with. you have low vacuum symptoms yet no lean codes-

 

[Blackout51]

key on engine off what is the TPS voltage at idle please.

reason I ask, is, I wonder if the throttle stop has been tampered with. you have low vacuum symptoms yet no lean codes-

I'll check it tomorrow, but it idled fine and no codes or anything before I changed the thermostat housing and valve cover gasket and intake manifold gasket, now is idling high, only other thing I did was clean the throttle body and the valve behind the iacv, also I just took the manifold back off to check hoses and change pcv and I took the valve behind the iacv out and it was coated in carbon really caked on and I just cleaned it spotless a few weeks ago and this isn't my main car so I barely drive it

 

[2000StreetRod]

resistance readings?

Just got the meter from harbor freight and tested then and both work good, . .

What was the ECT sensor resistance at the PCM connector?

Where did you measure the resistance of the engine temperature sender? What was the resistance? Does the engine temperature gauge work now?

 

[Blackout51]

What was the ECT sensor resistance at the PCM connector?

Where did you measure the resistance of the engine temperature sender? What was the resistance? Does the engine temperature gauge work now?

I don't remember the resistance off hand I'll check it tonight after work, but no the gauge still didn't work, and also just a thought but there was two didn't types of the bigger gauges I could of gotten, should I have gotten the cone shaped tip one or the one with a small cylinder shape on the tip and then the other sensor I replaced was the smaller diameter one

 

[2000StreetRod]

gauges vs sensors?

. . . and also just a thought but there was two didn't types of the bigger gauges I could of gotten, should I have gotten the cone shaped tip one or the one with a small cylinder shape on the tip and then the other sensor I replaced was the smaller diameter one

Your statement is puzzling. Sensors are the electrical devices in the thermostat housing.

Gauges are in the instrument cluster.

 

[Blackout51]

Your statement is puzzling. Sensors are the electrical devices in the thermostat housing.
View attachment 80144
Gauges are in the instrument cluster.

Sorry that was a little confusing I'll try and rephrase the question better, there are the two sensors in the thermostat housing, first which sensor controls the gauge and which controls the computer?, second, of the two sensors one is larger than the other, when I went to buy the new larger sensor there was two options one had a cone shaped tip and one had a small cylinder shape on the tip, which is the correct tip?