Jump to content

IGNORED

Stumped by my Fuel injection operation , cold idle ????


Recommended Posts

Posted (edited)

Continuing along my Fuel Injection journey, I had a problem with my cold idle being so low the engine would stall out. So after reading my FSM, and help from here, I deducted it was the Air Regulator Valve, I was able to find one and that did indeed, raise the cold idle engine speed, but now the 1500 cold idle rpms stay high and only after 20 minutes running does it drop to 1000 rpm's and even then I have to stop and raise the hood to get to the idle screw and lower the idle speed down to 800 rpm's. Now I don't see what else would keep the speed at high idle other than perhaps the coolant temperature sender being bad, I am pretty sure I don't have any vacuum leaks, but the engine didn't seem to have a vacuum leak before I installed the new Ari regulator Valve. But the gauge on the dash doesn't off and it reads normal ? So other than the AGV and or the temp sensor relaying faulty reading to the ECM, what am I missing here ?

Edited by Killain
Link to comment
Share on other sites


The cylinder head temp sensor signal only leans the fuel as the engine warms, it does not change the idle. The only way your car idle changes is if more air gets in. Look for vacuum leaks. Did you purchase a new secondary air valve or find a used one? It may be incorrectly adjusted or sticky. I had to adjust mine. 

 

  • Like 1
Link to comment
Share on other sites

ah, No I found a rebuilt 'Air Regulator Valve' Which did correct the cold idle engine operation. Before the new Valve, the engine wouldn't idle enough to keep running when the engine was cold and it would stall. But with the new valve it idles very high 1500 rpm's but now it doesn't come down for over a half an hour. Now the Air Regulator Valve isn't adjustable so what you get is all there is ?

Link to comment
Share on other sites

Posted (edited)
1 hour ago, Killain said:

with the new valve it idles very high 1500 rpm's but now it doesn't come down for over a half an hour.

This is a sign that there is no electrical power at (edit - actually should say "passing through".  The ground side must be there also to complete the circuit) the AAR plug.

Edited by Zed Head
  • Like 1
Link to comment
Share on other sites

So despite correcting for no cold idle operation, the valve isn't getting correct or any voltage ? Is that circuit protected by a fuse or fuse-able link ?

 

Thank you,

SANY0005.JPG

Link to comment
Share on other sites

It's on the same circuit as the fuel pump.  Looks like it grounds through pin 34.  You can test the whole circuit at the ECU connector.  The FSM instructions describe how to use the Start circuit to actuate the fuel pump relay to provide voltage. 

But you could also just disconnect the AAR and test for voltage at the AAR connector with the engine running.  The AAR should get power when the fuel pump does and the fuel pump only gets power when the engine is running.

image.png

image.png

Link to comment
Share on other sites

Posted (edited)

Ok Great, on page EF-24 it talks about the Thermotime switch. I never used a multimeter, so I got one and I'm teaching myself about how to use it. I will pull the Air regulator Valve connector and see if 1. it's getting any power and then see if I can measure the voltage. The last big repair job I did was try to repair my marriage, of course she been gone for the last 14 years, so I guess that wasn't very good fix ?

Edited by Killain
Link to comment
Share on other sites

1 hour ago, Killain said:

I never used a multimeter, so I got one and I'm teaching myself about how to use it. I will pull the Air regulator Valve connector and see if 1. it's getting any power and then see if I can measure the voltage.

You can also stick a Noid light in the connector and start the engine.  The light should stay on when the engine is running.

Link to comment
Share on other sites

Posted (edited)

It should only have 12V after about 10 seconds, if the thermotime switch is working correctly.  Otherwise, it should have 0 volts when you first turn on the power.  In any case, test it under a load.

Have you downloaded the Fuel Injection Bible, and flowwed the troubleshooting charts?

Edited by TomoHawk
Link to comment
Share on other sites

1 hour ago, TomoHawk said:

It should only have 12V after about 10 seconds, if the thermotime switch is working correctly.  Otherwise, it should have 0 volts when you first turn on the power.  In any case, test it under a load.

His problem is with the AAR, not the thermotime switch.  The AAR has power as long as the fuel pump has power. 

 

image.png

Link to comment
Share on other sites

It is just a heating coil inside. 12v one side and ground on the other. Here is what it looks like inside on the electrical side. I put mine in the freezer and looked inside to see how far open the port was then I heated it up in a shallow pan of water to see how far closed it went. 

I did an OHM check on the functioning one on my 81 and it shows 40 OHMS. The one in the picture has an open circuit so it is dead. 

 

20220623_070725.jpg

Link to comment
Share on other sites

20 hours ago, Killain said:

I know this sounds stupid, but is it possible I have the ARV plugged in backwards ?

It's a coil (much like the filament of an incandescent light bulb in this case - the filament itself doesn't actually care which way the electricity flows) so it'll work as long as one side is battery voltage and the other side ground. You should be able to see it work when it gets voltage if the hoses are disconnected. You can look through the hose connections and see the shuttle. It should be mostly open when it's cold and has no voltage. Once it has voltage, the coil will heat the bi-metal strip and cause it to bend, which moves the shuttle slowly until it closes the port. It takes a couple of minutes.

Edited by cgsheen1
  • Like 1
Link to comment
Share on other sites

1 hour ago, Killain said:

once it's fully warmed up is seems Ok

That would be because the coolant plate underneath the AAR has heated up.   That means that the valve is not binding.

All signs point to no electrical power through the AAR heating coil.

Unlikely that a vacuum leak would disappear when the engine warms up.

Just trying to be helpful.

  • Like 2
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

By using this site, you agree to our Privacy Policy and Guidelines. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.