Killain Posted June 20, 2022 Share #1 Posted June 20, 2022 (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 June 20, 2022 by Killain Link to comment https://www.classiczcars.com/topic/67578-stumped-by-my-fuel-injection-operation-cold-idle/ Share on other sites More sharing options...
kickstand80 Posted June 20, 2022 Share #2 Posted June 20, 2022 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. 1 Link to comment https://www.classiczcars.com/topic/67578-stumped-by-my-fuel-injection-operation-cold-idle/#findComment-641675 Share on other sites More sharing options...
Killain Posted June 20, 2022 Author Share #3 Posted June 20, 2022 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 https://www.classiczcars.com/topic/67578-stumped-by-my-fuel-injection-operation-cold-idle/#findComment-641681 Share on other sites More sharing options...
Zed Head Posted June 20, 2022 Share #4 Posted June 20, 2022 (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 June 20, 2022 by Zed Head 1 Link to comment https://www.classiczcars.com/topic/67578-stumped-by-my-fuel-injection-operation-cold-idle/#findComment-641682 Share on other sites More sharing options...
Killain Posted June 20, 2022 Author Share #5 Posted June 20, 2022 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, Link to comment https://www.classiczcars.com/topic/67578-stumped-by-my-fuel-injection-operation-cold-idle/#findComment-641684 Share on other sites More sharing options...
kickstand80 Posted June 20, 2022 Share #6 Posted June 20, 2022 (edited) Power on with key Edited June 22, 2022 by kickstand80 Link to comment https://www.classiczcars.com/topic/67578-stumped-by-my-fuel-injection-operation-cold-idle/#findComment-641686 Share on other sites More sharing options...
Zed Head Posted June 20, 2022 Share #7 Posted June 20, 2022 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. Link to comment https://www.classiczcars.com/topic/67578-stumped-by-my-fuel-injection-operation-cold-idle/#findComment-641687 Share on other sites More sharing options...
cgsheen1 Posted June 20, 2022 Share #8 Posted June 20, 2022 Check for power and also check the connector for corrosion / oxidation and clean it. It's a Bosch connector just like the injector connectors and can be replaced with a new one if necessary. Link to comment https://www.classiczcars.com/topic/67578-stumped-by-my-fuel-injection-operation-cold-idle/#findComment-641689 Share on other sites More sharing options...
Killain Posted June 20, 2022 Author Share #9 Posted June 20, 2022 (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 June 20, 2022 by Killain Link to comment https://www.classiczcars.com/topic/67578-stumped-by-my-fuel-injection-operation-cold-idle/#findComment-641693 Share on other sites More sharing options...
kickstand80 Posted June 20, 2022 Share #10 Posted June 20, 2022 IDK problematic wife / problematic Z? You can always sell the Z and get your money back! 1 Link to comment https://www.classiczcars.com/topic/67578-stumped-by-my-fuel-injection-operation-cold-idle/#findComment-641696 Share on other sites More sharing options...
Zed Head Posted June 20, 2022 Share #11 Posted June 20, 2022 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 https://www.classiczcars.com/topic/67578-stumped-by-my-fuel-injection-operation-cold-idle/#findComment-641698 Share on other sites More sharing options...
TomoHawk Posted June 20, 2022 Share #12 Posted June 20, 2022 (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 June 20, 2022 by TomoHawk Link to comment https://www.classiczcars.com/topic/67578-stumped-by-my-fuel-injection-operation-cold-idle/#findComment-641699 Share on other sites More sharing options...
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