No Power
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No Power
Working on 2003 Explorer 4x4. Seemed to be running fine till (apparently quite suddenly) it has no power. I have been looking for a vacuum leak. tested with vacuum tester and was showing signs of EGR Solenoid malfunction. So... off with the intake manifold and replaced the EGR solenoid and PCV. No improvement on power.
Can anyone tell me what triggers the EGR solenoid to pull the vacuum to the EGR Valve? I am wondering if the what is supposed to trigger the Solenoid is working properly. It was not pulling a vacuum on acceleration, most of the time. Ever now and again it would and when it did it would drop when you let go of the gas, as it should. Getting it to pull a vacuum was the problem. I have a vacuum of about 15 from the intake manifold.
Any thoughts would be greatly appreciated.
Can anyone tell me what triggers the EGR solenoid to pull the vacuum to the EGR Valve? I am wondering if the what is supposed to trigger the Solenoid is working properly. It was not pulling a vacuum on acceleration, most of the time. Ever now and again it would and when it did it would drop when you let go of the gas, as it should. Getting it to pull a vacuum was the problem. I have a vacuum of about 15 from the intake manifold.
Any thoughts would be greatly appreciated.
Logistics Pro
Joined: Jun 2009
Posts: 4,819
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From: Cedar Rapids, IA
The Differential Pressure Feedback EGR (DPFE) sensor provides EGR flow information to the PCM. The PCM uses that data, along with data from the ECT sensor, IAT sensor, TPS, head temperature sensor, and CKP sensor, to control the EGR valve via the EGR Vacuum Regulator (EVR) solenoid.
Have you tried disconnecting the vacuum hose from the EGR valve and plugging the hose to see if that changes the way the truck runs? You would then actuate the EGR valve with a manual pump to confirm that the EGR valve is not open during idle in the event the engine still runs roughly with the EGR disconnected.
-Rod
Have you tried disconnecting the vacuum hose from the EGR valve and plugging the hose to see if that changes the way the truck runs? You would then actuate the EGR valve with a manual pump to confirm that the EGR valve is not open during idle in the event the engine still runs roughly with the EGR disconnected.
-Rod
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Vacuum Test
Yes, I placed the vacuum tester on a T between the Solenoid and the Valve. The vacuum should go up to 5 when accelerating and drop when you let off the gas. I only got it to go to 3 or 4 a couple of times. The rest of the time it stayed below 1, if not 0.
Logistics Pro
Joined: Jun 2009
Posts: 4,819
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From: Cedar Rapids, IA
Using a T though doesn't really eliminate anything as it doesn't interrupt the vacuum circuit. I'm suggesting that you cap off the vacuum line to the EGR valve to take that out of the circuit, confirm the is closed at idle, then take the truck for a drive. If the truck still seems to have little power (which I suspect it will) then you can stop focusing on the EGR system and continue your search for the real problem.
I don't think an EGR that is closing correctly at idle but not opening quite correctly off idle will cause the symptoms you mentioned in your original post.
-Rod
I don't think an EGR that is closing correctly at idle but not opening quite correctly off idle will cause the symptoms you mentioned in your original post.
-Rod
Logistics Pro
Joined: Jun 2009
Posts: 4,819
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From: Cedar Rapids, IA
I'd suggest you check for other vacuum leaks. I don't recall all the history on what you've done to this Explorer, so I don't remember if you'd recently changes spark plugs and plug wires as well as intake manifold gaskets. Of course even if you did recently replace the plug wires, it's possible one is not seated well or, if they were inexpensive wires, that one or more wire is bad. With cheap wires in the past I've even encountered wires that were bad right out of the box.
Also confirm that the intake air tubing between the MAF and the throttle body is in good shape (no cracks) and properly connected. You could also try unplugging the MAF sensor. If the engine oddly starts to run better, this could be further evidence of a vacuum leak somewhere after the MAF.
Have you checked for any pending diagnostic codes?
-Rod
Also confirm that the intake air tubing between the MAF and the throttle body is in good shape (no cracks) and properly connected. You could also try unplugging the MAF sensor. If the engine oddly starts to run better, this could be further evidence of a vacuum leak somewhere after the MAF.
Have you checked for any pending diagnostic codes?
-Rod
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No Pending codes
I wish there were codes! It would help a lot.
I just had the intake manifold off and while it was off checked the gaskets (they were new in January). I will double check all the vacuum connections and the air intake tubing (just had all of that off too). I replace plugs, but not wires. I really thought I would have a misfire code if plug wires were bad, it does not idle roughly. Just no power.
I will try again in the morning.
Wish me luck!
I just had the intake manifold off and while it was off checked the gaskets (they were new in January). I will double check all the vacuum connections and the air intake tubing (just had all of that off too). I replace plugs, but not wires. I really thought I would have a misfire code if plug wires were bad, it does not idle roughly. Just no power.
I will try again in the morning.
Wish me luck!
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