Welcome Visitor! Please take a few seconds and Harrisburger
Member
- Joined
- Jul 3, 2012
- Messages
- 9
- Vehicle Year
- 1997
- Transmission
- Automatic
Hi guys,
I've got a '97 4.0 that has been having trouble starting sometimes, seems to be getting reduced gas mileage (but, I've been doing a little more city driving lately anyway, so it's hard to pinpoint the cause of it), and I'm hearing a rasping noise at lower speeds when accelerating lightly, especially while the engine is cool.
Probably the best of the three symptoms is the rasping or whirring noise coming from under the hood. It's especially loud when I turn the wheels to the left, but it's not wheel bearings and it keeps time with the engine when I rev it. I'd like to put it to you guys and see what all you say about it. My only thought is that it's the EGR system letting air into the intake and when it shouldn't be, or letting too much air in when it should be letting in less?
I took a voltmeter to the EGR vacuum control solenoid (it's fine), the DPFE (it's reading lower voltage than standard, .73 volts at idle with EGR valve closed, 2.73 volts at idle with EGR valve fully open as opposed to .9 and 3.0-4.5 volts according to the specs I'm seeing, but I don't know if the voltage is low enough to make the difference I'm seeing), and I also tested the TPS just in case it might be involved in determining when and how much exhaust gas to recirculate (it was perfect). I also vacuum tested the EGR valve itself and it operates well and holds vacuum. I've also looked at the vacuum hoses and can't find any defects.
So, is there anything else in the system that I might have overlooked that could be causing this problem? Is there another system on the truck that you might point to instead?
Anything else that could cause a rasping/ whirring noise to emanate from the intake/ hood in cadence with the engine?
Thanks!!
I've got a '97 4.0 that has been having trouble starting sometimes, seems to be getting reduced gas mileage (but, I've been doing a little more city driving lately anyway, so it's hard to pinpoint the cause of it), and I'm hearing a rasping noise at lower speeds when accelerating lightly, especially while the engine is cool.
Probably the best of the three symptoms is the rasping or whirring noise coming from under the hood. It's especially loud when I turn the wheels to the left, but it's not wheel bearings and it keeps time with the engine when I rev it. I'd like to put it to you guys and see what all you say about it. My only thought is that it's the EGR system letting air into the intake and when it shouldn't be, or letting too much air in when it should be letting in less?
I took a voltmeter to the EGR vacuum control solenoid (it's fine), the DPFE (it's reading lower voltage than standard, .73 volts at idle with EGR valve closed, 2.73 volts at idle with EGR valve fully open as opposed to .9 and 3.0-4.5 volts according to the specs I'm seeing, but I don't know if the voltage is low enough to make the difference I'm seeing), and I also tested the TPS just in case it might be involved in determining when and how much exhaust gas to recirculate (it was perfect). I also vacuum tested the EGR valve itself and it operates well and holds vacuum. I've also looked at the vacuum hoses and can't find any defects.
So, is there anything else in the system that I might have overlooked that could be causing this problem? Is there another system on the truck that you might point to instead?
Anything else that could cause a rasping/ whirring noise to emanate from the intake/ hood in cadence with the engine?
Thanks!!
