EGR shenanigans.... Im confounded
11-23-2011, 07:50 PM
#1
Senior Member
Thread Starter
EGR shenanigans.... Im confounded
Ok so here we go. I have a 1993 F150 5.0 4x4 with an auto trans. I went to a friends house to work on my truck to check the timing and replace some vacuum hoses. The timing was off by about 8 degrees and purred once we got it set. I replaced a couple vac lines and now have heat through my vents
now to the weird part. A couple weeks back the vac line on top of my egr valve had broke off. So I replaced the tip and reconnected it, restarted my truck and it ran terrible! Would chug hard like it wasn't firing on all cylinders. We attempted to check the timing while it was running and we couldn't even see the timing mark. I was twisting the dist and no help at all. We took the vac line off and it smoothed out and purred again. No issues at all. I took the egr valve off and cleaned it and removed the sensor to make sure it's gasket was good. The valve moves freely and will push air out of the vac port ok. The only thing we could come up with is there could be a hole in the diaphram letting air get through the valve. Also my truck is running very rich. I'm assuming the my o2 sensor needs replaced to help with that and give me a good starting point. My truck is pulling codes but I need to double check them before I post them.
Has anyone had this issue or know causes it? I had left the vac line off the egr valve and the truck runs fine now, but not having it function properly bugs me. I don't want to just start replacing things without having a starting point.
now to the weird part. A couple weeks back the vac line on top of my egr valve had broke off. So I replaced the tip and reconnected it, restarted my truck and it ran terrible! Would chug hard like it wasn't firing on all cylinders. We attempted to check the timing while it was running and we couldn't even see the timing mark. I was twisting the dist and no help at all. We took the vac line off and it smoothed out and purred again. No issues at all. I took the egr valve off and cleaned it and removed the sensor to make sure it's gasket was good. The valve moves freely and will push air out of the vac port ok. The only thing we could come up with is there could be a hole in the diaphram letting air get through the valve. Also my truck is running very rich. I'm assuming the my o2 sensor needs replaced to help with that and give me a good starting point. My truck is pulling codes but I need to double check them before I post them. Has anyone had this issue or know causes it? I had left the vac line off the egr valve and the truck runs fine now, but not having it function properly bugs me. I don't want to just start replacing things without having a starting point.
11-25-2011, 10:40 AM
#6
Senior Member
Or there is a leak in the pipe ftom EGR to manifold.
If EGR is always closed then you won't notice much difference. If stuck open or open at the wrong time, or leaking then the engine barely runs.
Last edited by klricks; 11-25-2011 at 10:44 AM.
11-25-2011, 11:22 AM
#7
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My experience is with older trucks but I don't think you should have vacuum to the EGR at idle, especially if engine is cold. On my 86 the EGR does not come on (vacuum) until about 1.5-2K RPM.
Or there is a leak in the pipe ftom EGR to manifold.
If EGR is always closed then you won't notice much difference. If stuck open or open at the wrong time, or leaking then the engine barely runs.
Or there is a leak in the pipe ftom EGR to manifold.
If EGR is always closed then you won't notice much difference. If stuck open or open at the wrong time, or leaking then the engine barely runs.
When the EGR Vacuum Regulator (EVR) is off, both ports vent slowly to atsmophere.
To test it mechanically check to see if vacuum is present at the EGR valve with the electrical connector unplugged from the EVR. The top port should not have vacuum! Because that would open the EGR at the wrong times.
With everything connected and the engine running ground out the pin 33 side. The EGR vavle should open and the engine RPM should change.
Last edited by ymeski56; 11-25-2011 at 11:36 AM.
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11-25-2011, 06:11 PM
#8
Senior Member
Thread Starter
Correct. Should be no Vac to EGR at idle. EGR is only supposed to provide secondary air under load/ increased RPM. Sound's like your EGR Vac Regulator.
When the EGR Vacuum Regulator (EVR) is off, both ports vent slowly to atsmophere.
To test it mechanically check to see if vacuum is present at the EGR valve with the electrical connector unplugged from the EVR. The top port should not have vacuum! Because that would open the EGR at the wrong times.
With everything connected and the engine running ground out the pin 33 side. The EGR vavle should open and the engine RPM should change.
When the EGR Vacuum Regulator (EVR) is off, both ports vent slowly to atsmophere.
To test it mechanically check to see if vacuum is present at the EGR valve with the electrical connector unplugged from the EVR. The top port should not have vacuum! Because that would open the EGR at the wrong times.
With everything connected and the engine running ground out the pin 33 side. The EGR vavle should open and the engine RPM should change.
this is going to be a noob reply in the purest sense
im glad i caught my mistake before you guys read it. lol im dumb hahaha. where is this part located so i can check it this coming week? this is my long weekend to work so i wont have time til about monday. i can try this week to pull the whole tube to check for leaks. unless there is a way to check without removal. thanks for the advice! this is really helping alot.
Last edited by 1990-5.0-4x4; 11-25-2011 at 06:15 PM.
11-25-2011, 07:24 PM
#10
Senior Member
Thread Starter
Correct. Should be no Vac to EGR at idle. EGR is only supposed to provide secondary air under load/ increased RPM. Sound's like your EGR Vac Regulator.
When the EGR Vacuum Regulator (EVR) is off, both ports vent slowly to atsmophere.
To test it mechanically check to see if vacuum is present at the EGR valve with the electrical connector unplugged from the EVR. The top port should not have vacuum! Because that would open the EGR at the wrong times.
With everything connected and the engine running ground out the pin 33 side. The EGR vavle should open and the engine RPM should change.
When the EGR Vacuum Regulator (EVR) is off, both ports vent slowly to atsmophere.
To test it mechanically check to see if vacuum is present at the EGR valve with the electrical connector unplugged from the EVR. The top port should not have vacuum! Because that would open the EGR at the wrong times.
With everything connected and the engine running ground out the pin 33 side. The EGR vavle should open and the engine RPM should change.
the lines the run from the ports labeled "to EGR valve" and "From vac source" are they rubber hoses? something that'd be worth replacing and seeing if thats where the leak might be? i have quite a bit of extra new vac lines laying around i can use, if it'd be worth doing anyways.
and that digram is a little fuzzy, but it looks like its above and to the left of my valve covers, towards the intake? possibly in the vacinity of my ignition coil?