ok well i converted my car to mass air successfully. I though my problem was the meter but it wasnt. I thought it was the computer but it wasnt and unfortunatly i bought a new one. So i start to play with things in the car. The car was running with a really rough idle. Sounded like it had a big cam in it. I pulled off the vacuum line to the egr valve and to my surprise the car idle completely normal. I plug the vacuum line back into the egr valve and it stutters and just dies. What would cause this? I pulled codes and got 91 and i think it was 34 and 41. I now have the vacuum line off the egr valve and capped off and it runs perfect but i would like to fix the problem and not just push it to the side. Any feedback will have. Thank you
EGR problem PLEASE HELP
- Thread starter xexitenglishx
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TrickStang37
New Member
- Oct 17, 2004
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well, you shouldnt be getting vacuum on that line at idle, so the check thing or whatever its called is letting vacuum get through when it shouldnt.
good on ya for finding it and not just leaving it (you could find detonation issues if you left it as you have it).
does the vac line you pulled off the EGR have vac in it at idle (it should show a max of 5" as i recall. but it should only show vac when the EGR should be open - NOT at idle)?
it sounds like the valve is leaking or the solenoid is opening the valve a little when it should not be. need more info to know.
i would recommend searching Joe's (Jrichker) posts for info on the EGR - his write ups are top notch and much more concise than i can put it.
good luck.
does the vac line you pulled off the EGR have vac in it at idle (it should show a max of 5" as i recall. but it should only show vac when the EGR should be open - NOT at idle)?
it sounds like the valve is leaking or the solenoid is opening the valve a little when it should not be. need more info to know.
i would recommend searching Joe's (Jrichker) posts for info on the EGR - his write ups are top notch and much more concise than i can put it.
good luck.
Michael Yount
Mustang Master
It could also be that someone simply hooked up the vacuum lines incorrectly and connected manifold vacuum directly to the egr valve. Full manifold vacuum should go to the evr switch (on the firewall); and then a line should run from the output vacuum port of the evr to the egr valve. The computer will tell the switch when and how much vacuum to apply to the egr valve.
The vacuum line is correctly hooked up to the egr switch. Itmust be the switch but when i pulled the vacuum line off the switch that was going directly to the manifold it was about the same amount of vacuum. Should i try to replace that part alone. Is tehr a was to clean it. I know it has a cover with some type of foam sponge filter thing. Is there any way to check that out? Thanks
Michael Yount
Mustang Master
I'd try to get a vacuum gauge on some of these lines so you have some better data to work with. Trying to determine vacuum available on different lines by telling how hard it's pulling on your thumb is not exactly scientific. Perhaps there's a leak in the line from the manifold to the evr - and that's both diminishing the vacuum signal to the egr AND accounting for the rough running.
Note that all resistance tests must be done with power off. Measuring resistance with a circuit powered on will give false readings and possibly damage the meter.
Look for a possible short between pin 33 on the computer (dark green wire) and ground. That would hold the EVR solenoid open and apply full vacuum to the EGR valve anytime the engine was running. Since this is a Mass Air conversion, did you move any of the EVR pins by mistake?
See http://fordfuelinjection.com/index.php?p=6 for computer wiring connector information.
Here’s an EGR test procedure I copied from cjones
to check the EGR valve:
bring the engine to normal temp.
connect a vacuum pump to the EGR Valve
apply 5 in vacuum to the valve.
if engine stumbled or died then EGR Valve and passage(there is a passageway through the heads and intake) are good.
if engine did NOT stumble or die then either the EGR Valve is bad and/or the passage is blocked.
if engine stumbled, connect vacuum gauge to the hose coming off of the EGR Valve
snap throttle to 2500 RPM’s (remember snap the throttle don't hold it there).
did the vacuum gauge show about 5 in vacuum?
if not, check for manifold vacuum at the EGR vacuum valve.
if you have manifold vacuum then connect vacuum gauge to the EGR valve side of the vacuum valve and snap throttle to 2500 RPM’s.
should read about 5 in vacuum
End of cjones's test.
Look for a possible short between pin 33 on the computer (dark green wire) and ground. That would hold the EVR solenoid open and apply full vacuum to the EGR valve anytime the engine was running. Since this is a Mass Air conversion, did you move any of the EVR pins by mistake?
See http://fordfuelinjection.com/index.php?p=6 for computer wiring connector information.
Here’s an EGR test procedure I copied from cjones
to check the EGR valve:
bring the engine to normal temp.
connect a vacuum pump to the EGR Valve
apply 5 in vacuum to the valve.
if engine stumbled or died then EGR Valve and passage(there is a passageway through the heads and intake) are good.
if engine did NOT stumble or die then either the EGR Valve is bad and/or the passage is blocked.
if engine stumbled, connect vacuum gauge to the hose coming off of the EGR Valve
snap throttle to 2500 RPM’s (remember snap the throttle don't hold it there).
did the vacuum gauge show about 5 in vacuum?
if not, check for manifold vacuum at the EGR vacuum valve.
if you have manifold vacuum then connect vacuum gauge to the EGR valve side of the vacuum valve and snap throttle to 2500 RPM’s.
should read about 5 in vacuum
End of cjones's test.
