Hey all, I need some advice. I just took off my throtty body and cleaned it thoroughly and when I put it back on, the engine idles real high. I sprayed starting fluid around the vacuum hoses and the engine never sped up. I pulled my codes and it's saying the EGR valve isn't opening properly. I thought that if an EGR valve wasn't working correctly, you would have an unusually low idle. I've recleaned the TB, IAC, and the EGR with no luck. The vacuum hoses associated with the TB were a little loose upon reinstallation, but even when I sprayed starting fluid around the lines, the RPMs never increased. I just don't want to replace my $50 EGR until I'm certain it's the problem. Any tips would be greatly appreciated.
Vacuum Problem
- Thread starter pattygook
- Start date
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Jimmy Neutron
Land of Confusion
Here is what I would do:
First I would unhook the battery with the lights on for about 10-15 seconds. This drains the system of all energy and basically resets the computer. It is possible that the TB was dirty enough that it restricted enough airflow that the computer now thinks the throttle is pressed down part way due to the additional airflow it is getting due to the enlarged (cleaned) TB. I would then run it for a few minutes to let the computer read all the sensors to start over from scratch.
If this does not cure your issue, have you tried adjusting the idle down manually? There is an idle ***** on the throttle linkage, if I remember correctly. Someone could have idled it up to keep it running instead of cleaning a dirty TB.
Just a few thoughts...
Please let us know how it goes!
J
First I would unhook the battery with the lights on for about 10-15 seconds. This drains the system of all energy and basically resets the computer. It is possible that the TB was dirty enough that it restricted enough airflow that the computer now thinks the throttle is pressed down part way due to the additional airflow it is getting due to the enlarged (cleaned) TB. I would then run it for a few minutes to let the computer read all the sensors to start over from scratch.
If this does not cure your issue, have you tried adjusting the idle down manually? There is an idle ***** on the throttle linkage, if I remember correctly. Someone could have idled it up to keep it running instead of cleaning a dirty TB.
Just a few thoughts...
Please let us know how it goes!
J
Well, I just replaced the vacuum hoses and reset the computer with your instructions and it idles correctly now. I do have a new question though. One of the first things I did was try to adjust the idle ***** to solve the problem, and now I need to readjust the idle. Right now I've got it set just above stalling speed. My manual says to set it to 750 RPMs, but I don't have a tach. Is there any kind of tach you can temporarily hook up to the engine just for setting idle speed? Or do you guys think it's fine where it's at? Thanks for the input.
Last edited by a moderator:
Jimmy Neutron
Land of Confusion
I mostly set idle by ear...
If it acts like it is going to die, then does; give it just a little more.
If it acts like it is going to die, then recovers; you are probably just about right.
Pointers:
Small, 1/16th turns go a long way.
It will idle differently cold than warm, so it is best to do it warm.
If it acts like it is going to die, then does; give it just a little more.
If it acts like it is going to die, then recovers; you are probably just about right.
Pointers:
Small, 1/16th turns go a long way.
It will idle differently cold than warm, so it is best to do it warm.
BroncoJoe19
Active member
Geeeez it had to be 35 years ago, the last time I hooked up a tach. Then a tach and dwell for checking my points. I think one just hooked the positive to the tach side of the coil, and grounded the other side. There were different scales for 6 and 8 cylinders.
