Tkx for help with problem, now new problem

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Mar 3, 2007 | 04:13 PM

the_sharkster

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From: Pa

Tkx for help with problem, now new problem

Thanks for all the info on getting my 1989 F-150 up and running after being transported. Now that I can start and be running, it is acting like it is loading up. I can hold the throttle down about half, and she runs fine. Go to idle, she shakes and loads up, then stalls. The previous owner had already installed a new idle air control valve. Could it be the computer? Just guessing.....

Any help at all will again be greatly appreciated !!

Last edited by the_sharkster; Mar 3, 2007 at 04:16 PM.

Mar 3, 2007 | 05:38 PM

mhg

Fleet Mechanic

Joined: Sep 2003

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From: savannah,ga

start by checking for vacuum leaks
the EGR is notorius for this
also check the fuel pressure regulator

Mar 3, 2007 | 05:55 PM

the_sharkster

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From: Pa

I unplugged the electrical connection on the egr and started her up. She ran great. Of course the check engine light came on, no surprise there. Plugged it back in, and back to square 1. Is there any way to clean the egr up? I assume it has carbon in it. Its gotta be expensive to replace it.

Mar 3, 2007 | 09:21 PM

nighthawk285

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Joined: Nov 2005

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From: La Grande, OR

you can take it off and soak it in some carb cleaner, that'll take off the carbon, just do a good job and you're all set....and it might not be as expensive as you think, you just gotta have the OEM number to get a replacement, or at least a price.

Mar 4, 2007 | 07:23 AM

subford

Fleet Owner

Joined: Aug 2005

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From: Easton,Ks

Quote:

Originally Posted by the_sharkster

I wonder if unpluging it would put the EEC computer into limp mode?
should not effect the running of the engine, it just reports back to the EEC computer how far open the EGR valve is. This sensor may have a short to ground and drop the 5-Volt reference voltage down that would change the running of the engine.

The EGR valve does not get a signal from the EEC computer to open at all until you have a warm engine and the throttle is in mid range.

I would check the wiring and connector plugs very close to see if they are bad.

EDIT:
I wonder if unplugging the electrical connection on the EGR would put the EEC computer into limp mode?
Did you get black smoke from the exhaust while it was unplugged?

Last edited by subford; Mar 4, 2007 at 07:30 AM.

Mar 4, 2007 | 09:55 AM

lv2race

Laughing Gas

Joined: Oct 2005

Posts: 1,226

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From: The OC

You may have a bad EVP Sensor, but your symptom sounds like a MAP Sensor. First thing you want to do is check for codes. Many parts houses will do this for free, you can get a code reader, or you can do it yourself. Check the links for more info.

http://fordfuelinjection.com/?p=13

http://www.thorssell.net/hbook/eectest.html

Mar 4, 2007 | 10:32 AM

subford

Fleet Owner

Joined: Aug 2005

Posts: 23,667

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From: Easton,Ks

My post above did not look like that in the editor, it should have looked like this.

Unplugging the electrical connection on the EGR should not effect the running of the engine, it just reports back to the EEC computer how far open the EGR valve is. This sensor may have a short to ground and drop the 5-Volt reference voltage down that would change the running of the engine.

The EGR valve does not get a signal from the EEC computer to open at all until you have a warm engine and the throttle is in mid range.

I would check the wiring and connector plugs very close to see if they are bad.

I wonder if unplugging the electrical connection on the EGR would put the EEC computer into limp mode?
Did you get black smoke from the exhaust while it was unplugged?