Ok,
I have only driven the truck a few times since I got it on Tuesday. Each time I drive it, the check engine light comes on. I borrowed a Ford EEC IV code reader from my dad, and it came up with two codes: one for a malfunctioning EGR and one for a disconnected/broken Manifold Absolute Pressure (MAP) sensor. I went out and bought a new MAP sensor, put it on, and it still does the same thing. I haven't checked to see if the code came back yet.

Is the EGR valve right up by the throttle body? Where is the solenoid? I have an EGR valve ordered from the local auto parts store, but I thought I'd better find out where it is. Could the high idle all be caused by the EGR valve? I think it might be what's making that grinding noise Im hearing.


Thank you.

 

Get a Haynes, if you haven't already. Check for the MAP code (you may have to clear the computer to see if it's still throwing one), and check that the wires to the sensor are good. The Haynes tells you how. Do the same for the EGR valve/sensor. It in on the pass. side, feeding from the header next to No. 1 cyl. into the intake. It is a stack consisting of the EGR tube, valve, and position sensor. There are many codes/malfunction modes for the EGR system. Which one did you get? If there is a leak in the valve, causing freash air to be drawn into the intake, it could cause high idle.
And did you find any vacuum leak sources/ get a definitive answer on the gaskets? A stethoscope may help narrow down that hiss.
Something I forgot before, check the throttle plate stop screw. If it was fiddled with, there's the problem. The factory puts paint on the screw, so you should be able to tell if the PO didn't repaint it. If you suspect it was fiddled with but cant be sure, pull of the intake tubes to the TB, tho plates should be just about closed.

-Mike

PS- the metal an metal grinding, was that a grinding or a scraping? When it comes in and out, are the rpms changing? As little as 50 rpm can cause a sound to come in and out. Another place a stethoscope would come in handy.

 

The codes I got were: 128 - disconnected/malfunctioning MAP sensor and 332 - insufficent EGR opperation.

I have a Chilton manual. I have always had good luck with them.
No, I haven't narrowed down the vacuum leak. I did unplug the IAC, the idle changed from 2900 down to 2000. I plugged it back in, and it jumped back up to 2900, then dropped down to 2000. I unpluged it again and nothing happened.
I have checked the throttle plate stop screw, it is actually threaded all the way out. The throttle isn't even touching the screw. The plates do look almost closed. When I moved them, it looked as if there was a film of liquid around them. Is this normal?

I hope the EGR valve/sensor is the problem, I really don't want to have to take the intake apart.

 

Chilton's works. That screw is so far out because someone else was tired of the problem. You have a vac leak. A big one. Get yourself a hand vac pump and start squeezing. While your out, get a stethoscope. With those and a multimeter you can do almost anything. To check for large area leaks, I still use spray. This is for things like the gaskets and manifolds/EGR systems, but I don't mind blowing myself up. You can also use the stethoscope to find and pinpoint them, but nothing in quite as positive a check as the engine reving. And have you looked at the PCV valve? Make sure the tube is connected from the valve cover to the PCV valve, and then to the manifold. The right tools are money you don't want to spend, but do it anyway.
-Mike

 

Ok, Thanks.

If it were you, where would you start looking? Replacing the intake manifold gaskets is more than I want to tackle. I am going to replace the EGR valve/sensor on Monday. I work at a car dealership (for now), should I have them replace the gaskets? It seems that and the EGR are the more common problems.

I will check the PCV valve hose tomorrow. I will see how much a vacuum pump and stethescope will cost when I get the EGR valve.



If I had known a high idle was going to be a big deal, I would've offered the PO less for the thing.

 

Its not a big deal, once you know what to look for. Spray some carb cleaner/ ether/ whatever you use arround the intake manifold (gaskets), wait a few seconds. Then try the rear pass. area of the engine (PCV), then the front pass. area (EGR). No RPM change, and its ste brake booster line or something off the vacuum tree. What trans is in it (vac or electronic control)? The hardest part of doing the gasket is dealing with any AIR emissions stuff if you have any. Not hard, but moderately difficult and annoying. Doesn't hurt to get a quote.
vac pumps are ~$34 and Stethoscopes ~$10.
-Mike

 

I recently had the problem with my 92 half ton 4x4 5.0. After throwing about 200bucks worth of parts at it,Ifigured out the upper intake gasket was bad.It's a relativly easy repair.The bummer was having to buy a whole intake gasket set just to get the one I needed.You mite try testing all the gadgets first via the haynes man. and a volt/ohm meter before buyin' a bunch of parts.You could probably replace the engine coolant temp. sensor just tobe sure [cheap part].The IAC has a little shuttle valve in it that can get kinda goobered up too.clean it with some carb cleaner.

 

Ok, thanks guys!

Mpc07005, I don't know which type of automatic transmission I have. I will spray some carb cleaner around those areas. If the RPMs don't change, what is the most likely problem? I will get a quote on how much the shop I work at (for now) will do the gaskets for.

 

If the RPM's don't change, I'll have to do some head scratchin. The older autos were vacuum controlled. Some of those hoses look exactly like 10 or 12 gauge wire. Just another place for leaks. I believe your vac tree should have one plugged unused port if it does not have a vac tranny (assuming it wasn't re-purposed). Hopefully, whatever it turns out to be, it won't be too bad. And test everything on the tree with a pump.
-Mike

 

You would have a C6, AOD, or E4OD. C6=vacuum, AOD=TV cable, E4OD=Computer controled.

C6=3speed, AOD=4 speed (overdrive), E4OD=4 speed (overdrive)

The E4OD will have a OD lockout button in the dash.

 

Ok, so according to what SCRebel described, I have an E4OD transmission.


I have found that it is the intake manifold gaskets that are bad. I sprayed starting fluid (didn't have carb cleaner) around the driver's side of the intake and the RPMs went up. I will also replace the EGR anyway.

 

I had the guys at work fix my truck, and it runs a whole lot better now. It idles at about 600-700 RPMs at opperating temp. I wasn't able to get the EGR replaced, as it's on there pretty tight. It runs ok as it is if you don't mind looking at the check engine light.

Ok, different issue. On my way home today, I noticed smoke coming from under the hood up by the cowl, but only when I was sitting at a stoplight. When I got home, I noticed it was coming from under the "overhanging" part if the intake manifold towards the rear of the engine. Is that where the PCV valve is? Could that be the cause of the smoke?

Other than the smoke issue, this truck is turning out to be a neat driver/project.

 

PB Blaster and heat
You only saw it when stopped because it was too little to be noticed while driving. That is where the PVC valve is, but it may also be any lubes that the shop used. If its doesn't burn off, get in there at night with a flashlight to trace it better.
-Mike

 

Great, thanks!