94 Escort Running Rough

Hello,

I can't figure out why my 94, 1.9, AT, 150K Escort is running rough. It started by idling rough but running smooth after giving it gas. Now it misses through out the entire RPM range. Here is a list of things I have already done. Any help would be greatly appreciated.

New timing belt
New IAC Valve
New vacuum lines
New injector
New EGR Vacuum solenoid
New MAF
Different Computer
New coil pack
New plugs and wires
Compression test (between 125 and 150 on all cylinders)
Fuel pressure test (tested good)
New fuel filter

In a nut shell, It has good fuel pressure and good spark, but it is still missing.
Thanks
Rob

Have you checked the vacuum? I'm wondering about a bad EGR valve. What about PCV valve?

I did replace the PCV valve and fittings. The EGR valve seems to be working fine. I havent actually checked to see what the vacuum readings are but I dod trace out all of the vacuum lines and replaced the bad ones.

my escort started running rough when the ground was failing (corrosion on/in ground cable), idling and on the highway. cleaning and replacing parts as needed made everything smooth again. seems too easy, but if you're still brainstorming..

Is the timing set correctly after the new belt installed... and is the tensioner tightened properly?
Possible vacuum leak from the intake manifold?
Demons?

'94 225k MT - It's hard to test load on an automatic trans but anytime i've had the problem most of the time it was electrical, specifically the spark plug wires or/and spark plug gap too wide. It would miss with heavy load at low RPM but be completely fine at high RPM, load or no load. Problem would get progressively worse. The "high quality" wires normally advertised as "double silicon" seem to offer too much resistance. The standard pair work better and last longer. (stay away from AutoZone) Wish had never got rid of the OEM set. The suggestion about cleaning up your battery and ground connections is a good one as well. If remember right I think there is also a grounding cable attached to the back of the head somewhere if you can find it. Also make sure that you have Motorcraft spark plugs and not Bosch or whatever.

Other times it was a timing belt stretch or slip.

If the waterpump is noisy (clacking noise) or the pulley wobbles on it's axis then replace it. That can also be a contributor. (to timing belt slip/wear issues)

When you say PCV fitting, did yout mean the fitting at the valve itself or the PCV elbow? At 150K, your PCV elbow is long gone.

When you say PCV fitting, did yout mean the fitting at the valve itself or the PCV elbow? At 150K, your PCV elbow is long gone.

That little elbow is one of the dumbest parts ever!

The elbow we are speaking of is the one on top of the intake manifold at the vacuum ports.

That little elbow is one of the dumbest parts ever!

The elbow we are speaking of is the one on top of the intake manifold at the vacuum ports.

Exactly! and you have to get it at the dealer too!

http://forum.videohelp.com/images/guides/p1490611/engine_02_small.jpg



As you can see, mine developed a hole in the back of it. you could not see this hole unless you were really looking for it!

http://forum.videohelp.com/images/guides/p1490611/engine_03_small.jpg

There are plastic and rubber vacuum hose parts available at the auto parts stores. Measuring the diameter of the original, used one plastic tee (couldn't find an elbow) and two short straight pieces. They had plugs for the other end of the tee.

Engineers are usually very intentional in what they do. They probably designed that hose to be easily collapsable as a backup incase the PCV valve failed. Don't want the intake sucking oil. Unfortunately age quickly takes the part out of spec, causing it to collapse prematurely.

Since you mentioned it, I also found EGR and related orifices in the intake clogged and cleaned them all out prior to reassembly. Didn't seem to affect anything though.

There are plastic and rubber vacuum hose parts available at the auto parts stores.

Not ones this size. Trust me, I looked.

(hate to recommend them for their otherwise crappy parts but...) Try AutoZone. That's where I rebuilt mine from. Of course the wall thickness will be different so it won't be an exact match. ;)

Those are great pictures.
I wouldnt blame an engineer for the item being bad. It was probably spec'd okay, but someone else at Ford whose job (and bonuses) depends on finding lower cost sources for parts, found a cheaper place to order up a production run of them. At least thats what I imagine, being a retired engineer, who in my career with the Fed. Govt. seldom got to do any engineering myself.

You indicate you've done "vacuum lines" ....all of them? There are some hard plastic lines running from the firewall down under the battery tray to the charcoal canister down in the lower left fender ...over time, the battery acid will eat through the plastic lines. This is what happened to mine and I replaced them with rubber lines. Also, it's important to use the right rubber hoses for the vacuum lines: make sure they are labelled for "fuel vapor". Ordinary rubber lines will rot quickly whe exposed to fuel vapor.

Your EGR valve may have good vacuum to it but if the diaphragm is weak or damaged the valve will act funky ....EGR valves are not that expensive and a malfunctioning one can make your motor run like crap.

Check the snugness of the bolts holding the intake manifold ...they can loosen over time.

Mike
95LX

You can have vacuum leaks at the vacuum devices themselves too. I've had plenty of vacuum actuators go bad.