I changed it not long after I started trying to get rid of the off-idle hesitation. I am going to try to sync it tomorrow at work.

My uncle just in formed me I can rob parts of a 4.9L he pulled out of his drag-up truck(blown head gasket or cracked head??). To bad he broke the Intake manifold and vacuum solenoids when he pulled it out. But the EGR valve seems to be good. and I have access to all the injectors and other parts.

 

After reading through the 20 page post by Alien, I am going to check along the same line but I am going to pull the codes first (again), clear them and as Sean said " drive it like a race car ".

I am going to rob some parts off my doner motor and they are going be as follows:
Throttle Assembly
EGR valve
IAC valve


Question what do I unplug to check the timing? I know there is something you have to unplug to take the computer out of the loop.

And isn't the timing supposed to be set on 10 degrees BTDC?

 

You will leave the control solenoids on and wiring to them hooked up. Leave the vacuum into them hooked up but cap the vacuum out. Leave the EGR on and leave that control solenoid hooked up as shown on the diagram. Remove the smog pump, control valves (the part the vacuum out of the solenoids runs to), and the air tubes. Weld the hole in the cat shut that the tube went to. While you're inspecting and cleaning the throttle body check the return spring on it. The timing specification will be on the vacuum hose diagram under the hood but I think it is 10 degrees before. You need to unplug the spout connector which should be near the distributor, it looks like a plastic plug that bridges two wires. Once timing is set, you need to clear the codes in the computer because a spout code will be set.

 

Don't change the EGR valve just because it won't hold vacuum. Thats old valves, later models with the back pressure from the exhaust system, I thought operated slightly different and thus a different test procedure. Please correct me if I'm off base.

 

Nope, EGR should hold when vacuum is applied.

 

Thanks Sean, wonder where I got my thought from? Do as Seans says, and I'll go back to the books.

 

Thanks for the information guys, I really think this is going to be a problem that is so obvious it crazy. But hopefully not as crazy as the Alien post.

New update. Changing the fuel filter did quiet down my pump. Ran some Sea Foam through the intake and cleaned the throttle body today. It was encrusted with carbon build-up. I cleaned it and reinstalled with a new gasket. No real change in idle. Checked the return springs Every thing was pretty tight. Took off the TPS and cleaned behind it. Do you think it is possible for the throttle body to be sucking air around the throttle shaft? I guess I could get some starting fluid and spray the throttle body along with the rest of the engine to check for vacuum leaks. I did find a vacuum line on top of the throttle body that was a loose fit. No change in Idle. Okay so pending the starting fluid test, I am going to say the TB is good.

I also cleaned the IAC again, no change in Idle speed, actually seems to take longer to idle down now. it is working but it seems like its delayed. If you rev the engine it will not go back to the same idle for about a minute. Thinking it could be a bad IAC or the fact that I had to reuse the old gasket. I also disconnected the IAC and started the truck the idle was the same. I thought the IAC was supposed to reset with the key off? Maybe the actuator isn't working right? Think I will try the one off the other engine. Along with the EGR valve (one at a time).

A plus is that after I cleared the codes and drove it it seem to accelerate better. I plan to drive it like I stole it for the next few days(don't these computers learn from the driving style?).

I tried the vacuum hose stethiscope method and it works decently. I now know that the ticking I hear when the truck idles is the injectors. One of them is kinda loud.


Where is the spout connector for a 93 4.9L?

 

by distributor or by ighition module by the ecu on the drivers side fender

 

RAIN RAIN RAIN and guess what.... RAIN. To bad my shop leaks on the outside and rains on the inside.

Okay update, I found the spout connector finally. It was twisted under another wire loom ontop of the fender well. I was beginning to think it was left off my truck. I found two marks on my crank pulley/damper one was a notch the other a line. I marked both with a black sharpie, but I think the line is the timing mark because it is at the pointer when the timing light is turned on. I cleaned the timing pointer but still cant really make out the numbers but the notches are there. I unplugged the connector, started the truck up, nothing unusual. Turned on the timing light and the mark is about 2 notches to the right hand side of the 0 degree mark ( the large notch).

I an not really familiar with fords, but if the engine rotates clockwise this setting would indicate the engine is retarded (I think) either 2 or 4 degrees, depending on the scale used for the notches. Please correct me if I am wrong.

Could this be a source of some of my problems? I know timing is Critical on engines. The vacuum tag say 10 degrees BTDC and if mine is 2-4 ATDC that is 12-14 degrees off. To me thats alot. The computer is set to adjust timing from a 10 degree BTDC base it probably can't compensate for the 14 degrees?

I plan to get a book today, and a EGR gasket, and a IAC gasket. I plan to pull codes tomorrow and possibly swap the EGR valve and the IAC with those on my doner engine.

The truck deffinately has more power since the cleaning. Thanks for any information, again.

p.s. any one have a picture of a clean timing pointer, in case the parts house doesn't have a manual?

 

That's pretty far off. The timing pointer should have V notches in it, the deep V notch should be 10 degrees BTDC. The computer won't compensate for off timing, it only assumes the timing is set correctly and makes its adjustments from there.