I posted this in the BC4x4.com site a while ago and haven't had many responses. Need more help.

I've got a stock F-150 Custom Inline-6.


"I've still got that surging problem when I cruise around town. It usually happens in second and third gear at low to mid range rpm. I also have no tachometer which is pain in the ***. It's like the engine misses. New plugs, wires, cap, rotor, fuel filter in the past 6 months. Cleaned fuel system with special cleaning juice, good oil and filter. I also replaced my O2 sensor and now that I recall, that is when the problem started.

I've checked my timing the other day with an old style gun. You splice between the boot and the plug and clip her up that way. I did it off of the #1 plug. Hook ups for the battery are the same as the new guns. My manual was pretty vague as to what I should be unclipping and plugging up.
There are three different ignition systems for that truck. I wasn't able to identify which one to go with. No yellow wires, no spout thinggy and there are many vacumm lines too. Then I read the sticker on the hood and it told me that the timing wasn't adjustable. It also informed of which system I had and it wasn't any of them in my manual.

I took a reading anyways and was about 1.5 inches from the last notch on the indicator (BTDC), more to the passenger's side that is. So my question is, how accurate is that reading that I took with nothing disconnected? Should I be changing it up? Would you think that timing is even my problem?"

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I got this response:
"One test that you can try to help pinpoint the problem is to pull the vacum line at the EGR valve side and plug the wire. Take the vehicle for a drive and see if their is an improvement. Your check engine light will come on."

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SO to that I responded:
"What will pulling the vacumm line at the EGR valve tell me? The EGR vacumm hose comes off sideways towards the master cylinder right? It's some cone shaped metal thing with some holes in it? We tested it with the snap-on computer back in november and it seemed allright. What is happening to my engine if there is an improvement? I have also found that it does the 'missing' when in low rpm in 4th gear.
Ummm also the hose that goes into the cat from some air control assembly has been disconnected and just shoots into the atmosphere. No cat on my truck either. I posted this message a few months ago and some guys told me that it might be my alternator. It seems to give out some good power, I don't notice my headlights diming or anything. To test it, do I put on all my electrical stuff (stereo, heat, fan, high beams etc...) and take a voltage reading with my multimeter?"

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And then the same guy wrote back:
"That should be the one....The EGR valve on the Six connects to the firewall side of the Intake manifold. It looks somewhat like a flying saucer and has a sensor with a vacuum line attached. What this test can confirm is if there is too much EGR flow for your vehicle.
What some people, who have this problem do is add a restrictor plate that reduces the diameter of the EGR passage or close it off entirely. This way they can leave the vacuum line attached and avoid any problems with the computer trying to compensate."

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SO since then I have disconnected the EGR vacumm line. I plugged it with a screw and also plugged the EGR valve with a hose/screw combo. My truck is running much better and is not surging at all. My check engine light hasn't come on either. So is this my problem: too much EGR flow? Should I be reducing the amount of flow through the valve or pipe?

I was also wondering how to correctly check my timing. Which wires to pull, which lines to plug?

Thanks for your patience as my message is pretty long.
Steph.

 

I blocked off my EGR valve 100%. It performs much better and I do not get any check engine light either. Made the restrictor plate out of thin sheet metal.

 

um, this might sound dumb, but where exactly is the EGR located/what does it looklike, what what is it supposed to do? and, if blocking it off makes the enigne so much better why do they put them in?
Mike S.
1979 F-100 302
1995 F-150 4.9L 4x4

 

On your 4.9 it is located on the throttle body between it and the firewall. It has a diaphram actuator with a vacuum line hooked to it and there is a wire hooked to it to tell the computer what position it is in. EGR means exhaust gas recirculation and this came about in the mid 70s to help bring down emmissions. What it does is recirculate some exhaust gas into the intake air and re-burns it in the combustion chamber. This does not help combustion though. It decreases your manifold vacuum and also decreases the amount of oxygen there is in the combustion air. It also preheats your combustion air some and this decreases the volumetric efficiency of the engine. Air, like any gas expands as it is heated ant therefore heated air contains less oxygen than cold air. This was blessed by the EPA, so we may have to live with it for a long time!

 

To install the restrictor plate do I just remove the two EGR mounting bolts and pull it loose or does the tube have to be broke loose or removed? Is it necessary to install a new gasket on each side of the plate? Gasket sealer? Thanks for the help, Can't wait to get rid of the annoying miss right before warm-up and the 13 mpg.

KWIKI
92 F150 4X4
4.9 5 SPEED

 

Take out the two mounting bolts, remove gasket and clean up gasket surfaces, install the metal plate between two gaskets and re-install. You do not have to unhook the tube, it will spring enough for you to do this.

 

[updated:LAST EDITED ON 28-May-02 AT 10:49 PM (EST)]Yes, like mantta said, two new gaskets are required.

Clean up the surfaces well first, though.

I used 1/8" sized holes to restrict it, but I probably should have just blocked it off altogether.

It really helped, and continues to help (I'm saying that to counter an old post in this forum that warned against my restrictor-plate recommendation), my around-town driveability.

Hey, you guys want to know a secret? I was going to post this in the 1987-1996 trucks forum, but i'm not sure those V-8 owners would notice it...

Now I have a MSD-6A, the restrictor plate (which, admittedly, was a monumental improvement-maker), and synthetic oil and syn. tranny in my M5OD, but THE single greatest improvement I've done to my drivetrain - one that I've noticed the difference in - was my recent change to Mobil 1 synthetic gear oil in the rear-end.

About three months ago I did top off the rear-end fluid with Pennzoil synthetic, but I knew I needed to change it out since it was the original stuff, and since the filler-magnet was covered with magnetized steel fragments then, and also again last Thursday.

That being the case, I pulled the cover & let it drain forever. I also fished around in there quite a bit with a small, powerful magnet, cleaning the particles off every time I pulled it out.

So that job was done and I didn't think much about it until I hit the highways for Memorial Day traveling. I'm telling ya, I noticed it was smoother and, especially, (what made me really notice was) I could stay in fifth gear longer than ever before. Now my truck has a 2.73 rear-end, so I still can't stay in fifth and do 75 MPH all of the time, nor do I even try since bringing up the RPM's and using fourth is probably better on the fuel mileages than mashing the gas pedal to try to stay in fifth is... but I digress...

My main surprise was that I was heading West when I noticed the improvement. I knew that the wind was going against me, but I figured maybe it just wasn't directly at me or something. But three separate direction trips later I'm quite pleased at the results (first was West on I-80, then, second, South on I-79, then north on I-79, then East on I-80).

What can I say? I *honestly* think I gained a few HP or some torque out of it. I wasn't looking for it - the rest of my drivetrain was already synthetic so it shouldn't have made much of a difference.

Now I'm not one to go racing around town, so that may be why I didn't notice anything right way. But two days after the change I took my trips and, while I don't "push" the engine around town, I am certainly pushing it a bit (and, thus, feeling the 'edge' of the drivetrain's maximum performance) while trying to maintain speed (no cruise control, and I'm fighting to stay in fifth for as long as sensibly possible).

Granted, I didn't have the truck for very long before I installed the MSD-6A, coil and ignition parts, so I'm really not sure if they gave me an initial great boost or not - but the only change I have done that I can honestly say had a noticeable improvement on the conservative way I drive (try to keep it below 2300 RPM's normally - but will go up to 3000 RPM for some on-ramps when forced to) is changing the rear end fluid.

Now, to be fair, I did just buy and install a new speed-sensor (a $12 magnetic pickup piece) for the rear-end. But that was two weeks ago, and I did do much the same highway driving with that piece in the truck without noticing any changes in the truck's performance.

And, also, my differential fluid had 87,xxx miles on it, and it was obviously full of miniscule metallic particles (but then I'm thinking this would be the same for anyone who waited that long to change the fluid). So that old fluid probably didn't have much lubricity left in it, and the metal particles didn't help much either.

The total I put in there was about 3.25 quarts.

If you have the original fluid in yours and do the switch (to regular or synthetic, but I'd suggest the synthetic), please post back after some highway driving and tell us if you experienced the same smooothness I got out of mine.

Yea, I hate the 2.73's , but boy am I happy with my truck right now.

I would have posted this as a post all by itself, but then I don't think many would have believed me, so I am throwing it in here. Hope it helps somebody.