random Miss

[RBrown]

I have a 89 ford f - 150 with 100.000mi and 5.0ltr. It has a random miss and evaluation of the plugs, wires and cap,rotor have uncoverd nothing. I want to check the codes but have no reader. Is there another way to check the codes?

[way2old]

I read the post on 10w40 and I think Venturi has it pretty well nailed with a basic tune up. If plugs were worn down, re-gapping would not help a whole lot. Hope it helps you and we don't care if you post on other forums as well. I feel the more minds that see a problem, the more chances you have to get a correct fix. Do us a favor and post back if it fixes it, or if problem still persists. Thanks. Tom

[Venturi]

Yea, I really want to be sure that the basic ignition system is in good shape before we start looking too deep into the computer system.

To answer your question about checking the codes; you can do it without a scan tool but it’s a pain and can be very confusing to do unless you’re familiar with the way Fords display their codes. Most part stores do sell a little code reader for Fords for about $30.00 but you can do the same thing with a testlight or an analog voltmeter.
The following link somewhat explains the types of Ford codes and how to display them.
Ford Code Retrieval

Try it if you want to but don’t say I didn’t warn you if wind up pulling your hair out in frustration.

[way2old]

Hey!! I'm not bald yet!! ;D

[RBrown]

Thanks guys! I was able to make some progress today and mostly because of the positive feedback that has created the motivation of having a group to verify my findings as good or bad. I have aquired a code reader of sorts without an instruction book but untill I can replace the worn spark plugs i'll just hold off on getting into that arena. I did replace the rotor and cap and after nightfall I'll look for arcing.

[way2old]

Thanks for the follow up. We like the feedback. That is the only way we know if we helped or not. looking forward to the results.

[Venturi]

Keep us posted on your progress. Like way2old said the feedback both positive and negative lets us know if we’re helping or not.

[RBrown]

OK gentelmen, Here is the scoop. I have replaced the sparkplugs, did a resistance test on the wires (ok) and replaced the cap and rotor. Checked the air cleaner (ok) and this is the best description I can give of what is going on. At startup, it reves high and imediatly will shut down. Sartup requires a steady application of fuel that results in a high rev then low followed with high rev and back to low several times before I can let it idle on its own. The idle is definatly steadier that before the new plugs.
While driving the truck, from a standing start small amounts of fuel will launch you but if you apply to much fuel it acts like it is loading up and will start to miss and pop. If I depress the throtle all the way is starts to pop and miss and continues this activity up into the higher rev range with little or no pop after it spools up.
On the highway, I cannot use overdrive because it will require to much throtle and will start to act as if it is loading up again. I don't hear any poping.
What do you recomend I look for at this stage?

[RBrown]

Good day to all who have running vehicles! I on the other hand still have'nt got it all worked out, Thats where you all come in I just completed a code check and I get a 11 for ok system then in the hard faults I get a 34 indicating a EVR or PFE durring a non running test. What are these devices and could they be behind my suspect condition?
What hours of online activity are you keeping?

[DanD]

With the running symptoms and now that code, I’m thinking you may have an EGR valve not fully seating or opening too easily. Due to a weak diaphragm spring or carbon build up in the valve.
Just a guess.
Dan.

[RBrown]

Thank you and if you could give me a general description of a location on the vehicle I will investigate the EGR valve. What types of test can I do and what should the results look like? What is the normal position of this valve and how do I verify that it is or is not functioning ?

[way2old]

The EGR sits on a tube and is bolted to the intake. If you stand in front of the truck, it is on your left center of engine. There is a small plastic piece on top of it that has 3 wires going to it. This is the positioning sensor. You can use a voltmeter from the green wire to the ground and check for voltage. There should be less than .9 volt on it. If the volts are over 1 volt, remove EGR and clean or replace. What you can do, is remove the vacuum line from the EGR and apply vacuum while engine is running. It should make the engine die or really close to dying. There is also an EGR vent valve that bleeds vacuum off so the valve closes. Follow the vacuum line from EGR to a small solenoid. That is the vent solenoid. There should be no vacuum on the EGR vacuum line at idle. Good luck and I hope this helps.

One question. You said you ohmed the wires and they had a good reading. What brand wires are they and the wire size? Sorry, 2 questions. You need at least 8mm wires on this truck. If they are aftermarket cheap set of wires, they can break down under load. On that subject, the coil and ignition module may break down under a high load application. Just typing as I think. Sorry for rambling. Good luck.

[RBrown]

Good day all. the wires are 8mm silicone but I see no manufacturer name. I fear that the wires as well as the plugs are original equipment. Note that the plugs were motorcraft that I replaced last night. And are you telling me that that EGR valve is UNDER that large alluminum intake thing?
PS I have noticed a memo regarding shutdown of the board for a while. Help Quickly!!!

[RBrown]

I think I found that EGR valve. Ford kindly mounted up on the side of the EFI intake. Is that right? What do I need to clean it, Carb cleaner?

[way2old]

Tou found it. To clean it you will need to remove from vehicle. There is a gasket behind it that will probably need replaced. Carburetor cleaner and a small stiff brush should do it. Look closely where the pintle drops down to close the passage. Be careful not to get the cleaner on the plastic sensor on top of it. Good luck.