Truck in sig.
1. 180psi 2. 184psi 3. 181psi 4. 178psi 5. 183psi 6. 176psi

I replaced the plugs and wires today. Found out the previous owner (prior to 89,000mi) had replaced the plugs with ac's non platinum. 5 of them had rounded off electrodes and the tips were thinned out where the spark hits. and the sixth half the tip was missing as well as the electrode porcelan was chipped away. They all were gapped at least .065 or more... Funny thing is it still ran smooth and I got 18.1 mpg averaged.

Are these numbers good? I got to say, I've been very impressed with this truck. Orignal engine and tranny and everything works so great. Even all the dents and scratches and no rust...

Also, should I reset the computer?...

Thanks, Dave

 

No reason to reset the computer. You can if you want to, won't hurt anything...won't really help anything, either.

Yes, good numbers of the test, all pretty close together. I'd be somewhat concerned about the missing electrode tip if it looks as thought it broke rather thatn was burned away, but your compression test results appear to show that no damage was done.

I once had an electrode tip break off and jam between the piston and cylinder wall, scoring both and causing a major loss of compression in that cylinder.

I hope you replaced them with Autolite or Motorcraft...IMHO AC is almost as bad as Champion.

 

Definately agree with you on the AC's. I replaced them with Motorcraft double platinum.
I looked inside the plug hole best I could, and then turned it over and didn't see or hear anything rattleing. Got lucky there. Truck has more power now than when I got it!

Thanks, Dave

 

But I bet you can get it to run even better. Sounds like a solid bottem end - less than 10 PSI variaton high to low - very good.

I don't agree with Dan. I think once you change any major engine component you should rest the PCM correction factors. You won't know if it will do any good unless you do it and probably can't really measure the difference unless you have before and after reset dyno runs. But the reason for correction factors is to tweak the A/F mix and spark advance curve to account for wearing components that then affect the emmissions. If you put the bad components back to good, shouldn't you tell the PCM right away so it doesn't take another month to figure it out on its own? (Kind of like not telling your nagging wife you fixed the washer and letting her keep on going to the laundry matt untill she figures out on her own the one at home works again - who needs the extra nagging?)

So Dan's probably driving off the point made that the truck was running fine with the messed up plugs. If you had no CEL or codes, he's probably right that resetting the PCM will have little affect...but maybe it will have a lot.

Here's how to really find out if it will run better. 1) Clean the MAF sensor, 2) change the plug wires (unless you're really on a budget - then Ohm them out first), 3) change your 2 O2 sensors (unless that budget again - you can test them first) 4) fuel and air filter, 5) add a cold air intake - really helps these motors, 6) add headers.

The maintenenace stuff is more of a just because you don't know the history and these things can mess up the A/F mix from the O2 readings. The performance stuff is what I've done and I can verify they help add HP.

 

Oh sure, disagree with the moderator...
Good thing I'm not sensitive about things like that!

There's always plenty I can learn from you guys. You do make a good point about speeding up the computer's re-learning process by resetting it, but as I understand it the Adaptive Strategies which continually monitor the changes in the system will only take about 10 minutes of driving to get the settings back to normal. I seem to recall something about it taking 50 start cycles (about 2 days for me) to erase the codes (if any) stored in the computer but of course resetting it will do that instantly.

 

Well, I've put about 250mi on it since work was done. Definately smoother and quicker acceleration! (duh ) New MAF sensor about 2 mo ago. As far as air intake, you say cold air. What is different between that and what I have now. My intake comes from front grill to airbox. I know a k&n filter pack will give me less restricted flow, but the truck is fine the way it is now. This is my "lil" work truck. Daily driver when I'm not delivering furnaces. And I can't justify spending that much money to gain 1 or 2 mpg.

Does bring up a good question though. Should I worry about the cat? The exhaust is original and still in great shape. Light surface rust but still solid. The tail pipe has that nice grayish black color. Later I am going to go out and clean the egr valve as I still have a little pinging at light acceleration/constant throttle position.

Otherwise this has been the most reliable vehicle I have ever owned. Still original ball joints, tie rod, u-joints, heck just about everything! (knock on wood) Doesn't leak or burn any fluids. auto 4x4 and hubs work flawlessly. The only thing broke now is the gas gauge. It has been like that since I owned the truck. I just go off the trip. I really hope ford doesn't pull a "boner" and discontinue the ranger line. However a Diesel would be nice! Thanks for all your help, Dave

Edit: What should be(was) the compression of these engines new?

 

Question, where is the egr valve? I can't seem to find that or the DPFE sensor.

 

1993 Ranger might not have an EGR valve. My 1993 Explorer does but it is a California car. I know for Explorers, 1993 and below Fed cars had no EGR but all did in 1994+.

I don't keep anything stock. So all my opinions are slanted towards modificationa dn performance. Yes, the K&N conical style air filter and a clean tubular intake tube is what I meant by cold air intake. Now that more air is going in, headers help get it out. Opening up the efficiencies of the motor's breathing opens up free HP. Not MPG but more power...Arrr!

As far as your ping, could be a variety of things. The basic tune up stuff like I said needs to be done first. You really need to have a baseline of "known, good" components that control the spark delivery and A/F mixture. If these are off, you can be chasing your tail because the PCM, and the correction factors, often does things the wrong way - It's all about garbage in, garbage out.

I've got mine running pretty darn good. But when the weather heats up, like it's doing now, I get a slight ping too on 87 octane, full throttle under load. OK with super though. I've looked all over for vac leaks. The O2's are relatively new but the scanner shows them switching perfectly so I gotta believe the A/F is about right (except when it pings obviously). Some will say that my K&N oil is dirtying up the MAF but cleaning the MAF doesn't help. Maybe I can try and put the sock one back on as it currently has a bigger Granatelli unit on it. If the EGR is working right, it doesn't go on under full throttle so that can't be it.

Dan - I'm not baggin on you. Thing is I really don't know exactly what the EEC-IV does/ I wish I had a copy of the code, or at least a logic diagram of the code - if this, then that. I only know in general what it does and what would make sense from an engine EFI control standpoint. I've heard 100 cold start cycles before the PCM will clear a code for a problem that is now fixed - maybe it is 50?

I know the PCM holds short term and long term correction factors. When the PCM is reset, are both cleared or just the short term? About 100 miles is what I typically see as the norm for the PCM to relearn itself...I would think that meant the short term as 100 miles is not very long, right.

I guess in layman's terms, if the PCM was receiving a lean condition from the left bank, and had been correcting by richening up that bank. With the plugs all black it's proven to actually be rich, not lean and the O2 sensor was found to be bad. Switch the O2 (clean off the plugs too) and now the O2 is sending the right info but the PCM is still correcting and running the left side rich. Now you have 50 or 100 or whatever miles of sooting up the plugs again. Why go through this when you can disconnected the battery and set the factors to 1 and have a clean burning engine immediately after fixing the O2? That's my simple minded point.

 

True indeed, because in that instance you're replacing a bad sensor and you would want to reset the computer. But since all LilDuke did was replace plugs and wires, I was thinking that it wouldn't make much difference.

Have you read Charles Probst's books on Ford Fuel Injection and Electronic Engine Control? I have them and they're excellent, although a bit over my head at times. I wish I had time to sit down and really read them cover to cover, but I wind up sitting in my "office" and studying them piecemeal when I'm looking for the answer to a specific problem.

Well worth the bucks though.

 

No I never heard about this Author. Just A-holes like Jerry at SCT who because they used to work at Ford designing PCM profiles, think they own the market on this knowledge. It's just stupid in this day and age why we have to struggle to understand the car's basic control schemes. No one is going to loose a dime if the controls logic to a EEC-IV is made public knowledge. Not the basics on how a PCM works, everyone know that. But the specifics of each and every calibration code, sensor voltage limits, temperature ranges, the + and - results to the correction factors, the interaction between short and long term correction factors...how these things actually work!

 

I highly recommend these books. I refer to them constantly, and if you really want to gain a better understanding of Ford's EFI systems, these should prove invaluable. One covers the earlier years, '80-'87 and the other covers '88-'93.

http://www.amazon.com/gp/product/083...Fencoding=UTF8

http://www.amazon.com/gp/product/083...lance&n=283155

 

Checking the plug wire resistance will only tell you if the core material has broken down. It will NOT tell you if the insulation has broken down, which will cause misfire.....