Steve83

Still no pics - use a real computer. And read this caption:


(phone app link)

Axios

I'm not sure what the problem is, I went on my computer last night, and uploaded the picture in my last post. I can see it in the computer as well as now on my phone. And thanks for the link, it will come in handy.

Steve83

It might have been my crappy ISP that didn't load the pic earlier... I can see it now. That's a lot of soot, which indicates recent (but not necessarily CURRENT) overfueling. Of course, the entire combustion chamber is coated, so even if it's no longer overfueling, the old soot can still be transferred onto the new plugs. Removing it takes some effort...

With the engine FULLY warmed-up & running above idle (like ~1800-2500 RPM), drip clean water slowly into the throttle body. NOT fast enough to hydraulic the engine; but just enough to make it run slightly rougher, and to create a cloud of ugly brownish smoke from the tailpipe (make sure there's nothing nearby to get stained). When the cloud turns mostly white (usually within a minute or 2), the combustion chambers are clean.

Then try cleaning the new fouled plugs, and see if they foul up again. If not, put new clean plugs in.

I still don't see the fuel pressure.


(phone app link)

Axios

I need to pull fuel pressure yet. I have a persistent code 126 at this point which us the only code showing. Could a fuel pressure issue or fpr cause a code 126 with way overfueling?

raski

Pull the vacuum line off the fpr. Raw fuel could be getting introduced into the vacuum line. EGR and low fuel pressure will lean out the mixture. The fpr actually is to keep the fuel pressure from going too high. Also change out that coil and your wires. Shouldn't be that corrosion on the terminal.

Axios

I checked the vac line, and there is no fuel in it. It could be stuck open, I guess. I need to get a gauge on the rail.

Steve83

I don't have all the codes memorized. When you post one, include the number AND the complete definition.


(phone app link)

The MAP is the only part I recommend swapping instead of diagnosing. I collect used ones in JYs, and test them in the parking lot, or on the drive home. All '87-95 smallblock F-series MAPs (& some from other Fords) are interchangeable. MAPs are known to simply fail, and a bad MAP could cause the overfueling.


(phone app link)

Axios

Right. I replaced the MAP, and the code still remains there on a KOER test. I also get a code 173 (HEGO SENSOR FAULT - Indicates RICH) persistantly with KOER, forgot about that. Code 111 system pass KOEO and Memory KOEO. I replaced the map because short of checking the signal return and voltage wires, without a scope there is no way to really tell if the sensor is actually doing what it should. Sorry, I have most 2 digit and 3 digit EECIV codes memorized, I've had to over the years lol

Steve83

With what (brand, PN, source)? Did you keep the original? If there was no change, the original is probably just as good as the replacement.Did you clear the codes? Don't disconnect the battery.That's revealing... If the EEC knows the mixture is rich, and it's still overfueling, then the overfueling is probably NOT a result of the EEC holding the injectors open longer. It's more likely a leaking FPR (which you checked, and it's not) or high fuel pressure, or the first leaking fuel injector I've ever heard of on these trucks.

But you should CHECK to see if the HEGO is actually stuck rich.


(phone app link)Yes, you can use a tachometer. But it's not worth the effort.

Axios

So I rented a fuel oressure tester.... but it was such a pile of crap that I'm not sure if my readings are accurate. It looked like about 54psi while idling rough, when revved it would dip slightly at tip in, about 2psI and then climb. KOEO pressure looked close to 30PSI and it looked like it held. The reason why I'm suspicious of those readings is because it took almost a half hour to get any kind of reading on the gauge, and even then it was so gd slow that it almost took 4 minutes for the gauge to top out at idle. I'm going to have to find another gauge and re-test.