Thanks Chris . I Believe the FDM is the Fuel pump Assembly .

 

OK, I'm looking at the book now.

I'm betting your engine wasn't warmed up before running this test? That could be skewing some results, and some of the stuff it's reporting can be ignored because we didn't perform some steps I told you to not worry about the other day.

If we wanted to rerun the test as per the book... warm up the engine, shut it off, wait 10 seconds, start the engine again. Then...~~~




In any event, for this test, the computer is reporting:

116 332 411 538 536 632


116 = Engine Coolant Temp (ECT) higher or lower than expected
332 = Insufficient EGR flow detected

411 = Cannot control RPM during KOER low RPM check

538 = Insufficient RPM change during KOER dynamic response test

536 = Brake On/Off (BOO) circuit failure / not actuated during KOER
632 = Transmission Control Switch (TCS) circuit did not change states during KOER


Ignore the last 2 errors, they're most likely from not performing the above steps, but the 538 could be coming from either not doing that WOT procedure, or it could be because the TPS needs attention.

Could also be from other stuff, read below.

116 and 332 could be because the engine wasn't warmed up or could be from other causes, we'd have to rerun the test to verify or disqualify those results.



This leaves us with 411, cannot control RPM.



OK, lessee what the book says about your CM results from the other day:
BTW the computer remembers the previous 80 engine warm-up cycles.

112 = Intake Air Temp (IAT) sensor circuit below minimum voltage / 254°F indicated
113 = Intake Air Temp (IAT) sensor circuit above maximum voltage / -40°F indicated

122 = Throttle Position (TP) sensor circuit below minimum voltage
123 = Throttle Position (TP) sensor circuit above minimum voltage

327 = EGR (EVP/PFE/DPFE) circuit below minimum voltage
334 = EGR (EVP) closed valve voltage higher than expected

542 = Fuel pump circuit open - PCM to motor ground
556 = Fuel pump relay primary circuit failure



~~




This truck is reporting a lot of problems, it's no wonder it runs poorly.

OK.... Locate, remove, open up, inspect the inside of the computer and look for burnt components as shown here:




and for leaking capacitors:

as shown in this thread.





~~

Could also be that you have a terrifically-unmaintened and/or hacked truck. For how long did your friend have it, and how much history of it do you know?

If it hasn't been maintained all its life, there's a chance that that many sensors have simply given up the ghost over the years, OR their electrical connections are dirty, or the wiring is melted/shorted someplace. In addition to the fuel delivery circuitry, it is complaining about:.

IAT
TPS
EVP
Maybe ECT (warmed up engine or not)

All that stuff being bad all at once would certainly account for the thing running like crap.

Pictures and descriptions of a lot of the sensors can be found here:

Fuel Injection Technical Library » Sensors

Those fuel pump circuit errors concern me... Yes, Charlie is right, check your fuel pressure, too.

After servicing the engine and/or wiring, rerun the tests. The way to clear the codes is to disconnect that jumper wire while it's spitting codes out to you.



Let us know what you decide or if you have more questions.

BTW after watching that KOER video, I wouldn't say that engine sounds fine or normal.



BTW the computer is located here:



BTW my source for all this info is the Ford Powertrain Control / Emissions Diagnosis Service Manual FPS-12106-93 (1993 version)

 

Compression is good, so no concerns there.

Given all the codes you're getting, I'd be a little suspicious of the engine swap - more specifically the electronics aspect of it. Were all the sensors swapped over from the original 1990 EEC-IV engine?

Also, as pointed out above, pull that PCM and take a look inside (T-15 bit required). I bet you'll find leaking capacitors.

 

Fdm is fuel delivery module. In 90 Ford used 1 high pressure pump per tank. They did away with the pump in the fuel rail, and the reserve can. He has the 1 pump per tank set up

This picture of the location of the computer is for 92 to 97, the computer is accessed from inside of the fender well.




From 87-91, the computer is in the same location, but you must remove the kick panel to remove the computer.

To do so, you use a 10 mm socket to remove the bolt holding the harness in from the firewall side
You then remove the kick panel from the inside, and unbolt the hold down bracket.
You then can remove the computer.

 

The truck was missing the ATC sensor which I replaced . I'm also puzzled by the smog air stuff there are two sensors by the egr sensor and only one has hoses hookd up to it and the air pump goes to the cat only not the air charge tube on the intake . I see the parts store website they had a diverter that went to both the cat and charge tube but. They no longer sell them ?

I will pull the ecm tonight and see whats going on . Thanks agian for the help.

 

"...only one has hoses hookd up to it and the air pump goes to the cat only not the air charge tube on the intake..." A good place to start is by fixing that....and whatever else in the system(s) has been removed, unplugged or otherwise is not functioning properly.

 

Thanks, Charlie! I found that picture on the 'net someplace, it was already doctored up and seemed to match what I remember seeing in the JY so I was hoping it was accurate for this guy. Guess it wasn't, so thanks for the correction.

 

No problem Chris. 87 to 97 are all my babies now, lol. I've updated,lol, all my 80-86's are gone

 

This is a good point. The OP had mentioned the engine was changed from OBD2 to OBD1 but I have no idea if the sensors are the same or not.

One way to tell might be to go to a parts store web site, look up the part number to one of the sensors and write it down, then look up the same part for an OBD2 model and see if they're the same part numbers or not.

 

Generally speaking, Ford changed the connector type consistent with the change from OBD1 to OBD2. In some cases, the part is the same, just a different connector, but in other cases, the part changed too.

It does sound like things are a bit funky and hap-hazard with respect to the emissions stuff. I'd vote for removing as much of it as you can; at a minimum, make sure any open connections (vacuum or otherwise), have been plugged off.

 

That's pretty much what I figured would be the case but don't have enough experience with OBDII to speak definitively.

See, this is where you and me differ radically... I would vote to NOT remove the emissions stuff - at least at this point - as doing so can be a sure-fire way to cause yourself operational/running/performance problems and/or computer-reported errors. Of course, getting negative results like that depends on the calbration from the factory and what all is done to change things, and it can be hard to sit here at a computer and just type this stuff without actually seeing the truck in person.

But, in general, I vote to not remove that stuff as it's not going to do any real harm or affect performance drastically (assuming the stuff is working as designed). The biggest performance hits in engines of this era result from low compression and retarded valve timing, and this can't be changed without a somewhat major engine rebuild.

 

There isn't a day goes by but someone has a vehicle that some profound bit of re-engineering like removing, plugging, unplugging, etc., has been performed and then they wonder why it runs like feces.

 

Yeah, tell me about it! I hang out mostly in 80-86 and 1984/85/86 is when Ford transitioned the I-6 and 302 (and 351W 2bbl) from DuraSpark II to DuraSpark III and EEC-IV and Feedback Carburetors, ultimately to EFI.

We get a fair number of people with problems a PO caused by "cleaning up the engine bay" or "removing all that emissions crap" or some such garbage like that. Some of that stuff isn't emissions-related at all but is to help operational ability, but people don't understand that and don't bother to learn.



On a different note, I just became aware the 4.9L/300 cid 6-banger never came from Ford with an OBD II computer system, Ford had transitioned to the V6 engines when they stopped production in 1996.

That should make things easier for the OP....

 

True point Chris. The v/8 trucks changed in 94. I 6 stayed the same for 2 more years

There are some changes on the 4.9 through the years, but most of those happened between 89-90

 

Fair point. In fact, I do often tell people to return things to stock when they've made a mess of things trying to do some sort of "upgrade". My suggestion here was in the context of stuff already gone missing/broken/left open/ etc, and thus it might take some significant effort to return it to stock.

FWIW, I recently went through this process myself when I replaced my 4.9 with another, and initially intended to leave all the emissions stuff in place. But after breaking some things in the R&R process, I changed course and went for the "emissions delete" option. I have no regrets at all.