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[turbostd]

I am trying to get my uncles 90 f150 running right for him. It has a fuel injected 300 straight six in it. I was running pretty crappy and he had someone do a tuneup for him and now it runs like shit. The thing wont idle on its own but if you hold the gas down it seems fine. It is running so rich that the brand new plugs he put in are carbon fouled already. Someone told him its the fuel pump but its getting enough gas to foul the fuck out of the plugs so i don't think that's it. Anyone know enough about these eecIV 6s to know wtf would cause this? Is it the coil or module? Im a chevy/honda guy myself so im at a loss.

[patsmx5]

Put a timing light on each wire while it's idling and see if you're getting consistent fire on each cylinder. The modules on those go bad sometimes, also the fiber-plastic cam gears are bad about stripping out, though that's probably not the problem if it runs.  Spray some WD40 in the distributor cap and see what happens. Can't remember if the I6's have a MAF sensor, but if it does, clean it with MAF sensor cleaner.

[Joseph Davis]

Use jumper cables to ground block to battery, and block to chassis.  The stock woven ground straps corrode and become resistances which cause those trucks to run rich.  It's the first thing I'd check.

After that check coolant temp sensor, MAP.  The coolant temp sensors will sometimes break off internally, they usually wobble when you (unplug them and) grab the body, but sometimes you have to yank them out and inspect.  Regardless a multimeter will tell all.  The MAPs don't go bad often (in my experience) but they are kind of wierd in that they put put a frequency that changes with manifold pressure and not a linear-ish voltage.

[Joseph Davis]

Put a timing light on each wire while it's idling and see if you're getting consistent fire on each cylinder. The modules on those go bad sometimes, also the fiber-plastic cam gears are bad about stripping out, though that's probably not the problem if it runs.  Spray some WD40 in the distributor cap and see what happens. Can't remember if the I6's have a MAF sensor, but if it does, clean it with MAF sensor cleaner.

How does the ignition system cause a rich running condition?  Zero mention of misfires, dude.

[turbostd]

It does misfire but im sure its caused by the rich condition. Thanks jd ill check everything you mentioned when I go over to work on it later.

[patsmx5]

Put a timing light on each wire while it's idling and see if you're getting consistent fire on each cylinder. The modules on those go bad sometimes, also the fiber-plastic cam gears are bad about stripping out, though that's probably not the problem if it runs.  Spray some WD40 in the distributor cap and see what happens. Can't remember if the I6's have a MAF sensor, but if it does, clean it with MAF sensor cleaner.

How does the ignition system cause a rich running condition?  Zero mention of misfires, dude.

He said it runs like shit, so it could be ignition related. Misfires, fouls plugs. Or runs rich, fouls plugs. And every ford I6 I've ever seen mess up had either ignition problems or dual fuel pump problems.

[turbostd]

I was really hoping to go to the jy and get a coil/dizzy and tb for this thing but my local yard only had 1 truck with a fi/6 and all those parts where gone already.

Put a timing light on each wire while it's idling and see if you're getting consistent fire on each cylinder. The modules on those go bad sometimes, also the fiber-plastic cam gears are bad about stripping out, though that's probably not the problem if it runs.  Spray some WD40 in the distributor cap and see what happens. Can't remember if the I6's have a MAF sensor, but if it does, clean it with MAF sensor cleaner.

How does the ignition system cause a rich running condition?  Zero mention of misfires, dude.

He said it runs like shit, so it could be ignition related. Misfires, fouls plugs. Or runs rich, fouls plugs. And every ford I6 I've ever seen mess up had either ignition problems or dual fuel pump problems.

This truck does indeed have the dual tanks. However only the front tank is in use as the rear leaks. Most of these trucks i have worked on have 3 pumps one in each tank and then a frame mounted one I was surprised to only see the 2 intanks on this one.

[Joseph Davis]

Why does everyone always hate on the TFI?  That shit has always treated me right.

[turbostd]

wait the 5.0 truck tbs work on the 300/4.9 damn i wish i known this yesterday the jy be me has tons of truck 5.0s just no 4.9s lol.

[j.h.christ]

that motor will run forever.

[Joseph Davis]

that motor will run forever.

-1

It needs rod bearings every 250K.

[92CXyD]

that motor will run forever.

-1

It needs rod bearings every 250K.

Yeah 250K for an ancient designed motor is forever. ;D

[turbostd]

that motor will run forever.

-1

It needs rod bearings every 250K.

Guess ill be doing rod bearings in it soon its at 200k lol, Anyhow I just got back from messing with it. I pulled the codes and a map sensor code came up. We unplugged the electrical connector and it ran a lot better so I guess that means the sensor is bad. I am going to the jy in the morning to get another one to make sure before we buy a $120 sensor lol.

[Joseph Davis]

Any Ford truck will have it, at least up until your model year.  Also 86-88 Muffstank, and probably 90% of FoMoCo vehicles from those years.

[turbostd]

thanks jd hopefully this fixed the problem lol.

[Joseph Davis]

Check the vacuum line going to/from FTW.

[turbostd]

Well we got it running good again. Well as good as a 200k 300/6 can run lol. You would never guess what was wrong. Whoever did the tuneup on it didnt put the rotor on right in the dizzy and then just put the cap on ontop of it. We started to take the dizzy apart to change the module and the where like wtf this isnt right. The rotor was rubbing on the cap.

[patsmx5]

Put a timing light on each wire while it's idling and see if you're getting consistent fire on each cylinder. The modules on those go bad sometimes, also the fiber-plastic cam gears are bad about stripping out, though that's probably not the problem if it runs.  Spray some WD40 in the distributor cap and see what happens. Can't remember if the I6's have a MAF sensor, but if it does, clean it with MAF sensor cleaner.

How does the ignition system cause a rich running condition?  Zero mention of misfires, dude.

Well we got it running good again. Well as good as a 200k 300/6 can run lol. You would never guess what was wrong. Whoever did the tuneup on it didnt put the rotor on right in the dizzy and then just put the cap on ontop of it. We started to take the dizzy apart to change the module and the where like wtf this isnt right. The rotor was rubbing on the cap.

[turbostd]

Oh the tps and map where also bad lol forgot about that part. this truck has seen little to no matnence in the last 100k of its life so a bunch of shit went all at once.