Alright guys i've finally decided to get my engine running a little better and would like your help as to what you beleive is wrong with it. So here it go's the motor is a 1988 fuel injected 300-6 It's in a 1977 f-150 custom 4x4. Right now it develops a small miss at high rpms in third gear (about 3000 rpms at 50 mph). The truck is running super rich (black tail pipe and smells bad with fouled plugs). So i'm guessing my 02 sensor or sensors are probably the major cause of that. Where are my 02 sensor(s) located and should i just buy new or should cleaning them fix it possibly?. The upper rpm pull at highway speeds is horrible and it tops out at about 80mph (if that's just how a 300-6 is so be it i'm just stating what i've noticed). It also surges at an idle jumping up and down about 100-200 rpms at a time. After the truck get's out of startup loop and is ideling it idles fine at about 700-800 rpms but, it still surges about 50rpms or more at a time.

I will soon have a new fuel filter, tank, sending unit and all that junk replaced. I have new plugs and wires and air filter (the plugs are already dirtied up with carbon). It has new gear lube in both diff's in my tranny and new oil and oil filter in it. The truck does seem to possibly over heat though. That will be fixed soon too. first i'm going to wire up a oil pressure gauge and water temp and amp gauge and if it says i'm getting very warm i will put a new bigger radiater in it (it has a new fan and fan clutch).

Anyways possibly post some symptoms your motors had and how you fixed them and that would probably lead me in the right direction. Any suggestions help blah blah blah is appreciated so t/y ahead of time

 

probally is the O2 sensor. it should be located ether on the downpipe just after the Exhaust manifolds or on the exhaust manifolds. Can you pull codes on the 88 computer to tell you what it is?
My truck used to run hot turns out the Rad was plugged up. Put an all metal one in from Napa and it runs right at the N in normal.


DT

 

Well i took it to my neighbors house earlier tonight and he adjusted my timing much closer than it was (he's a mechanic). He tried doing it by light but, we couldn't find the reference mark on my harmonic dampner. So after playing with it trying to find it quite a few times he adjusted by ear it's much better than it was. I bought a new ignition switch for the truck and a new 02 sensor because, it must be the 02 making it run as rich as it is. I also bought a set of triple gauges (amp,water temp, and oil pressure) and a clock with inside and outside digital thermostat for no apparent reason...... So i suppose it will be a while before i have my coolant flushed unless i decide to do it myself.

 

The biggest problem about flushing the coolant is where to dispose of it. That's the problem i had. My local dump took it for free. If it wasn't a law i'd just dump it out back in a field.

DT

 

Well today hasn't worked out to well yet, yesterday around 1:00am i decided to try and put the 02 sensor in, since it looked quite simple. Well i can't get the damn thing out i mean it's realy stuck and i have some pretty strong arms. I'm starting to round off the nut that tightens it down so thats not good... I suppose i'll go out and spray more penetrating oil on it and tap it with a hammer in different directions to see if i can loosen it up. If not i think i'll have to cut it out and install a new 02 bunge in it's place. I also am trying to put my new gauges in too but, don't know for sure where my coolant temperature sending unit is (i beleive it's on the fitting on top of my water pump but, i'm not 100% so i can't put my water tempg gauge in yet. I also don't know where to find a oil pressure port at to install the oil pressure gauge. Lastly as for my amp meter i need wire to install it so i've basically got nothing done today so far except annoyed myself.

 

Break the top off the old one. Then take a deep socket and a breaker bar and it should come off. I tried using a wrench on my dad's 00' when i changed the O2 sensors and it was a pain. I couldn't budge it and i'm pretty big at 6'2 250. Turns out the ear on the wrench was hitting the collector flange where i couldn't see it.

Ok for the collant sensor. Should be on the thermostat housing at least it is on my 85' sticking strait up with 2 wires coming from it.

For the oil if you want to keep your stock guage inplace also you need to go to lowes or home deopt and get a Tee fitting and a short pice of pipe. The oil sendor is located on the driverside just below the liftercover at the rear of the block.

If you need any pictures to help you out i'll take some of my oil sendor setup and where the water sendor is.

DT

 

wow your a lot of help and knowledgeable for your age quite t/y i'm off to brake the 02 sensors top off to get it off then i'll wire the water temp gauge then see if i can figure out where to get oil pressure at t/y alot.

 

Well thanks. I've been working on trucks since i was able to walk. I learned alot from my dad he's an automotive metalergical engineer. Deals with metals and what not and designs suspensions.

Dude you must have some serious light to be working on your truck at 1 in the morning. Unless you have a garage.

Later

DT

 

might want to check engine vacume. engin evacume can tell you a lot about an engine.

 

Omfg guys that 02 sensor makes an unbeleivable difference completely different truck i'm driving now.... It will 80mph so much faster than it use to. It use to be as soon as it was in 4th gear your done good luck accelerating. I'll bet the truck will top out around 90 mph (not bad for being in a 1977 pickup) now. There is an unbeleivable difference and the smell is much better in the exhaust now too... I think i might take my spark plugs out and dip them in gasoline to get all the carbon deposits off them because, carbon is no more lol. Anyways i'm extremely happy now.

I also found out that my truck doesn't seem to be overheating either although i didn't get to beat the snot out of it to make sure my new temp gauge didn't rise. It stayed at 195 the whole time (thermostat is a 195 t-stat). I still have to wire my oil pressure gauge in but, i'm super happy now so i figured if any1 is in doubt of needing a new 02 sensor go buy 1 it made a world of difference for me.

 

Well good it finally worked out for you.
90!!! I'm jealous. I'm @3000 doing 67. i've had it up to 80 once but i usually cruise at 65 on the 3 miles of interstate i go on to school.

I put a 180 in my truck when i put the new radiator in might change it out to the factory 195 later it seems to run really cool.

DT

 

I have 1 last quick question about my motor until i get a little more money lol so here it gos, the motor is a 1988 300-6 efi where does the hose off my pcv valve connect to? Mine is just hanging there unconnected (huge vaccum leak). Give a good explanation to plz because, i usually can't find things when i'm looking for them unless i know where they are lol.

 

on the 95's it is:
Passenger side of the intake manifold just below the vacuum tree.

 

thank you