Ok guys, anyone who has an opinion on this, PLEASE help!! I'm at my witts end with an 84 Turbo Coupe, 2.3T-5spd car. It runs fun with your foot into the throttle and at idle, but at a constant speed and under a light load it bucks and chugs so hard it's knocked itself out of gear!! I'm fed up with it and ready to yank it in favor of an all mechanical 5.0/5spd so at least I know what I'm dealing with!!! LOL
Here's the details on the car:
Stock 2.3 Turbo Coupe, 126,00+ miles (obvious signs of previous engine work: no paint on head, new clean gaskets etc) Was told upon purchase car had new injectors (green tops).
Upon purchase I did a complete tune-up including: plugs, cap, rotor, 8mm silicone wires, and even a fuel pressure regulator. Adjusted timing and it ran "good" (still not great) then slowly got worse. As a side note, the best MPG I've gotten from it has been 19.8....think it should be better as my other Turbo Bird got much better mileage. Ok, back on track....new in-tank fuel pump and sock (why do these cars have TWO pumps anyways!?!) and 2 new Throttle Position Sensors (TPS's-thought maybe first one was bad as the box it came in was kinda beat up, swapped it at O'Reilly's for another). Only thing I haven't swapped out yet is the fuel filter.
Car runs ok in the morning when it's cool out and even after it warms up to operating temps.....but anything over outside temp of say 70 degrees, the car will buck and chug even before I can get out of the driveway.
I'm at a loss here....I'm starting to think its the distributor? I've been all over the engine bay looking for vacuum lines that are broken, loose, cracked etc and have found nothing. I've also compared this car to it's twin in my garage and have found only 2 differences:
EGR has been blocked off with a plate and vacuum line to it is capped off.....and a small plate between the IAC (idle air control valve) and throttle body, it has a Ford part number on it and also has two set screws that will change idle if you mess with it (?).
I know this is a shot in the dark asking for a diagnosis online....but any suggestions at this point and time would be helpful!!!
Later, RAY
what brand of silicone spark plug wires? I put a set of taylor spiropro's on mine when it was stock and it ran like absolute garbage. missed every so often and bucked pretty good. I run msd's now, but I also have a crane ignition on it now. Usually when they are stock, pretty much everyone will tell you to run motorcraft wires.
Aw come on dont threaten to slow the car down with a 5.0!
Dont know anything about the plate on the IAC you speak of.
EGR blocked off will lower MPG slightly I think.
Make sure all your tune-up parts are MOTORCRAFT before jumping to conclusions. Even those nice looking Napa parts you know all about are inferior. My car missed until I went all Motorcraft. They're very picky.
Never had it *that* rough though.
Whens the last time you been up this way?
A problem that severe would almost certainly store codes in the computer. Why not try pulling the codes and tell us what the cars saying. Beats guessing.
+1 on pulling codes.
+1 on Motorcraft parts. Also heard KEM is good, but haven't tried them.
Lastly, the condition you describe to me sounds like the TPS has a flat spot, but it could be a number of things.
Codes first.
Also, the IAC shouldn't be blocked off (if that's what you mean by the small plate).
Wow, plug wire BRAND may have this much effect on it? Picky lil SOB's huh? LOL I have a full set of Ford Racing 8.8mm blue 5.0 wires on the shelf, I may just thrwo 4 of them on it and see how that goes. Opinions there?
Chuck, I don't think the IAC is actually blocked off, I think it's an "adaptor" plate for extra tuning....? I am parting out a '90 F150 with the I-6 motor and it has the same plate on it. (see pic) Maybe it needs to be pulled off and some new gaskets swapped back in.
I had the codes pulled from the car...nothing came up.....but that was also almost a month ago. May try again and see if thats changed.
Thanks for the help so far guys. Like I said diagnosing a problemlike this online is a -shoot, but I'm not about to just keep throwing parts at it in hopes of finding the right thing!!
I'll keep ya posted on what I find.
Oh wow, sorry the pic's so big, thought I had it down sized correctly!!
Never seen a plate like that, I know its not on mine!
Id yank it.
have you considered running a compression test? sounds just like the 2.8 that was in my S10 that had a dead cylinder
If the timing was off it would buck like that, take that plate out you shouldnt need it.
Ah yes of course, check the cam timing!
Compression test sounds good too. Cam timing first though since that will have an effect on compression.
Last but not least make a trip up here and drop it off at my old mans place outside of swanton!
I bought a spacer identical to that one when I had my 5.0 about 10 years ago. You turn in those allen screws and it regulates the air flow; back 'em out to allow more air flow. It was designed as a mechanical fix for a faulty IAC.
I'm sure it isn't helping things with that engine.
AH HA!! Someone's actually seen the mystery plate and knows what its for!! Cool!!
As for a compression test, that may have to wait a while as my Bronco is taking up my time and workable garage space right now.....it puked a tranny, yay.
As far as dropping my car off anywhere....no thanks man, I'll get it tuned right and drive it 'til it dies completely!! LOL
Thanks for all the ideas guys, I may be able to spend a few minutes on it this weekend and let ya know what happens with taking that plate off, swapping out plug wires and checking the timing. Keepin my fingers crossed on any and all options!! THANKS!!
from my experiences, I use autolite 764 plugs gapped at .34 and motorcraft wires. set timing at a base line of 10* with the spout connector removed. set your TPS at .97v by probing the green wire for positive and the black for negative with the key on engine off. try those things and see if your problem goes away.