Modded Mustang Forums banner

1 - 20 of 38 Posts

·
Registered
Joined
·
3,357 Posts
Discussion Starter #1
ive been having problems with my 88 speed density car for a while but now its getting to where i cant drive it. it runs rough, starts cuttin out past 4k, wont idle most of the time and it drops rpm or dies when i push the clutch in. it knocks when the clutch is in but i have found nothing wrong with the clutch. today is started knocking when it would drop rpm while idle surging. you can hear the faintest of knock when its idleing fine(on the rare event)

i pulled the codes and only got codes for the egr system(which i deleted)
cyl balance test was a pass

fuel pressure is right around 40, just a touch high but i dont think its the problem

timing is 12 deg

92octane pump gas

it used to idle around 17in/mg vacuum but dropped to 15 and now is falling below that

oil pressure is under 20lbs at idle, it goes up with rpm but drops under load

i checked as much wiring as i could

plugs are new and look good, not burnt or oiled

wires are newer within 2 years
newer cap and rotor
coil ohmed out fine

just put a known working iac on it

no vacuum leaks

i have breathers on the valve covers that have some kind of small amount of smoke or steam that come from them, pcv is blocked off

newer fuel pressure regulator the stock and holly failed

new tps

im stumped i cant find any failing parts and cant get this thing to run for the life of me. any ideas???
 

·
Registered
Joined
·
3,357 Posts
Discussion Starter #3
im not sure i just got in in my head i should put them on a while ago. im looking for a set of stock valve covers to go back to how it was.
 

·
Banned
Joined
·
11,614 Posts
im not sure i just got in in my head i should put them on a while ago. im looking for a set of stock valve covers to go back to how it was.
thats my guess too, is it in the harness with the injector wires for the passenger side?
 

·
Banned
Joined
·
11,614 Posts
wtf i quoted something in a diff thread and it posted here:lmao :lmao :lmao sorry
 

·
Registered
Joined
·
3,357 Posts
Discussion Starter #8
any ideas guys? i start college monday and i dont know how im getting there till this gets fixed
 

·
Registered
Joined
·
540 Posts
it used to idle around 17in/mg vacuum but dropped to 15 and now is falling below that


no vacuum leaks
Are you sure that there's no leaks? I would check again, because losing vacuum sure sounds like a vacuum leak to me. Unless there is broken valves or some else internal damage.
 

·
Registered
Joined
·
3,357 Posts
Discussion Starter #10
im starting to think its internal, ive checked out all the vacuum lines and replaced nearly all of them. and even when i had higher vacuum i still had the same problems, just not as severe
 

·
Registered
Joined
·
5,556 Posts
20psi oil pressure??? uh if thats right then yes its internally.... if it falls below 30 EVER you should instantly turn your car off before u hurt ****. it should idle at 40 and drive around at 60

hows the water look? hows the oil look? could have a blown headgasket.

MAP sensor?

timing at 12* with spout out right??
 

·
Registered
Joined
·
3,357 Posts
Discussion Starter #14
the water and oil havent mixed so i dont think its a head gasket

i can try the map sensor off my sisters car, the map and bap are the same right? her's is mass air

and yes timing is with the spout out
 

·
Sheriff Metal Face
Joined
·
5,579 Posts
the water and oil havent mixed so i dont think its a head gasket

i can try the map sensor off my sisters car, the map and bap are the same right? her's is mass air

and yes timing is with the spout out
Yeah, map and bap sensors are the same thing. Just make sure you hook up the vacuum line to it on your car.
 

·
Registered
Joined
·
3,357 Posts
Discussion Starter #16 (Edited)
i put the other map on and adjusted the idle and i can get it to idle most of the time, ir runs just slightly better if at all.

did a compression test and this is what i got
1-120psi
2- less than130
3- less than120
4-120
5-130
6-130
7-125
8-105

plug 1 looked tan and all the others looked brand new
 

·
Registered
Joined
·
3,357 Posts
Discussion Starter #18
thats what i figured. im gonna be looking for a new motor, we rebuilt it last spring, and had the machine work done at a napa store, i think the guy that did the work ****ed it over, i had to re-hone the cylinders cause he didnt do that right, who knows if he did anything else right, we didnt check a thing, he machined it, measured, and pulled parts we didnt double check anything. last time im gonna let that happen.
 

·
Registered
Joined
·
3 Posts
No offense to anyone, but a couple of cylinders with not-great compression or ~20 psi of oil pressure at hot idle is not going to make the car undriveable. It's obviously not the healthiest engine in the world, but it should be decent.

You can have a serious fuel restriction and show good fuel pressure in park. The supply line on my Tbird was almost entirely bent in half, but it would rev just fine in park and had almost 40 psi of fuel pressure. I'd replace the fuel and air filters immediately.
 

·
Registered
Joined
·
3,357 Posts
Discussion Starter #20
ive replaced the fuel filter twice already, i was thinking an injector might be bad or the fpr is going bad again, but those are hard to diagnose and i dont want to waste money on those if they arent bad, i will check my fuel lines tomorrow though
 
1 - 20 of 38 Posts
Top