88 Mustang GT runs rich

MALACHI

MALACHI

Forum Member
Ok, a friend of mine made the mistake of buying someone elses "project car".

It was born an 88 LX w/2.3 engine. A past owner swapped in a 5.0HO. They seemed to convert all the wiring and ECM over. HOWEVER, the car runs pig rich, black smoke, hard to start when cold and fouling plugs pretty regular.
He is NOT a mechanical type, so I have been doing my best to try and help him

Things I have installed with brand new:
both O2 sensors
new plugs, wires, cap/rotor, ignition coil
FPR
fuel filter (unrelated)
replaced a few possible leaking vacuum lines
I double checked that the ECM is correct.
Car is running speed density, not MAF.


I am NOT a Mustang guy. I am not a quailified trouble shooter on these cars at all.
I was wondering if a local Mustang guy could help him out? He is so frustrated, he is wanting to convert to carby to make the thing run right.

We both live in Southfield. Anyone around who wants to help a guy go fast? I am pretty sure he will throw you a few bucks if you can help out.
 
What color are the fuel injectors? They should be yellow/orange. If they are baby blue, red, dark blue, or Green, they are too big for a stock speed density system.
Another thing to check is the MAP sensor. It may be supplying incorrect information to the ECM. Also check the fuel pressure. It may have an aftermarket regulator that is cranked way up. Pressure should be 38-42 psi with the engine running and the vacuum line removed from the regulator.
 
Oops, I noticed that you replaced the regulator. Check the fuel pressure anyway. The return line could be pinched, clogged or something.
 
It does indeed have the correct injectors. That was an early thought and I checked em all.

I un-fortunatly do not have a vacuum pump to check the MAP or any means of testing the fuel pressure.

I do know hiw wife is getting pretty pissed about the 2 black spots of carbon on the driveway it leaves everytime he fires it up.
 
A fuel pressure gauge is about $30-$40 at Murrays. I think the MAP sensor is also about $30. I'd throw a new one in and see.
 
your smarter then you act I swear. early ford SD cars had a problem with fialing coolant temp sensors. Cuase alot of problems very similar to what your describing. Also whats the part # on the ecu. It should be behind the kick panel. Could be the wrong ECU.

BigWheelinBubba said:
Is the coolant temp sensor hooked up?
Click to expand...
 
I am for sure that is is plugged in. Whether or not it works is something I can find out. What is the resistance values? Hot/cold

This is the diagram I have been working with for sensors. (see attached)

Here is a photo I took initally of the ECM to make sure it was correct. Sorry abuot the angle, it was hard to get in there though.

0928081849.jpg
 

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Sean said:
your smarter then you act I swear. early ford SD cars had a problem with fialing coolant temp sensors. Cuase alot of problems very similar to what your describing. Also whats the part # on the ecu. It should be behind the kick panel. Could be the wrong ECU.
Click to expand...
:thefinger

I always wanted to be an automotive tech growing up, but somehow i ended up doing what i do because i need action in my life :confused:
 
Yes it is auto trans. I have NOT taken it apart to check for chipping or other mods.

The car is a garage made mutt. Still with 4lug wheels, and too much rust and undercarridge damage if you ask me. As I said early on, he bought someones project car and we have no idea what all might have been done. I am 90% sure none of the internals were touched. They randomly spray painted various parts of the motor, but the valleys of the intake are caked with old grime and gunk.
 
Coolant Temp Sensor was replaced w/new
Intake Temp Sensor was replaced w/new

Still getting unburned fuel in the exhaust system.

I popped off the plenum and replaced the gasket. Checked all over for vacuum leaks and found none.
I ran a fuel pressure test and found 34 at idle and 40-41 with no vacuum. Book says 35 with vac and 45 without if I remeber right.

New plugs, new wires, new coil, new cap, new rotor, correct injectors, new O2 sensors....I am running out of things to check.

MAP sensor is next I guess.
Any other ideas guys?

Car has been running better though after each step. There was a point where it did not run at all.
 
Tyr unplgging the 02 sensors if the car has a camshaft alot of times it'll get pissy and if the 02 sensors fial from oil fouling etc they can also stick lean and really richen the car up quiet a bit.

Do you have a hose going directly from the intake manifold to the MAP sensor or is it going into that stupid log Vacum log ????.

MALACHI said:
Coolant Temp Sensor was replaced w/new
Intake Temp Sensor was replaced w/new

Still getting unburned fuel in the exhaust system.

I popped off the plenum and replaced the gasket. Checked all over for vacuum leaks and found none.
I ran a fuel pressure test and found 34 at idle and 40-41 with no vacuum. Book says 35 with vac and 45 without if I remeber right.

New plugs, new wires, new coil, new cap, new rotor, correct injectors, new O2 sensors....I am running out of things to check.

MAP sensor is next I guess.
Any other ideas guys?

Car has been running better though after each step. There was a point where it did not run at all.
Click to expand...
 
The O2s were both installed brand new. It still pukes out fuel.
I "doubt" the internals of the motor were ever touched, due tot eh volume of grime and debris in the intake valleys. I highly doubt the motor has ever been apart since new judging by the nuts, bolts and gaskets I have found and replaced thus far. It looks pretty stock to me.
At this point only failed ECM or MAP could be at issue. Or timing. But that tends to affect the drivablity in most cars I have run across. This car runs well mostly, just super nasty rich.
To start you must only "tap" the starter, not crank for any length of time.
 
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