88 Mustang 5.0 wont turn over 3500 rpms

lpp5.0 said:

I have a 1988 Mustang GT 5.0 5-speed with speed density. At the moment it wont turn over 3500 rpms. I've changed the fuel pump, fuel pressure regulator, distributor, ECM, MAP Sensor and spark plugs. I'm getting fire to all 8 wires, the module tested good at a Auto Zone store and all I can think of next is the fuel injectors. Please help!!!!!!

Click to expand...

clogged fuel filter?

Dump the codes and see what the computer says is wrong…Codes may be present in the computer even if the Check Engine light isn’t on.

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.

See Troublcodes.net Trouble Codes OBD & OBD2 Trouble Codes and Technical info & Tool Store. By BAT Auto Technical





If your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.



The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.



The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.


There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.

What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

Alternate methods:
For those who are intimidated by all the wires & connections, see Actron® for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

Or for a nicer scanner see EQUUS DIGITAL FORD CODE READER (3145) – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.

Dirty MAF!

If codes aren't revealing, you might find the coil is going south. Ditto for the TFI (bench tests on intermittantly-functioning parts are hit or miss).

You are running copper spark plugs, right?

HISSIN50 said:

If codes aren't revealing, you might find the coil is going south. Ditto for the TFI (bench tests on intermittantly-functioning parts are hit or miss).

You are running copper spark plugs, right?

Click to expand...

+1

Sounds exactly what I went through last year, I couldnt go over 3000 rpm, it turned out to be the TFI; I dumped the codes and everything...nothing. I eventually went to AZ and I tested the TFI myself about 30 times and it passed. I still suspected it for some reason, so I pulled a TFI form the junkyard and the car finally right; then I bought a brand new one right after that

.

exaust could be stoped up.

exhaust

lpp5.0 said:

I have a 1988 Mustang GT 5.0 5-speed with speed density. At the moment it wont turn over 3500 rpms. I've changed the fuel pump, fuel pressure regulator, distributor, ECM, MAP Sensor and spark plugs. I'm getting fire to all 8 wires, the module tested good at a Auto Zone store and all I can think of next is the fuel injectors. Please help!!!!!!

Click to expand...

how about exhaust,,,clogged cats/muffler can cause lack of power

]how about exhaust,,,clogged cats/muffler can cause lack of power[/QUOTE]


+1.

do cats seem to glow after running a bit? if so... time to pull em off...