My 5.0 won't start...HELP!

it maybe your igntion swith thats what my problem was and im runnin a holley 195 fuel pump works great and aeromotive regualtor

check under the driver seat and see if you unplugged the fuel pump relay...

also in the hatch there is the inertia switch which is the second fuel relay. my friend got sick of his busting cause once it happend it kept happening so he by-passed it and rigged his fuel pump up to a direct switch so he can turn it on and off at his own will.

when u turn the key in the on position do you hear the pump turn on at all? like that whining noise?

check to see if you're getting 12v at both wires on your inertia switch (its in your trunk, behind drivers side taillight). If you only get 12v at your red wire and not the red w/ black stripe, your inertia switch is open or fried. try pushing the reset button on top, make sure its plugged in, and try starting it again. If you have voltage at both wires then its not your inertia switch I guess. was your fuel pump ever replaced? and was it whinning really loud? Mine went out at about 102,000miles on my old 89 5.0. Fuel pump replacement isn't too hard to do if its your problem...saves lots of money to do it yourself too. you can put any fuel pump in you want.. stock replacement, 155, 190, 255lph any would work. If you plan on doing anymore mods I'd put atleast a 190 in. Don't worry about it giving you too much fuel, any unused fuel gets returned to the tank anyway. and a bigger pump won't have to work as hard as the stock size one.

I just went through the same thing with my '89. Over the last few weeks I noticed that the fuel pump's whine seemed to be getting louder. Well, while driving down the road the car started losing power and finally stalled, then refused to start. At that point, when I turned the key on, the fuel pump wouldn't prime. The fuel pump relay and interia switch tested fine...Turned out the pump was shot (130,000 miles) I ended up going with a stock replacement b/c I have no intention of any serious mods in the future. I got the entire in-tank assembly for about $100 (pump, hanger, screen, etc) The tank was kind of rusty on top and was nearly impossible to get the old pump out, so I went with a new tank, new gas guage sending unit, and new fuel pump; and don't forget the tank straps. $360 dollars worth of parts by the time it was done, but at least I know it's done right.

If your car has no rust on any of the parts, you should be able to simply replace the pump. (assuming you determine that the pump is the problem)

Holley makes some very good high volume pumps that will fit your stock hanger, check out the prices from jeg's and summit.

check the ignition module on the distributor.


i had that go out on me , and i thought is was the fuel pump.

it won't give spark.

good luck, laters

im confused. have you determined whether you are missing fuel or spark yet?

for the fuel side, if you hear nothing happening when you should hear priming, i would continue to check the wiring. even when a pump dies, it often keeps making noise.

make sure you have juice egressing the FP relay to the pump. there is a fusible link off the solenoid that feeds the pump, via the FP relay switching.

i would recommend more troubleshooting before tossing parts in - if you guessed wrong, that sucks.
good luck.

Cranks OK, but No Start Checklist for Fuel Injected Mustangs

1.) Remove push on connector from starter solenoid and turn ignition switch on. Place car in neutral or Park. Remove coil wire from distributor & and hold 3/8” away from engine block. Jumper the screw to the big bolt on the starter solenoid that has the battery wire connected to it. You should get a nice fat blue spark.
Most of the items are electrical in nature, so a test light, or even better, a voltmeter, is helpful to be sure they have power to them.
No spark, possible failed items in order of their probability:
A.) Coil
B.) TFI module
C.) PIP sensor in distributor
D.) ECC relay next to computer - look for 12 volts at the fuel injector red wires
E.) Fuse links in wiring harness - look for 12 volts at the fuel injector red wires
F.) Ignition switch - look for 12 volts at the fuel injector red wires
G.) Computer

2.) Spark at coil wire, pull #1 plug wire off at the spark plug and check to see spark. No spark, possible failed items in order of their probability:
A.) Moisture inside distributor – remove cap, dry off & spray with WD40
B.) Distributor cap
C.) Rotor
D.) Spark Plug wires
E.) Coil weak or intermittent - you should see 3/8" fat blue spark with a good coil

3.) Spark at spark plug, but no start.
Next, get a can of starting fluid (ether) from your local auto parts store: costs a $1.30 or so. Then pull the air duct off at the throttle body elbow, open the throttle, and spray the ether in it. Reconnect the air duct and try to start the car. Do not try to start the car without reconnecting the air duct.
Two reasons:
1.) If it backfires, the chance for a serious fire is increased.
2.) On Mass Air cars, the computer needs to measure the MAF flow once the engine starts.
If it starts then, you have a fuel management issue. Continue the checklist with emphasis of fuel related items that follow. If it doesn’t ,then it is a computer or timing issue: see Step 4.

Clue – listen for the fuel pump to prime when you first turn the ignition switch on. It should run for 5-20 seconds and shut off. To trick the fuel pump into running, find the ECC test connector and jump the connector in the lower RH corner to ground. See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html for a description of the test connector. If the relay & inertia switch are OK, you will have power to the pump. Check fuel pressure – remove the cap from the schrader valve behind the alternator and depress the core. Fuel should squirt out, catch it in a rag. Beware of fire hazard when you do this. In pinch you can use a tire pressure gauge to measure the fuel pressure. It may not be completely accurate, but you will have some clue as to how much pressure you have.

No fuel pressure, possible failed items in order of their probability:
A.) Tripped inertia switch – Coupe & hatch cars hide it under the plastic trim covering the driver's side taillight. Use the voltmeter or test light to make sure you have power to both sides of the switch
B.) Fuel pump power relay – located under the driver’s seat in most stangs built before 92. On 92 and later model cars it is located below the Mass Air Flow meter. Look for 12 volts at the Pink/Black wire on the fuel pump relay.
C.) Clogged fuel filter
D.) Failed fuel pump
E.) Blown fuse link in wiring harness. Look for 12 volts at the Orange/Lt Blue wire on the fuel pump relay
F.) Fuel pressure regulator failed. Remove vacuum line from regulator and inspect for fuel escaping while pump is running.

Fuel pressure OK, the injectors are not firing.

A.) A Noid light available from Autozone, is one way to test the injector wiring.
B.) I like to use an old injector with compressed air applied to the injector where the fuel rail would normally connect. I hook the whole thing up, apply compressed air to the injector and stick it in a paper cup of soapy water. When the engine cranks with the ignition switch on, if the injector fires, it makes bubbles. Cheap if you have the stuff laying around, and works good too.

a.) Pull an injector wire connector off and look for 12 volts on the red wire when the ignition switch is on.
b.) No power, then look for problems with the 10 pin connecter (salt & pepper shakers at the rear of the upper manifold).
c.) No power and the 10 pin connections are good: look for broken wiring between the orange/black wire on the ECC relay and the red wire for the 10 pin connectors.


4.) Spark & fuel pressure OK.

A.) Failed IAB (no airflow to start engine). Press the throttle ¼ way down and try to start the car.
B.) Failed computer (not very likely)
C.) Engine ignition or cam timing off only likely if the engine has been worked on recently).
D.) Firing order off: HO & 351 use a different firing order from the non HO engines.

Your pump is going t/u ...... replacement is a lot easier then it seems.

For under $150 yo'll be on your way.