hot starting issues - not the starter!

jadedinpa

Founding Member
Aug 2, 2002
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lancaster, pa
yes you've heard it before, " my stang won't start when it's hot" well my stang won't start when it's hot :lol: it's not the starter, it cranks the same as when it's cold. i've heard people mention TFI module as being the culprit, but i put a "used" one on and still have the same symptoms- not that i'm ruling that out.

any suggestions?
 
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Fuel pump. Put a guage on it the next time it happens and check your fuel pressure. My dad had a 90 GT that did the same thing. It left him stranded 2 hours from home, he let it cool down for 45 minutes, then it was fine. It started right up and made it home. We changed the pump and it never did it to him again.
 
Well i just went through the same problem last summer.....Do you have a mini starter?...They are a good investment as mine is great....But I would also try checking the starter relay near the battery. Replace your battery cables and check the neg. ground to the block under the water pump as mine was "arching" or whatever you call it when I started the car.
 
the fuel pump was supposedly replaced before i bought it.....
i don't have a mini starter- just the regular big one. it cranks fine even when it's warm... maybe it's cranking a weensy bit slower? would that cause it to not fire?
 
should be a schrader valve on the fuel rail, no?

the two things that are most likely to lead to heat related crap out when starting (cranks but does not start) are TFI and FP, as mentioned.
ground a plug wire or check fuel pressure when this happens. this will tell you if it is fuel or electric. go from there. a parts store can bench test a TFI module if it helps ya. i would take a hair dryer to warm it up (or do something to warm it up - even tape it to the motor and drive to the parts store in another car, so it simulates being hot to where it wont start) before testing. :)

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
E.) Fuse links in wiring harness
F.) Ignition switch
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.
C.) Clogged fuel filter
D.) Failed fuel pump
E.) Blown fuse link in wiring harness.
F.) Fuel pressure regulator failed. Remove vacuum line from regulator and inspect for fuel escaping while pump is running.

4.) Spark & fuel 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 form the non HO engines.
 
sea ya said:
i thing that i see overlooked "i found out the hard way"
the ECM coolent temp. sending unit...right side of engine,
behind alt. on top...if its bad mine would crank & run,
but when eng. temp. came up to normal it would'nt
crank until it cooled down... good luck chuck

i don't think an 86 has that sensor :shrug:
 
rowdie- stang said:
I had the same problem with mine after I installed my battery in the hatch,
You have to make sure you still have a ground wire from the battery to the engine block in the same location that the stock wire was.

i'm gonna check out my battery cables soon, they are in the stock spots so i don't see that as being the problem. they are huge too! like 1/0 gauge