Hot start issue..

tfi modual... its on the distributer. sounds like that is the problem.

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.) MSD or Crane ignition box if so equipped
B.) Coil
C.) TFI module
D.) PIP sensor in distributor
E.) ECC relay next to computer - look for 12 volts at the fuel injector red wires
F.) Fuse links in wiring harness - look for 12 volts at the fuel injector red wires. All the fuse links live in a bundle up near the starter solenoid.
G.) Ignition switch - look for 12 volts at the ignition coil red/lt green wire.
H.) Computer

See the following links for wiring diagrams...

http://www.autozone.com/servlet/UiB..._us/0900823d/80/16/71/3c/0900823d8016713c.jsp for 79-88 model cars

http://www.autozone.com/servlet/UiB..._us/0900823d/80/19/59/5a/0900823d8019595a.jsp for 89-93 model cars

http://www.autozone.com/servlet/UiB..._us/0900823d/80/1d/db/3c/0900823d801ddb3c.jsp for 94-98 model cars


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/article...c-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. The fuse links live in the wiring harness near the starter solenoid.
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.
HO & 351W 1-3-7-2-6-5-4-8
Non HO 1-5-4-2-6-3-7-8
E.) No start when hot - Press the throttle to the floor & try starting it if you get this far. If it starts, replace the ECT.

well some say the TFI module causes similar problems, but I would assume if it were the TFI, the car would have problems running, not just starting.

Have you considered heat soak on the starter?

vapor lock is when the fuel gets hot and starts to boil and vaporize in the lines, which isn't common with these cars because of the return fuel system; the fuel cycles and any extra fuel is sent back to the tank, which cools it down. I'd suggest heat soak on the starter. You could maybe do an ohm test of some sort....I'm sure there's a post about doing that somewhere, although I'm not sure how. Sorry.

Good Luck.

briano said:

heat soak on the starter? never heard of that. How does that not get the car to fire? I better update with all info that I know of.. the car will crank until the battery dies, just won't fire when its hot.

I brought over a known good distrib with tfi module and still nothing. I just left his place after he put the stock upper and lower back on, car started right up. we let it get warm until the thermostat opened, then shut it off. waited 5 minutes and car woudl not start. You can time it almost about an hour and it will fire right up.

I am honestly out of ideas and he is at his wits end...

Click to expand...

Yes, after thinking about it, I wasn't sure if the car was cranking, but since we know it is, definately not the starter.

Here is a list from "How to understand, service and modify Ford Fuel Injection and Electronic Engine Control" by Charles O. Probst, SAE

No Start/Normal Crank
Ignition:
Electrical Connections
Secondary Ignition Wires
Spark Plugs Fouled
Ignition Switch
TFI IV:
Ignition Coil
Ignition Module
Rotor Alignment
Distributer Cap, Adapter
Rotor and Stator
DIS/EDIS:
Single and Dual Hall Crankshaft Sensors
Hall Camshaft Sensor
DIS/EDIS Ignition Module Coil Packs

Fuel Throttle Body:
Fuel Filter
Fuel Pump
Pump Switch (in VAF meter)
Water/Dirt/Rust contamination in fuel
Fuel Lines
Tank(Fuel Supply)
Fuel Sender Filter
Fuel Pressure Regulator
Injectors
Inertia Switch

Now, I know most of that doesn't even apply to your situation and looking over it, I can't pick anything that stands out to me that would cause the problem you describe. Sorry and good luck.

Maybe Yount and HISSIN will pop in soon.

so i just cruised this real quick. if it cranks hot but wont start: when it does this, has he tried flooring the gas pedal while (AND ONLY WHILE) cranking it? that will help with a flood condition/saturation in the chamber. guys with bigger squirters have to do this sometimes, but it applies if one is running rich for some reason (or after extended cranking in any tune). worth a quick check/try, IMHO.

good luck.

I read over this one more time real quick, so If i missed this sorry, but I thought you said you replaced the ECT sensor, but that could have been a different thread.

One time, I remember reading that a guy (I thinke ECU 5.0) replaced the sensor that tells the computer the temp of the car and I believe that's the ACT sensor, which I believe is on the metal pipe that bolts down to the lower intake that coolant flows through to go to the heater core. He replaced the sensor and I think that fixed his problem, which, I believe, was similar to what you are experiencing.

ECT is the engine coolant temp sensor. i think it has the biggest 'pull' with engine management (or mismanagement) amongst the ECT and ACT (IAT = same). They are both thermistors which can get out of calibration. if totally gone, it should toss a code, but if anything, like James said, it could be miscalibrated (incorrect for given situations, but not out of absolute parameters). one can check the resistance values at various temps (Jrichker has posted the tables before if desiring the values). i would still think it would fire at some point, somehow, when hot (even if a sensor is kaputt).

and you know for sure you have spark and injector firing when this occurs? (sorry, this thread is kind of recursive and hard to find the good stuff. ).

and no codes (88 has no functional CEL)? im sure i missed that part but i gotta run.

good luck.

briano said:

do you mean the IAT sensor? Idle Air Temp?..I know which one you are talking about and I had asked this to someone else and they said that would not cause this..I have no clue. I do have a spare one of these he can try though. I originally thought this was the issue myself..

Click to expand...

I actually mean the ECT (Engine Coolant Temperature) sensor, which tells the computer the temperature of the coolant. As HISSIN mentioned, IAT is the same as the ACT (Air Charge Temperature).

After reading a bit, Probst says that both the ECT and ACT could cause hard cold starts (I believe due to more resistance when cold than hot - opposite of most sensors), but doesn't mention anything about the problems you are experiencing.

He did mention that a low coolant level could cause the ECT to be off, for what it's worth.

If you could, get a full list of mods this car has. Does he have stock injectors? Was the MAF calibrated to match injectors?

briano said:

Thanks, but just to clarify..this is a HOT start issue. the car will crank and start if it is cold, but will NOT after it is warm.

he has changed tfi modules, distrib, and everything else known to man..

is there such thing as vapor lock or heat soak???
Could a simple thermostat being faulty cause something like this??

TIA

Click to expand...

The checklist is good to eliminate things that work so that you are left to look for the things that don't work, with either a hot or cold engine.

Look at the last item on the checklist - No start when hot - Press the throttle to the floor & try starting it if you get this far. If it starts, replace the ECT. This may be of particular help to you.

A lot of posts and the answer is probably up there already.
I didn't read them all so I apologize if I am repeating some one.
My experiences with hot start problems have been either
insufficient oil flow
OR
bad grounds

I have had the ground problem come up twice on two different cars.
Bad grounds (or any other related cable/connection) would be my first guess. Visual inspection can do wonders.

My first car,a 1967 Chevy II Nova had terrible heat soak problems(long tube headers were real close to the starter).Its symtoms were,it would not click or crank when it got hot.After about 20 minutes,it would start up again.I used to carry around an antifreeze jug full of water to pour on it to help cool it own.It worked!!!If this is your problem,which I dont think it is,you my want to get some thermal wrap for the exhaust.


Also,I doubt if you have a vaper lock issue.My stock pump in my 91 GT in warm weather was sunonamous for vaper locking.It would stall when I was driving and not start back up till it cooled down. A new pump was the cure.

I had that same problem after putting new motor together so I installed a mini-starter and upgraded to a 3g alternator and problem solved! Don't know which of the two fixed the problem, but while I was under there I decided to do both.
ps- When I tried starting the car after to was warm it cranked fine for a few seconds then really struggled to crank over like too much compression for the stock starter.

did you ever get this problem fixed my car is doing the excact samething