I have a strange stall/no start issue, need advice.

[Fett]

I have been having this really odd problem that I can't figure out. I'm hoping someone might have had a similar experience.

It started a few weeks ago, car was running fine. Went into a store, came out and the car wouldn't start. After a few minutes of trying to start it and tinkering with it, it finally just started. It would crank, just not start. The whole time I seemed to have plenty of battery power, all electronics were fine. I had fuel pressure, I released the pressure, primed the pump, and checked for pressure again. So I know it's not a fuel problem. While looking under the hood I checked for any bad/missing grounds. I looked under the dizzy cap and found the tip of the rotor was slightly worn and there was some black scarring on the contacts under the cap. I checked to see if I had power to the coil and to the dizzy, which I did. After a while it just started up again. On the way back to work it died on me while driving. No loss of radio or electrical components, it just died...no sputtering, the motor just stopped running. I rolled into a parking spot, waited a second and tried to start it, started up just fine. For the next few weeks the car has been running with no issues.

Today I ran up to Home Depot, driving down the road it just died again. Again, no electrical loss, the motor just, quickly, died. I rolled into a parking lot and tried starting it again....it would just crank but not start. So I started tinkering with all the same things I did the last time, everything seemed fine...just like the last time. I used some sand paper and cleaned off each contact under the dizzy cap, and the tip of the rotor. Put it back on and the car started up just fine. Started down the street again and it died again. Rolled into another parking lot, went ahead and cleaned off the contacts again, making sure they were perfectly clean. Tried to start it with no avail. So I just sat there, giving the key a turn every 30 seconds or so. Each time same thing, it would just crank but not start. Sometimes I let it crank for a few seconds, others I just gave it a normal, short crank. After a while, it just started back up again and made it home.

I figure it has to be spark related...somehow. Either the dizzy itself, maybe TFI, or possibly coil....maybe cap and rotor. Not sure where exactly to look at this point. The problem is this is a very erratic problem, so it's not like I will have a "Yup, that was it" moment. So simply swapping out parts won't give me an answer. I will just have to try it and hope it doesn't fail me. Even if I try one part at a time, it could take months to narrow it down.

I forget what I have in my signature as far as mods go, as I have changed a few things. Right now I have a rebuilt Motorcraft dizzy (Pep Boys), an MSD cap, Motorcraft rotor. Excel coil, and I have removed my MDS 6AL. I have been running that setup for almost a year.

 

[DeVus1]

Sure, try here: click me for answer

 

[Fett]

Sure, try here: click me for answer

Thanks for your help....I'll be sure to add you to my Christmas list.


If you want to get "technical"....there are quite a few "technical" questions in the "non-technical" forum. So "technically" speaking, some topics are difficult to gauge whether or not they are "technical" or "non-technical". For instance, while a "technically" a "technical" problem.....I always believed the "technical" forum was more for "technical" modifications and whatnot. Where as the "non-technical" forum was more for topics that "technically" swayed away from the modification aspects of owning and operating a Mustang. "Technically" that may not be the case....but it is how I always perceived it...."technically". I guess I am "technically" asking for forgiveness for my "technical" mistake of placing a "technical" question in the "non-technical" forum. Thank you for correcting me and steering me in the proper direction.

 

[5.0Droptop]

It sounds like the tfi to me Fett. I would remove it and take the tfi and have it tested(autozone etc will do it free), Make them test it several times untill it gets hot. Sounds like its breaking down under heat load.

 

[DeVus1]

all that stuff by you.

Hope this helps:

Technical: Having special skill or practical knowledge especially in a mechanical or scientific field (emphasis on mechanical)

In the "Tech" section, you will find "Technicians" that have "Technical" knowledge of the mechanics of a motor vehicle. So "technically" talk is for subjects not pertaining to "Tech."

Here is a good example: Check out my broken Mustang at 65mph

Glad I could help and I look forward to receiving your Christmas Card next year.

 

[Fett]

It sounds like the tfi to me Fett. I would remove it and take the tfi and have it tested(autozone etc will do it free), Make them test it several times untill it gets hot. Sounds like its breaking down under heat load.

Sounds about right. After thinking about my habits, the past few weeks I have only really driven the car to and from work, about 2 miles....where as the two times it did this to me I had driven further/longer. I think I have my old TFI laying around, so I'll swap them out and go get the one on the car now tested.

 

[5.0Droptop]

Sounds like a good place to start.

 

[Fett]

Hope this helps:

Technical: Having special skill or practical knowledge especially in a mechanical or scientific field (emphasis on mechanical)

In the "Tech" section, you will find "Technicians" that have "Technical" knowledge of the mechanics of a motor vehicle. So "technically" talk is for subjects not pertaining to "Tech."

Here is a good example: Check out my broken Mustang at 65mph

Glad I could help and I look forward to receiving your Christmas Card next year.

But alas....

Is this a backfire?

Gears or Cam?

what block would you get?

Tune up parts (which to get?)

3.73's v 4.10's

Aftermarket Stereo Help?

SN95 brakes quick question

and

Door handle linkage?

"Technically" these are all "technical" questions or topics geared towards people with "technical" knowledge of the mechanics of a motor vehicle, no?


In all seriousness, perhaps a "problems" forum would help. That way all "general discussion" would be in "talk", all "technical" questions and discussions pertaining to modifications would go in "tech", and the "problems" forum would be for those looking for help or advice about a specific problem.

 

[DeVus1]

More gibberish by you

No. Your examples are asking for opinions. Which cam should I get or which wheels are better are a matter of opinion and answers are not necessarily given by anyone with any technical knowledge of the subject, only their experience with the particular object(s).

Thanks for playing though.

 

[Fett]

No. Your examples are asking for opinions. Which cam should I get or which wheels are better are a matter of opinion and answers are not necessarily given by anyone with any technical knowledge of the subject, only their experience with the particular object(s).

Thanks for playing though.

Hrm...so the "SN95 brakes" and "stereo help" threads were asking for opinions, and not actually asking technical questions?

Interesting, in that case...I was looking for opinions as to what my problem could possibly be.

Either way, you could have simply ignored my thread or given some useful advice. But I suppose being the "forum police" works just as well. I mean, every forum has to have that one guy who just must point out when someone posts in the wrong forum in some clever but unoriginal fashion. As my Daughter is fond of saying "nobody likes a tattle-tale".

Thank YOU for playing.

 

[DeVus1]

Hrm...so the "SN95 brakes" and "stereo help" threads were asking for opinions, and not actually asking technical questions?

el oh el at this.

Either way, you could have simply ignored my thread or given some useful advice. But I suppose being the "forum police" works just as well. I mean, every forum has to have that one guy who just must point out when someone posts in the wrong forum in some clever but unoriginal fashion. As my Daughter is fond of saying "nobody likes a tattle-tale".

Seriously? That's your best shot? I don't care what forum you post this is in, I pasted a link that better help solve your issue, since some of the Tech guys don't watch the talk side much. As my capital letter D for daughter is fond of saying "nobody likes a dumas."

Game. Set. Match. Good luck with your stall happy Mustang.

 

[HISSIN50]

When it won't restart, give a quick check for spark. If present, use a noid light or LED test light to check for injector pulsing.

Knowing if one or both are there will help you find a direction to pursue.

 

[jrichker]

The answer is in here..




Cranks OK, but No Start Checklist for Fuel Injected Mustangs

A word about this checklist before you start: it is arranged in a specific order to put the most likely failure items first. That will save you time, energy and money. Start at the top of the list and work your way down. Jumping around will possibly cause you to miss just what you need to see to find and fix the problem. Don’t skip any steps because the next step depends on the last step working correctly.

Revised 14-Sept-2008 to add warning about over fusing circuits
All text applies to all models unless stated otherwise.

Note: 94-95 specific changes are in red

1.) Remove push on connector (small red/blue wire) from starter solenoid and turn ignition switch on. Place car in neutral or Park and set the parking brake. Remove the coil wire from distributor & and hold it 3/8” away from the 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. The PIP sensor supplies the timing pulse to trigger the TFI and injectors. See paragraph 5A - a noid light will tell if the pip is working by flashing when the engine is cranking.
E.) No ECC or computer power - ECC or computer relay failure
86-93 models only: ECC relay next to computer - look for 12 volts at the fuel injector red wires
94-95 models only: EEC or PCM power relay in the constant control relay module. Look for 12 volts at the fuel injector red wires.
F.) No ECC or computer power - fuse or fuse link failure
86-93 models only: 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.
94-95 models only: 20 amp EEC fuse in the engine compartment fuse box. Look for 12 volts at the fuel injector red wires.
G.) Ignition switch - look for 12 volts at the ignition coil red/lt green wire. No 12 volts, blown fuse link or faulty ignition switch. Remove the plastic from around the ignition switch and look for 12 volts on the red/green wire with the switch in the Run position. No 12 volts and the ignition switch is faulty. If 12 volts is present in the Run position, then the fuse or fuse link is blown.
Note: fuses or fuse links blow for a reason. Don’t replace either a fuse or fuse link with one with a larger rating than stock. Doing so invites an electrical fire.
Ignition fuse links may be replaced with an inline fuse holder and 5 amp fuse for troubleshooting purposes.
94-95 models only: Check inside fuse panel for fuse #18 blown – 20 amp fuse
H.) Bad or missing secondary power ground. It is located between the back of the intake manifold and the driver's side firewall. It supplies ground for the alternator, A/C compressor clutch and other electrical accessories such as the gauges.
I.) Missing or loose computer power ground. The computer has its own dedicated power ground that comes off the ground pigtail on the battery ground wire. Due to it's proximity to the battery, it may become corroded by acid fumes from the battery. It is a black cylinder about 2 1/2" long by 1" diameter with a black/lt green wire. You'll find it up next to the starter solenoid where the wire goes into the wiring harness
J.) Computer
K.) Engine fires briefly, but dies immediately when the key is released to the Run position. Crank the engine & when it fires off, pull the small push on connector (red wire) off the starter relay (Looks like it is stuck on a screw). Hold the switch in the crank position: if it continues to run there is a problem with either the ignition switch or TFI module. Check for 12 volts at the red/green wire on the coil with the switch in the Run position. Good 12 volts, then replace the TFI. No 12 volts, replace the ignition switch.

See the following links for wiring diagrams...

AutoZone.com | Vehicle Selection - Year for 79-88 model Mustangs
Computer/fuel pump/ignition wiring diagram, 86 model http://www.autozone.com/images/cds/gif/large/0900823d80167158.gif
Computer/fuel pump/ignition wiring diagram, 87 model http://www.autozone.com/images/cds/gif/large/0900823d8016715e.gif
Ignition wiring diagram, 87 model http://www.autozone.com/images/cds/gif/large/0900823d8016715f.gif
Computer/fuel pump wiring diagram, 88 model http://www.autozone.com/images/cds/gif/large/0900823d80167162.gif[
Ignition wiring diagram, 88 model http://www.autozone.com/images/cds/gif/large/0900823d80167163.gif

AutoZone.com | Vehicle Selection - Year for 89-93 model Mustangs
Computer/fuel pump/ignition wiring diagram, 89-90 cars http://www.autozone.com/images/cds/gif/large/0900823d8019595f.gif
Computer/fuel pump/ignition wiring diagram, 91-93 cars
http://www.autozone.com/images/cds/gif/large/0900823d80195960.gif

http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_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 EEC test connector and jump the connector in the Upper RH corner to ground. The EEC connector is near the wiper motor and LH hood hinge.

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 a 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. If you have any doubts about having sufficient fuel flow/pressure, rent a fuel pressure test gauge from the auto parts store. That will tell you for sure if you have adequate fuel pressure.


4.) 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.) 86-90 models only: Blown fuse link in wiring harness. Look for 12 volts at the Orange/Lt Blue wire on the fuel pump relay.
91-93 models only Blown fuse link in wiring harness. Look for 12 volts at the Pink/Black wire on the fuel pump relay.
The fuse links for all model years 86-93 live in the wiring harness near the starter solenoid.
94-95 models only: 20 amp fuel pump fuse in the engine compartment fuse box. Look for 12 volts at the Dark green/yellow wire on the constant control relay module.
F.) Engine seem to load up on fuel and may have black smoke at the tailpipe. Fuel pressure regulator failed. Remove the vacuum line from the regulator and inspect for fuel escaping while the pump is running. If fuel is coming out the vacuum port, the regulator has failed. Check the regulator vacuum line for fuel too. Disconnect it from the engine and blow air though it. If you find gas, the regulator has failed.

5.) Fuel pressure OK, the injectors are not firing.
A.) A noid light available from any auto parts store, is one way to test the injector wiring.
The noid light plugs into the fuel injector harness in place of any easily accessible injector. Plug it in and it will flash if the injector is firing.
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.
D.) Pull an injector wire connector off and look for 12 volts on the red wire when the ignition switch is on.
E.) No power, then look for problems with the 10 pin connecter (salt & pepper shakers at the rear of the upper manifold).
F.) 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.
G.) TPS voltage exceeds 3.7 volts with the throttle closed. This will shut off the injectors, since the computer uses this strategy to clear a flooded engine. Use a DVM, a pair of safety pins, and probe the black/white and green wires to measure the TPS voltage.
On a 94-95 Mustang, probe the black/white and grey/white wires to measure the TPS voltage.
It should be .5-.99 volts with the key on, engine not running. Note that if the black/white wire (signal ground) has a bad connection, you will get some strange readings. Make a second measurement using the battery post as the ground to eliminate any ground problems. If the readings are different by more than 5%, you may have a high resistance condition in the black/white signal ground circuit.

6.) Spark & fuel pressure OK.
A.) Failed IAB or improperly set base idle (no airflow to start engine). Press the throttle ¼ way down and try to start the car. See the "Surging Idle Checklist for help with all your idle/stall problems.
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.
F. ) Engine that has had the heads off or valves adjusted. Do a compression test to make sure the valves are not adjusted too tight. You should have a minimum of 90 PSI on a cold engine.