94 5.0 turns over but will not start!

angeljenylynn · Mar 31, 2007

My 1994 mustang GT 5.0 will not start. engine rotates. checked for spark at distributor, has spark. replaced fuel filter.

replaced ignition module, this caused it to start right up, drove it a ways, everything working fine, brought it home, parked it, it didn't start the next day (today). (this is what happened the first time it wouldn't start, basically, it was running fine... then would not start, randomly, out of the blue!)

i want to check the relay that controls the fuel injectors, but i don't know which one it is. i also think it is unlikely there's anything wrong with the relay since it started right up after i changed the ignition module. (it started three times after i changed the module, but after it sat overnight is when it wouldn't start again, this morning).

help!

The Green GT · Mar 31, 2007

Check for spark and injector pulsing. If both are gon then your PIP went south. This happens alot around this time of year. The heat affects them. Mine went last year.

angeljenylynn · Mar 31, 2007

thing is, i DO have spark.

miller92063 · Mar 31, 2007

try to crank it a few times, if it doesn't start, press the pedal to the floor and try starting it then.
If it does start let up ASAP.
If this works, more than likely it is flooding= injector stuck open

95mustang_gt · Mar 31, 2007

how about gas?is your driveway flat?sometimes it can be something stupid like that

drewzx3 · Mar 31, 2007

When you turn the key on do you hear the fuel pump come one?

HISSIN50 · Mar 31, 2007

There is no relay for the injectors. They are fed with key-on power (constantly) and the computer has drivers which modulate the injectors.

If you're sure you have spark *when the car won't start*, then checking fuel pressure is the right idea.

You need to pull codes as well. Something as simple as an ECT that's out of calibration can cause cold start issues. If the sensor isnt out of absolute specs, a code won't even be thrown. The ECT is a thermistor. If you disconnect the electrical connector to it and put a DMM across the leads, you should see 40K Ohms+ at 50*F or less (colder).

Good luck.

angeljenylynn · Mar 31, 2007

miller92063 said:
try to crank it a few times, if it doesn't start, press the pedal to the floor and try starting it then.
If it does start let up ASAP.
If this works, more than likely it is flooding= injector stuck open

already tried that. doesn't work.

thanks.

angeljenylynn · Mar 31, 2007

95mustang_gt said:
how about gas?is your driveway flat?sometimes it can be something stupid like that

it has gas, yes... and yes the driveway is flat.

angeljenylynn · Mar 31, 2007

drewzx3 said:
When you turn the key on do you hear the fuel pump come one?

yep, sure do. and it's getting gas now, because i can smell it after i try to start. and now it's doing a bit more than just turning the engine. now it sounds like its *really* wanting to start but can't.

angeljenylynn · Mar 31, 2007

book said there was a relay, that's why i said that. ??

don't know what you are trying to get across by putting "when the car won't start" in astericks, but to clarify... of course i'm not getting spark when i'm not trying to start the car, (which i doubt is what you meant, but just in case...), and i have checked for spark at the distributor while trying to start the car. now unless its only sparking when i'm checking it, and i just checked it again about 30 minutes ago... then it's definitely sparking.

how do i get the codes for my car? the new readers only read post 96 vehicles. and i can't drive it down to auto zone and get it read.

also, do you have any idea why changing the ignition module would make it start right up, and then not work the next day? what about the pickup coil or stator in the distrubutor?

HISSIN50 said:
There is no relay for the injectors. They are fed with key-on power (constantly) and the computer has drivers which modulate the injectors.

If you're sure you have spark *when the car won't start*, then checking fuel pressure is the right idea.

You need to pull codes as well. Something as simple as an ECT that's out of calibration can cause cold start issues. If the sensor isnt out of absolute specs, a code won't even be thrown. The ECT is a thermistor. If you disconnect the electrical connector to it and put a DMM across the leads, you should see 40K Ohms+ at 50*F or less (colder).

Good luck.

HISSIN50 · Mar 31, 2007

angeljenylynn said:
book said there was a relay, that's why i said that. ??

don't know what you are trying to get across by putting "when the car won't start" in astericks, but to clarify... of course i'm not getting spark when i'm not trying to start the car, (which i doubt is what you meant, but just in case...), and i have checked for spark at the distributor while trying to start the car. now unless its only sparking when i'm checking it, and i just checked it again about 30 minutes ago... then it's definitely sparking.

how do i get the codes for my car? the new readers only read post 96 vehicles. and i can't drive it down to auto zone and get it read.

also, do you have any idea why changing the ignition module would make it start right up, and then not work the next day? what about the pickup coil or stator in the distrubutor?

I was just trying to reiterate the importance of testing systems only when they are acting up (otherwise tests are invalid). Intermittant starting problems can be a real PITA to diagnose. You are obviously performing valid testing and the comment wasn't meant as any sort of knock on you.

I have tried to help folks who PM me before and it would turn out that the diagnostics I outlined were performed while the car would start.

I don't know what the 'book' was talkin about with regard to a relay for the fuel injectors. The closest iteration of a relay in that systems is that the key-on power for the injectors comes from the EEC relay, which is housed inside the CCRM. If the EEC relay fails, you will have massive and widespread systems failures.

To retrieve the codes, see here. The pictures on that site show where a Fox STC is. Ours is in the same spot but on the passenger side of the engine bay.

The issue with the ignition module aspect is that as far as we know, you always had spark (so replacing the module was moot?). Perhaps you have a bad wiring connection and it was luck that 'goosing' the wiring while the module was installed fixed the issue until the connection was bumped again.

I really dont have any hot ideas, other than what has been mentioned.

Good luck.

angeljenylynn · Mar 31, 2007

thanks. i'm going to go attempt the self test right now.

oh, and i changed the ignition module because it didn't seem to be getting fuel... and the guy at auto zone told me that a faulty one may cause either no spark, no fuel, or none of either... so that's why i changed that.

thanks for all your help!

HISSIN50 said:
I was just trying to reiterate the importance of testing systems only when they are acting up (otherwise tests are invalid). Intermittant starting problems can be a real PITA to diagnose. You are obviously performing valid testing and the comment wasn't meant as any sort of knock on you.

I have tried to help folks who PM me before and it would turn out that the diagnostics I outlined were performed while the car would start.

I don't know what the 'book' was talkin about with regard to a relay for the fuel injectors. The closest iteration of a relay in that systems is that the key-on power for the injectors comes from the EEC relay, which is housed inside the CCRM. If the EEC relay fails, you will have massive and widespread systems failures.

To retrieve the codes, see here. The pictures on that site show where a Fox STC is. Ours is in the same spot but on the passenger side of the engine bay.

The issue with the ignition module aspect is that as far as we know, you always had spark (so replacing the module was moot?). Perhaps you have a bad wiring connection and it was luck that 'goosing' the wiring while the module was installed fixed the issue until the connection was bumped again.

I really dont have any hot ideas, other than what has been mentioned.

Good luck.

RAD · Mar 31, 2007

bad gas? or water in the tank?

angeljenylynn · Apr 2, 2007

ran the codes, got code 33, egr valve opening not detected. been told that wouldn't cause it to not start though.

got some starting fluid, sprayed right into the intake, put the pedal half way down and tried to crank it, sounded like it WANTED to start real bad, more so than it has been. but it only did that once. now the battery's on charge cuz it went dead. guhhh.

brought my ignition module down to auto zone to make sure it was working... he tested it for me, and the first test run he did on it, it didnt work, but he ran the test again and it DID work... but he went ahead and gave me a new one. but i put that one in this morning, still didn't start... and what i said above came after all that.

i'm about to pull my hair out.

HISSIN50 said:
To retrieve the codes, see here. The pictures on that site show where a Fox STC is. Ours is in the same spot but on the passenger side of the engine bay.

HISSIN50 · Apr 2, 2007

If you suspect a fuel delivery issue, ensure you have proper fuel pressure and buy a noid light. The noid light is a 5 dollar test light that sits on an injector connector. It will flash to let you know the injectors are getting the proper 12 volt and ground signals to fire. A *good* parts store will have them, and some crappier parts stores have them too (I say this so time isnt wasted driving from one store to another if you decide a noid light sounds like a good thing to have. Call the stores first).

Don't do anything with the gas pedal when you try to start it. Once you reach ~3.71 TPS volts, the injectors are shut off while cranking. It does not take very much pedal depression to achieve this. An EFI car should not require any pedal jockeying to start up. Playing with the pedal is an old carb habit that's hard for some of us to break.

I agree that your EGR code should not cause an issue unless the EGR is stuck open. A piece of carbon can wedge under the seat and hold the valve open. In said case, the car would run horribly or not even catch.
Quick, cheap test: Grab a couple feet of vac line (extra windshield washer fluid line might fit, if you have that lying around). Go to the EGR valve and remove the OEM vac line from the EGR valve's nipple. Put one end of your hose on the EGR valve nipple and lightly suck on the other end of the line while watching the EGR valve's diaphram (it's in plain sight). You should see the diaphram open and close with as little as a couple inches of vacuum (somewhere between drinking a soda and milkshake through a straw). If you dont see that diaphram move in and out a fair bit, it might be hung up. There's a quick way to disconnect the incoming gasses from it but I won't clog up this post with that.

Good luck.

angeljenylynn · Apr 2, 2007

i did the vacuum test... egr did open and close. i disconnected it to make sure nothing was corroded at the connections, or not dirty or anything, and then i forgot to put the connection back ON...

tried to start the car again...

CAR STARTS

realized i hadn't reconnected it.

waited a while, started up again. cut it off, started up again.

*crossing fingers*

someone told me to reconnect the egr to see if that makes it NOT start again... but i'm scared to do that now! will anything BAD happen if i just leave the egr disconnected???

HISSIN50 said:
If you suspect a fuel delivery issue, ensure you have proper fuel pressure and buy a noid light. The noid light is a 5 dollar test light that sits on an injector connector. It will flash to let you know the injectors are getting the proper 12 volt and ground signals to fire. A *good* parts store will have them, and some crappier parts stores have them too (I say this so time isnt wasted driving from one store to another if you decide a noid light sounds like a good thing to have. Call the stores first).

Don't do anything with the gas pedal when you try to start it. Once you reach ~3.71 TPS volts, the injectors are shut off while cranking. It does not take very much pedal depression to achieve this. An EFI car should not require any pedal jockeying to start up. Playing with the pedal is an old carb habit that's hard for some of us to break.

I agree that your EGR code should not cause an issue unless the EGR is stuck open. A piece of carbon can wedge under the seat and hold the valve open. In said case, the car would run horribly or not even catch.
Quick, cheap test: Grab a couple feet of vac line (extra windshield washer fluid line might fit, if you have that lying around). Go to the EGR valve and remove the OEM vac line from the EGR valve's nipple. Put one end of your hose on the EGR valve nipple and lightly suck on the other end of the line while watching the EGR valve's diaphram (it's in plain sight). You should see the diaphram open and close with as little as a couple inches of vacuum (somewhere between drinking a soda and milkshake through a straw). If you dont see that diaphram move in and out a fair bit, it might be hung up. There's a quick way to disconnect the incoming gasses from it but I won't clog up this post with that.

Good luck.

Fopar · Apr 3, 2007

reconnnect the EGR nothing bad will happen, if it acts up then you've obviously found your problem. I'm not terribly familiar with the smog stuff but if the connector on the EGR is for a sensor that tells the computer the EGR position then that'll likely cause the problems you mention. It may not be stuck open it could just be a faulty sensor... if it acts up time for a new EGR (like 100$ )

angeljenylynn · Apr 3, 2007

yeah, almost $150 at the ford dealer here.

gonna try that in the morning.

Fopar said:
reconnnect the EGR nothing bad will happen, if it acts up then you've obviously found your problem. I'm not terribly familiar with the smog stuff but if the connector on the EGR is for a sensor that tells the computer the EGR position then that'll likely cause the problems you mention. It may not be stuck open it could just be a faulty sensor... if it acts up time for a new EGR (like 100$ )

HISSIN50 · Apr 3, 2007

I have the feeling the car starting is happen-chance. When an EGR code is logged, the computer is supposed to shut off the EGR function. The only caveat is if the valve is physically held open by a piece of coke (which was the reason for my vacuum test suggestion above).

If the car does act up again, keep a pair of mechanics gloves with you. Jostle all the same items you touched tonight and see if the issue can be narrowed down. Sometimes the wires in these electrical connectors start to back out and provide intermittant connections.

Good luck.

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