1998 GT has a bug need help

bubbleheadracin · Feb 18, 2011

OK guys I bought a 1998 GT automatic with 150,000 miles on it a couple of weeks ago. I've been driving it without any trouble until the other day. I got home parked it and went into the house, a couple of hours later I was going to leave and it would not start. It will turn over, but not crank. I was told a few things that it could be so I replaced them and still will not start. I replaced the cam sensor, coils, crank sensor, fuel filter, plugs and wires and still nothing. I checked all of the fuses and they are good. I checked to make sure it was firing and it is. The fuel pump was replaced before I got it, but I checked it anyways and it works. I really don't know that much about the 4.6's, because this is the first one I've owned. I've had alot of the fox body cars. Do the 4.6's have a map sensor? I know on the fox body cars if the map sensor was bad it would act this way. I call the parts store and they said it didn't. I thought ford may have changed the name to something else other than a map sensor. Any help will be greatly appreciated. Don't know what else to do.

Thanks

nyuk98gt · Feb 18, 2011

bubbleheadracing:

Fuel pump or CCRM (contains the fuel pump relay) would be my guess. Is fuel reaching the Schrader valve on the rail? If not, start tracing the wiring back to the pump. Is there power from the CCRM? Is there power at the inertia relay? Is there power at the pump? If you run a wire to the FP, does it run? If not, then the pump is dead.

HTH,

Chris

GDawg · Feb 19, 2011

Yep, I'd head right to the fuel pump and see if it's working or not. If not, check fuses and voltage.

mrvax · Feb 19, 2011

Agree. Sounds like a fuel pump issue.

wmburns · Feb 20, 2011

Since you stated that you checked the fuel pump and it is good, we will assume that you know what you are doing (you do hear the fuel pump running and there is confirmed fuel pressure at the rail right?).

You also stated that the plugs are firing.

Will assume that if the theft light was blinking, you would have mentioned that (Right?). Especially after changing all of those parts.

So....what else could cause a crank with not start????

How about a bad IAC? Hold the throttle half way open during cranking. Does this improve starting?

Next try disconnecting the MAF sensor. Does it try to start now?

screamin gt · Feb 20, 2011

pats? did you get more than one key with the car? if so have you tried both keys? Just thinking one may have been cut for a spare but not programmed. just another thought.

bubbleheadracin · Feb 20, 2011

wmburns said:
Since you stated that you checked the fuel pump and it is good, we will assume that you know what you are doing (you do hear the fuel pump running and there is confirmed fuel pressure at the rail right?).

You also stated that the plugs are firing.

Will assume that if the theft light was blinking, you would have mentioned that (Right?). Especially after changing all of those parts.

So....what else could cause a crank with not start????

How about a bad IAC? Hold the throttle half way open during cranking. Does this improve starting?

Next try disconnecting the MAF sensor. Does it try to start now?

Fuel pump is good with pressure at the rail. I have tried holding the throttle half way and all the way open with no improvement. I haven't paid any attention to the theft light, but will check tomorrow. What does it mean if the theft light is not blinking? I will check the MAF sensor also. I took a can of starting fluid and it will crank and try to run as long as you keep spraying it. May have been the wrong thing to do, but wanted to see if it would try to run. What does this mean? Is there a relay or something causing it to do this? I know my 92 had a similar issue and it was the map sensor. I was told this car doesn't have a map sensor.

Thanks again for the help.

bubbleheadracin · Feb 20, 2011

screamin gt said:
pats? did you get more than one key with the car? if so have you tried both keys? Just thinking one may have been cut for a spare but not programmed. just another thought.

They are the factory keys.

wmburns · Feb 21, 2011

Starts with starting fluid but won't continue to run. That means is NOT a PATS (theft) problem. That also means that the CKP sensor is not dead.

Holding the throttle halfway open doesn't make any difference. Nor does disconnectiong the MAF electrical connector.

And you are POSITIVE there are no large vacuum leaks between the MAF sensor and the throttle body. As well as no blown fuses.

Does the motor make normal "chug-chug" sounds as it is cranking?

Are the grounds around the battery clean and tight?

How did you measure fuel pressure?

Next, confirm there is +12 volts with the key on at the IAC and spot check several of the fuel injectors. The fuel injector VPWR wire will be the wire that is the same color at all injectors. What we are trying to do is to confirm if there is an electrical problem or another reason why you aren't getting enough fuel.

If there is +12 volts at the injectors, consider renting/buying a set of "noid" style test lights from your local autoparts store. This can be used to confirm a firing pulse across each injector.

bubbleheadracin · Feb 21, 2011

wmburns said:
Starts with starting fluid but won't continue to run. That means is NOT a PATS (theft) problem. That also means that the CKP sensor is not dead.

Holding the throttle halfway open doesn't make any difference. Nor does disconnectiong the MAF electrical connector.

And you are POSITIVE there are no large vacuum leaks between the MAF sensor and the throttle body. As well as no blown fuses.

Does the motor make normal "chug-chug" sounds as it is cranking?

Are the grounds around the battery clean and tight?

How did you measure fuel pressure?

Next, confirm there is +12 volts with the key on at the IAC and spot check several of the fuel injectors. The fuel injector VPWR wire will be the wire that is the same color at all injectors. What we are trying to do is to confirm if there is an electrical problem or another reason why you aren't getting enough fuel.

If there is +12 volts at the injectors, consider renting/buying a set of "noid" style test lights from your local autoparts store. This can be used to confirm a firing pulse across each injector.

I unpluged the MAF sensor and it didn't change anything. Checked for any vacuum leaks and didn't find any between the to. When trying to start, the car sounds like it always did. I checked the fuse panel underneath the hood and under the dash and all of the fuses were good. I will check the volts and the injectors later tonight. I checked the fuel pressure with a gauge that screws into the valve on the fuel rail. Will double check the ground also.

Thanks again for the help.

bubbleheadracin · Feb 23, 2011

wmburns said:
Starts with starting fluid but won't continue to run. That means is NOT a PATS (theft) problem. That also means that the CKP sensor is not dead.

Holding the throttle halfway open doesn't make any difference. Nor does disconnectiong the MAF electrical connector.

And you are POSITIVE there are no large vacuum leaks between the MAF sensor and the throttle body. As well as no blown fuses.

Does the motor make normal "chug-chug" sounds as it is cranking?

Are the grounds around the battery clean and tight?

How did you measure fuel pressure?

Next, confirm there is +12 volts with the key on at the IAC and spot check several of the fuel injectors. The fuel injector VPWR wire will be the wire that is the same color at all injectors. What we are trying to do is to confirm if there is an electrical problem or another reason why you aren't getting enough fuel.

If there is +12 volts at the injectors, consider renting/buying a set of "noid" style test lights from your local autoparts store. This can be used to confirm a firing pulse across each injector.

Checked the volts at the IAC and it checked ok. Also checked each injector and all of them are the same also. I will check the pulse on the injector tomorrow afternoon. I'm ready to pull what little bit of hair I have left out. This car is driving me nuts. I noticed today that it sounds if the motor is dragging a little. Is it possible for it to jump time?

joshjwc9 · Feb 23, 2011

Are you sure the battery isn't dead or the terminals are loose? I'd rather start with the small stuff and go from there. The battery might have killed itself and not have enough cranking amps to turn the car over..

hotcobra03 · Feb 23, 2011

no start

good one...i help a guy with a 99 gt..his would crank over ,he had fuel but no spark...

hes ended up being a short in the pats module

listen to burns...and stop changing parts..it would be hard to tell if the parts your putting in are good..ive gotten bad parts before,even when you think they are new...

if you need more help on how to test componets before replacing chiltons library is free and has alot of info on how to test stuff...its all in there just alittle hard to find

Gale Cengage Product Failure

bubbleheadracin · Feb 27, 2011

I've checked everything that has been listed and it all checks out ok. Is there anyway to check to see if it has jumped timing? I've got fuel and spark what do ya'll think it could be? Is there anything else to check before I dig deeper?
Thanks

Sonic04GT · Feb 27, 2011

Good luck man. I hope you get it fixed because I'm anxious to see what the issue is at this point I think you've hit nearly everything.

stang88j · Feb 27, 2011

id check the ground real good my buddies 97 cobra did the same thing after days of messing with things.the ground wire was weak changed it and bam started right up.do a compression test if it jumped time compression will be low in cylinders

midnightdriver · Feb 28, 2011

bubbleheadracin said:
I've checked everything that has been listed and it all checks out ok. Is there anyway to check to see if it has jumped timing? I've got fuel and spark what do ya'll think it could be? Is there anything else to check before I dig deeper?
Thanks

Grab a scanner and check your ecu (engine computer). My money is on a computer problem, such as it not reading all parameters correctly not letting the engine fire.

You have spark because engine ran with started fluid

But you don't have injectors firing which is the problem. You have fuel (at the rail) but if it doesn't get to the cylinders (doesn't run after start fluid is stopped) then you still have a FUEL problem.

I suggest take it to Ford and get a diagnostic test run, rather then continuing to throw your money in every direction.

thats my $ .02

1998 GT has a bug need help

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