98 Cobra won't Start

9

98BBCobra

New Member

Jul 11, 2007

9

0

0

Aug 29, 2010

#1

• Aug 29, 2010

• #1

Well as if all was not busy enough this year. I now have an 8 month old baby girl so I have not had much time to play with my "toys" lately. I just went to pull my Cobra out of the garage after not driving it for a few (probably 10) months and it fires up no problem. I'm thinking that's my girl. Then all of a sudden it dies. That is odd. I try to start it up again and nothing. I push it out of the garage so that I can get a better look at it. I inspected the hoses and everything under the car to insure that there was no fuel leaking. I then checked the inertia switch in the truck. Everything looks good. I had to run to the auto parts store to get a fuel line removal tool and now it is dark. Tomorrow after work I will remove the fuel line and see if I am getting fuel to the rail. Does anyone else have any ideas as to what the problem may be?

 

wmburns

SN Certified Technician

Aug 14, 2009

5,892

514

204

Houston Texas

Aug 30, 2010

#2

• Aug 30, 2010

• #2

Does it crank at all or does it crank with no-start?

When the key in placed into the run position, the theft light should come on for 3 seconds. After a 3 second "prove out", the theft light should go off.

What is the theft light doing?

For the 1996-1998 Model Year, Anti-theft (PATS) causes a no-crank symptom when activated.

For the 1999-2004 MY, PATS disables fuel and spark. This causes a crank with no-start.

Do you hear the fuel pump run when the key is turned to the "run" position without starting? Repeatly cycle the key off/on/off/on and listen for the fuel pump.

If the symptom is crank with no-start, try holding the throttle half way open. Does that improve starting?

What is the condition of the fuel? After setting for such a long time, the possibility of bad gas should be considered. See if a very small amount of starting fluid sprayed into the manifold lets the motor start. If it does and then dies, look closer at a fuel related problem.

 

K

Kilgore Trout

Fried or Broiled ?

10 Year Member

Mar 30, 2005

4,749

95

134

Aug 30, 2010

#3

• Aug 30, 2010

• #3

Did you stabilize the fuel 10 months ago? Its probably bad gas.

 

9

98BBCobra

New Member

Jul 11, 2007

9

0

0

Aug 30, 2010

#4

• Aug 30, 2010

• #4

The engine cranks, but does not start. The theft light goes on for about 3 seconds and turns off like you said. I did not stabilize the gas because I did not think it would be that long. Anyway I picked up a set of fuel line removal tools so I can check to make sure that there is gas to the rail. From there I will look into the bad gas. Thanks for the replies I will update tonight.

 

9

98BBCobra

New Member

Jul 11, 2007

9

0

0

Aug 30, 2010

#5

• Aug 30, 2010

• #5

Well no luck. I pulled the fuel line off of the fuel rail and turned the key on. I then went to the fuel filter and did the same. It seems like the pump may have gone out. It seems odd that the pump would just go out. Any ideas? Thanks

 

jeremy canter

Member

Dec 2, 2008

402

0

17

Orange County , NY

Aug 31, 2010

#6

• Aug 31, 2010

• #6

I have a pump if you pay the shipping >

 

wmburns

SN Certified Technician

Aug 14, 2009

5,892

514

204

Houston Texas

Aug 31, 2010

#7

• Aug 31, 2010

• #7

Good idea to confirm the fuses and power to the fuel pump before dropping the tank.

 

Twista

Active Member

May 7, 2004

510

2

29

@ the z00 in chicago

Aug 31, 2010

#8

• Aug 31, 2010

• #8

fuses

 

9

98BBCobra

New Member

Jul 11, 2007

9

0

0

Aug 31, 2010

#9

• Aug 31, 2010

• #9

Ok checked the fuses and they are fine. That was actually the first thing I check since they are so easy. I have not checked the power though. How would I go about this. Just disconnect the connector near the rear bumper and then hook up a DC voltmeter to the connector to make sure there is power when the key is turned to the on position?

 

wmburns

SN Certified Technician

Aug 14, 2009

5,892

514

204

Houston Texas

Aug 31, 2010

#10

• Aug 31, 2010

• #10

Check for power at the IFS cutoff switch in the trunk with the key on. The IFS is an easy point to test for power because it is a simple switch that is easily accessed.

If you have power at the IFS, suspect a bad fuel pump.

If you do not have power, look first at the fuel pump relay.

 

9

98BBCobra

New Member

Jul 11, 2007

9

0

0

Sep 4, 2010

#11

• Sep 4, 2010

• #11

Ok I pulled the connector off the the switch in the trunk. Put the key in and turned to on. I am getting about 6V what should I be getting? Interestingly enough when I plugged it back in and tried to start the car it fired for just a fraction of a second. This makes me wonder could this switch be bad? The red button on top is pushed down is this how it is supposed to be? I was also looking for a fuel pump relay and could not find one. There is a high amp fuse in the engine label fuel pump, but there are no "cube relays" listed as fuel pump. Am I looking in the wrong spot? Thanks for all the help so far.

 

wmburns

SN Certified Technician

Aug 14, 2009

5,892

514

204

Houston Texas

Sep 4, 2010

#12

• Sep 4, 2010

• #12

The CCRM is the fuel pump on/off relay. However the 1996-1998 DOHC uses an additional two speed relay. There has to be voltage at the IFS switch.

The IFS is a cut off switch. Push the button in to reset. That's it. As a switch, the voltage should be the same on both sides when connected. If not, there's a problem.

Try this for a test. Run a jumpper test wire directly from battery positive to the IFS switch. Does the car start now?

Once the voltage measurements have been confirmed, the list of failure points is very small.

 

9

98BBCobra

New Member

Jul 11, 2007

9

0

0

Sep 4, 2010

#13

• Sep 4, 2010

• #13

OK now I am going to show my inexperience here. When I look at the IFS I only see one connector at the bottom of the switch. I disconnected the connector and checked both pins to a nice clean bolt (ground) in the trunk. 1 read 0V the other read 6V. Is there another way to check this?

 

wmburns

SN Certified Technician

Aug 14, 2009

5,892

514

204

Houston Texas

Sep 4, 2010

#14

• Sep 4, 2010

• #14

Update. I reviewed the wiring diagram a little closer and missed something. The DOHC uses a slightly different fuel pump set up than the SOHC. There is a separate fuel pump "speed" relay that switches between low-speed and high-speed mode.

In low-speed mode the power is passed through a resister to reduce the voltage. I suspect the 6 volt test at the IFS is the result of the power supply being in low-speed mode.

In a nut shell, this confirms power to the fuel pump. Since NOTHING comes out if the fuel filter is disconnected, IMO this confirms the diagnosis of a bad fuel pump.

Sorry just a liitle slow on the differences between DOHC/SOHC for the 1996-1998 MY.

Good luck.

 

9

98BBCobra

New Member

Jul 11, 2007

9

0

0

Sep 5, 2010

#15

• Sep 5, 2010

• #15

Thank you to all who helped. It was the fuel pump. Dropped the tank today and replaced with a Walbro 255. Took a little bit of modification to get it to fit, but now she is running great again. Plus now when I do add some sort of forced injection I should be good to go pump wise.

Thanks again!