Fuel 95 Cobra Won't Start - Bad Fuel Pump?

W

WHTEVNM

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Jul 20, 2014

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#1

• Jul 20, 2014

• #1

Last week I was pulling into my garage from work and my Cobra just died and hasn’t started since. It will crank and when I sprayed starter fluid in the throttle body and cranked it, it started up. This leads me to believe that I have spark and the ignition system is good. When I turn the key I can hear a buzzing noise from the CCRM in the front of the car so that leads me to believe that the CCRM is good. As far as I can tell, I cannot hear the fuel pump prime the system when I turn the key. I have checked all fuses and they are good, replaced the fuel filter, checked the inertia switch, and checked the schrader valve. When I crank the key and compress the core of the schrader valve, a little bit of fuel trickles out. If the fuel pump was good, I would imagine that a spray of fuel would come out of the valve. I believe that the fuel pump is bad but before I take on the large task of replacing it, I wanted to see what other opinions are out there. Thanks for reading!

 

toyman

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Jul 20, 2014

#2

• Jul 20, 2014

• #2

WHTEVNM said:

Last week I was pulling into my garage from work and my Cobra just died and hasn’t started since. It will crank and when I sprayed starter fluid in the throttle body and cranked it, it started up. This leads me to believe that I have spark and the ignition system is good. When I turn the key I can hear a buzzing noise from the CCRM in the front of the car so that leads me to believe that the CCRM is good. As far as I can tell, I cannot hear the fuel pump prime the system when I turn the key. I have checked all fuses and they are good, replaced the fuel filter, checked the inertia switch, and checked the schrader valve. When I crank the key and compress the core of the schrader valve, a little bit of fuel trickles out. If the fuel pump was good, I would imagine that a spray of fuel would come out of the valve. I believe that the fuel pump is bad but before I take on the large task of replacing it, I wanted to see what other opinions are out there. Thanks for reading!

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Test for pressure first. The buzzing sound from the CCRM may also mean the fuel pump relay isn't engaging. Remove the vacuum line to the FPR and ensure there is no hint of gas at that connection. Also check/replace the fuel filter Lots of things may be at play here.

 

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WHTEVNM

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#3

• Jul 20, 2014

• #3

Thanks for the response. I have heard of the PIP sensor in the dizzy going bad in these cars but, like I said, when we spray starter fluid in the throttle body the car will start so I do have spark. Now I’m starting to think that the issue is the CCRM. I put my ear up to the fuel tank and had someone turn the key and can definitely say that the fuel pump makes a buzzing noise to prime the system. I also put a voltmeter on the wire harness plug to the fuel tank and it was getting voltage. Maybe not enough from the CCRM to prime the system? I got about 9.8 volts. How much does the fuel pump require? Also, when the key is turned, the CCRM makes about 3 or 4 clicking noises. Is that normal? If I do get a new CCRM how do I know I get the correct one? Sorry for all of the questions. I really want to get this car up and running. I just bought it a month ago.

 

toyman

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Jul 20, 2014

#4

• Jul 20, 2014

• #4

Should see 12+volts. Remove and clean the battery to engine and engine to chassis grounds. Replace any cables that appear suspect such as corrosion under the cable sheathing. Bad grounds can cause many operating issues.

 

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WHTEVNM

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Jul 21, 2014

#5

• Jul 21, 2014

• #5

Is it normal for the CCRM to make clicking noises when the key is turned on?

 

jrichker

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Jul 21, 2014

#6

• Jul 21, 2014

• #6

Two resources:

 

toyman

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Jul 21, 2014

#7

• Jul 21, 2014

• #7

I suspect you will hear the relays engage. Low voltage might also cause the relays to momentarily open and close creating a clicking sound. You are jumping all over the place. Start by pulling the trouble codes and confirm the grounds as suggested earlier.

 

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WHTEVNM

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Jul 21, 2014

#8

• Jul 21, 2014

• #8

I hooked up a fuel pressure gauge to the schrader valve and the system isn’t being pressurized. No reading on the gauge with the key on or when I crank the motor. The fuel pump is getting power and I had someone crank the motor while I hit the fuel tank to try and get the pump going but nothing happened. Even though I can hear the pump buzzing when the key is on and a little fuel jumps out of the schrader valve when the core is compressed and the motor is cranked, it doesn’t seem to be priming the system. At this point I think I will order a fuel pump. Any issues with this pump?

http://www.latemodelrestoration.com...ng-Walbro-255-Lhp-High-Pressure-Fuel-Pump-Kit

 

toyman

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Jul 21, 2014

#9

• Jul 21, 2014

• #9

It doesn't give the model number. You want a Walbro GSS340 255 lph pump. However, I would be more concerned about the 9.8 volts than the pump at this point.

 

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WHTEVNM

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Jul 21, 2014

#10

• Jul 21, 2014

• #10

Well I have been working on it for about a week, cranking it everyday. The battery is probably drained a little. Couldn't that be a possible cause for the low voltage?

 

toyman

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Jul 22, 2014

#11

• Jul 22, 2014

• #11

IIRC the pump need a minimum 11v. Same may apply to the ECU as well. Without having a fully charged battery you are wasting time guessing about possible causes. You need to approach these things in a logical and rational manner. First a fully charged battery is about 12.6 volts. Second you need solid grounds for the return path. If these two conditions are not met you are just going to continue floundering.

 

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WHTEVNM

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Jul 22, 2014

#12

• Jul 22, 2014

• #12

How am I floundering here? I think it's pretty narrowed down. The car starts when starter fluid is sprayed into the throttle body so it has spark and air, leaving the problem to be in the fuel system. I changed the fuel filter, checked the inertia switch, checked the fuel pressure (there is none), checked the FPR (slight smell of fuel in the vac hose but not overwhelming and not leaking fuel), and verified that there is power to the fuel pump. The pump is receiving voltage and I can hear it when the key is on. I guess I can check the voltage again to try and get a more accurate reading but there is power going back there. What other logic or rational is there than to look to the fuel pump as the problem?

 

toyman

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Jul 22, 2014

#13

• Jul 22, 2014

• #13

9.8 volts is not adequate. A hum from the fuel pump doesn't mean it's pumping and in fact if the voltage is only 9.8v that's probably all the pump will do (hum or buzz). If there is even a hint of gas smell from the FPR the internal diaphragm must be leaking. It may only be a pin hole but if you smell gas it's leaking. Solve the voltage issue first then see what happens. BTW you don't need to crank the engine to pressurize the fuel lines. Just turning the key to run will start the pump for a couple of seconds, assuming there is proper voltage.

 

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WHTEVNM

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Jul 28, 2014

#14

• Jul 28, 2014

• #14

It turns out that it was the fuel pump. I got the assembly out of the tank and the hose that connects the pump to the fuel lines was completely shredded and falling apart! It was a crazy sight. Anyway, I threw in the Walbro GSS340 and she started right up. Thanks for the help everyone!