What's the possibility of 2 bad fuel pumps?

[2tall]

What\'s the possibility of 2 bad fuel pumps?

I had my old fuel pump replaced because it would take forever and a day to start up for work in the morning (it would crank 8+ times before turning over), then the pump would whine like I didn't buy it an engagement ring for a couple minutes.

Lately it started doing it again and I took it in, but the mechanic said he couldn't get it to happen and thought that perhaps my radar detector sucked to much juice as it remained plugged in all night.

The last week I've had the detector unplugged (and I coincidentally got my first Viper speeding ticket - ouch) and still have to crank 3-5 times before turn over, with accompaning whine afterwards.

Do I have another bad pump? Is this normal operation? Could it be something else?

Inquiring tall people want to know.

 

[Steve-Indy]

Re: What\'s the possibility of 2 bad fuel pumps?

Might want the tech to check fuel pressure again...clogged fuel filter or crimped fuel line ???

 

[racetech]

Re: What\'s the possibility of 2 bad fuel pumps?

I may have some info about that issue that could help. Yesterday, I was talking to one of my most respected racing buddies (many times nat. champ & world record holder) about Viper fuel system issues. He doesn't race Vipers himself, but deals with those who modify them all the time. I have been planning my "attack" as far as engine mods on my own and was concerned about the best way to deal with fuel delivery issues, partiularly feeding this baby enough and with the right fuel curve.

He warned me that the fuel pump & delivery system is the weak link in the Viper. He said that it's entirely inadequate from a pressure/flow standpoint and that I'll also be facing wiring issues. It's no big deal to install a better pump, but it is his understanding that the higher current draw causes a cascade of other problems. There's apparently a weak link somewhere at a bulkhead connection and the wire itself is just not up to the task--that I'll wind up having to rewire the entire circuit.

This makes me wonder if you could already be having some issues with too much resistance in the circuit. It sure wouldn't be the first time someone got two bad parts in a row, but you're right to be suspicious about that. As far as thermostats, I once got THREE bad ones in a row--all from the same manufacturer! They wouldn't open at all when dropped into boiling water.

Back to the topic--fuel systems can be tested for both flow rate and pressure (you MUST check both!!) and your shop should be equipped to do so. If I were working on it, I'd run a voltage drop test to see if the wiring may be the root problem.

I'd love to hear from those who have made major changes to their engine. I'm fortunate to have the best possible help when it comes to cylinder head mods & camshafts, but I have no clear plan on what to do with the fuel pump & lines. I'll be adding something in the neighborhood of 150 hp with my planned changes and I'd love to hear from others who were able to solve the fuel delivery issues--including the pump, lines, and wiring.

Thanks!

 

[8AVETTE]

Re: What\'s the possibility of 2 bad fuel pumps?

I would say that the ether the battery is week from the detector or the ECU is bad. Had the same thing happen to me on a 98 GTS.

 

[Jack B]

Re: What\'s the possibility of 2 bad fuel pumps?

Racetech:

the Viper fuel pump is good for at least 600 rwhp, therefore, approx 700 brake hp. I have watched the AF ratio very closely and the pump can maintain 11.5 - 12 at over 600 rwhp.

Jack B