1994 RT/10 Fuel pump not working?

[Roccojet]

Good afternoon!

Gonna try to keep it short but provide as much info as I can.

I was just recently passed down a 1994 RT 10. Car just has over 20,000 miles on it. It has rarely been driven and it’s spent most of its time sitting in the garage covered.

Before it was passed down to me, the very first owner (i’m 3rd) had a viper 600HF aftermarket alarm system installed. Pretty much in the years sitting the car was consistently jumped and just ran around the block or two and evidently sat long periods of times. 2nd owner went through like 4 battery replacements.

The alarm kept draining it so I’m in the process of removing the aftermarket one entirely so I don’t gotta deal with the extra BS. There used to be two key fobs, one for the factory alarm and one for the aftermarket alarm. I only have the factory alarm key fob and no longer have the aftermarket one.

With the battery replacements in past there has been no issues with putting a new one in and starting it. You could always here the fuel pump “Whine” for a couple seconds after ignition.

Since losing the aftermarket key fob, and trying to start with new battery, It’ll crank and crank but no fuel pump whine. (Probably cause no fuel pump = no fuel) I suspect who installed the alarm wired it in such to shut off fuel pump when alarm is armed. There is a valet button in which i’ve tried to go through the motions of pushing which disabled alarm but still no prime.

What i’ve checked / tried:
Made sure battery cables seated properly and little red line to positive is in tact

Pulled fuse aftermarket alarm (fuse wasn’t in it before and don’t know the amp rating of the slot)

Put a fuse in to hear aftermarket alarm barley “whirl” (sounds like the loud crazy horn with the viper system it’s on it’s last breath because it’s very quiet and staticky ) after i hit valet button to disable

Checked relay in truck wires going across trunk top portion center and hear the relay click 1 time when ignition is on.

That’s all i’ve done (pretty much all i’d know to check so far by looking at forums)

Any recommendations? Thanks!

 

[Steve-Indy]

While there are a considerable number of Gen I Vipers that have developed fuel pump issues, I would start with a new fuel pump relay...or jump contacts in socket to determine if the fuel pump will run.

By the way, the click may be the signal for the relay, but does it have 12 volts on pin 30 ? Are you SURE that there is continuity from battery to relay socket as that small red wire is easily damaged.

 

[Roccojet]

While there are a considerable number of Gen I Vipers that have developed fuel pump issues, I would start with a new fuel pump relay...or jump contacts in socket to determine if the fuel pump will run.

By the way, the click may be the signal for the relay, but does it have 12 volts on pin 30 ? Are you SURE that there is continuity from battery to relay socket as that small red wire is easily damaged.

I’ll triple check the small red wire for continuity and then i’ll check the voltage for pin 30! I’ll check back with you in morning!

 

[Roccojet]

While there are a considerable number of Gen I Vipers that have developed fuel pump issues, I would start with a new fuel pump relay...or jump contacts in socket to determine if the fuel pump will run.

By the way, the click may be the signal for the relay, but does it have 12 volts on pin 30 ? Are you SURE that there is continuity from battery to relay socket as that small red wire is easily damaged.

so got my voltmeter out and the little red wire connected to the battery has 12 V running all the way up. On the relay I tested and the relay clicks when connected to my external battery source and I also did an ohm test on it and it brought it back down to zero so I’m pretty sure the relay is good.

 

[TexasViper35]

After trying to start it have you pulled a spark plug to see if it’s wet with gasoline? I think I would rather do that than assume that the fuel pump is disabled by the alarm. It’s fast and simple. Not sure about Vipers, but my Porsche 928 fuel pump only runs for 2-3 seconds at Key On and that’s it, it doesn’t run again and stay on until after the car actually starts.

That aside, I would suspect that you aren’t going to get any joy until the aftermarket alarm is completely removed. It shouldn’t be that difficult to research your model to see the installation instructions and then reverse them. Double check that the factory setup is unmolested and correct.

If still no go check your relay chart to find another duplicate of your fuel pump relay and swap them, or just put a new relay, all of the relays actually that are connected to the fuel system. Relays are notorious in older cars.

I‘ve never done it to a Viper, but in older Porsches you can put a jumper wire in place of the fuel pump relay to turn it on and see if the pump still works, the car will start and drive as normal. But you’ll need to pull the wire out to shut it off when you are done.

Lastly, all of this neglect to having a battery in good condition over these many years, but I imagine all of those jump starts especially, could have caused damage to other parts, the alternator for certain but also perhaps the computer. But you are a ways from having to look in to that possibility.

Anyway, good luck! Hopefully it is just that alarm.

 

[Steve-Indy]

As I said, after determining continuity of red wire feed, I would start with another relay or a jumper wire to see if fuel pump turns on.

You can test for fuel pressure at the rails by opening Schrader valve mounted on intake manifold...location depends of whether you have early 94 or later 94 (how many stripes on yours...4 or 3?).

I find that these problems are more efficiently solved with a verbal discussion.

 

[Roccojet]

Update: Just got through removing the aftermarket alarm System entirely. Pretty much the only wires that were tapped into is a blue wire up right behind the steering column underneath the dash,( Not including the door wires for the door popper but I left those there in case i want to add a basic door popper kit) and the yellow wire in same area that was cut in half mounted to another relay underneath the dashboard. After that has all been removed I reconnected those yellow wires. Everything works the same as far as cranking and unlocking goes. Mine has the 3 stripes.

I put the battery back on the charger just to maintain it while I do work and of course I have it disconnected from the main car. Do you guys know which relay I could maybe pickup from my auto store and modify to work for the fuel pump?

Last, i’ve also heard rumors
of the ASD but when I turn ignition I do hear 1 click kind of coming from engine bay area. I have OEM fob and don’t believe ASD would be an issue. But worth a check.

In the meantime I will check the pressure as well as pool some of the clothes to see if there’s any fuel on them

 

[Steve-Indy]

Your model's Schrader valve should be at the rear of the passenger side of the IM, facing the center of the engine just in front of the windshield cowling. It should be covered with a knurled brass know. If it squirts out into a rag, you are getting action from the fuel pump.

Take the fuel pump relay to the parts store for matching.

ASD relay is third one in from...can swap with starter which is fourth relay in from outside.

 

[TexasViper35]

After trying it next time and while you have a spark plug out, ground it and check for spark. If you haven’t already checked that.

Did you buy / inherit the car in this non-running condition?

 

[Roccojet]

Update: Pulled off Valve cap and not a single drop of fluid came out. Tried to press down and still no joy.
Swapped ASD relay with Starter relay, no changes. Swapped fuel relay, (Same as the ones for starter /ASD) with starter and still no pump. Made sure it still cranked as much as I wanted to just to see if ASD still worked.

Got spark from plug as well.

I also inherited in non working condition.

I’m starting to maybe think the fuel pump may be the issue itself unless i missed anything else

 

[TexasViper35]

Yikes, it could be anything then. Since someone sold or passed the car along in this condition, because they likely made many attempts at fixing it and came up short. If your diagnostic skills are not so great you might consider stopping now and having a Viper Specialist have a go at it for you, with the equipment that may be needed.

You don’t want to throw new parts, like a fuel pump, at the car hoping that’s the problem, it can get expensive doing that. You can jumper the fuel pump relay to check to see if that corrects things and the car starts, you should be able to hear it running with the jumper in place. It sounds and is electrical but it’s pretty simple really. Pull the relay and read the diagram that should be printed on it, you’ll need to make a jumper wire out of a legnth of wire and two spades that are the same size as those on that relay. There may be photos on the internet at this site. If you want to be fancy about it you can put a switch in the middle of the wire. It can be very short for just a plain jumper or really long for one with the switch.

You checked fuses though, right? How long has it been sitting?

 

[Roccojet]

Yikes, it could be anything then. Since someone sold or passed the car along in this condition, because they likely made many attempts at fixing it and came up short. If your diagnostic skills are not so great you might consider stopping now and having a Viper Specialist have a go at it for you, with the equipment that may be needed.

You don’t want to throw new parts, like a fuel pump, at the car hoping that’s the problem, it can get expensive doing that. You can jumper the fuel pump relay to check to see if that corrects things and the car starts, you should be able to hear it running with the jumper in place. It sounds and is electrical but it’s pretty simple really. Pull the relay and read the diagram that should be printed on it, you’ll need to make a jumper wire out of a legnth of wire and two spades that are the same size as those on that relay. There may be photos on the internet at this site. If you want to be fancy about it you can put a switch in the middle of the wire. It can be very short for just a plain jumper or really long for one with the switch.

You checked fuses though, right? How long has it been sitting?

definitely going to try the jumper wire. as far as the fuses I don’t think there’s any more fuses other than the relay for the fuel pump itself. I’ve tried to research some material the main two things I keep finding a ASD relay and fuel pump relay.

I would say the last time the car has been started was 2018 and it had bad gas in it which it was parked and siphoned out. since then, battery was dead, replaced fuel filter, and that’s pretty much it. Everything else stayed the same expect the recent taking out of alarm to try to solve the issue

My number is 210-606-0271 if it’s easier to text. I appreciate all the help so far!

 

[TexasViper35]

I found a article that may be helpful to you. But this part is what you can try very easily:

”The most common "solution" for most owners is to cycle the ignition key between the OFF and RUN mode (but not CRANK yet) about 6 times, letting it sit in the RUN position for 2 seconds while the pump runs (after 2 seconds the ECU will shut the pump off). By doing this, the pressure in the fuel lines is built up. On the 7th time, the engine is cranked and will hopefully start up.”

Read this link when you can.

Dodge Viper Fuel Relay Controller

Dodge Viper Fuel Relay Controller: Some early Dodge Viper automobiles are difficult to start after lack of operation for more than a few hours. The problem is due to a fuel pump defect which allows an undesired slow bleed-off of fuel pressure. For various reasons, this is difficult t…

www.instructables.com

It certainly gives more value to trying to jump the relay because to replace the pump you’ll need to cut a hole in the car, man…

Good luck!

 

[viperbob]

I had the fuel pump replaced on my Red '94 under warranty back in 1998.

 

[Red Vroom]

These Fuel Pumps can be problematic especially after they sit for a while in hot garages with little fuel in the tank. The vapors cause expansion and pressure in tank which damages the fuel pump assembly. Best to remove the gas cap when sitting for long periods to prevent this. In my case, has to open up bottom of trunk to get to tank, fuel pump assembly and remove it for rebuilding. Real pain.

 

[wilks25]

Just throwing this out there. My 93 fuel pump stopped working a couple of years ago and I sent the car to a dealership. I was told that battery acid leaked down on the wire to the fuel pump which obviously broke the connection. This is what they told me so I assume the wiring is under the battery box. Worth a check either way that the wiring is intact.....

 

[Roccojet]

Thanks all for the replies this far! Going to pull the fuel tank out to manually test the future! I think i’ve exhausted all the recommendations above, but if the fuel pump works when out then i know i got something electrical going on! Will update as I go!

 

[TexasViper35]

I’m curious, what happened when you put a jump wire in place of the fuel pump relay? You should have been able to hear the fuel pump making a whining / buzzing sound.

 

[Roccojet]

I’m curious, what happened when you put a jump wire in place of the fuel pump relay? You should have been able to hear the fuel pump making a whining / buzzing sound.

When I used the jumper wire no sound at all. Both areas getting 12v as well

 

[obaa996]

relays are pretty easy to check. Parts shops may have a relay checker; basically a board with different relay sockets you can plug the relay into. If not, you can check them yourself with a meter and battery; google "relay pin diagram" with the pin numbers on the relay (probably 30/85/86/87|87a). For a relay with those numbers, you'd apply voltage to 85/86, and resistance between 30/87 should drop to zero.

 

[Roccojet]

Hey all! So the latest update regarding the fuel pump issue. I have completely taken out the aftermarket alarm system and rewired it back to factory specs. That still did not solve the issue. I also swapped a couple relays to see if that was the issue, no luck. Check the wires by the battery no luck. Bought a brand new battery no luck. So after getting the tank removed today this is what I found regarding the entire fuel assembly. What can I do to rebuild this one or is it best just to go ahead and buy the real build version for about $1300? Tank was a PIA to get out but got it out. if anyone is looking for advice by all means I can tell you what I ran into and what works best for me. Best thing about it is I did I had to drop a single fender liner to get it out.

 

[Real_Maverick]

Personally, I'd send the whole thing in for a rebuild. In the next year or two, I'll need to do the same on my 95. My check valve leaks back into the tank, so I've put the timer solution on for now. Eventually, I'll need to pull the whole tank like you did and send the assembly in for rebuild. Would love a good step by step on how you took it out.

VIPER Gen 1 & 2

 

[WeGoRTw]

For the check valve can’t you do just the $130 fuel pump?

I am having a fuel leak as well when tank is full; know what grommet that is?

 

[Steve-Indy]

Grommet is MOPAR part number 5217578

They come two to a pack for about $8

 

[Chad Spackman]

I didn’t read the whole thread so forgive me if this doesn’t seem relevant. but if the pump is bad, that is quite a roundabout way to get there. You’ve done the hard part (pulling the tank). Pull the pump and test it. If you need instructions I’ll be happy to help. It’s easy to remove, easy to test, and easy to replace. But, if you decide to also replace pressure regulator and thus replace that little hose between the pump and regulator (or re-use that hose), then there is more you need to know. Mostly about what bits to buy. I’m happy to help there too

 

[GTS Dean]

For other similar, useful exhibits, check the sticky thread '850HP on a stock fuel pump' Frankly, this thread should be sticky as well.