Security.. Fuel Pump.. Problems!?

At Wal-Mart tonight I was sitting in my driver seat pressing the lock function of the vehicle joking with my girlfriend not letting her in the vehicle. Well the alarm started going off so I put my key in the ignition to start it and it wouldn't start. The car was cranking but acting like no fuel was getting to the engine. I had 2 of my buddies come and look at it. One seems to think that the aftermarket security alarm is keeping the fuel pump from delievery any fuel to the engine..

When I put the key in the on position I don't hear the winding of fuel pump.. We did spray some starter fluid into the engine and it fired up.. But quit shortly after...

I need some suggestions..

It's a 2002 Blazer Extreme with a Viper Security Alarm.. I don't know what model of the alarm is...

And I wasn't having problems before hand starting the car.. 88,000 miles..

Thanks..

Is the alarm designed/hooked up to disable the vehicle in case of theft? I don't think it's supposed to cut off the fuel pump even if it is. Check all fuses and wiring, make sure you didn't short or fry anything. Make sure you're getting spark. Then test the fuel pump.

Sounds like you messed with a good thing. I don't think anyone can tell you if the pump was wired into the alarm. Might have been. You will need to see if power & ground is getting to the pump. If it is, then you have a long road ahead of you. What is the alarm knocking out.

We have already tested for spark and everything is okay in that department.. Like I said we sprayed some starter fluid into the throttle body and the engine did kick but only long enough it to burn off the starter fluid.

I don't know much about the security because I bought the vehicle that way.

We have already tested for spark and everything is okay in that department.. Like I said we sprayed some starter fluid into the throttle body and the engine did kick but only long enough it to burn off the starter fluid.

I don't know much about the security because I bought the vehicle that way.
You're gonna have to find out as much as you can about that alarm system. It sounds like it disabled something, and if you were in the car when it was going off its certainly possible.

I didn't ask you if it was getting spark, I asked if the fuel pump was getting power. In the tank,can you hear it? Is there pressure?Are the injectors getting a pulse?. Like I said, you have a long road ahead. Shortcut= take out alarm and re-connect any connections it may have cut ( the installer may have run circuts through the alarm ).

No we can't hear the fuel pump engaging.. Can't check for power becaue the vehicle is not here with me at the moment... Will check tomorrow..

There should be a reset procedure on the alarm system.
Alarm instruction manual may tell you.
Try locking doors with the ign key and unlocking them with the ign key.
Some after market alarms have a reset button on them.
If all else fails disconnect neg battery cable and hook it back up.
Then lock and unlock doors with a key.
Or if security light is staying on on dash after key is turned on try the key on 10 minutes and off and then on 10 minutes 3 times and see if it will start.

Something that has been brought to my attention is VATS.. I know you guys might say that since I have a aftermarket alarm that VATS had to have been by-passed but my remote start has never worked which makes me believe they didn't hook up the remote start..

Is it possible that VATS is keeping my vehicle from starting? And if so.. What do I need to do?

No.. I dont see the VATS being involved with the Viper. There should be a reset toggle or button of some sort that comes with that alarm system. It is designed to keep the basic thief from using the reset. It is usually in a hidden place like under the dash and such. You need to put your key in the ignition and hit that button at the same time to start the vehicle. This may or may not help. Also, some of those alarms in fact did shut down the fuel pump. Obviously to keep someone from stealing your vehicle. It is a long road to uninstalling that system. My advice would be to take it to a Viper distributor and have them help you figure it out. May or may not cost you a bit to do it...

Funny... Who got the last laugh in this scenario?? Bet your girlfriend is dieing over this one. Either way, I do not think its a standard vehicle problem, and you need to focus your thoughts on that alarm system. Good Luck !!

Update.. had a guy take it home and look it over.. He switched the coil and nothing changed.. Then he used a test light to see if power was being distributed to the coil.. And it come back as no power...

So suggestions..

So we took out the alarm system and that is not the problem.. We used a test light to test voltage across the Fuel pump coil.. I signal from the starter to the fuel pump relay isn't there.. What could be bad?? Starter switch?

Oil pressure switch is cutting out fuel pump when oil pressure is low. Maybe it's the oil pressure switch??

So we took out the alarm system and that is not the problem.. We used a test light to test voltage across the Fuel pump coil.. I signal from the starter to the fuel pump relay isn't there.. What could be bad?? Starter switch?

Go back to the basic testing.
Are you getting spark to more than one spark plug?
Do you have 12 volt ign power to fuel pump relay?
Is the fuel pump turning on ign turn on 2-3 second prime?
MT

Go back to the basic testing.
Are you getting spark to more than one spark plug?
Do you have 12 volt ign power to fuel pump relay?
Is the fuel pump turning on ign turn on 2-3 second prime?
MT


We are getting spark..

The Fuel Pump relay has 4 pins one is ground, one stays hot all the time and the other two control the relay coil. The switch is getting power but, when the key is turnedto the on position, no power is going to the coil which allows power to be sent to the fuel pump.

No the fuel pump does nothing..

The PCM turns on the fuel pump relay.

But first swap relays with another one of same no.
There should be several in the relay box.

Next find the gray wire or fuel pump prime test wire from relay to fuel pump and jumper it with a 12 volt fused jumper wire.
If fuel pump runs and it will start.
Your relay is bad or pcm is shutting off relay.
If fuel pump will not run with it jumpered the fuel pump or wiring is bad.

Let us know how this test goes.
MT

After testing the gray wire we found that we had voltage. So we just decided to drop the tank and get a new fuel pump... That fixed it.. All this running around for just that..

My buddy can't believe it was that because it just happened out of no where..

What else would you guys suggest to do while the vehicle is still up and half was takin apart.. (Not really) In all seriousness... What else should I change or clean before we finish..

It did pick a strange time to quit.
But they do that sometimes.
Always install.
New fuel filter.
Make sure you use a good quality AC Delco / or Delphi fuel pump module.
And make sure the wiring plug to fuel pump is good.
Some have a wiring plug change over.

And always keep over a 1/4 tank of fuel in the tank.
Good Luck

And always keep over a 1/4 tank of fuel in the tank.

I keep hearing this, but why? I seem remember a few years ago there was a post where someone ran one of these fuel pumps on the bench dry (it may have been pumping fluid, but it wasn't submerged) for about a month and it never hurt a thing.

Is there any studies or reports to support the 1/4 tank theory?

I keep hearing this, but why? I seem remember a few years ago there was a post where someone ran one of these fuel pumps on the bench dry (it may have been pumping fluid, but it wasn't submerged) for about a month and it never hurt a thing.

Is there any studies or reports to support the 1/4 tank theory?

Bench test is a long way from a fuel pump in the tank pumping 65 lbs of pressure.

The pump needs fuel in the tank to cool it and lubricate it.

Over the last 30 years years I have noticed that.
People that keep 1/4 tank or more of fuel in there tank replace a lot less fuel pumps than people that run them empty.

The pump need fuel in the tank to cool it and lubricate it.

People that keep 1/4 tank or more of fuel in there tank replace a lot less fuel pumps than people that run them empty.

I knew that all along (the cooling and lubricating), and it makes perfect sense, I just wonder if the statistics back up the excessive replacement. Thanks for yor reply.

I knew that all along (the cooling and lubricating), and it makes perfect sense, I just wonder if the statistics back up the excessive replacement. Thanks for yor reply.

I have worked on cars and trucks for over 45 years.
Some Big trucks had them 45 years ago in the tank and the had the same problem.
Run the tank empty and they were replacing the fuel pump.
I have watched cars and light trucks with them for 30 years.
Same problem run the empty and you replace the fuel pump.
That is good enough statics for me.

But if you want book statics do a google search.
MT

I have worked on cars and trucks for over 45 years.
Some Big trucks had them 45 years ago in the tank and the had the same problem.
Run the tank empty and they were replacing the fuel pump.
I have watched cars and light trucks with them for 30 years.
Same problem run the empty and you replace the fuel pump.
That is good enough statics for me.

But if you want book statics do a google search.
MT

As I said Brother, it makes perfect sense. Clogged fuel filters and a host of other issues may also contribute. We'll probably never know.

Yes dirty filters and even bad wiring and ground to fuel pump..
The wiring is to a fuel pump is not very hevey.
Bad wirng can take out a fuel pump to.

If you know some people that always run there tank low before putting gas in.
Watch and see how many ful pumps they replace compared to people that keep a 1/4 tank or more of fuel in them.
MT.

Yes dirty filters and even bad wiring and ground to fuel pump..
The wiring is to a fuel pump is not very hevey.
Bad wirng can take out a fuel pump to.

If you know some people that always run there tank low before putting gas in.
Watch and see how many ful pumps they replace compared to people that keep a 1/4 tank or more of fuel in them.
MT.

Just as food for thought, I have owned 4 different Blazers/Jimmy's. An 89, a 93, and 2001 Blazers, and a 2000 Jimmy. Out of the 4, I have only 1 fuel Pump go bad, and that was on the 93. I have always run them to empty or near empty. My 89 had 200,000 miles on it with the original fuel pump when I sold it. Maybe I am just lucky. Routine maintenance goes along way.

It certainly makes sense to keep the tank 1/4 full if you want to discipline your self to do it. Factor in the wife and kids and it is a new ball game.:grinyes:

I have a lot of respect for you and anyone else that has twisted wrenches for that long. I have been doing it for 35+ years myself, but never did it for a living.:wink:

Thanks MT for all your contributions.