Someone accidentally put regular gas in my '02 z28

**Resa** · 04-06-2014, 08:29 PM

My husband tagged along on a work trip. He ran out of gas looking for a gas station. Roadside Assistance brought a gallon of regular gas. He thought surely he'd be able to make it from where he was to a gas station, but sadly he didnt make it more than 1/10 of a mile. Now, despite adding the right gas and changing the fuel filter, she won't run. Help?!?!

**Too Fast** · 04-07-2014, 02:54 AM

Burning regular gas won't hurt the car, but will somewhat affect the HP output.

How is the fuel pressure? Should be 58 psi or a bit higher with key on, engine off.

**pajeff02** · 04-07-2014, 02:58 AM

So called "regular gas" will not hurt anything. The PCM is loaded with both high and low octane spark tables and the engine has knock sensors that retard timing in the event detonation is detected. It sounds like the fuel pump may have fried and the first thing to do is check your fuel pressure at the rail. As posted, it should be 58 psi when you energize the ignition. If you have zero pressure, start by checking the fuse and fuel pump relay. If they are good, can you hear the pump run when you turn the key?

**jfl330** · 04-07-2014, 04:06 AM

Regular gas is not the issue, running the fuel pump dry may be the issue. It uses the gas to cool itself. As mentioned above, check fuel pump fuse and relay.
Also as mentioned above, can you hear the pump prime when you turn on the ignition?

**Resa** · 04-07-2014, 04:35 AM

Yes, you do hear the fuel pump prime when you start the engine. That's what is so frustrating. It sounds like it should run, but doesn't.

**SteveC** · 04-07-2014, 07:56 AM

Running the fuel pump dry is the culprit, you probably burned it out. The gasoline is actually the lubricant for the fuel pump.

In my mind, even the 91 octane gas is crap, reminds me of the "MOGAS" used while I was in the navy, in their pickup trucks.

Bring back the 100-103 octane gasoline, that's the ticket.

**cammed goat** · 04-07-2014, 04:46 PM

How often is the car ran with the fuel gauge in the red? I ask as repetetive driving with very little fuel will kill the fuel pump. I've never heard of a fuel pump dying after ONE trip drying up the tank.

**az gt eater** · 04-07-2014, 06:24 PM

How about sludge getting in the filter? Or is that a myth?

**2002ssslp** · 04-07-2014, 06:30 PM

What is you fuel pressure at the rail ? It should be between 55 and 60 psi

**pajeff02** · 04-08-2014, 02:46 AM

Originally Posted by az gt eater

How about sludge getting in the filter? Or is that a myth?

If the car often sits for extended periods with "old" gas in the tank, then sludge would be a possibility. However, it would most likely plug the pre-filter in the tank rather than the in line filter under the car.

**Guerrillakilla13** · 04-08-2014, 07:22 AM

I must opt for a bad fuel pump as well. On both my fbodies they either died on the road, or idled very weakly. Both refused to start.

**!!!FAST!!!** · 04-10-2014, 02:12 PM

Originally Posted by SteveC

Running the fuel pump dry is the culprit, you probably burned it out. The gasoline is actually the lubricant for the fuel pump.

In my mind, even the 91 octane gas is crap, reminds me of the "MOGAS" used while I was in the navy, in their pickup trucks.

Bring back the 100-103 octane gasoline, that's the ticket.

Ahh...MOGAS. All gone now, nothing but F-76 and JP-5. Convert to E-85. upwards of 105 octane.

**DaddySS** · 04-14-2014, 02:31 PM

I would invest in a fuel pressure tester and check the pressure at the rail as the first step.

**JayTA98** · 04-18-2014, 04:15 AM

Before you get more frustrated you need to check the fuel pressure at the fuel rail like the rest of the members have suggested. It should be around 58 psi. If you don't have 58 psi is either bad, clogged, leaking internally or not receiving enough voltage. Before you can determine any of this you need a fuel pressure reading.

If you have 58 psi at the fuel rail then your fuel pump is not causing the issue.

**JayTA98** · 04-18-2014, 04:19 AM

not to steal the OP thread but you guys are talking about different octanes. If I put regular in my car I get knocking sound under moderate to heavy acceleration. I put 91 most of the time and the noise is less. If I put 93 I don't notice the noise as much. Is this normal then?

**Too Fast** · 04-20-2014, 06:43 AM

You shouldn't here any knocking with 93 octane. Our normal OE tune is for 91 octane. If you are hearing some with 91 or especially 93, then you have a bad knock sensor(s), not sensing the knock, or it could be some carbon build up in the cylinder. Also, it could be from too much oil being burned/ingested, if you don't have a catch can. Seems I read that somewhere, maybe HP Pontiac, about some burst knock somebody had that a PCV catch can fixed. Or it could have been an out-of-calibrated air intake sensor, I can't remember exactly, but it was an LS1 Trans Am they were working on.

**JayTA98** · 04-20-2014, 08:54 AM

I have catch can and replaced the knock sensors when I upgraded to ls6 intake. I always heard the knocking since I own the car. Weird

**cammed goat** · 04-20-2014, 06:06 PM

What brand gas are you using?

**JayTA98** · 04-20-2014, 06:35 PM

Originally Posted by cammed goat

What brand gas are you using?

well it depends. I get mine mine lately at wawa but thru the years mostly BP, Hess, Racetrack and Mobil are most of the visit places

**cammed goat** · 04-20-2014, 06:42 PM

Keep using BP, and Mobil and keep us posted. Some no-brand stations could have water in their tanks and be pumping the fuel into cars without checking the tanks underground.