Driving home from work last week, I stopped for gas, then got back on the highway. I went about 2 miles and it cut out on me. If I eased off the gas, it would keep running, if I added throttle, it would cut out. I feathered the throttle -losing speed, and babied it to a truck chain up area at the mouth of Parley's canyon. I barely...and I mean BARELY made it off the highway and into the chain up area before it died completely.

The fears of Aklim and other forum members was realized! My Optic-Car "left me stranded on the side of the highway"! My life was in danger! Do I regret having an OPTI? Did the opti endanger my life? Was the opti even the problem??


No, it wasn't/didn't. The tach never wavered, as my car cut out and slowed to a stop. Opti was good, and still is. So what cause the cut out? Well, it acted like it was losing fuel. I got out and opened the hood, removed the cap on my fuel rail Schrader valve, pushed the valve and got about a table spoon full of fuel, and then some hot air. Huh. I reached in the car, cycled the key (to run the pump) and then pressed the Schrader valve again...nothing. Well, had to be the pump. Right?

Called my wife, she brought the Duramax and a strap, but took her 2 hours to get to me b/c she was busy. By the time she got there, car fired right up and ran fine. I drove it home. WTF?

When I got home, I checked the plug at the fuel tank, looked fine. Un plugged, plugged back in a few times. I there a gauge on it, took it for a drive, 41-47 PSI. Spec. So, I threw my scan tool in it, and left the pressure gauge hooked up and resumed driving/commuting with it. Today, I was out running errands with it, and I pulled into a place, shut it off. When I came out, it fired right up, then sagged to a LOW RPM, then recovered. Weird. I put it in reverse, started to let out the clutch and it almost died on me. DIdn't want to go. I messed around with it in the parking log for a minute and then it wouldn't do anything other than idle. I Set the brake, got out and opened the hood, looked at my gauge and is read 12 PSI. Huh. I shut it down, opened the drain on the gauge and got maybe 1/2 cup of gas, then a bunch of warm air. It puffed air for so long, we went to the rear, opened the gas cap to see if the tank was pressurized (it wasn't) and went back to the front of the car...it was still hissing out air. When done, I closed the valve, cycled the key again and got 10 lbs. I started it, and still, only 10 lbs. I waited there for about 1/2 hour, then cycled the key and saw 5,10,...15, before the pump shut off. Huh. I cycled it again and 10,....20, 30, 40 "click". Hot damn...I'm back in action! I fired it up and it ran all the way home, 41-47 PSI.


I GUESS I need a fuel pump...hut WTC does sitting have to do w/the pump working, or not!? It never stopped working...it would always run and build some pressure. I have to say...this is one I've never seen before. Kooky.

 

I would take a look at the screen on the pump and any debris in the tank. Also have a look at the pulser or the by-pass to make sure it is in tack.
If you had a cracked or broken rubber line you would probably be smelling gas.

 

Yeah...I'll look at it all when I pull the pump. The symptoms aren't weird....it's that they go away. That's freakin' WEIRD.

 

Any chance its siphoning from the return line when the pump turns off?

 

Cardo called. He said you have a vacuum leak in your Opti..........

 

What's up with this Cardo guy? He was heckling me in another thread

 

IDK what is up w/him. I feel that he used to be a pretty good contributor, but lately, he's been a PITA. Just an argumentative dude, lately. Ask him to run a test to show his point...he won't do it, just wants to argue and call names more. Probably a good guy but maybe has **** going on? IDK.



LOL! That was funny. I'll have to runs some diagnostics on my 12v "opti-vac".



.

 

Hello there Tom400CFI,

That sounds pretty strange, have you figured out where the air is coming from? Is it even possible to "pull air" into a pressurized fuel system? The only way I can think of would be if the tank was low on fuel and it gulped a bit of air here and there.

I would also check the Fuel Pump Relay to see if it has anything to do with it. But the pump being under fuel would not have any way of sucking air into the closed system, Same goes for the pulsator. Is your fuel system stock or have you modified it?

Do you think that getting the gas might have had something to do with it? How low was the fuel when you filled it up?

We will all have to mull this one over, you have a challenging issue there, that is for sure.

Please enlighten us when you do make the discovery of the source of this problem! Having the scanner running should help. My old Laptop backup used to monitor the engine continuously and when the problem occurred you simply pushed the space bar to record 10 minutes before up to the actual problem occurring.

Best regards,
Chris

 

So i had this crazy thing happen to me a few weeks ago.
Car was going fine down the freeway, then i start loosing power.
I keep going as long as i feathered the pedal, then randomly it gets better, so i go on my way.

I stop to get the car alignment done for the final time, all is fine.

I get back into the car to head into the office for a little bit, right before i pull off of the freeway it acts up again.
It's running rough, but still running.
I pull into the parking lot and the car dies, i coast into a parking spot.
The car won't restart.

I head into the office, get some stuff done and head back to the car and it won't start.
I have a fuel pressure gauge on my aremotive regulator but it's toast (new one in a box at home) so I'm blind.
I have had issues with the regulator before where i don't get pressure rise so i tap it with a pair of pliers and try it again.

Sucess!!!

I head home and the car barely made it.
I stop at a light and it dies, i jump out and tap on the regulator and it fires back up.
I do this a few more times before i get home.

I think i need to rebuild the regulator, no problem i have the parts on hand!
I rebuild the regulator, install the new pressure gauge, and fire up the car.

Idle I'm @12psi, i should be like 15-16 (cfi).
I disconnect the vac line expecting to see ut go over 22psi, but it holds steady at 12.
I think no way, i install a different pressure gauge, same thing.
I pull the regulator apart thinking i f'd up, it looks great.
So i think i have a bad pump.
I order a new unit, and a few days later i install it.

What i found made me slap my forehead.
The little hose between the pump and the strainer came off just enough where i got some pressure.
Failure point, oem style plastic clamp/clip.

I installed the new pump since it was an upgrade, and used the supplied metal clamps!

What i don't get is why tapping the regulator worked...

 

Man...your symptoms sound just like mine. I don't know:

How air got in my rails/lines
Why sitting and waiting has "worked"


Ctmccloskey, Fuel system is box-stock. I'll be interested to see what I find when I pull the pump. As for pump sucking air, first failure was right after topping off w/fuel. Second (yesterday), it was still near full. Relay is working; every time I cycle the key, pump does run...just doesn't always build 40 lbs.

 

Can a torn FPR diaphragm allow air to enter from the vac tube?

 

^Not very well. Pressure in the fuel rail should almost always be higher than the pressure in the intake side of the regulator. I think I may have found the problem. Anyone else have issues what what you see below?

 

Turns out I had the pulsator fail a few weeks ago on a brand new unit. See thread here https://www.corvetteforum.com/forums...r-failure.html
Somehow the symptoms were similar to yours except it didn't start back after sitting.
The consensus is to replace this POS with some submersible fuel hose... I replaced the pump with a new Bosch unit that comes with the proper hose and my fuel pressure now holds well after key off.

 

Neat, pretty much the same problem i had but mine being with the hose.

Submersible fuel line is a pita to source and expensive.
I have a very short piece left over, it's used but i think it will be too short to replace that parts void.

 

I just move the pump back into alignment with the pulsator, straightening everything out, then bent the pump brackets so that they'd hold the pump proper/square with the pulsator. Been running perfect ever since. Oh, I put a new pick up screen on since I was there, but the old one wasn't causing any issues.