I'm having some issues with my 2002 Camaro where it is hard to start, surges at idle, and bogs when any throttle is applied. I owned this car once before and bought it back from the person I sold it to in January. It drove great and made the 100 mile drive home without issue. It sat in my garage from then until this weekend while I did some maintenance like replacing the window motors and waited for the salt on the roads to wash away. I did let the battery die during this time because I didn't realize my tender got unplugged. It was hard to start today, which I attributed to the amount of time it had sat. It started after 3-4 tries and as I was letting it warm up and idle for a bit, I noticed that it started surging at idle a couple hundred RPM, up and down ever 3-5 seconds. I hopped in to drive it around the block and it seemed to hesitate a little bit under very light acceleration. If I gave it more throttle it bogged down and bucked. I decided to head back home, and the total trip was about 1 mile. As I was pulling it into the driveway which is on a grade, it died under throttle and it currently sits in that spot. It'll eventually start after 10-15 tries and kind of sputter and run roughly. Even the slightest amount of throttle results in it bucking and it will eventually die if the throttle persists.

It's an e85 car, has dual Walbro in-tank fuel pumps, an Aeromotive FPR, and 80lb/hr injectors. The gauge on the rails is reading 20-23 PSI while it's idling, I'm not sure if it's so low because of how low and rough the idle is or if the low fuel pressure is the cause, but I suspect that it's either going lean or rich with the throttle and dying. I dont have a scan tool. I tested the voltage on both sides of the fused leads powering the fuel pumps and they're over 12v. The pumps prime like I'd expect and run several seconds after it dies before eventually shutting off. Because my driveway is a fairly steep grade I can't roll it into the garage and I surely can't get it up onto ramps, so my access to the underside of the car is pretty limited. Visual inspection didn't reveal any loose hoses or wires. I did have a battery pack jump starter hooked to it last night to get some juice to the battery and then I put the battery tender on it. The tender said the batter was fully charged this morning, and the way the starter sounds when turning the ignition, it seems as though it has plenty of voltage to turn the engine over.

I'm a little perplexed because it was running perfectly the last time I drove it in January and the only work I've done to it didn't involve the engine bay, so I'm having a hard time determining what the issue may be. There were no check engine lights generated during any of this.

Any input is appreciated!

 

Sounds like the fuel pump is bad, sometimes that's just happens.

When the fuel pump in my Jetta went bad, it would drive normal until the turbo started making bodost, then the air pushing back against the fuel coming out of the injectors would overpower the fuel pump and it would stop accelerating. I put a new fuel pump in it and it was back to normal.

 

Based on the fuel pressure reading it does seem like fuel system may be involved, but it has two pumps in the tank, I figure even a single should be able to deliver sufficient fuel at idle while still under vacuum. Maybe something affecting both is going on, but again, they prime loudly as they always have and the voltage is fine. I can’t even make it close to boost, the lightest touch of the gas pedal and it starts to die.

 

whats the status on the filter?

 

The in-line filter? To be honest, not sure. I can’t get underneath it to access it right now.

 

yeah, it sounded like you were in a bit of a space predicament, I was just trying to think of anything that would restrict fuel flow to the injectors since you mentioned your PSI was in the 20's at the engine.

 

If I recall correctly it’s a 10an feed and factory return. Maybe I could put ramps behind the back wheels and let gravity roll it onto those to get access. But I’m not optimistic I could get it back off there for a tow if it came down to it - sigh. Just seems odd to me it drove perfectly when I brought it home and then now it’s choking.

appreciate the input so far!

 

After doing some more reading on low fuel pressure issues others have had, I thought it was worth mentioning that after the engine shuts off, the gauge on my Aeromotive fuel pressure regulator goes straight to zero PSI. It sounds like what should be happening is that some pressure remains in the rails for a period of time even after the engine stops. I haven't been able to watch what happens on the FPR gauge when someone turns the ignition to "on" and the pumps prime, but unless the engine is running the gauge is reading zero.

EDIT - I disassembled the regulator and the diaphragm still looks good. I setup my camera to record the FPR gauge when the pumps prime and when I attempt to start the car, and the fuel pressure gets to 19 or 20 PSI and that's it.

 

There's a tune/diagnostics forum for these issues.

 

Likely too late now, but I agree with you.

 

Sorry, that sub forum sounded to me like tuning, and diagnostics related to tuning. This was not tuning, so I did not put it there.

I got the car running again, turns out the fuel line in the tank that both pumps feed into ruptured somehow. I replaced the line and it started right up.

 

^^^ Good! You got it fixed!
Was the original hose made for immersion in fuel?
I've seen that hose failure when the hose that is not, will get soft and cause the blowout.

 

Based on the SAE code written on the side it was suitable for immersion. It's probably about 9 years old, so who knows. I'm going to investigate a better long term solution but for now it's running as expected.