HELP Fuel Pressure Issue? Need to fix this.

[g0thiac]

So the Caprice has been doing well since I had the electrical fuel pump installed.

The throttle response was amazing, and my MPG was great. Generally, my improvment experience was quite a surprise.

Then comes the heat of summer. And the vapor locking has me stalled in traffic 5 times now. So I did my research, and today decided to hook up the return line I left disconnected before, with a three way brass T fitting, which so far has no leaks.

To be double sure, I chose to wrap my hoses in foil, and the vapor lock I haven’t seen which is good.

But now I’m having the same problems again with acceleration, that I did with the mechanical pump. Not as bad, but still. As I can still slowly go up, and it will be fine.

However if I punch the gas, it instantly stalls.

I think it might be the sender unit tube for one of the lines.

Has anyone else experienced something like this? Thanks.

 

[g0thiac]

So I had to park the car, it’s become undrivable at this point. Can anyone tell me after watching this what you think? As you can see I tried to keep it going but it stalled.

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Last night I replaced the return line, long story but it has helped the idle. But it’s still falling flat.

My guess is, the cheap fuel pump needs to be thrown out and replaced, the screen is dirty in the sender unit, I kinda suspect also too though.

I hope it’s not a carburetor issue. Maybe too I wonder if it could be ignition related, because this usually is the worst on hot weather days.

 

[Clone TIE Pilot]

What type of carburetor are you using?

 

[ck80]

If you're concerned about how much fuel is actually making it all the way to the carb something like this would let you see:

Inline FP gauge

Lots of ways you could rig it up temporarily for a few test pulls that show what the pressure is when you experience the symptoms. If FP remains constant though during the symptom you can eliminate certain things one at a time

 

[g0thiac]

What type of carburetor are you using?

QJet, E4ME ver.

 

[g0thiac]

If you're concerned about how much fuel is actually making it all the way to the carb something like this would let you see:

Inline FP gauge

Lots of ways you could rig it up temporarily for a few test pulls that show what the pressure is when you experience the symptoms. If FP remains constant though during the symptom you can eliminate certain things one at a time

Good point, is there any specific place I should add it? My fuel pump is installed near the fuel tank.

Or can I just have it next to the carb for quick access? As for sure I need to monitor that.

 

[ck80]

Good point, is there any specific place I should add it? My fuel pump is installed near the fuel tank.

Or can I just have it next to the carb for quick access? As for sure I need to monitor that.

Well, here's the thing. I wouldn't leave it in. Just like the see through fuel filters, I think any item that splits a fuel line and goes to the heat underhood is too much of a long term hazard.

BUT

I do think the devices have their place for diagnostic purposes. For example, not sure what you're running for fuel line from the fuel rail at frame up to carb. If any of it was rubber you could make a TEMPORARY extension with slow gradual loop that ran to this thing, then back down to carb. Then you could mount it somewhere again, TEMPORARY, that is visible from inside car (clamped to edge of hood?) So when it acted up you could see the numbers of what's going on.

But, if you have crud in the tank you've got crud in the tank. I'd think your fuel filter would show that though as some junk should make it past the sock and pump if that were the case.

 

[Clone TIE Pilot]

An in tank fuel pump is the most ideal setup. Besides fuel pump issues it could also be sticky needle valve or faulty accel pump. Push the accel pump stem down by hand and release, it should snap right back up without any delays.

 

[g0thiac]

Thank you guys for the help so far. I will keep updating, as I do the necessary work going forward haha.

 

[Clone TIE Pilot]

If you are still running CCC you probably want to look at the air fuel mixture dwell with either a analog dwell meter or a OBD1 scanner like the Alltest Brainmaster.