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1967 Mercury Cougar XR7
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So, we're still getting the lack of fuel at wot after warm up. There was a change after we installed the fpv, hasn't died on us yet.

Is there a method I can try to test for fuel vaporizing in the line? We're going to check for a clog in the fuel return line also.

There was a ridiculous amount of rust in the tank when we pick the car up. I flushed the supply line and didn't think to do the return........
You shouldn't have fuel 'vaporizing' in the lines on an EFI car, ever. But the fuel pump has a real problem pulling fuel if there's a restriction in the sock or anywhere else on the 'suction' side. It will burn itself up quickly if starved too, so that's a very serious consideration. It can push against significant blockage, but they don't suck well.

My thought is to clean out the tank and put a new sock on first! And completely flush all lines.
 

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1989/1991? 5.0
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10 Posts
Discussion Starter · #22 · (Edited)
Ok back at it again. Before I did anything with the fuel lines, pump, or anything with the fueling system, I took the car for a spin with the fuel pressure gauge hooked up. Also ran codes one more time.

For the codes:
KOEO.
o 85
c 18 and 96

KOER.
4
44
94

Experience during run:
Tach bounced every few minutes.
During tach bouncing the rear end felt like it wanted to lock up.
Did die once at stop light but instantly fired back up.

Fuel pressure held strong 100% percent of the time never dropping below 30 psi.
Just a slight pressure on the skinny petal when accelerating, pressure would go to 40 and I topped the pressure at around 43 psi.
Note: I did run with the fuel cap loose.
It's been about 30 minutes and the pressure is at 15 psi at the moment.

Editing again

Time the car again and set it as it should be. Set to 10* without spout. Dropped back a few degrees with spout installed.

Ran codes
KOER
4
46
6
64

In that order.
 

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713 Posts
94, 44, 46 are all smog pump/thermactor related. I dont think we've talked about these but they can all be ignored. I assume the previous owner yanked that stuff out.

85 is Canister purge failure, this is probably from the gas cap being off.

4 and 6 arent codes, curious what these should actually be, maybe 22 and 33?

The CEL should illuminate 4 times before all the tests run to let you know it is an 8 cylinder car, this could be the 4 you are picking up.

64 - Intake Air Temperature/Air Charge Temperature Circuit Grounded (O,CM,R) . This should trigger the CEL to be illuminated at all times the failure is present, one of the few that can do this.


Is this a stick car? what RPM is it bucking at? lugging or normal cruising rpm? Stock cam is pretty forgiving, i used to lug around at 1100rpm in 5th. My current cam doesn't like anything lower than 1500rpm at part throttle, maybe the previous owner through something in. If its occurring at an RPM higher than 1500rpm, disregard what i said.
 

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1989/1991? 5.0
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10 Posts
Discussion Starter · #24 ·
Automatic trans. Usually low rpms on the random bucking. Cruising around 1k

Checked the codes running again....
Koeo 85
Koer 94, 44, and 5

Sometimes the code reader will not show the number of cylinders. I'm using an Innova code reader.

Seriously considering pulling the engine and starting fresh. Complete rebuilding everything from the bottom up. At least it would allow me to feel like I'm getting somewhere with this.....
 
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