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Discussion Starter · #1 ·
What eaxctly is the stock fuel pressure supposed to be?
I have been driving around the last 2 days with my Guage connected.
At idle it stays at 32 Psi When I get on it then it jumps to 40Psi.

I know I need a new pump soon. When I shut it off all fuel pressure drops to Zero.

But I am chasing a problem with it running rich and Pinging when hot. When it is cold it runs strong. But drops off some and pings when hot.

The timing chain was done a couple of Months ago and is dead on. The balancer is good. I have to run Below 10 degrees on the timing to make the Pinging minimal.

I have more tests to do but wanted to get all the info I can about Fuel pressure.

Thanks for All Advise.
 

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I had the same problem a while back but mine would backfire and then just shut right down and it was the fuel pump. Not sure if this will help any but I figured I may as well let you know.
 

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Forgot to add this but my pressure before it got hot and started acting up was normally around 35psi
 

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Discussion Starter · #4 ·
Today I was finally able to hook my scanner up and read codes.
I pulled a 21 coolant temp sensor code
I also pulled a 34 EVP voltage which im not sure what it is.

In the next day or so I will buy a new coolant temp sensor and install and see if the code comes back.
 

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First, I can tell you your problem has nothing to do with Fuel Pressure. I don't recall what the spec is for it.

Your codes- EVP is "egr valve posistion". An egr valve not functioning properly will cause the engine to ping badly. Probably your problem. You may also have a carbon build up in the heads, which can raise compression and cause pinging, but this is less likely. Don't just replace the sensor, its more likely the valve itself or the passages in the TB being clogged. You'll have to check everything out to know for sure.

The ECT code probalby is the sensor- if its sending a lean signal to the PCM that too could cause pinging. Could be a combo of different problems. Once fixed you should be able to get 14-16 deg advance w/o pinging. Try prem gas, helps sometimes- its all I run.
 

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Discussion Starter · #6 ·
UPDATE:Installed Temp sensor today seems to run a little better but still pings some. Haven't had time to clear the code yet but will tomorrow. I am also going to run Valve cleaner through it and then take it from there.
 

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from what I have read...

Your fuel pressure should hold for at least 5 minutes after shut down If not you could have a leak somewhere. Maybe an injector leaking or the check valve in the pump or the pressure regulator. The pressure on my 95 gt is suppose to be between 35 and 40 psi the advise on the EGR is right on. It can cause a lot of trouble if clogged or if it has a gasket leak or is stuck open. Also I have read after installing new sensors don't just clear the codes but disconnect the battery for a few minutes to reset the computers memory so it can relearn from the new input signals it will be recieving. I don't remember where I got this but it seam to work well after my O2 sensor change a few weeks back
Hope this helps:wavey
 

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My fuel pressure holds for hours , sometimes longer.

Set to 40 psi with the vacuum disconnected and no further adjustment is needed.
 
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