New Overheating Issue and Growing Laundry list of Frustration

[Boxbot]

So today, the car didn't want to rev when cold. If I pushed the gas pedal, the revs dropped and it threatened to stall. Stayed that way until the temp gauge moved off the bottom. Felt like the car had bananas in the tailpipe. What is causing this now?!

[David T]

I would put the fuel pressure gauge on and watch the control pressure as the car warms up. If ti is not within specs the CPR needs to be rebuilt. This is assuming the car runs OK once it warms up. The CPR acts like a choke on a carburetor. It richens the A/F mixture till the motor warms up to make the car drivable.

[Boxbot]

I would put the fuel pressure gauge on and watch the control pressure as the car warms up. If ti is not within specs the CPR needs to be rebuilt. This is assuming the car runs OK once it warms up. The CPR acts like a choke on a carburetor. It richens the A/F mixture till the motor warms up to make the car drivable.

Car does run ok as soon as it starts to warm up (when needle moves even slightly off the bottom mark) but then the lack of throttle is replaced with a noticeable idle hunt that I didn't have previously surging from 600 RPM to about 1,000 RPM, causing the oil press and battery to drop as well - whether or not the A/C is on. Related issue or 2 different issues?

[David T]

Surging (once the idle system activates and the ECU goes into "closed loop") is a sign of vacuum leaks and/or a sticky/dirty idle motor. Can also be a sign of dirty injectors and time for a tune-up. Again, if you are having issues during warm-up it is usually the CPR. From your comments it sounds like you need a tune-up and a rebuilt CPR.

[Boxbot]

Surging (once the idle system activates and the ECU goes into "closed loop") is a sign of vacuum leaks and/or a sticky/dirty idle motor. Can also be a sign of dirty injectors and time for a tune-up. Again, if you are having issues during warm-up it is usually the CPR. From your comments it sounds like you need a tune-up and a rebuilt CPR.

Shop pulled and examined the CPR and say it is in good shape. They diagnosed the fuel pressure as being too high and are trying to diagnose.

[David T]

If the Primary Pressure is too high it is either a restricted return line or the Primary Pressure Regulator needs to be adjusted. Once the shop can get that set they should recheck the Control Pressure, watching it as the motor warms up, making sure it is within spec.

[opethmike]

If the Primary Pressure is too high it is either a restricted return line or the Primary Pressure Regulator needs to be adjusted. Once the shop can get that set they should recheck the Control Pressure, watching it as the motor warms up, making sure it is within spec.

*eats Dave*

[Boxbot]

Return line is clear. Pressure is still too high. Recommended they look at primary pressure regulator per your comments. Any other known culprits?

[Bitsyncmaster]

Return line is clear. Pressure is still too high. Recommended they look at primary pressure regulator per your comments. Any other known culprits?

What pressure are they reading? I wonder if they hooked up the gauge correctly. It is pretty easy to pull the return hose from the pump and see if any fuel is returning.

[Boxbot]

450 Kpa.