Quick question re: metering arm pressure

[tista]

Still chasing my hot start problems and before you ask, I've not pressure checked the system, and yes, I know I'm an idiot for not doing this.

Onto the simple question. When I shut the car off, if the metering arm moved freely upwards, right away, does that suggest a stuck piston in the FD? When the car is running the metering arm is resistant to movement and when forcibly moved, causes the engine to slow and then die.

I know there are many factors that go into fuel pressure maintenance when the car is shut down - I'm just trying to narrow things down as I've already replaced the check valve at the pump, the fuel pump itself and the Accumulator as well as cleaning and checking the WUR (though I admit it still may be the problem).

Thanks for any insight.

[boyt911sc]

Have you checked your residual fuel pressure? You replaced your FP check valve, FP, Fuel Accumulator, and WUR were they all defective? Your Primary Pressure Valve (PPV) located inside your fuel distributor could be leaking too. Test and verify.

Tony

[tista]

I've not tested any pressures - I replaced some old parts there were the more obvious and regular culprits in the hot no-start issue. I know you're a guru and I appreciate the question, and it's a no. Really just wanted the answer to the pressure on the arm vis-a-vis how that relates directly to the plunger on the FD. I'm pretty certain that if there was any fuel pressure remaining in the FD, the plunger would provide resistance to the metering arm. From what you're saying, the PPV is part of this conversation as well, even with the metering arm showing no resistance immediately after shutting the car down?

Thanks

Originally Posted by boyt911sc

Have you checked your residual fuel pressure? You replaced your FP check valve, FP, Fuel Accumulator, and WUR were they all defective? Your Primary Pressure Valve (PPV) located inside your fuel distributor could be leaking too. Test and verify.

Tony

[boyt911sc]

Originally Posted by tista

I've not tested any pressures - I replaced some old parts there were the more obvious and regular culprits in the hot no-start issue. I know you're a guru and I appreciate the question, and it's a no. Really just wanted the answer to the pressure on the arm vis-a-vis how that relates directly to the plunger on the FD. I'm pretty certain that if there was any fuel pressure remaining in the FD, the plunger would provide resistance to the metering arm. From what you're saying, the PPV is part of this conversation as well, even with the metering arm showing no resistance immediately after shutting the car down?

Thanks

Tista,

After shutdown of the motor, there will be resistance against the Sensor Plate Lever/Arm caused by the residual pressure of the control pressure. Take a visual inspection if the plunger is completely down and resting on the roller bearing (lever arm). So you replaced parts after parts without verifying those CIS parts to be defective?

So what is next to replace? WUR? FD? A pressure gauge tester is a mandatory tool for fuel injection troubleshooting other wise, you are just doing guess-work troubleshooting. Sometimes you get lucky but you can not rely on luck all the time.

Tony

[PeteKz]

Ditto what Tony said about throwing parts at the problem. Instead of troubleshooting, you have spent hundreds of dollars on stuff that was okay.

A CIS gauge set is under $100. Here's a general purpose FI test kit that is much more stuff than you need, but only costs about $50, and Jeff B will drop it at your door in a few days:

https://www.amazon.com/BETOOLL-Injection-Pressure-Tester-Gauge/dp/B01L17TPT2/?_encoding=UTF8&pd_rd_w=d2iuk&content-id=amzn1.sym.12c47663-8a7e-43d5-9c0a-9fb1870a90c3&pf_rd_p=12c47663-8a7e-43d5-9c0a-9fb1870a90c3&pf_rd_r=27XV8GNRHX34JTHNQ1TC&pd_rd_wg=5K81x&pd_rd_r=cc83501a-9969-49d6-91b5-1958e9a5676a&ref_=pd_hp_d_atf_dealz_cs&th=1

Next, warm restart problems generally are caused by loss of residual pressure (RP) before the engine has cooled down. When you get your gauge set you can see how long it holds RP. But a quick test consists of waiting 15 minutes or so after you shut off the engine, then crack open the line to or from the fuel filter. You should get a spurt of fuel of about a teaspoon or two. If you get no spurt, just some dripping, then you are losing RP too soon.

[tista]

Thanks guys - I've run from them pressure testing equipment long enough. I've order the S&G kit and watched the Joe Engineer video. I'm going to get to the bottom of this properly.