Chasing my tail with starting issue 88 3.2 - Page 2

wazzz · wazzz's Garage

Yes the diaphragm can become porous with time and leak fuel. You should also check the pressure damper on the other side. It can also let some fuel go thru its diaphragm. This can create a warm start issue I was told.

Will follow your CV boot replacement. Also need to do the four of them on my 88.

FA-18C · 03-30-2022, 08:11 AM

Wazz - not currently having a warm start issue, and in checking the vaccum fittings, that side was bone dry...so fingers crossed because there are no good options that don't push $600 for replacement.

On the CVs, my D side was done last fall by PO, I bought the P side from place that had them in stock..ahem. With stub axle. Right now I am expecting that if I can get the axle nut and CV bolts off without drama, that this should not be horrible. It is really just 7 bolts and a nut, cleaning up etc... What could possibly go wrong.

I think we should have an 87-89 page to cover things that are unique to the G50 3.2s...this is one, I almost bought the CV without the stub axle...

FA-18C · 04-16-2022, 02:53 AM

Overcome by general spring clean up and business, but did finish installing FPR, and once I received my fan housing and fan back from powder and cerakoting, installed new alternator. Got rid of howl from alternator bearings going out...and the car starts so much better.

As a side, it appears the FPR was seeping fuel into vacuum, with that addressed, smoke is considerably less on start (actually is likely condensation at this point). Given the FPR was bad from sitting, I have to assume the damper is likely not in tip top condition as well. Just choking on the $500 price tag.

Any alternative options out there with any success? A damper install would round out the fuel system - pump, check valve, filter, engine hoses, injectors, pressure regulator, all sensors, wires, cap & rotor, plugs, vacuum fittings...

boyt911sc · boyt911sc's Garage

Chris,

Do you have a pressure gauge kit? I read this thread from start to end and never saw anything about your fuel pressures (residual and control)? Did you perform a residual pressure test for the FP check valve? Have you done a test to locate sources of unmetered air?

Why was the FPR replaced? What was wrong with it? Test and confirm they are defective before replacing part/s. Keep us posted.

Tony

FA-18C · 04-16-2022, 04:05 AM

Tony, on another post I addressed loss of pressure requiring cranking. Came up with fuel pump, and bled off. Check valve helped some, but fuel in vacuum line at FPR was evident. Huge difference after changing out.

boyt911sc · boyt911sc's Garage

Quote:

Originally Posted by FA-18C

Tony, on another post I addressed loss of pressure requiring cranking. Came up with fuel pump, and bled off. Check valve helped some, but fuel in vacuum line at FPR was evident. Huge difference after changing out.

Connect a pressure gauge at the test port and test run the FP. What are your control and residual pressures? Do you know how to test run the FP without running the motor? This a basic test procedure you should know by now. Keep us posted.

Tony

FA-18C · 04-16-2022, 08:35 AM

Tony, as I said, yes I know how to do that, and fuel pressure from fuel pump not cranking is 35-37, once started it is around 30 ish. Residual was the issue creating hard start. It would bleed off from 30 to almost nothing very quickly, minutes. Check valve addressed that to an extent, after 20 min it was about 12psi. In the process of looking for vacuum leaks found that the FPR was allowing gas into the vacuum line. So I replaced the FPR. Starts really well now, good idle. I bought the car after it had been laid up for 10+ years, so am pondering the lifespan of the damper.

Residual now is around 15-17psi.

boyt911sc · boyt911sc's Garage

Quote:

Originally Posted by FA-18C

Residual now is around 15-17psi.

Residual pressure is determined from P1 (initial fuel pressure) to P2 (residual pressure) under a certain period of time (mins.). How long (mins.) after the FP has stopped 15~17 psi. was observed? 10 mins.? 15 mins.? 20 mins.? Keep us posted.

Tony

FA-18C · 04-16-2022, 10:37 AM

~20 minutes. I am waiting for a fitting and am going to install an oil filled fuel pressure gauge and mount in the engine bay over a weekend and capture some data under different timeframes. Starts on first crank now, and if I run an errand and hop back in the car within 15-20 minutes, starts at the key turn (partial crank - if that makes sense). Cold start in the morning usually 1 - 2 potatoes, but no stumbling as if fuel starved which was an issue before. And the FPR vacuum is clear - no fuel.

Starting well and running solid right now, so have shifted focus to replacement of CV axle. Need to get a couple of tools to support (socket for axle bolt), and figure out fluid change in G50. Then I need to decide if I want to brave installing a premuffler when I do my oil return tubes. And will have to make the decision on if I want to remove the heat exchangers and refresh that hardware...or not.

At some point in the future I hope to get up to one of your rebuilding course to educate myself better in prep for future decisions. Working on this car is my therapy, and often find myself doing things because I want to, rather than the absolute need.

scarceller · scarceller's Garage

With engine running test FP, at idle it needs to be 30-32PSI then still at idle remove the vacuum line from the FPR and the pressure must increase to 36-38PSI.

Then attach a hose to the fuel test port and put other end of hose in 1 gallon milk jug, then hot wire the FP fuse with engine off, this will run the pump. Run the pump for exactly 1 minute and you must have more than 1/2 gallon in the jug. A healthy 3.2L pump will fill the jug to 3/4 gallon. This is a fuel delivery rate test and can fail if the screen in the tank is blocked.

FA-18C · 04-19-2022, 05:14 PM

Thanks Sal - I think that between changing out the fuel pump check valve, FPR and my fuel tank strainer that I have sorted my fuel system. Fuel pressures as previously stated are consistent with your numbers and the tech manual charts. My residual after 20 min. varies from 12-15psi the last couple of checks. The pump has 2K miles on it, and I replaced the fuel filter 300 miles ago. After I tackle some other items may check the volume.

I have read a LOT of your posts, and am thankful for your detailed info. I am reviewing the various options for a wide band O2 sensor and AF gage, but want to stay analog. This will be a late summer project based on some other priorities right now. I suspect I am still running a tad bit rich and look forward to dialing in...