Randy V

A few days ago when pulling out of my garage the car stumbled then stalled. It started up right away and all seemed fine.

Today after sitting in a parking lot (after a short drive) it refused to start. Turns over strong and no injector clicking noises.

I tried swapping the fuel pump relay with no success.

After waiting about 30 minutes for a flat bed I tried again and it started fine and ran smooth all the way home.

After shutting down in the garage car won't start now after sitting 40 an hour or so.

Any ideas what I should consider next?

Thanks.

Kevin in Atlanta

Last time you replaced the CPS?

worf928

History of engine speed sensor (aka CPS?)

polecat702

I just replaced my CPS, Hall Sensor, internal & external fuel pumps, lines and filter. Probably time for all 4 like my car. Plus I changed out all the 53 relays, cleaned all the grounds.

Randy V

Pretty much everything was replaced when GB did my stroker motor last October.

Car is now sitting in the driveway and once again won't start.

I can hear the fuel pump energize when the key is placed in position 2.

Mongo

Crank sensor is falling victim to heat soak. The fun part is getting the little f***er out.

Good luck!

Randy V

Both no-starts occurred when engine was cold. Pay attention grasshopper.

worf928

You are hearing the PSD pump.

If you are actually hearing the fuel pump with the key in 'run' then your LH has failed.

Randy V

OK, my mistake Dave - must be the PSD pump.

Appreciate you hanging in to help me get this resolved!

GregBBRD

Randy:

You're on the "24 hour a day call Greg anytime" plan....unlimited minutes!

Call my cell when stuff like this happens.

I haven't been spending as much time on Rennlist since Gretchen banned me and said I have absolutely nothing to "contribute to the 928 Forum". I figure he can answer all the technical questions from here on out!

Doubtful CPS....brand new Bosch sensor a few months ago. Extremely low failure part, when plastic is still in one piece (for about 10 years or so).

First step...check fuel pump function.

Fuel pump should run when the key is turned to the crank position. If you can get someone to turn the key, go stick your head at the rear right corner.....right where that chunk of metal that covers the fuel pump is located. Have someone "tick" the car into the start position quickly.....listen for the pump. If in doubt, remove that cover (2-10mm nuts) and put your hand on the actual pump while someone "ticks" the starter once. If the pump doesn't run (and you have the cover off), put your hand on it and see if it "twitches".

If it neither twitches nor runs, Check the fuel pump fuse...#38. If good, pull the fuel pump relay, grab a piece of wire, and jumper from "87" to "30". Key does not have to be on. Immediately check to see if the pump runs....if it is seized, that "jumper wire" can get hot and the fuse can blow. (There is still a fuse in line, so no danger of major electrical short.)

If the pump runs and sounds normal, leave the jumper in and crank the car to see if it will run.

Report back.

dr bob

Randy --

Fuel pump and LH get power via small wires that connect to the battery positive terminal. Verify that those connections are clean and tight.

Randy V

Much thanks, GB (F that spambotjackhole), and Bob - will dive in the morning and report back.

Much appreciation.

GregBBRD

Yell if you get confused/have questions. I don't carry my cell in the shop, so I sometimes won't see a call for hours....unless it rings while I'm walking by.

Call the shop, if I don't answer. I'll tell Mary to let you through....this should be easy to solve.

Randy V

I was out of town for the past few days so am just now tackling this. Of course, now the car is starting fine.

How can I troubleshoot the fuel pump if it is operating somewhat correctly? Will I be able to detect a failing pump by noise, or heat being generated from the failure?

Can anyone point me to a good thread that details the pump rtemoval procedure?

Here's where I'm at right now:

dr bob

The main pump is external to the tank on the bottom. Your picture shows the top cover for the return line and the level sender. Removing the outer pump is pretty simple, as you can squeeze the suction line from the tank to keep all the gas in there from falling out on the floor. For cars that include the in-tank pump too, you'll need to drain the tank completely before trying to extract it for replacement or even inspection.

[grits teeth as he suggests:] Connect a fuel pressure gauge to the rail and see when pressure comes up as you go through the start-up procedure. Leave it on as you shut the engine down and watch to see how and how long it takes for pressure to decay.

A simple sniff test of the vacuum hoses to FPR and dampers will give you a clue if they are leaking. Run the cold engine briefly, then immediately sniff the lines for fuel. MitiVac the diaphragms too to make sure they hold vacuum.