Engine quits after 7 minutes

[kieranod1]

Thank you Paul, I will try this out this evening and let you know. Again thanks for the help!

[kieranod1]

Hi Paul, just returned from the shop. I followed your procedure and I'm showing 7.1 on the meter and 60psi on the fuel pressure. Could there be something else going on?

[Paul Workman]

Originally Posted by kieranod1

Hi Paul, just returned from the shop. I followed your procedure and I'm showing 7.1 on the meter and 60psi on the fuel pressure. Could there be something else going on?

The current reading, tho close to the low parameter, is a bit lower than I'd like. I'd want to investigate the pumps individually - just for grins...

So, to check the pumps individually, pull the fuse for one of the pumps (either one) and measure the individual current draw (the current draw is additive so subtracting the draw of one from the total will give you the draw for the other).

FUEL-AIR-SPARK! Something is missing...

So, if the fuel pressure remains at 45 ? when the engine quits, then my suggestion is to conduct your own dynamic scan (to record "before & after" data), or employ a shop with the scanning ability - as the logical way to "cut to the chase".

(My scanner (AutoXray) does have the capability described, but is no longer available. However, there are some shops with OBD-I scanning ability, AND Dominic or Marc or Pete and others can suggest software and a tablet, etc. to set you up to scan you Z. (Money spent fort the capability to perform static and dynamic monitoring is well worth every penny!).

[kieranod1]

Hi Paul, just came from the workshop, I started the Z and pulled the FP1 fuse and she kept running. Both pumps are new so I'm wondering if the relay may be faulty but I can't find the location in the shop manual, can you help or am I on the wrong track?

[max76]

Originally Posted by kieranod1

Hi Paul, just came from the workshop, I started the Z and pulled the FP1 fuse and she kept running. Both pumps are new so I'm wondering if the relay may be faulty but I can't find the location in the shop manual, can you help or am I on the wrong track?

Do you check mthe yellow connector above fuel pump assembly?

[A26B]

Originally Posted by kieranod1

Hi Paul, just came from the workshop, I started the Z and pulled the FP1 fuse and she kept running. Both pumps are new so I'm wondering if the relay may be faulty but I can't find the location in the shop manual, can you help or am I on the wrong track?

If the engine is cold, the engine will continue to run on the Secondary Pump, until the engine warms up to 160~170F ( I have forgotten the exact temp). Then, the secondary pump will shut down. What you did, only proves the Secondary Pump is working. It does nothing to verify the Primary Pump.

So, at cold start, if you either (1) let it continue to run with the FP1 fuse removed, until the Secondary Pump shuts down automatically, or (2) pull only the FP2 fuse, you can determine whether the Primary Fuel Pump is functioning properly. Engine dies, Primary Pump is not functioning properly.

You have been advised previously to test each individual pump separately with a fuel pressure gauge at the rail, key on, engine off & monitor leakdown for a couple of minutes.. Testing fuel pressure with both pumps operating together when the engine is cold will only tell you that at least one pump is functioning.

[LGAFF]

I think at this point i would be pulling and replacing 2 pumps ?for the 125 bucks and 25 minutes it would be worth it

[kieranod1]

To all you guys out there, I'm sorry for doubting you! You were right, my new #1
fuel pump had failed. I have it on the bench now and just need to source a new one, any recommendations? Thanks for all your help this, is a cool website and you guys are the pro's.

[tpepmeie]

Originally Posted by A26B

If the engine is cold, the engine will continue to run on the Secondary Pump, until the engine warms up to 160~170F ( I have forgotten the exact temp). Then, the secondary pump will shut down. What you did, only proves the Secondary Pump is working. It does nothing to verify the Primary Pump.

The primary pump will shut off at 80C, or about 177F coolant temp. (It's not time limited, per se, but the OP said about 7 mins, which could coincide with the engine warm up time to 80C).

Also, merely having the Full Power key on does not signal the 2nd pump to turn on. After the warmup period, the 2nd pump is commanded on at a certain "relative fuel demand", ie high engine load.

I am convinced there is a failure of the primary pump, or that circuit.

updated: Looks like our posts crossed, I see you have diagnosed the problem.

[dredgeguy]

Originally Posted by kieranod1

To all you guys out there, I'm sorry for doubting you! You were right, my new #1
fuel pump had failed. I have it on the bench now and just need to source a new one, any recommendations? Thanks for all your help this, is a cool website and you guys are the pro's.

RockAutoP-240KC
https://www.rockauto.com/en/parts/pe...fuel+pump,6256