Randy V

Car would not start last night.

Battery good, engine turns well, just does not fire.

Tried swapping the fuel pump relay - no help.

No injector clicking noise, so don't suspect the LH.

The fuel pressure guage I had installed on the fuel rail stays at zero so it appears the fuel pump is not energizing.

Thoughts?

Thanks.

SeanR

Fuse, relay, crank position sensor or the fuel pump finally went out.

soontobered84

Randy,
All 3 of the LH's I have had rebuilt did not provide the ground to energize the fuel pump relay. Instead of using another relay, try jumpering the fuel pump at 30 and 87. I drove the Stepson to SITM with a jumper at the fuel pump, and it was fine, but I had an on/off switch inline so I could turn it off when stopped.

dr bob

Randy--

Got one of those siamesed jumper pigtail switches for the FP relay socket? Try that and see if the pump runs. That simple diagnostic cuts the available causes in half. If the pump runs with jumper, the problem is somewhere between the CPS and the FP relay, including the EZK and the LH. If the pump doesn't run, think connection in the battery well (one of the red aux wires on the battery plus post), the fuse/fuseholder, or the pump(s). Divide and conquer.

dr bob

...And I have a spare/loaner 013 LH box (full diagnistics) rebuilt on the shelf here if you need it to test. PM me and we'll work out logistics.

AO

If the injectors are not clicking, then it's not the fuel pump relay or fuel pump (but you may still want to check fuse #38 to be sure). I would look at the LH relay (XXV).

It may also be the EZK relay (XXII) because I think the CPS signal runs through the EZK first, and then to the LH. WIthout this signal the LH will not energize the fuel pump or run the injectors.

John Speake

Do you have spark ?

Randy V

Haven't checked spark yet - running down the fuel pump as it is not pressurizing the system. The fuel pressure guage comes in handy as a first-tier diagnostic tool.

Thanks for the suggestions so far, gents. I had to drop the car at my 928 mech as I needed to get into the office.

Jumpering 30 and 87 of the fuel pump relay did not get power to the pump. We do have power at the relay.

How would we test to determine if it is the security system imobilizing the ignition/fuel pump?

neilh

Randy, by 'power at the relay' do you mean the relay is energised, or that you have +12v at fuse 38? Jumpering 30 to 87 will give you 12v at the fuse, irrespective of any other condition, as its a feed directly from the battery, and the pumps should run.
WSM 97 page 479.

Tony

Fuse...same one that powers the O2 sensor. Have alook at that on the fuse chart. dont have one handy with me here on the beach

Randy V

Thanks, T - checked fuse 38 already and it looks good. Will do a continuity test on it to verify though.

neilh

Jumpering 30 to 87 on teh relay will give you 12v at the fuse, irrespective of any other condition, as its a feed directly from the battery, and the pumps should run.
When you check fuse contuinity, look for +12v from both ends of it to ground.

Randy V

Thanks, Neil - will check and verify.

Randy V

While I'm thinking of it what does 'LH' and 'EZK' stand for?

We toss the term around so frequently I don't recall what they are acronyms for.

BC

i have the hammer on loan right now, so its in San Diego