Hawkeyes

I replaced the dash & pod on my '89 S-4 last week and have not been able to start the shark since!!!

I have since gone over all the various connectors I pulled and reconnected, but cannot find anything that did not go back together the same way it came out. Oh, one exception - a thin (16ga?) brown and green wire with white insulator on female end that was in the 928 wiring bundle connected to the (aftermarket) CD/stereo. It did not appear to be connected to anything so I left it alone. On reinspection there is a bladed terminal as part of the sheet metal housing the AC/Heater. It's just under the console header, passenger side. I connected and disconnected it while trying to start, but made no difference.

I tested all the relays and fuses, especially EZK, LH, Relay X & Fuel Pump/O2, and all check out. I pulled and tested each one in the Horn relay spot. Also checked for 12v power at terminal 30 at each relay - all checked out.

The LH brain was rebuilt/upgraded by Rich A. 2 years ago - Rich told me he's had zero returns/failures.

The engine is getting good spark - I checked with a remote start & spare wire-to-ground.

Everything else on the car works fine - lights, doors, mirrors, horn, door dinger, stereo, locks, seats, hatch, sunroof...

The starter spins over fine but the engine will not fire up. I jumpered the fuel pump relay with a remote on/off switch & let it pump while spinning the starter. Still nothing.

I pulled a spark plug from each cylinder bank for a visual - they were wet, but did not smell heavily of fuel. In fact, there is virtually no fuel smell at the exhaust or under hood - makes me think that is the reason it's not firing? Gas tank is half-full & jumpered pump (used-from 928 International) is audible when I switch it on.

I thought it may have flooded from repeated attempts to start, so I switched off the fuel pump, held throttle to the floor & tried again. It didn't even fire once. Did the same with pump switched on...nothing.

I've been at this since Friday & have hit a brick wall - I hate the thought of trailering my shark to some leather-smocked Porsche doctor who will ask contemptuously whatever made me think I could fix my own car, then proceed to lighten my wallet by $1k or so!

But I'm fresh out of ideas...what am I missing?

Hawkeyes

ErnestSw

Sounds like the fuel has been cut off. Could be a crank sensor failure.

taffelman

You should check the fuel pressure to rule out the fuel pump before getting insane.

I had a similir no-start issue. Fuel pump sounded ok, but it did not pump fuel. To check, take of the big nut on the front end of the passenger side fuelrail, be careful not to loose the sealing pinball when taking the nut off, then connect a clear hose to the outlet and put in a container. Crank it and check if there is any fuel coming out. It should pump out about 0.35 gallons in 30 seconds.

This takes only a few minutes to check and will confirm if your fuelpump is good or bad.

Garth S

Check the ignition monitoring relay for lit red/green diodes: if activated, it cuts the injection pulse. Another check is to connect a noid light to any injector plug ... 'flashes' verify the injector is being pulsed. Loosen any one of the fuel lines to verify pressure at the rails.

Hawkeyes

Hi All,

Thanks to you guys I'm getting closer to a solution!

ErnestSw;
Checked crank sensor, it is OK & I'm getting good spark.

Garth;
Checked for lit diodes - none. I don't have a noid light, but I'm shopping for one now so I can check injector pulse.

Taffelman:
Great suggestion!
I did as you said and found that fuel flows at spec when fuel pump relay is jumpered. I then put a known good relay in the XX spot and spun the starter - no fuel flowing at all. Turned the ignition on & tried again - nothing.

OK, so now I know I've got good spark & the fuel pump works. I jumpered the fuel pump relay and again attempted to start the shark. Nothing. Then I sprayed a couple shots of MAF cleaner into the intake & cranked over the engine. It caught immediately, 'vrooom', then died. I tried the same with fuel pump relay toggled & then with a known good relay. Made no difference.

It will fire with the MAF cleaner fluid, but is not getting any fuel.

I pulled the alarm relay behind the glove compartment to make sure I hadn't broken something while reinstalling the dash - it was fine.

What in the world could I have done during the dash R&R that would cause shark to shut off fuel to the cylinders?

All suggestions/thoughts welcomed!

Hawkeyes

RngTrtl

Anti-theft device got disturbed and is disabling the fuel injectors? Just a thought.

Bill Ball

If it fires on MAF cleaner, then you know you have a fuel delivery issue. If you have jumpered the FP and it is delivering fuel, then that points to the injectors. I would do a LH brain swap despite the fact you have rebuilt one installed. The noid light would help in this regard as well. Prior to that, you could use a mechanic's stethoscope (or small dowel rod) on an injector body as the motor is cranked and see if you hear the injector solenoid click as it fires. I agree it's not the crank sensor. It's not the injection monitoring system, as that has a delay before it actuates, and it knocks out only 4 cylinders. However, in the outside chance it has gone bonkers, you can bypass it by pulling the plug to that relay and jumpering the pins 1 , 3 and 5 together on the plug. The antitheft relay plug behind the glovebox can be jumpered 15 to 87 to bypass that.

Hawkeyes

Thanks Bill. Progress to date...

Tested continuity on fuel pump circuit LH pin 20 to FPRelay 85) and the injector circuit (LH pin 21 to LHRelay 85).

Jumpered LH Relay 30 & 87, got 12v at LH pin 18.

LH pin 17 ground is good.

Checked voltage at injectors (this at Rich's suggestion). I'm getting .05 volts instead of 12.

Ah hah!

Rich suggested I trace circuit from LH pin 18 (where I'm getting 12 volts) to the injectors. Wiring schematics show a red/black wire from LH pin 18 to a 'welding point' (square box with #2 in it) that feeds eight red/black wires , one to each injector.

Now if I can just find that junction, I may have the solution at hand. Thought it may have been the T18 14 pin connector I 'refurbished', but no such luck. Probably something I jammed up when running the stereo wiring up the relay panel side.

News at 10...

Hawkeyes

Hawkeyes

OK, got 12v at injectors - resoldered 'weld'connection. Still wont start - no pulse at injectors, no fuel pump when turning over. WTH??? Rich coaching me thru it, one more test before throwing in the towel.

How come you guys didn't tell me what a BIAATCH these ****-built electrics are?

Hawkeyes

IcemanG17

What is it with bizzare no start-run problems lately!?!?!?!?!? Damm a bunch of us are going through it......at this point I would pull the LH and hopefully swap it into another car for testing.....of course the best thing to do is send it in to get tested and probably rebuilt....is anyone close to you?

John Speake

You may have 12v at injectors when they are not firing (not taking current) but there may still be a poor joint in the path that drops the voltage when the LH tries to fire them.

The injectors take about 6 amps.

marton

The only thing that I can think of that you could disturb when in the dash/pod area is an earth. But if the injectors have an earthing problem then I would expect there would be other problems at the same time

Marton

John Speake

The injectors are grounded by the LH ECU, so problem is likely to be on the feed side.

No fuel pump, and no injector signal shows that LH either has no power or is not receiving rpm pulses from the EZK.

Make sure you have a spark still, to verify EZK is OK.

Hawkeyes

John,

Thanks for the input.

I did as you suggested & yes, I do still have spark at engine rotation. At Rich's advice, the last testing on this circuit was performed as follows:

* verified 12 V at the fuel injectors with ignition turned on.
* plugged a Noid injector light into the injector socket
* unplugged EZK connector
* plugged one end of a jumper wire into EZK connector socket 35 (has constant 12 V )
* with ignition on, plugged the other side of the jumper wire into EZK connector socket 13

"This provides a 0 to 12 V transition to the LH & LH should provide one injection pulse (ground switch) for each time the jumper wire is plugged into EZK socket 13, i.e. Noid light should illuminate each time the wire is plugged in."

In my case there was nothing - no Noid light, nothing to indicate there was power between the connections. I repeated the test twice more with the same result.

So yesterday I pulled the LH & overnighted it to Rich at Electronik Repair for testing. If it has failed, it will be the first one to do so since he's been rebuilding them.

If it hasn't failed I'm REALLY at a loss determine root cause. It's weird - car ran great prior to shutdown for dash R&R. Fuel injectors were rebuilt at Phoenix Exotic MW in January, less than 2000 miles ago. Dan did a thorough inspection on the car at the same time - did over $4k in maintenance/repairs. I don't think he'd have missed anything obvious.

Anyway, thanks guys for the input. It's really helpful to know theres someone out there who's been through it.

Hawkeyes

John Speake

OK, what Rich suggested is intended to simulate an rpm pulse which is fed from the EZK to the LH. It is this signal that tells the LH that the engine is turning, and to energise the fuel pump relay and also of course to fire the injectors.

I assume you did confirm that there was 12v on pin 35 EZK.

One thought occurs to me - the rev counter is fed from that same signal, from EZK 13 (to pin 1 LH).
If you managed to short that signal to ground, or break the path, then this could explain why the dash R&R has caused this problem.

Try measuring continuity between pin 13 EZK and pin 1 LH (should be less that 1 ohm) . If that is OK, then try measuring the resistance Between that feed and chassis. It should be a high resistance (several k ohms).