CoachTom

New to me: 1986.5 Engine: M28/43 5-Speed

What started out as a vacuum repair has resulted in an engine no start condition.

I have also spent a day reading old posts trying to see where the disconnect might be, but no answers.

The car was running as well as could be prior to maintenance.
Issue: Brake booster vacuum tee broken off to HVAC/ Cruise/ Accumulator AND engine forward short fuel line was bulging needing to be replaced.

What was "touched" in the repair:
- Brake booster tee and gasket/bushing replaced. One way valve and vacuum lines re-attached correctly.
- (4) fuel lines replaced. So, engine fuel depressurized on engine and drained at "replacement" connections.
- 7-way vacuum connector replaced as the intake connection to the Throttle Valve (large vacuum line) was rotted not connected at the 7-way. New 7-way installed and vacuum lines connections validated, correctly installed per the WSM.
- All spark plugs replaced
- All engine ground points cleaned and additional points firewall forward, Dremel brass brushed, "DeOxit" sprayed, then after assembly coated with "CorrosionX". 14 pin connector also cleaned, but looked good before removal.

After finishing, I didn't know if I had to bleed the fuel system. When the ignition key was turned on, I did not hear the fuel pump running. I did not turn over engine, but went and removed fuel pump relay (XX) and jumpered. The fuel pump ran continuously and I heard fuel travelling through the "fuel cooler". I didn't hear it circulating fuel anywhere else, only at the back of the engine.

Then, engine would not start with Fuel Relay reinstalled, or if removed and jumpered with fuel pump buzzing. The tach would bounce up to 3K as the engine rotated.

Additional conditions: O2 sensor not installed. No port on Cat or wire seen to even connect the O2 sensor to,
No sputter, no fuel smell in the exhaust of being flooded.

Have not tried starting fluid, pulling a plug to see if wet, or timing light/spark check of ignition.

Any additional steps and all help greatly appreciated....


V/R

Tom

Leon Speed

Ok, try to start it, pull a plug to see if it is wet. I bet the plug will be wet and your issue is electrical, something was disturbed during ground point /14 pin connector cleaning.

John Speake

Check for spark..... everything else is dependant of the EZ-F working correctly.

76FJ55

I assume the engine cranks but doesn't start.

jumper the EZF, LH and Fuel pump relays try again, and let us kow what happens.

Vincent C.

check the plug for the crank sensor....vinnie

auzivision

This is where I would concentrate my efforts first since it worked before and not after messing with them.

The engine needs to be grounded real good for the injectors to fire. Stray resistance can cause unusual problems.

The 14 pin is like voodoo magic with the wires contained therein looking good on the outside and corroded on the inside. Might try wiggling harness gently while cranking and see if it fires. IIRC the plug itself is pretty good, but the wires leading into it are finicky.

auzivision

Yes, this test is too easy not to perform. Taking note of your low post count, following is a quick and easy way to check... just FYI.

It's as simple as pulling a plug, reconnecting the wire and lying it on the shock tower nut (don't hold)... then jump in car and crank... the spark should be visible from the drivers seat while peaking under the hood.

I stand corrected. I'd probably checkspark first before crawling under to redo the engine ground down under second. Maybe I'm just a siss... but to me messing with the 14 pin is just asking for it.

Also, if I'm not mistaken, if the tach needle bounces while cranking the CPS is ok... I'm sure other can confirm.

76FJ55

The ground connections would be good to verify. I don't think you need to concentrate on the 14 pin though. The only critical in it for getting an engine to start and run is the one that goes to the starter itself. If the engine cranks, then the 14 pin is good enough to get it running. All the power for the engine management comes direct from the battery on the two small lines from the positive post, and goes through the relays I mentioned earlier. If you jumper these relays the engine management is essentially a standalone system.

CoachTom

Thanks for the roadmap...
Yes, engine cranks, but will not fire.
Tonight when i get to car, i will check spark as suggested.
Crank Position Sensor is firmly connected and i used Safety Wire to cross connect it to insure it did not disconnect as it was struggling to stay in its bracket.

How i would check the ground? All of the connections were cleaned mechanically, then used "DeOxit" on them, tightened, then sprayed with anti corrosion. The engine cranks, so the main ground i cleaned is good as well as the battery ground i cleaned as well. This ground issue has me baffled as to how it works for high amperage, but could not at low amps.

Could anyone tell me which pins i would need to shunt for bypassing or jumpering the EZF and LH?

Now that the vacuum is repaired, could that affect the ECF as it probably wasn't getting a vacuum sense due to the 7-way not being connected?

Any idea where the O2 sensor wiring get connected to?

Will report back later!

Thanks,
Tom

CoachTom

No run on Ether.
Tachometer rotates to 3000 and then steadies at a few hundred during crank.
Fuel pump did not run with key on or when cranking.
Fuel pump jumpered, fuel heard travelling through piping at back of engine in fuel cooler.
Fuel will come out at front hose which was recently replaced when its connection to Fuel Damper is loosened. I do not know pressure.

Spark plug on shock tower, very weak spark. fired every second. sort of a yellow/brown spark, not a bright blue snapping spark. Spark plug appeared to be dry, not wet from flooding.

All engine grounds rechecked. All tight, sparkly clean, and wires tight in their looms. I also cleaned the positive jumper post connections by the 14 way junction. All clean and sparkly now. New battery, battery ground cleaned and shiny.

I took fuel relay apart, inside looked brand new as if never used. No pitting or arcing remnants on contacts.
Prior to starts, i had 12.5 volts on the jumper post. I attached a starting charger to the battery and had over 13 volts for cranking.

Where to now? I am at a loss as the engine ran before... Weak spark, fuel pump not cycling.

Mrmerlin

.remove the coil wires and inspect them for corrosion,
also make sure that wires are not touching any metal along their run.
If you have not already done so it might be a good idea to swap in a new crank position sensor tying it with mechanics wire may have damaged the connector

76FJ55

EZF relay is XVI
Fual pump relay is XX
LH relay is XXV
To jump (bypass) the relay; remove the relay and place a jumper wire between pin 30 and 87 in the CE panel.

the grounds for the EZF are just above the CE panel, it may be worth claening them if you haven't already.

928mac

I cant believe no one said it yet.

you have to keep those vacuum repair guys away from your car. lol

sorry, could not resist. good luck with your repairs.

CoachTom

No joy...

Jumpered: EZF relay,Fuel pump relay, and LH relay. no start, sputter, or kick.

Air, fuel, spark:

- I covered the MAF intake with my hand as the engine cranked and my hand was stuck to the intake: plenty of suction or "air".

- I cracked the lines at the end of the fuel rail passenger side and fuel was leaking, cracked the line on the regulator up front connected to the dampener, fuel comes out. With fuel pump relay jumpered, pump buzzes and fuel is heard circulating in back of engine.

- Plug pulled and spark seen. not bright blue or with any snapping, but still a white/ yellow color, enough so that it should ignite.

Still no run... even with a shot of Ether.

I checked grounds: engine, front of engine, back of engine, and the grounds on the CE are clean and good. I also grounded engine with jumper cables to insure ground.
The two ignition controllers in front of the radiator are clean and connections tight.
At the coils, both leads have battery voltage.
All new spark plugs replaced one at a time so no mix up o wiring.
CPS connection tight and good.

For the life of me, i cannot understand the issue with this non start or to even get a sputter...

Anomaly: fuel pump does not run with starter engaged, only when jumpered. No fuel pressure known, no guage installed.

Help?

Tom
1986.5 M28/43 5-Speed

John Speake

The fuel pump does not run until the engine is cranking and the EZ-F ECU puts out a 12v square wave at 2x engine rpm on pin 1 of the LH ECU.

The behaviour of the rev counter isn't typical, I think this is indicative of a problem with EZ-F system. Are you quite sure all the grounds are connected ?

Try disconnecting the LH ECU plug, with a DVM on ohms, check that pin 5 and pin 25 are a good low resistance short to chassis. Then connect a DVM on a.c. volts from pin 1 to ground pin 25, crank the engine and you should see something like 4v a.c volts depending on the response time of the meter.

I've attached a diagram of the LH 25 way plug, courtesy of Porken.

It would also be useful to confirm a good ground connection for the EZ-F ECU, measure pin 12 to a good chassis point. I've also attached the EZ-F diagram from Ken...