Mrmerlin

nice post John, thanks

CoachTom

John,
WILCO.

I will post results later.

Understand that the fuel pump only runs when engine crank or running, but mine isn't at all unless jumpered. There also isn't any MAF burnoff when engine crank ends with switch off...

The "rev counter" meaning "tach"?? The behavior of the needle bouncing to 3k then modulating at around 100 rpm as the engine cranks is abnormal?

What troubles me most is that i shut the "running" car down to work on vacuum lines, "while I was at it" changed the spark plugs and cleaned the grounds thoroughly. Battery was disconnected through out the processes. How does it happen to appear that i somehow have a catastrophic failure of my computer systems on board???

Just cannot fathom the extent of this failure...

Do you have a local agent this side of the pond to test black boxes?

V/R

Tom

John Speake

]John,
WILCO.

I will post results later.

Understand that the fuel pump only runs when engine crank or running, but mine isn't at all unless jumpered. There also isn't any MAF burnoff when engine crank ends with switch off...
>>>>>>>>>>>>>>
MAF will only burn off when engine has run at more than about 2000rpm and has reached normal operating temperature.
<<<<<<<<<<<<<<<<<<<<<<<


The "rev counter" meaning "tach"?? The behavior of the needle bouncing to 3k then modulating at around 100 rpm as the engine cranks is abnormal?
>>>>>>>>>>>>>>>
Yes, tach... not normal...
<<<<<<<<<<<<<<<<<<<<<<<

What troubles me most is that i shut the "running" car down to work on vacuum lines, "while I was at it" changed the spark plugs and cleaned the grounds thoroughly. Battery was disconnected through out the processes. How does it happen to appear that i somehow have a catastrophic failure of my computer systems on board???
<<<<<<<<<<<<<<<<<<
The LH2.2 and EZ-F on your car are very relaible compared to S4 and later. I repair 1 LH2.2 for every 100 >87 LH2.3 ECUs.
>>>>>>>>>>>>>>>>>>>>

Just cannot fathom the extent of this failure...
>>>>>>>>>>>>>>>>>
That's why I asked about a "missed" ground point.....
<<<<<<<<<<<<<<<<<<

Do you have a local agent this side of the pond to test black boxes?
<<<<<<<<<<<<<<
I have a US agent (see sig) but he doesn't have the facility to test your ECUs.

John

Pfc. Parts

Tom, when you pulled the plug wire did you check to see if the plug was wet? I'm wondering if your injectors are firing.

elgreco

Where are you located maybe you can bring your Lh to someone and have it plug in to there own car and see if it fires.

John Speake

I would suggest to test both EZ-F and LH.

CoachTom

I pulled plugs, at least the easy ones and they were all dry. This was even after the Fuel Pump was jumpered.
I could not hear any clicking or clacking of injectors as i was up close to organ pipe box with ear. no stethoscope to get a better sound signature.

I know mistakes happen and mis routings of pieces and parts happen, but with this, i was very methodical in my repair of each individual ground point, each spark plug worked individually, and the vacuum lines as a separate entity. I was and am totally flabbergasted by this running car not starting or even exhibiting these anomalies as identified by John Speake: Tach not displaying correctly during start, no fuel pump run during start...

John, so with the robustness of the LH 2.2 and the car running prior to this maintenance event, it could be surmised that it could be some other issue? I did go over the grounds one third time today as well. Tonight i will be checking voltage and grounds at the pins you described.

Last questions: should both ring terminals of the coils be reading battery voltage (which is what i have)? AND how bright and snappy should my spark be?

I am located in Huntsville Alabama.

Thanks, i do miss driving this car.

Tom
1986.5 M28/43 5 Speed
HSV

CoachTom

Update:
LH Control Unit Plug low resistance to ground and to each other.

AC volts across pin 1 to 25 during crank was 0.25 to 0.30 fluctuating.

EZ-F pin 12: good ground.

Two ground points bright and shiny with about 8 ground wires tired to them. All cleaned on CE.

Hope this helped clear up the current situation, awaiting additional instructions as I do not knows the logic from pin 16 of EZF to pin 1 of LH... Or what it controls.

Greatly appreciate the patience and support!

Tom

Mrmerlin

have you checked the TPS harness at the top of the water bridge?

if its old the connector will crack and the wires will come loose Roger sells new short harnesses

I would also recommend you install a new crank position sensor,
. this connector can also crack and the wires will come loose.

Pull the plenums off and inspect the injector harnesses.

Remove the connectors for the computers and inspect them for corrosion.

Inspect and test for voltage the ICV .

Remove the temp 2 sensor connector and inspect the wires for shedding insulation,
if this is bad then cut the wires and replace the connector NAPA, Sells them.

Remove the MAF connector and inspect the wires under the boot,
yes you cut it open,
if the wires are shedding insulation consider buying a new engine harness,
reseal it by gently wrapping it with vulcanizing tape or silicone tape.

If the spark plug wires are old then replace them as well as the coil wires.

I had an 86 that had a bad engine harness virtually every connector or wire going to the connector was damaged ,
A good used harness had the engine running well.
Forgot mention everything that I listed was also replaced

Check the harness where it comes from behind the engine maybe you have damaged it .
since you have an old car your really going to have to replace a bunch of parts,
ITs OK for you to do this as the next failure will be many miles ahead.

Also replace the O2 sensor.
Get the MAF rebuilt.
Replace the ICV
Replace the TPS harness
Replace the crank position sensor.
Spark plug wires, Replace them
Inspect the caps and rotors, replace as necessary
Clean all of the relays,
any relay with corroded pins should be opened and inspected.
Clean the fuse slots , verify the correct fuses are installed and the correct empty slots are also empty.
After you get done with all of this cleaning,
you check for loose battery connections and or corroded ground wire,
usually the ground strap should be replaced

Pfc. Parts

Tom, since the 928 is batch fired and all the plugs you pulled were dry, and you had no ignition, I'd suggest first checking that *all* the plugs are dry. If so, you may have a short in the harness that fires the injectors. A single short anywhere along the harness will cause all the injectors to fail, which might be the root of your problem.

CoachTom

Stan, will start at the front and work my way back from the TPS. It could have been jiggled when I replaced the front fuel line, but will see. The CPS connection on the back valley is cracked and I secured the two halves with safety wire to insure they did not separate. The CPS has good contact and also was not corroded, it just did not lock into the mating connector because it was cracked. is there a ready available harness supplier or second hand ones out there? assume the second hand would be more of the same as the wires do not appear to be tinned.

Scott, regard ignition... I did have spark. Not the bright blue pop that i am used to seeing, but this car is new to me and did not know what normal was. There is a yellow/gold spark that coincides with TDC as the piston is blowing air out as the spark fires... So, the injectors are wired in series, like old Christmas lights; when one fails on the string, they all fail? Is there any specific check on the harness to the injector to verify? I guess i am going to need to find a wiring diagram for this stuff...

John, Low voltage on the A/C test (0.31vac) is indicative of a failure of the LH, EZF or both? Or is that some other timing issue that presents itself that way?? If i can find another set of computers to swap, will my current configuration fry a the different set of computers and do they have to be the same year as mine? Are there any comparable substitutes?

Tom
1986.5 M28/43 5 Speed
HSV

John Speake

I would expect that voltage to be much higher, but the result does depend on your DVM's response times. If the signal is really that low then it indicates an EZ-F problem or a short on it's output.

As the LH doesn't activate the fuel pump, then that does tally with the low signal on pin 1 LH.

Your car is a 5 speed - please double check you don't have a relay plugged into the kick down relay position, as that will kill the signal on pin 1 LH.

You can buy male and female 3 pin connector parts for your CPS from Roger Tyson.

I am more inclined to think the problem lies with the CPS and its wiring.

Longer term, Stan's thorough refresh is recommended.

Pfc. Parts

Tom, by "no ignition" I just meant the fuel didn't seem to ignite, not that you didn't have spark.

Yep, from the wiring diagrams the injectors are set up like Christmas tree lights, there's a ground and a switched 12v signal that runs to all the injectors at the same time. If the signal wire gets shorted anywhere in the path the injectors won't open, it's a classic "no start" failure.

There are a few ways to test this, one way is to pull an injector connection and hook up a noid light, then crank the engine after removing the coil wires to prevent it from starting, since you'll need to remove an intake plenum to get at the injectors.

Another way is to use a mechanics stethoscope to listen to an injector, when they open and close there's a pretty loud click. You don't have to take off the plenum for that one but positioning the scope can be a little tricky.

Seems like a good bet the injectors aren't firing since you have spark, you've got fuel pressure at the rail, and you have dry plugs.

rexpontius

any news?

CoachTom

Sorry for the lack of Commo, work has me away this week. Car is still a good looking paper weight and not running.

First thing Saturday morning is:
-to check CPS wiring and connection.
-TPS sensor wiring
-Noid light on Injectors.
-verify resistance on Primary and Secondary leads of Coils. (battery voltage at leads now).
-Fuel pressure check and volume in 30 seconds.
-Verify MAF OHM setting.
-New Rotors and Distributers to be installed being careful to mark wiring.

I did make sure there was fuel in the tank, at least half full.

I do not know where the impulse comes from that signals the LH to turn on the fuel pump as it is still not running when cranked.

Spark plugs were still firing last i tried to start car, but it was a yellow, not the bright blue or snap you would expect to hear.

Any ideas and all help appreciated!!!

V/R

Tom