Kevin in Atlanta

Yeah my Radio Shack multimeter sounds a tone when I touch the leads together.

Kevin in Atlanta

All the diagnosis I can perform with a multi-meter and noid has been completed and all the readings are in keeping with the posts I have read. I am going to pull the trigger and buy a oscilloscope this week to complete my diagnosing tasks.

The only thing I found in my non-op injectors search was #18 on the connector had one of its four tangs ever so slightly bent away. I used a pick to coax it back into shape.

While I wait on that and few parts from Roger I decided to press on and swap out the the CE panel. The PO's mechanics in search of why the anti-lock on the pod is always lit apparently applied too much force pressing its relay in and broke two of the four relay supports. See below. XVII - the two lower ones are missing.

I have a 88 CE all cleaned and prepped at the ready.

Hilton

If you have a laptop (or other small windows powered device) I recommend getting a 2-channel USB digital o'scope. Having a second channel comes in handy a lot, and the ability to run on a laptop means taking screenshots etc. is easier.

I've had a Hantek one for a few years - the equivalent of their current 2000-series. Mine is equivalent to the bottom end (DSO-2090 - 40MHz total, so 20MHz (50MS/s) per channel) - altho' I have found lately I'd like one which can work at radio frequency levels (for testing/calibrating old hifi tuners), so at some point I'll upgrade.

You can pick up their cheapest model, the 6022BE for less than $70 on ebay, and it has quite a following on eevblog, including open-source-developed software for it which improves on the stock hantek stuff:

http://www.eevblog.com/forum/testgea...z-usb-dso/810/

Kevin in Atlanta

CE panel has been swapped with one I had on the shelf. Cleaned all the fuse blocks and reseated all the relays after deoxit treatment. Noticed that the antilock message was lit during the attempted starts and no other warnings - a bit of research lead me to replace the central warning brain under the dead pedal and now all warnings appear when the key is in the first position. Does anybody repair these brains? Should have my parts tomorrow to resume testing.

worf928

Rich Andrade does.

Mrmerlin

the ignition switch has a few detents .
off = 0
acc =1
run=2
crank=3

So all of the warning lights should come on for a bulb check in the run position=2.

NOTE once the engine starts and the alternator begins charging the warning lights should all go out,
except for the brake lights and the E brake.

These will go out once the brakes are applied and the E brake is released

Perusal of the owners manual outlines what is controlled with the key.

Based on info provided your ignition switch is bad.

NOTE antilock light on after start means the fuse or relay on the CE panel is probably bad,
NOTE anti lock comes on after the car reaches 5 mph then its probably a sensor or broken wire to sensor.

Kevin in Atlanta

replaced the relays with new ones from Roger.
replaced the CPS from Roger
repaired the CPS harness connector
replaced the CE panel with one from an 88 A/T car I parted out to address broken anti-lock relay block - removed the kickdown and reverse lights relay and replaced the latter with the bridge.
cleaned all the grounds
replaced the central warning brain

Retraced all my diagnosis steps - all passed - including resistance testing of CPS from the EZK connector. The only outlier was the MP IX - resistance should be zero. In my tests I got .3 for a second or two and then 0.00. And it is repeatable.

With both computers attached no noid and no spark and no fuel pump. Using my multimeter there was 12v on one side of the injector clip and voltage went from 12v to 9v and stays there when I crank the engine.

With the EZK disconnected Noid light is on as soon as key goes on and goes off while cranking. The noid is a lot brighter than I remember from my earlier tests. Still no fuel pump.

When I jumpered the fuel pump i hear the fuel pump, but the pressure never gets higher than 20# and bleeds down quickly. There may be a fuel related problem, too. PO said they dropped and cleaned the tank and replaced the fuel pump and filter. I did remove the regulator and damper to get at the CPS harness connector and replace the CPS. I have read that there is no orientation for either - have I got that right?

I tested the LH in another 87 yesterday. I am using a 87 computer in an 88.

Before I did all the above the noid blinked, the sparkplugs fired, fuel built and held 60# of fuel pressure.

Could there be a problem with the EZK harness? The connector pins look ok.

Is this a case of the corrupted tach signal?

If this were my daily driver I would be tearing my hair out...

EMan 928

Hey Kevin,

I had a very similar issue with my 87 5 speed. Tried most of the above recommendations with no luck. Then, AO and DaveK9 were working on it one day and they made the decision to remove the wire that goes to the tach. They couldn't figure out how to disconnect it from the CE panel, so they cut it. As soon as they did that, the car fired right up. Seems the wire to the tach was the issue. Don't know if it will work for you, but might be worth a shot. Best of luck!

dr bob

Kevin--

Is the EZK the original? They don't fail at the same rate as the LH brain, but...

The EZK processes the CPS sensor signal and some others to generate the tach pulses that the LH needs to tell that the engine is cranking. Feeder from the battery, EZK relay, alarm system (disables EZK and therefore the LH for no-start), then EZK box itself. That would be my testing order, since I don't have a spare EZK handy.

I sometimes use my baby oscilloscope when I get this deep so I can see stuff that the simple voltmeter misses. You had one on your list IIRC.

I'm not close to WSM's so can't share specific guidance. But if you happen to have an EZK in your spares collection, it's a simple plug in to find out if that's the cause.

Kevin in Atlanta

I did try another EZK - same result. I had an offer from a fellow lister who might have a scope. If that does not pan out I will get one this week.

i am also considering disabling the alarm. We tried locking the car with the driver side window down and pulled the door handle and the alarm did not go off - if that adds anything.

Mrmerlin

Does it look like the car has an intank pump?

what is the power reading at the fuel pump positive post while jumpered?

take a jumper and connect to a good ground and to the negative side of the pump.

Then jumper the pump and see if the pressure comes up.

Clean all of the brown wire connections in the spare tire well,

and clean all of the wires that go to the battery terminals.
Inspect the 14 pin connector at the hot post for shedding insulation.

if none of these things make it run,
then while cranking,
have someone move the harness around at the back of the engine /coolant bottle.

Kevin in Atlanta

Today I removed the MAF connector to look for wiring issues at the connector. I pulled some of the MAF connector boot for my inspection and twisted it to look for broken or touching wire.

I left it disconnected and when I turned the key on with the EZK computer disconnected no noid light no fuel pump action. Whereas before I had a noid light following those steps.

I reattached the MAF

Turned the key to the first position with the EZK connected - - no noid but the fuel pump came on and off. I was unable to repeat this with successive tries.

Then I disconnected the EZK and when I turned the key to the first position the fuel pump came on, the noid light came on strong and the all the injectors stated clicking in random. A classic LH computer failure symptom!

Not sure what to make of that.

Kevin in Atlanta

I need to clarify something.

The results where the injectors clicked rapidly, the noid was light and the fuel pump ran up to 60# of pressure was when the battery charger was set to 40 amp charge. Anything less than that and the fuel pump would not come on constant - a brief 1 second burst followed by a pause and another 1 second burst and then silence. Also the noid light would flash as I turned the key to the off position.

I have reached out to a automotive electrical technician to come by and have a look.

John Speake

The 40A battery charger was almost certainly the reason for the LH ECU failure. There would have been a nice big surge when you connected that up.

There may also be a heavy current drain is you needed that much grunt to hold up the battery voltage (or the battery is toast)

worf928

Your debugging process is not focused. Concentrate on spark first. And spark only. Disconnect fuel-related components: LH, LH relay, etc., to get them out of the circuit. Make the electrical system as simple as possible through disconnection and removal. Remove fuses, relays, etc., until only stuff needed to make spark work is connected. Make spark work. Then begin reconnecting bits.

You have to decompose this problem into manageable bits.