Another ignition module failure?

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Originally Posted by Dougal

Hotwire or flapper?

Either way it could be worth putting a wide-band O2 sensor up the exhaust to see what it's doing wrong.
It took all the mystery out of my 93.

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1989 3.5 Flapper
Cheers

Throttle position sensor ?

Air leak in or around the idle stepper motor?

Any vacuum hoses past their use-by date?


Did you put any money in the collection plate at Church last week ?:angel:

Edit: x2 on the wideband sensor... at least you'll know what kind of mixture (lean/rich) it's trying to run on !
There's a few on the evilbay. Around $180 or so, but may need a 'US postal address.

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Originally Posted by Charles

1989 3.5 Flapper
Cheers

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Of course being a flapper it doesn't have a stepper motor idle control valve but the hoses around the front mounted idle control valve can split something shocking and suck air. I've seen them fall off often enough.


Carefully lift the plastic lid off the flapper and see if manipulating the arm makes it run better. Pushing the arm in the direction of more air flow will richen the mixture. You can move the spring clips and dial it around a bit for more/less fuel.

Then I'd disconnect the cold start valve at the top of the plenum, if it's opening too much it'll drown the engine.

Mine lost all 4 cylinders on the right bank, it was cured by resoldering the 2 power transistors on the ECU board, these joints are a known trouble spot.

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Originally Posted by Dave109

Mine lost all 4 cylinders on the right bank, it was cured by resoldering the 2 power transistors on the ECU board, these joints are a known trouble spot.

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Dave, you must be psychic!!!!

Wow....after going through the ignition components again and further reducing the reluctor air gap to .005" proving I have enough spark at all plugs to weld with....The Bosch conversion is excellent, thanks beeutey:D
I just came in from the shed to see if anyone had heard of a reason for dropping cylinders 2,4,6 & 8.......as removing those leads while running makes no difference but taking just one lead of the 1,3,5 & 7 bank kills the engine.

Can anyone point me in the direction of a "how to" for the power transistor fix?

I can see alight at the end of the tunnel.....

Charles

First check every connector and wire going to your dead bank... Do it again to be sure. :o

Find your ECU. Unplug it, plug it back in a few times and try again. (this is your last connector/chance!) Nope?

Pull it out, carefully undo the case and expose the circuit board.

With a magnifying glass and lots of light, inspect the solder joints, the biggest on the widest tracks should be the power transistors. But look at them all whilst you're there...-Looking for a frosting appearance or differant 'silver' sheen, this is a classic Dry Joint. Obvious mis-flow of solder, or a crack between solder blob and track...or the transistor's leg (has 3 connections, body may be one.) Worst case would be a dead transistor.:( Replaceable, AFAIK:)

Take pics of what you find. (also 'cos I've never pulled mine apart ! :angel:)

You have experience or confidence in electronic soldering ?

I had Valiants from the first electronic ignition models through to the CM ELB system. I had to replace a number of the Chrysler modules. Instant failure, no warning. The ELB units would get tired or the run system fail and the unit would switch to " limp home" mode. No warning, just poor performance and the fuel gauge dropping at an alarming rate. My cure for electronic ills in these was a Jaycar electronic ignition kit switched by a points distributor from a Hemi 215. You wire these in so when the electronics fail you swap over two wires and drive on points and coil. As to Ford autokraft rubbish, my Falcon ute has, in 200,000 k's, had three modules replaced and two complete distributor & module assemblies. One of these was almost fried to ashes. The cure? Throw the Ford rubbish in the bin and replace with Bosch.

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Originally Posted by Charles

Dave, you must be psychic!!!!

Wow....after going through the ignition components again and further reducing the reluctor air gap to .005" proving I have enough spark at all plugs to weld with....The Bosch conversion is excellent, thanks beeutey:D
I just came in from the shed to see if anyone had heard of a reason for dropping cylinders 2,4,6 & 8.......as removing those leads while running makes no difference but taking just one lead of the 1,3,5 & 7 bank kills the engine.

Can anyone point me in the direction of a "how to" for the power transistor fix?

I can see alight at the end of the tunnel.....

Charles

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G`day ,

if you haven`t you may want to check your resistor pack and the related wires/connectors .

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Originally Posted by superquag

First check every connector and wire going to your dead bank... Do it again to be sure. :o

Find your ECU. Unplug it, plug it back in a few times and try again. (this is your last connector/chance!) Nope?

Pull it out, carefully undo the case and expose the circuit board.

With a magnifying glass and lots of light, inspect the solder joints, the biggest on the widest tracks should be the power transistors. But look at them all whilst you're there...-Looking for a frosting appearance or differant 'silver' sheen, this is a classic Dry Joint. Obvious mis-flow of solder, or a crack between solder blob and track...or the transistor's leg (has 3 connections, body may be one.) Worst case would be a dead transistor.:( Replaceable, AFAIK:)

Take pics of what you find. (also 'cos I've never pulled mine apart ! :angel:)

You have experience or confidence in electronic soldering ?

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Hi Super,
Thanks for the info....my soldering skills are woeful so taking the ecu to a friend who restores electronics as a hobby.....

The previous owner had waterproofed the ecu in a large plastic lunchbox with about 2kg of silastic plus a venting system.....was a bastard to remove gently!!

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Originally Posted by Charles

Hi Super,
Thanks for the info....my soldering skills are woeful so taking the ecu to a friend who restores electronics as a hobby.....

The previous owner had waterproofed the ecu in a large plastic lunchbox with about 2kg of silastic plus a venting system.....was a bastard to remove gently!!

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Hah, it's already been underwater at least once! Wanna buy a cheap ECU and as much wiring I can pull out? I'm wrecking an '89 Rangie with a 3.5 flapper engine. Send me a PM if you do.