'91 Sidekick dying randomly and not starting(no spark)

[kingofthekeys]

So I have a '91 suzuki sidekick I bought from a neighbor for an amazing deal but it has problems. You drive it for a while and then it dies. You might drive it for a month or a week or a day or an hour it doesn't matter it just dies randomly. Sometimes you can start it right back up and other times you can't because there is no spark. ECM has been replaced as well as the ignition and a few other various parts. Grounds seem to be okay. Sound Like a loose wire or something. I would take it in to get the computer checked but my neighbor says he did that before and when he got it to the dealer it started right up, they checked it over and it came out fine. Help! Has anybody else had a similar experiance and anybody know what it might be?

I'm only 14 and don't mave a whole lot of engine knowledge so if you can put it into something that I would understand better, that would be fantastic

[jtgh]

hello , you are way smarter than me at 14.
loss of spark ( assuming the rotor ,cap wires and plugs are good)

you need few things.

CAS pulse generator in base of dizzy must be good and sending signals to ECU.
ECU good.
power and GROUND ! good to ECU.
bad ignitor ( ecu drives the ignitor ( a big transistor ) and this pulses the coil for spark. so bad coil.

here is a simplified drawing that can really help.

there is a zero dollar test for the ignitor and coil, ask me how.

http://carfix.stufftoread.com/Schem-...-1991-jtgh.jpg

[jtgh]

what engine 8valve or 16 , look at valve cover, black plain = 8v , fancy aluminum says 16 valves.?
which

[kingofthekeys]

Definately a 16 valve. Thanks for the help. So I need to check:
1: the pulse generator near the base of the dizzy
2: the ECU
3: Power and ground to ECU
4: Ignitor
Is that correct?
Ignitor and coil test?

[jtgh]

This is an intermittant problem , they can be horrific ! hair falling out and all.
Like a horse with 3 legs , huh ?
if the car goes dead and stays dead, this becomes and easy problem.


I Forgot the grail ,
all fuses above left knee must be good, FI , igntion and Dome fuse.
yes, dome powerS ECU too. (it is the ECU memory pin)

make sure the fuses there do not have bent or rusted pins, at the fuse or in the socket, when you remove the fuse make sure socket pin closes on its self ,or it is sprung.

one can look at the Dizzy plug and remove it and inspect the pins for damage or
corrosion (oxidation, rust or contamination).
remember all these cars have connectors that have a lock, do not force them
one must wiggle the lever and then pull (depress lever) and unplug.
This connectors,are UNobtainium , a rear element found only in NAPAL.

the next connector is at the Ignitor and coil, this one is a bear to remove.
there is a metal bail the must be tickled just right to unlock it, just take your time.
inspect for wire damage or contam. inside the connector.

the coil conn . is much easier to pull and inspect.


that is it for inspection.


If car goes hard fail , you can do the below test on the dIZZY.

the dizzy (cas) can be tested with a scope,but you dont have that.
one muse connect an LED to it and spin the engine and the LED WILL FLASH.

THIS IS The easier of the 2 tests.
http://carfix.stufftoread.com/IGN_ti...izzy-test1.jpg
this is the schematic of your diZZY, (DISTRIBUTOR in pure english) but we call it a dizzy, do not remove it. ( that makes another bag of worms)


finding an intermittant usually requires, throwing parts (expensive) or waiting for it to hard fail, or taking readings with a voltmeter , when it dies.( and then starts working)
catching it , is very hard.
cheers.

[kingofthekeys]

Thanks so much. I will definately check everything you've mentioned. 1 question.
Is there a difference between the ECM and the ECU or are they referring to the same unit?

[kelikran]

Same thing, engine control module/enginge control unit.

[kingofthekeys]

Thanks a lot
As soon as I have the chance I will be checking all the things on your list. If you think of anything else that might help me out, I would surely be grateful.
Thanks again

[jtgh]

intermittants are the most difficult things in the world to cure.

i have made special tools just to catch them.

I have a black box, that finds a drop in 12dc battery power.
a 1 bit memory. in fact that is what it is a simple flip/flop IC.

I found an open harness , once that was where no human could go.
i bypassed it.

pros have a DSO that can do that. Digital storage scope.

if you lose spark, the one would monitor the cas signal.
or the input sig to the ignitor.
changes are 1 or the other are dropping out.

if that is too hard, and it is. one can just throw in a used dizzy.
or replace that corner cap in the ECU , it is very unreliable , it is. $1 fix too.

if i had few tools and had this car.
id replace the ECU capacitor first,
then replace the DIzzy ( any used one should be good, they rarely fail)

other than reseating all related connectors and inspecting them for corrosion.
there you go.

[woodcarver]

Another point to check may be the battery itself. My sons truck would die at the oddest times and we knew the battery was as old as the truck (2001 Ranger) and this did fix the problem. Even with a "charged" battery you may have a dead cell.

This is my first post and I want to say many thanks to JTGH and everyone else for the great info and support.
Mac