[SierraDan]

I have a 95 Sierra, 1.3 carby.
Yesterday the zook was hesitating on the odd occasion while driving I put it down to the empty tank, refilled it. It gradually got worse to the point the car would just shut off entirely and I'd end up rolling down the street.

I've figured it must be the ignition because when it hesitates the tacho drops to zero instantly.

What could be the problem?
Is there a way to diagnose/test the ignition without replacing bits (spending money).

Cheers.

[JrZook]

Start off by checking all the wiring and connectors to the dizzy and coil. Pull em apart and clean them. Check all the earth's as well.

Run the thing at night and have a look under the bonnet in the dark and check for sparks around the dizzy and coil.

[gypsy]

if u run it empty check your fuel filter

[JrZook]

gypsy wrote:

if u run it empty check your fuel filter

How does that cause the tacho to go to zero straight away.?

[SierraDan]

JrZook wrote:

Start off by checking all the wiring and connectors to the dizzy and coil. Pull em apart and clean them. Check all the earth's as well.

Run the thing at night and have a look under the bonnet in the dark and check for sparks around the dizzy and coil.

I've checked all the connections they're all good.

So check for sparks coming from the insulation?
I did get an awesome shock the other week..

[JrZook]

SierraDan wrote:

JrZook wrote:

Start off by checking all the wiring and connectors to the dizzy and coil. Pull em apart and clean them. Check all the earth's as well.

Run the thing at night and have a look under the bonnet in the dark and check for sparks around the dizzy and coil.

I've checked all the connections they're all good.

So check for sparks coming from the insulation?
I did get an awesome shock the other week..

This could be leading to something. If it has been breaking down for a while you mite be able to see where its been happening. The arc's will leave a white cloudy looking marks

[atari4x4]

fire it up at night with no other lights/light pollution around & you might be able to see the arc.

[gypsy]

JrZook wrote:

gypsy wrote:

if u run it empty check your fuel filter

How does that cause the tacho to go to zero straight away.?

well no fuel engine dont run so tacho

[SSSIERA]

how much play is there in your dizzy (wobble the rottor around thats what was wrong with mine and it was heistating, and stalling)

[Ben_Sierra]

gypsy wrote:

JrZook wrote:

gypsy wrote:

if u run it empty check your fuel filter

How does that cause the tacho to go to zero straight away.?

well no fuel engine dont run so tacho

The tacho is driven by the coil... The engine revs don't instantly drop to zero when it hesitates...

[SuziBlu]

atari4x4 wrote:

fire it up at night with no other lights/light pollution around & you might be able to see the arc.

Most wonderful test.

Lightning has a way of telling you where a problem lies.

[gypsy]

mine use to do it all the time run it low on fuel filter would get blocked car would hesitates tacho would drop to nothen sit for 5 min then off we go again

[SierraDan]

No lightning that I can see..

[SierraDan]

gypsy wrote:

mine use to do it all the time run it low on fuel filter would get blocked car would hesitates tacho would drop to nothen sit for 5 min then off we go again

Filters are relatively new. Its not fuel though. Its ignition. tacho drops and engine keeps on turning for a little bit(no detonation just momentum rolling off). Ignition is coming to a halt ie NO ignition. No ignition no spark no bang no drive.

[JrZook]

SierraDan wrote:

No lightning that I can see..

Hose it down with water and try again to see if they come out. Does it miss only when hot?

[JrZook]

gypsy wrote:

mine use to do it all the time run it low on fuel filter would get blocked car would hesitates tacho would drop to nothen sit for 5 min then off we go again

Lol WTF?? While the engine is turning over with the ignition on, the coil will be firing regardless of if it starving for fuel or not........

[TasRat]

Another cause might be dizzy cap, lift off cap and inspect contacts and rotor.
If car is dying without missing check coil HV lead from coil to dizzy, other plug leads would only drop one plug.

I agree with an early reply, check all electric connections including ignition switch or plug on the back.

I've found a terminal to the resistor adjacent to the dizzy is loose on mine, it'll need a clean an tighten.

[gypsy]

no shit i fix cars 4 a living. I Thort the same thing i put new dizzy in new coil new plugs leads same thing changed fuel tanks and filter all good. If royce get on here he mite remember me asking him about it

[SierraDan]

JrZook wrote:

SierraDan wrote:

No lightning that I can see..

Hose it down with water and try again to see if they come out. Does it miss only when hot?

I'll have a go tomorrow after work.

Nah, i warmed it up for a minute or so then drove out of my driveway and it started to die and then i was completely stopped a couple of metres down the street. So not hot but not fresh cold.

[atari4x4]

whats the ignition barrel & key look like, it isn't bouncing back to acc with slop in the barrel?

[matty]

it could be a tumer.

[joe5701]

run 12v straight to + on the coil run it see how it goes, if it runs fine start checking back down the line from there. if it runs like shit its in the dizzy or coil, it aint getting to earth. if its arking from the coil or leads some where the tach should still work cause the tach signal comes from the - side of the coil. the way I see it the only way the tach wiil just drop is if the coil looses 12v or earth signal. correct me if I'm wrong but thats my understanding of it.

[SierraDan]

matty wrote:

it could be a tumer.

its NOT a tumour..*crappy austrian accent*

[SierraDan]

atari4x4 wrote:

whats the ignition barrel & key look like, it isn't bouncing back to acc with slop in the barrel?

Nah its all pretty solid.

[royce]

What do you do to make it restart?

[SierraDan]

Turn the key. Its indecisive about whether it wants to work or not.

[SuziBlu]

Sounds like its in the barrel.

[royce]

so it restarts straight away or sometimes it takes a while or do you have to hold your tongue the right way?

pottering off on an assumption is a surefire way to get you stuffing around and not fixing a thing

find the fault, when it dies MEASURE if you have power at the coil positive, if so then MEASURE you have a switching signal on the negative side of the coil, if you dont have either you have somewhere to go, if it does its something else

[shep]

something i have seen a couple of times is the solder at the back of the ignition barrel
melting/deteriorating and randomly causing issues with the way the car runs.

try giving the wires at the barrel a wobble and see it they fall off.

[SierraDan]

royce wrote:

so it restarts straight away or sometimes it takes a while or do you have to hold your tongue the right way?

pottering off on an assumption is a surefire way to get you stuffing around and not fixing a thing

find the fault, when it dies MEASURE if you have power at the coil positive, if so then MEASURE you have a switching signal on the negative side of the coil, if you dont have either you have somewhere to go, if it does its something else

Sometimes it takes a good 10mins of trying to start it to get it to kick over but doesn't run. It's a real shit fight to get home while it's throwing the tantrum.

That's what I was after. Where to test. So will a circuit test light be fine for checking the coil terminals or should I be testing for a specific voltage on a multimeter?