1990 5.7 Won't Start

[carzan]

I've tried to find an answer in previous threads with no success.

I have a 1990 Silverado 1/2ton 2WD, 5.7 liter 700R4. 320,000Kms

Vehicle had been running great, drove home from work, parked it, next morning wouldn't start. Cranked over no problem, just doesn't fire up.

Month before problem I installed new cap & rotor, and spark plugs.

What I've checked:
-I have fuel
-Injectors are working
-fuel pump works
-have spark
-checked new cap and rotor - appears fine
-pulled a spark plug to check for flooding - none
-added fuel in throttlebody- no change
-tried a new coil - no change

I figure with both fuel and spark it should fire up, - no!

Haven't been able to check without assistant.
-ignition timing

Is it possible the timing chain has jumped?
something inside dist. has shifted/failed?

Once again have fuel and spark, cranks over well, just doesn't fire up.

Ed

 

[96-1500]

Sounds like timing but you'd think you would at least get a kick or something if you've got fuel/fire. Might try an Ignition Control Module, sometimes they get a little wonky when they go.
Could possibly be a worn distributor gear, too. Seems to be a common issue. I would check timing first and replace the control module in the distributor. They are inexpensive and if it doesn't help, keep the old one for a spare as they are an extremely, extremely common problem on TBI trucks.

I'm no expert but I have worked on a fair share of these.

PS: unrelated, but if your truck is a 1990 I think you'd have a 700R4, not a 4L60E

 

[carzan]

I'll check the timing next when I get a helper.

You're right about the tranny, wishful thinking. Wish it had a vortec as well.

 

[96-1500]

Wish it had a vortec as well.

They're great until stuff starts to go wrong...

Let us know how you make out.

 

[firefighter_2319]

I've tried to find an answer in previous threads with no success.

I have a 1990 Silverado 1/2ton 2WD, 5.7 liter 700R4. 320,000Kms

Vehicle had been running great, drove home from work, parked it, next morning wouldn't start. Cranked over no problem, just doesn't fire up.

Month before problem I installed new cap & rotor, and spark plugs.

What I've checked:
-I have fuel
-Injectors are working
-fuel pump works
-have spark
-checked new cap and rotor - appears fine
-pulled a spark plug to check for flooding - none
-added fuel in throttlebody- no change
-tried a new coil - no change

I figure with both fuel and spark it should fire up, - no!

Haven't been able to check without assistant.
-ignition timing

Is it possible the timing chain has jumped?
something inside dist. has shifted/failed?

Once again have fuel and spark, cranks over well, just doesn't fire up.

Ed[/QUOTE
if you had fuel and spark, yes you should have got something.....what color is your spark? blue or orange. you want a blue spark not orange. orange means weak and blue meaning hot

 

[firefighter_2319]

yup i hate computers lol

 

[carzan]

Colour of spark hard to tell in daylight. However using the coil lead it will jump a 1/2" gap.

Still waiting for a decent day and an assistant to check timing.

 

[carzan]

update

Today got the neighbor to assist me.
while cranking, the timing light would flash inconsistently. (even attached to coil lead) flash pause, flash flash pause....

Have a new distributor on order. Maybe next weekend i'll have another go at it.

 

[jcoatswo]

Did you take the distributor out at any point? Could be that the distributor is 180 degrees out. Happened to me when I replaced my engine caused me to have about a 2 hour headache while I ran through just about everything you tried.

 

[carzan]

Fixed

Few weeks ago went to check the timing. No spark at all. So figured must be the ICM as suggested. (finally failed completely). Last weekend I put the new distributor in. Aftermarket unit. Still no spark. I had noticed before putting it in the reluctor and pick-up gap looked funny. Popped the cap off and adjusted position of the pick-up. Finally had spark.

Today I finally got the new distributor positioned right and the timing adjusted. Starts up great now.