weak spark

[GlenAM]

I have a 92 Fleetwood Flair P-30, 454 and it appears to have a weak spark. It will not start. I have replaced the coil and it didn't change anything and it has a new battery. I could use help with this. thanks.

 

[Ray-IN]

I assume the engine has new spark-plugs, new plug wires, new coil. If all those are working properly and the engine is getting fuel, the engine should start and idle with a weak spark

 

[GlenAM]

Thank you for your response. The engine does have new plugs, plug wires, coil, and battery, and many other new parts. And yes it is getting fuel. I have a difficult time telling if the spark is weak but everything appears to defy the laws of science. that is what is so frustrating about it.

 

[Utclmjmpr]

Will it start,, or try to,, with starting fluid instead of gas.?? >>>Dan

 

[GlenAM]

Thank you for your response. No it will not start. It does try to off and on. I haven't tried starter fluid but I will get some.

 

[Ray-IN]

Well, another question. Has the engine ran since replacing spark plug wires? I ask because one time I replaced plug wires and got one hole off on the distributor, of course the engine would not start or run.

 

[GlenAM]

That is very interesting. I have checked that many times and I believe I have things in the right place, The firing order is another thing I have checked. I think I have a few clues to work on. I believe things will work out if I keep mucking with it? I will let you know. Thanks again.

 

[jubileee]

Have you replaced the ignition control module (ICM)?

 

[Ex-Calif]

Thank you for your response. The engine does have new plugs, plug wires, coil, and battery, and many other new parts. And yes it is getting fuel. I have a difficult time telling if the spark is weak but everything appears to defy the laws of science. that is what is so frustrating about it.

I am with the limited use of starter fluid.

Depending on how you are checking the spark but basically it should be blue-ish to white hot. A yellow-ish spark is a weak spark.

If it chugs with starter fluid you can focus on fuel. I am guessing in 1992 it was a carburetor. My 1996 has throttle body fuel injection.

Fuel pump would be my next suspect. I presume in your efforts you installed a new fuel filter? Did you flush and fill the gas and if not how old do you reckon the gas is?

If you drain some gas is there any water in it?

 

[Dan_Frisbie]

That is very interesting. I have checked that many times and I believe I have things in the right place, The firing order is another thing I have checked. I think I have a few clues to work on. I believe things will work out if I keep mucking with it? I will let you know. Thanks again.

The first question that I have is did it run before you started messing with it?
If so, the start to undo the things that you did.
If it wasn’t running before you began the tune-up, then you have an existing problem
Is it fuel injected or carbureted?
At what degree has the ignition timing been set?
Have you verified the mechanical (camshaft) timing?
Are you getting any popping, backfires, “almost” starts, etc? Anything to indicate that you have air/fuel/ignition and correct mechanical and electric timing?

It could have jumped camshaft time.
The ignition timing could be so far out that it won’t start.
Does it have 12vdc at the input to the coil WHILE the starter is turning?

 

[GlenAM]

Have you replaced the ignition control module (ICM)?

Have you replaced the ignition control module (ICM)?

I haven't tried to replace any ICM. I assume that if it was bad then the thing wouldn't fire at all.?

 

[GlenAM]

I am with the limited use of starter fluid.

Depending on how you are checking the spark but basically it should be blue-ish to white hot. A yellow-ish spark is a weak spark.

If it chugs with starter fluid you can focus on fuel. I am guessing in 1992 it was a carburetor. My 1996 has throttle body fuel injection.

Fuel pump would be my next suspect. I presume in your efforts you installed a new fuel filter? Did you flush and fill the gas and if not how old do you reckon the gas is?

If you drain some gas is there any water in it?

Thank you for your help. It is on TBI . It has a new fuel pump and filter. I pumped out the old gas and put in all fresh stuff.

 

[Gr8bawana]

As was already asked but not answered, was it running before you started messing with it?

 

[GlenAM]

As was already asked but not answered, was it running before you started messing with it?

It was running wonderful last summer and then just sitting over the winter is what did this. Sorry I should have mentioned that.

 

[Ray-IN]

It was running wonderful last summer and then just sitting over the winter is what did this. Sorry I should have mentioned that.

That to me does indicate bad fuel. Did you also flush out the fuel lines between tank and TBI while emptying the fuel tank and replacing with fresh gas? Have you tried using starting fluid as suggested?
Hey, this is a group-effort project, we'll eventually stumble over the actual cause of the no-start problem.

 

[GlenAM]

I sure appreciate everyone's input. I haven't tried the starter fluid yet. The unit is parked an hour from my house where the rent was cheaper. I will be going out in a day or two. I will be trying the starter fluid then.

 

[DonTom]

I have a 92 Fleetwood Flair P-30, 454 and it appears to have a weak spark.

That is meaningless, if you're checking the spark at the spark plug. Many vehicles which "appear" to have a weak spark on the plug have a very high voltage spark in reality. And sometimes even vice versa.

Test your spark gap with one of these thingies and find out how strong your "weak" spark really is.

-Don- Reno, NV

 

[GlenAM]

That's an interesting gadget. I will have to look into that.

 

[TheBar]

I didn't see distributor cap and rotor mentioned. My son once sold his Yukon to a relative because it barely ran. The relative was honest and undid the deal when he found the only problem was the rotor was burned up.

 

[GlenAM]

I didn't see distributor cap and rotor mentioned. My son once sold his Yukon to a relative because it barely ran. The relative was honest and undid the deal when he found the only problem was the rotor was burned up.

Thank you for your thoughts. The cap and rotor are both brand new. I once had a brand new rotor on another vehicle that was a composit material and it was bad from the outset. Can you believe that?