Misfiring EA82

[STiVI]

Hi all. New to the forum. I'm hoping there is someone out there who has had this experience and can help me out, as I'm running out of options.

 

I have an '85 DL Wagon that has started to misfire under load. It also makes a bit of a mechanical noise when misfiring - more pronounced when cold. Anyway, the misfiring generally occurs at, I suppose, around 3,000rpm and goes away with higher revs. I have so far:

 

• Run metho through the fuel to pick up and disperse any water in the fuel;
  
• Replaced the fuel filter;
  
• Replaced the plugs and distributor cap (car improved after this - I am yet to replace the leads and rotor button but will be doing so soon);
  
• Tested the compression to rule out burnt valves and/or cracked pistons; and
  
• Checked head gaskets - still intact.
  

If anyone has any suggestions as to where to go to from here, they will be most appreciated.

[Skip]

Vi,

Welcome aboard the good ship USMB.

 

I'm going to guess this lump has a carby on it.

From your description it sure sounds like it is going lean

when the problem occurs.

 

The mechanical noise could be preignition....

 

Have you checked the vacuum advance on the disty and or messed about with the ignition timing lately?

I'd have a look at it just to take it out of the equation.

 

Make sure while you in there the disty's mecanical advance isn't knackered.

 

Some one will surely say check for possible vacuum leaks,

especially in the intake runners next to the sparking plugs,

if air is entering unmetered, the cylinder being fed could go lean and misfire.

 

Ever hear any popping out the intake?

How's the engine temp?

 

Do you mates have "Seafoam" carb cleaner available?

You could have a clogged transfer port in

the carby, this stuff is truly "magic in a bottle".

 

Sorry for all the q's

[85Sub4WD]

Glad you joined! - USMB is a very valueable resource

 

I have an 85 GL - I'll bet it is the disty advance or vacuum - one of the two.

 

I had the same problem as you on my car at one point and found that the vacuum advance had turned into one gummed-up piece of crap.

 

I had the same problem as you a second time, and found a bad vacuum line - though vacuum leaks will likely cause a crappy idle - a bad disty advance probably won't.

[NorthWet]

Welcome!

 

Skip and 85Sub4WD gave you some good info/suggestions, so I am going to go for the obvious. Make sure that you change out those spark plug leads.

 

My EA82T had odd misfire at various spots sprinkled throughout its RPM range, prob wherever the mixture leaned a bit or ignition conditions became a little tough.

 

The best troubleshooting advice that I ever got was from a book I read some 30 years ago: Always make sure that the ignition system is right before messing with the intake/carburetion. (Of course, this was back when things were simpler, carbs didn't have wires, and their were only one or two vacuum lines on the whole engine. )

 

Good luck!

[STiVI]

Thanks for the responses so far. Sorry, I should have pointed out that it is carburetted, not fuel injected. Some extra points I should also make, the misfiring just came out of the blue - drove up a hill OK and down the other side, up the next hill and I thought I had suddenly encountered a very strong headwind the car struggled so much. Don't know if this has any bearing on the diagnosis.

 

Skip, never heard any popping from the intake, but engine temps start heading north after extended work, but I put that down to the fact that the engine is misfiring and having to work harder. I haven't seen Seafoam carby cleaner here in Oz, but now that I know about it, I will see if I can source it from somewhere. I will also be checking the timing (hopefully this weekend).

 

NorthWet - I agree with you and I am going to be replacing pretty much everything in the ignition first. Just clicked over the 400,000km mark, so components may be a little worn. I am waiting for a set of leads to be delivered, along with a new rotor button. I am also thining I will replace the ignition coil - I have been told that an ignition coil either works or it doesn't , no in between, but I suppose it can't hurt (and the workshop manual also suggests this as a possible remedy). What do you think?

 

85Sub4WD - I will also do as you suggest. I did find the vacuum advance line was disconnected, but I think I did that when I was changing the plugs. I will however check what I can.

 

I really appreciate the responses so far. I'll keep you up to date on the outcomes.