Pinto Misfire And Unleaded Markings On Head

[Guest Stuartl]

This is the way I was thinking Mower Man. I will check the valve clearances and report back. Longboarder, I know anything is possible but to replace the items that have been replaced one by one with new and have exactly the same symptoms would be a hell of a coincidence so I am thinking along the lines of trying something so far left alone first. What else can be wrong electrically? I know that aside of the new coil that is fitted (I still have the old one)another one has also been tried.

 

I really appreciate all of the replies and suggestions on this topic and hope I can get it sorted in time for at least one show this year!

 

Cheers,

 

Stuart

[Guest mcramsay]

im going with longboarder on this one, the valves are the first point of contact for heat within the cylinder, so they are going to get very hot very quickly. any clearance issues would show up long before the 30 mins. but check the clearances as it can only help to have them set right.

[Guest mcramsay]

also another thing, if you have a timing light, when the car starts miss firing, attach the timing light to the plug lead of the missing cylinder, and then check for a spark(press the button on the gun, if it flashes you know you have a spark). that will tell you if you are gettin a miss fire due to a bad air/ fuel mixture or if you have no spark...if you have no spark then you know the problem is electrical. if you have got a spark then do a compression check immediatley, (do one on the cold engine first) and then compare the results. if your losing compression when the engine is hot then you know you have some kind of expansion issue. failing that its got to be some kind of fueling issue, but as already said that would show up before 30 mins of running.

Edited June 6, 2010 by mcramsay

[Longboarder]

I took the first post to say cold and hot compression tests had been done and were OK. Would be worth repeating a hot test at some stage.

I would think that valve recession and closed gaps would be a long shot, would show earlier than 30 minutes and would expect this to have been checked during the previous investigations. Certainly worth doing as well.

 

Was just giving the problem my best shot for what it's worth which may not be much when Stuart has tried three coils but it doesn't sound mechanical to me.

 

Nigel

[Grim]

what about an intermittent block of the fuel line? something in the tank?

[Guest Stuartl]

I took the first post to say cold and hot compression tests had been done and were OK. Would be worth repeating a hot test at some stage.

I would think that valve recession and closed gaps would be a long shot, would show earlier than 30 minutes and would expect this to have been checked during the previous investigations. Certainly worth doing as well.

 

Was just giving the problem my best shot for what it's worth which may not be much when Stuart has tried three coils but it doesn't sound mechanical to me.

 

Nigel

 

Nigel,

 

I have re-read my reply and would like to stress that I value your suggestions very much and dont want it to sound like I am dismissing your ideas, far from it! I have no doubt that you are far more savvy with engines than me and value your input greatly along with all the other contributees!

 

Regards Stuart

[agent_zed]

Hi Stuart,

just wanted to add to longboarders point that although some of your electrical items have been replaced and are therefore assumed to be ok, it may not be the items themselves but the location. Ive heard of people on here saying that there coils and ecu's were in a position that got hot and couldn't cool themselves as they should. This would kind of tie up in that it could take a good 30 mins to get them hot from the radiant heat of the engine. Might be worth checking where your electrics run if you have the bonnet off.

 

hth

[Guest Stuartl]

Hi Stuart,

just wanted to add to longboarders point that although some of your electrical items have been replaced and are therefore assumed to be ok, it may not be the items themselves but the location. Ive heard of people on here saying that there coils and ecu's were in a position that got hot and couldn't cool themselves as they should. This would kind of tie up in that it could take a good 30 mins to get them hot from the radiant heat of the engine. Might be worth checking where your electrics run if you have the bonnet off.

 

hth

 

I think I will pop off the bonnet and run it on the drive as you suggest and check the temperature around the sensitive components periodically. Looking at the layout everything 'important' seems well positioned and well ventilated. What I need to do I guess is ask more about when this started happening and if it just happened suddenly one day......

 

Engine faults aside, I LOVE the car, its a very eye catching car and I am really looking forward to personalising her and getting out on the lovely roads we have where I live.

[Guest marsbar]

Hi Stuart, when the car starts to missfire or stops, what is the temperature of the coil? If it is hot to touch, then the insulation of the oil has broken down, this will cause other electrical short problems.

Hope its something simple like this.

[Guest Stuartl]

While some of you are no doubt enjoying driving your cars today I am tinkering with mine!

 

Latest observations:

 

Ran the car today and sure enough after about 25 minutes it developed a misfire and died.

 

Temp gauge read within normal.

 

Fuel filter between pump and carb was 3/4 full of fuel.

 

Coil was only slightly warm.

 

I checked for air leaks around inlet manifold and engine and inlet manifold and carb with spray of WD40, no apparent leaks.

 

Still smells like it is running very rich.

 

Auto choke is switching off ok.

 

The ignition module is well out the way of any real heat

 

Going to let it cool down then do a compression test cold then hot.

 

As usual, any ideas etc etc gratefully received!

[Guest mcramsay]

wait a day, let the engine get completley cold. and then compression check, run the car, and then immediatley after it conks out compression test when hot. if there is something going on you will see it immediatley. if the compression looks the same then im starting to think mixture or electrical. i would get a colour tune so you can actually see whats going on inside the cylinder, (you can tell if the mixture is rich lean or correct) also i would replace every electrical item, such as sparks, HT leads, rotor arm, dizzy, points and coil (even though you have been through three! try to get one that is known to work!!) if the compression test doesnt show up anything obvious then i would be 99% sure the problem isnt mechanical!

[Guest mower man]

Hi Stuart it's got to stupid time

1 remove air filter [when cold ]

2 start engine and run up to operaiing temp ,not just on idle but a few blips and at least a couple of 1/2 min sessions at2/3000 rpm

all the while watching the choke butterfly

3 let the engine idle to this 25/30 min period again whatching the choke b/fly is it shutting and gassing the engine up ?

4 the above prob would probably not show up on the road bcause the speed of the air through the carb will overcome the spring pressure which operates the autochoke but at idle this does not happen and the engine gasses up and stops

Ihad this prob once or twice on Fords and resetting the auto choke cured it the worst case Iresorted to fitting a manual choke system!!!!! the choke flap does not need to be fully closed to gas the engine up at idle but if left long enough will shut the engine down, Hope this helps BTW did you get the cheque ? thers no rush just wanted to know you got it sort your engie probs and send the manifold when you get sorted regards mower man

[Guest Stuartl]

Hi chaps, thanks for the replies.

 

Something odd has happened now.....

 

Let the car cool down for about two hours, checked the valve clearances, all inlets seemed a bit tight, exhausts ok.

 

Cleaned and regapped plugs. Tried to restart, it wont fire. Tried to hold ht lead to block but no spark. Flattened battery a bit so now on charge till footie duties are over.....

 

Mower man, ran it earlier without the air filter and the auto choke seems to be working fine which was a tad disappointing as this would have been an easy fix!

 

I have a colortune and have put a posting on here this afternoon as I need the 18mm adapter, had this thing for years, never opened it now need another part, DOH!!

 

Mower man , many thanks, I did get the chq, am off on Monday so will take it to main post office, did try on Thursday but the local post office wouldnt accept it as it was 'too big'. Need to go out of town to sorting office

[Guest Stuartl]

Just another observation....

 

Out of the dizzy there are two wires plus what appears to be an earth wire with a home made connection to the dizzy body. All three of these go into a 3 pin connector plug. However, on the other side of this plug there are only two wires plus a third wire which appears to be 'blanked off' by the previous owner or the one before him. Does this make sense?

[Guest peter2b2002]

any chance that you may be getting a vapour lock in/near the carb?

peter2b