48 Guests, 0 Users

Author Topic: Engine misfires badly after warmup  (Read 1218 times)

0 Members and 1 Guest are viewing this topic.

Offline ponyboy

  • Pinto Member
  • **
  • Posts: 60
  • FeedBack: +2/-0
  • Gender: Male
  • '73 woodgrain wagon

  • Total Badges: 5
    Badges: (View All)
    Poll Voter Topic Starter Windows User Tenth year Anniversary Fifth year Anniversary
Engine misfires badly after warmup
« on: June 23, 2018, 07:32:28 PM »

I'm having an unusual problem with my 1973 2.0. It starts and idles perfectly, and drives fine, IF you take off immediately after starting. But after several minutes it starts cutting out. This started happening about a month ago. After it has cooled down completely, it starts and runs fine again. The compression is fine, I just adjusted the valves (after the problem started) None were very far off. Carb is stock except all choke parts have been removed except the shaft the choke plate goes on. A choke is not needed here in Phoenix, AZ. I cannot find any vacuum leaks. Plugs look fine. It is getting plenty of gas to the carb. Points ajustment is fine according to the manual. Other than checking compression, plugs, valves. and points nothing else has been touched. I'm assuming it has to do with heat and not time, though that could be wrong. It just about has to be in the fuel or ignition systems. Anyone ever heard of this before? Any ideas would definitely be appreciated. Thank you. Jerry

Offline nnn0wqk

  • Pinto Member
  • **
  • Posts: 96
  • FeedBack: +24/-0
  • Gender: Male
  • Another Pinto Driver

  • Total Badges: 5
    Badges: (View All)
    Topic Starter Poll Voter Windows User Tenth year Anniversary Fifth year Anniversary
Re: Engine misfires badly after warmup
« Reply #1 on: June 23, 2018, 11:10:56 PM »
Bad condenser or coil are 2 things that heat will effect. Might check them before doing anything else.

Offline LongTimeFordMan

  • PCCA VIP
  • Pinto Sr. Member
  • ***
  • Posts: 375
  • FeedBack: +181/-0
  • Gender: Male
  • 1973 Red Pinto Wagon

  • Total Badges: 5
    Badges: (View All)
    Topic Starter Signature Windows User Linux User Mobile User
Re: Engine misfires badly after warmup
« Reply #2 on: June 25, 2018, 11:49:50 AM »
A pertronix electronic ignition module makes a major improvement in performance and reliability over the point ign.  If you decide to updgrade let me know as I have done the mod and found a ppa e to tap into the wiring at the ign switch to supply the 12 v non resistor power needed for the pertronix.
Red 1973 pinto wagon DD, SoCal desert car, Factory 4 speed, 3.40 gears, Stock engine, 14" rims and tires, 60 K original miles

Offline ponyboy

  • Pinto Member
  • **
  • Posts: 60
  • FeedBack: +2/-0
  • Gender: Male
  • '73 woodgrain wagon

  • Total Badges: 5
    Badges: (View All)
    Poll Voter Topic Starter Windows User Tenth year Anniversary Fifth year Anniversary
Re: Engine misfires badly after warmup
« Reply #3 on: June 25, 2018, 11:33:00 PM »
Sounds great. Can you give me a part number? And what all do I need to buy? Does it fit the stock distributor? Thanks. Jerry

Offline Wittsend

  • Pinto Master
  • *****
  • Posts: 2242
  • FeedBack: +241/-0

  • Total Badges: 8
    Badges: (View All)
    Tenth year Anniversary Mobile User Topic Starter Poll Voter 1000 Posts Linux User Windows User Fifth year Anniversary
Re: Engine misfires badly after warmup
« Reply #4 on: June 25, 2018, 11:52:13 PM »
Sounds great. Can you give me a part number? And what all do I need to buy? Does it fit the stock distributor? Thanks. Jerry

Look at their Catalog http://www.pertronix.com/catalogs/pdf/ptx/2018/Pertronix2018.pdf  because there are different versions. I'd avoid the Ingnitor I because if the ignition is left on for more than 30 seconds (without the engine running) you run the risk of burning it up!  I have the Ignitor I on my SBC powered Studebaker and I have a quick release plug under the hood to save it from getting cooked. But it is a pain to remember (or not!).

Yes, the device fits the stock distributor/cap.  A couple of points to understand:

1. The device replaces point, but does exactly what points do. That being it (electronically) grounds and then releases to generate a spark.  This way it works with your stock setup. It does not provide a pulsed 12 + to the coil like so many assume. The "electronics" part is switching on and off to ground.

2. As LTFM already stated the Pertronix itself runs off 12V. And that needs to come from the ignition switch. The coil gets its + voltage through the resistor (again just like stock). A common mistake is that people derive the voltage for the Pertronix from the resistive side of the coil and the lower voltage causes problems.

Offline LongTimeFordMan

  • PCCA VIP
  • Pinto Sr. Member
  • ***
  • Posts: 375
  • FeedBack: +181/-0
  • Gender: Male
  • 1973 Red Pinto Wagon

  • Total Badges: 5
    Badges: (View All)
    Topic Starter Signature Windows User Linux User Mobile User
Re: Engine misfires badly after warmup
« Reply #5 on: June 25, 2018, 11:53:11 PM »
Heres a link to the pertronix website.

Pertronix.com

The tech support number is (909) 547-9058

There are a few options that fit the pinto with the bosch distbutor, the tech support person can provide you with a part umber for the module and coil. You can then source them online from amazon, ebay, summit, etc.

If you use the pertronix coil, it requires a connention directly to the ign switch. The switch is located on the steering column near the clutch/brake pedal support.

The ign wire is red with a green stripe and passes thru a connector on the lect side of the column.

You can splice a direct connection to the ign coil from here.

I can supply some pix if you need them.

Also.. if the problem isnt the ign, then upgrading to the pertronix wont help.

Ill make some pix tomorrow

Red 1973 pinto wagon DD, SoCal desert car, Factory 4 speed, 3.40 gears, Stock engine, 14" rims and tires, 60 K original miles

Offline Wittsend

  • Pinto Master
  • *****
  • Posts: 2242
  • FeedBack: +241/-0

  • Total Badges: 8
    Badges: (View All)
    Tenth year Anniversary Mobile User Topic Starter Poll Voter 1000 Posts Linux User Windows User Fifth year Anniversary
Re: Engine misfires badly after warmup
« Reply #6 on: June 25, 2018, 11:55:54 PM »
There you go, in less than 58 seconds you got two answers!

Offline LongTimeFordMan

  • PCCA VIP
  • Pinto Sr. Member
  • ***
  • Posts: 375
  • FeedBack: +181/-0
  • Gender: Male
  • 1973 Red Pinto Wagon

  • Total Badges: 5
    Badges: (View All)
    Topic Starter Signature Windows User Linux User Mobile User
Re: Engine misfires badly after warmup
« Reply #7 on: June 26, 2018, 12:05:30 AM »
Also.. has anyone actually experienced having  a series I ignitor fail?  I may be lucky but ive had one installed for 3 years with no problems.. i also discussed the "problem" with tech support and they did not seem to be concerned our reliably.

They explained that the difference between the series i and ii was that the ii had the ability to optomize the dwell time but with a 4 cylinder that wasnt critical especially with the pertronix coil.
Red 1973 pinto wagon DD, SoCal desert car, Factory 4 speed, 3.40 gears, Stock engine, 14" rims and tires, 60 K original miles

Offline Wittsend

  • Pinto Master
  • *****
  • Posts: 2242
  • FeedBack: +241/-0

  • Total Badges: 8
    Badges: (View All)
    Tenth year Anniversary Mobile User Topic Starter Poll Voter 1000 Posts Linux User Windows User Fifth year Anniversary
Re: Engine misfires badly after warmup
« Reply #8 on: June 26, 2018, 12:27:50 AM »
I know a number of people who used the Ignitor I in their Sunbeam Tigers and had the unit fry.  When they went to the Ignitor II the problem went away.  Maybe a bad batch?  Maybe that spread into folke lore???? Maybe new versions are redesigned?

 I was fortunate in that I got a rebuilt Delco distributor with the Ignitor I already present for $25 - with shipped off Ebay. Can't beat that price. Me, I'd rather be safe than sorry so if I need the igniton on but the car isn't runnng I pull the wire.

Offline LongTimeFordMan

  • PCCA VIP
  • Pinto Sr. Member
  • ***
  • Posts: 375
  • FeedBack: +181/-0
  • Gender: Male
  • 1973 Red Pinto Wagon

  • Total Badges: 5
    Badges: (View All)
    Topic Starter Signature Windows User Linux User Mobile User
Re: Engine misfires badly after warmup
« Reply #9 on: June 26, 2018, 01:11:54 AM »
Pertronix
ignitor I 1847v
Ignitor II 91847v
Red 1973 pinto wagon DD, SoCal desert car, Factory 4 speed, 3.40 gears, Stock engine, 14" rims and tires, 60 K original miles

Offline ponyboy

  • Pinto Member
  • **
  • Posts: 60
  • FeedBack: +2/-0
  • Gender: Male
  • '73 woodgrain wagon

  • Total Badges: 5
    Badges: (View All)
    Poll Voter Topic Starter Windows User Tenth year Anniversary Fifth year Anniversary
Re: Engine misfires badly after warmup
« Reply #10 on: June 26, 2018, 10:26:55 PM »
OK, I really appreciate all the information. I pretty much get it. I have a lot of experience with the original GM HEI. What goes in the distributer is basically a Hall Effect sensor. I would love to go that way, but since I don't know for sure if the problem is in the ignition, I can pretty much replace the entire ignition system ( wires, cap, rotor, points, condenser, and coil for a lot less with Autozone parts. The only thing left is the distributor itself. It has occurred to me that there could be a mechanical problem with it. I have replaced a number of distributors in other cars, especially '70s cars, due to shaft and bushing wear, which allowed side to side play in the shaft and the cam that opens and closes the points. I've owned this car for 14 years and had very little problems with the points and condenser ignition. I may just go ahead and replace the stock parts, and if that solves the problem, I could go to electronic ignition later. And if it doesn't, then at least it has ruled it out as the cause of the problem. Again thanks for all the help. Jerry

Offline LongTimeFordMan

  • PCCA VIP
  • Pinto Sr. Member
  • ***
  • Posts: 375
  • FeedBack: +181/-0
  • Gender: Male
  • 1973 Red Pinto Wagon

  • Total Badges: 5
    Badges: (View All)
    Topic Starter Signature Windows User Linux User Mobile User
Re: Engine misfires badly after warmup
« Reply #11 on: June 26, 2018, 10:39:52 PM »
Chances are that the problem isnt a mechanical one with the distributor or it would miss all the time not just when hot. The bosch distributors are pretty reliable. If in doubt just check for lateral wobble. Its usually the points, point rubbing block or condenser that fails

I also.spoke to the pertronix tech support today and he verified that the pertronix ignitor I can fail from.overheati ng if the ign is left on. But could not specify a time, just that it should tolerate a few minutes, not just 30 seconds. The ignitor Ii is protected from overheating. The ignitor functions like the points current flows continuously thru coil and module except when it is briefly interrupted by the magnetic pulse as the magnet passes the module.
Red 1973 pinto wagon DD, SoCal desert car, Factory 4 speed, 3.40 gears, Stock engine, 14" rims and tires, 60 K original miles

Offline oldkayaker

  • Pinto Sr. Member
  • ****
  • Posts: 743
  • FeedBack: +113/-0
  • Gender: Male

  • Total Badges: 5
    Badges: (View All)
    Topic Starter Signature Windows User Tenth year Anniversary Fifth year Anniversary
Re: Engine misfires badly after warmup
« Reply #12 on: June 27, 2018, 06:55:54 AM »
Before spending money, inspect the dist. cap terminals.  If they are aluminum, corrosion can become a problem.  Clean both the rotor side and the ignition wire side of the terminals.  My 2.0 started running bad one day and traced it down to corrosion in the cap where the ignition wires plug in.  I scrapped the corrosion out and it ran good again.  Always bought caps with copper/brass terminals after that.  Aluminum oxide is apparently a good insulator.  This is a long shot, but it is a cheap check.
Jerry J - Jupiter, Florida

Offline Wittsend

  • Pinto Master
  • *****
  • Posts: 2242
  • FeedBack: +241/-0

  • Total Badges: 8
    Badges: (View All)
    Tenth year Anniversary Mobile User Topic Starter Poll Voter 1000 Posts Linux User Windows User Fifth year Anniversary
Re: Engine misfires badly after warmup
« Reply #13 on: June 27, 2018, 11:43:16 AM »
LTFM thanks for checking in with Pertronix on the Ignitor I.  While 30 second and a few minutes  (a vague term for them to use) are quite different numbers, it is still a relatively short period of time for one to accidentally leave the ignition on and kill the module.  I wonder why they would continue to sell the module all these years with that "defect" given that they have to warranty it???

Regarding the distributor cap, I have found the curved edge of a hacksaw blade works well to scrape off corrosion on the  internal lugs. A light filing cleans the end of the rotor. And, steel wool works well to clean out the internal plug wire sockets.  Just remember every time they get cleaned the gap is increased. So, at some point they need to be replaced. 

Offline LongTimeFordMan

  • PCCA VIP
  • Pinto Sr. Member
  • ***
  • Posts: 375
  • FeedBack: +181/-0
  • Gender: Male
  • 1973 Red Pinto Wagon

  • Total Badges: 5
    Badges: (View All)
    Topic Starter Signature Windows User Linux User Mobile User
Re: Engine misfires badly after warmup
« Reply #14 on: June 27, 2018, 11:55:34 AM »
Well the ignitor i was revolutionary in its time. I think it first appeared in the 90s when the only other option was the allison optical unit. And Im sure it was used in thousands of vehcles successfully.  It is basically just an on off switch triggered by a magnetic pulse..  so when current flows it gets hot.. but it cant be too sensitive since while the engine is running it is only "off" for a few thousands of a second virtually a 100 per cent duty cycle, but it works ok then.. not much different from being on continuously..

Anyway.. they work if you dont mis connect them and the series ii are available
Red 1973 pinto wagon DD, SoCal desert car, Factory 4 speed, 3.40 gears, Stock engine, 14" rims and tires, 60 K original miles

Offline pinto_one

  • Pinto Master
  • *****
  • Posts: 1001
  • FeedBack: +70/-0
  • Gender: Male
  • Pinto-One

  • Total Badges: 10
    Badges: (View All)
    1000 Posts Photographer Tenth year Anniversary Topic Starter Signature Poll Voter Mobile User Apple User Windows User Fifth year Anniversary
Re: Engine misfires badly after warmup
« Reply #15 on: June 27, 2018, 01:31:05 PM »
the stock 2.0 ign was a very reliable unit when set up right , problems start when parts get changed by persons with no knowlge of what they are doing and some important parts gets damaged , one is the ground strap from the point plate to the bottom plate get removed or broken and later tossed , cheep (china ) point and condenser , or a wrong type of coil installed , good parts are getting hard to find for the old point ign systems , most here just convert to electrnic , some are good and a few will later fail and by then no replacement for it , good news is still used the same 2.0 up untel 2000 in the transit vans , with fuel injection and overdrive automatics ,  last 2.0 I worked on was back in the late 80,s and my converion was around twenty buck at the wrecker yards , I use to work at a ford ,volvo and mercides dealer, late 70s , found you could take the 78 up volvo guts and install them into the pinto unit , yes the are both bosch units , yep they take the same caps and rotors like the bug engines , used the volvo ign module (never seen one fail) and the stock bosch blue coil , they put out some spark , used the wire that ran to the stock coil to a relay (so I would not have to remove the dash to get at the resistor wire inside of the harness ) and ran the full 12 volts to the relay from the battery , but back to the same problem , how many 78 up volvos can you find now , or you can check out england e-bay motors and find a stock electrinic 2.0 unit and use a GM ign module on it ,  this is what I have done in the past , hope its of good use to someone here ,
76 Pinto sedan V6 , 79 pinto cruiser wagon V6 soon to be diesel or 4.0

Offline Srt

  • Original Pangra Master Builder
  • PCCA VIP
  • Pinto Master
  • ***
  • Posts: 1339
  • FeedBack: +100/-0
  • Gender: Male
  • Pinto Stampede ROCKS

  • Total Badges: 10
    Badges: (View All)
    Topic Starter Signature Tenth year Anniversary Poll Voter Linux User Mobile User Windows User 1000 Posts Fifth year Anniversary Photographer
Re: Engine misfires badly after warmup
« Reply #16 on: June 27, 2018, 03:35:15 PM »
did you check your plug wires?
the only substitute for cubic inches is BOOST!!!

Offline ponyboy

  • Pinto Member
  • **
  • Posts: 60
  • FeedBack: +2/-0
  • Gender: Male
  • '73 woodgrain wagon

  • Total Badges: 5
    Badges: (View All)
    Poll Voter Topic Starter Windows User Tenth year Anniversary Fifth year Anniversary
Re: Engine misfires badly after warmup
« Reply #17 on: July 01, 2018, 02:30:22 PM »
Plug wires were new when I replaced the engine with a rebuilt one about 10 years ago. They still check out ok. But the engine starts up and runs fine until it warms up. It idles perfectly. For now I have decided to go with stock parts, to see if the ignition is actually the problem. I found everything at O'reillys. I got a new coil, points and condenser, cap and rotor. If that doesn't help I'll replace the wires. Not expensive. That's the entire ignition system except for the distributor. I could not find any play in the distributor shaft, but it takes very little. But as was said, it runs fine to begin with. I haven't had a chance to replace the parts yet. I'm in Phoenix, AZ, and I work in the A/C business. Pretty busy right now.

Offline Wittsend

  • Pinto Master
  • *****
  • Posts: 2242
  • FeedBack: +241/-0

  • Total Badges: 8
    Badges: (View All)
    Tenth year Anniversary Mobile User Topic Starter Poll Voter 1000 Posts Linux User Windows User Fifth year Anniversary
Re: Engine misfires badly after warmup
« Reply #18 on: July 01, 2018, 04:40:29 PM »
Does your car still have the "Decel" valve?  That is the only thing I can think of other than ignition or carburetor. We will see when you do the ignition parts swap.  If that doesn't help I'd look and see if the careb fuel level to too high. You stated it was getting plent of gas so I'm assuming it is not starvation, but it could be fuel spilling out the bowl vent.

Back to the Decel valve ... . My understanding is it bleeds air under de-acceleration (hence the name). If that is tripping too early or jamming open it might be a cause.  Most people have removed them but you may need it for a smog test in AZ.  So, it may be present.

Offline ponyboy

  • Pinto Member
  • **
  • Posts: 60
  • FeedBack: +2/-0
  • Gender: Male
  • '73 woodgrain wagon

  • Total Badges: 5
    Badges: (View All)
    Poll Voter Topic Starter Windows User Tenth year Anniversary Fifth year Anniversary
Re: Engine misfires badly after warmup
« Reply #19 on: July 04, 2018, 12:56:03 PM »
All emissions parts except the PCV valve are gone. It does not have to pass AZ emissions, because I have it insured and registered as a collector car. I haven't had a chance to replace any of the parts yet, but I may have a lead on the problem. It could be the condenser. I have the Haynes manual 204, which covers the Pinto through 1974. In chapter 4 page 119 step 5, it says "If the engine becomes difficult to start or begins to miss after several miles of running and the breaker points show signs of burning, then the condition of the condenser must be suspect" I checked the points when I adjusted them, but maybe didn't get a good enough look at them. The distributor is buried down beneath the alternator bracket, and it's hard to avoid shadows when looking down there with a flashlight. I may remove the alternator and bracket for better access. I have new points, condenser, cap and rotor. I'm going to replace all of that stuff, and see if it solves the problem. I'm about 90% sure it's the ignition system, there is not much in a carburetor that can suddenly go wrong, especially since the choke and all  emissions crap have been removed. It's supposed to hit 110 degrees today, just too hot to work on a car in the driveway. I can't use it right now anyway, the A/C doesn't work. No parts or refrigerant available to repair it. A whole new aftermarket system would have to be installed, that's about $2000 worth of parts.