Here's the deal..
The car sat since 2006, and I got her running finally after lots of work. The car now has a #4 cylinder missfire that seems to clear up on the higher RPMS. Listed below are the tests and/or repairs...
Compression test with results: 1- 150 2- 150 3- 155 4- 160
Changed all 4 plugs & wires, swapped the distributor with a different unit, checked all 4 wires with the timing light to see if they were hitting, cam timing- on the dot
Tested ignition coil- within specs on both primary & secondary circuits
Had module checked & it tested good at Advance Auto
Everytime I pull the number 4 plug it is getting fouled out with gas. All the other 3 plugs are firing with no problem.
What should I check next?? ???
Matt, if you are SURE you have a good, hot spark on #4, (pull the wire with it running and see if you get any change) you may have mechanical issues. Like a worn cam lobe. That can give you a miss at idle and smooth out as you rev the engine. Usually gives a tap tap noise as well.
Replaced the cam in 2007 with a roller cam, so I doubt it is that. One reason it wouldn't be mechanical is just yesterday the car had lots of problem starting but whenI did get her started she ran so smooth you woulda thought she had a brand new engine & all. When I get off work tomorrow I will try what you suggested and pull the spark plug wire off when the car is running.
Oh, forgot to mention... no tapping noise whatsoever.
Yea, with the roller you're good. Be sure to use insulated plug wire type pliers so you don't get bitten!! :surprised:
Did a little research for you. My pinto book says a bad PVC, ruptured fuel pump diaphragm, or too cold a plug. Have you rebuild this engine yet? Hope this helps!!
Actually I just got done with a tranny swap, as well as rebuilding the engine.
Gee wheez, I took that from the Holy Chilton Bible! Did you use discount air in your tires, then?
That explains lots :lol: I have found more mistakes in the Haynes & Chilton books when compared to the Ford book it ain't funny. I have all of them in case one helps more than the other. Funny thing. According to the Haynes book my ignition coil is bad. According to the Ford book it isn't. Chilton didn't have any specs to go by at all.
Try a different spark plug, or switch places with another plug. I have had brand new spark plugs that are cracked or something, and ground out on the head or spark somewhere other than where they should causing a dead cylinder. That problem was very frustrating because I never would have suspected a bad plug since I had JUST replaced them.
vacuum leak?
Quote from: pintoguy76 on June 29, 2009, 01:45:25 AM
Try a different spark plug, or switch places with another plug. I have had brand new spark plugs that are cracked or something, and ground out on the head or spark somewhere other than where they should causing a dead cylinder. That problem was very frustrating because I never would have suspected a bad plug since I had JUST replaced them.
That's what stumped me. I put in another spark plug & fouled out just as bad.
What srt said.
Have you checked the firing order to make sure it is correct? 1-3-4-2. Been there done that, too. ;D :D ;D :D I had it set to 1-4-3-2 and it would start and run but missfire pretty bad. If its not that you might check to see if raw fuel is going down the intake. Other than that I am stumped. The intake valve is pretty obviously working since the plug is getting wet. You have compression also. It cant be the exhaust valve, because the fuel would atleast burn in that case and when the intake valve opened it would push all the exhaust back up into the intake and then youd really have some nasty issues. The only other problem would have to be, in some absolutely crazy once in a life time deal, where the spark plug cant get a ground in the head, Which I just cant see happening since it screws into the head and seats down against it. There are so many ways it can get grounded.
Well the plugs are out of the engine so I can't say for sure where I had the wires on but I'm about 99 percent sure it was correct. As for a possible vac leak, the top plug on the vacuum tree was shot. While it looked to be on and sealed I went to remove it & had no resistance at all. There was also a small brake bleeder screw dust cap on a smaller tee. When I go to the parts store to get another spark plug I am going to get those plugs replaced on the vacuum tree as well.
My guesses the plug or wire are bad for #4. Or the cap or rotor are bad and not making contact for #4.
Checked the cap & rotor when I first noticed the miss & they are good. Replaced the wires & rechecked the #4 wire yesterday. I substituted a known good plug in the #4 cylinder and ended up with another fouled out plug.
Makes no sense. Everything everyone is suggesting seems to make no difference. I am beginning to think the car is just mad because I woke her up from her two year sleep.
Even further out guess, is the rotor OK in the distributor?
Was a vacuum leak on the tree mounted on the number 4 intake runner. I replaced a couple rotted caps on the tee & she fired right up with zero missing. The distributor in the car currently has a broken electrical connector & burned up wiring so I'm gonna go ahead and swap that out with a different one.
Good job Matt. Now go out and :fastcar: that thing.
Funny you mention that Gerhard... I just got back from driving her around the block. I can't drive her any more than that because she doesn't have current tags or insurance but I still loved the looks I got from the neighbors & a guy in an old Ford F150.
During all the excitement of getting the car running I failed to thank those that pointed out the problem of the vacuum leak. While earthquake & SRT both said it could be a vacuum leak, Bill AKA 77turbopinto pointed out the vacuum tree was more than likely the issue.
Thanks to all that helped me out, and Bill for pointing out the vacuum tree in the #4 cylinder could cause a problem like I had. Now to get the car all legal to drive ;D
the solution to your problem points out EXACTLY what is great about this 'community' of Pinto enthusiasts.
it has probably already happened to someone else and all you had to do was ask!
now that's cool
What srt said ;D.
Matt,
Congratulations on getting her running - I knew if you hung in there long enough, it would all work out!
Dwayne :smile:
Ah, He's just trying to show off for Blu and make me jealous because mine ain't running! :P
Is it working?? Blu's gotta be impressed lmao.