I am running a 351W with a 302 cam in the 54. I just cant figure out this electrical (?) froblem. After about 1k miles of no problems, coming home the other day, the engine started running rough. I have been running Accel electronic ignition. It appeared that i had an electrical problem .My first thought was the Accel was dying..... Threw the timing light on each spark plug wire and found the center two cylinders on each bank were dead. ( weird). It runs on 4 cyl but barely. Verified live cyl by use of infrared temp gun...... Heres a list of what i have tried. Installed old set of points, rotor and cap..Verified points were gapped corect Tried 3 coils New plugs Swapped some plug wires. Problem stayed with original dead cylinders Did compression check..all 140 to 160 Measured all plug wire for correct ohms reading Tried spraying starting fluid while it was running to see if the others would catch It is definately a lack of spark problem My next test is going to be on the workbench. Distributor, plugs, wire all coming off. Anyone have any thoughts on this one Thanks for any advice. 65 yrs driving i havent had a problem that has stlumped me like this one
Not sure how this would happen if it ran 1000 miles with no problem but with those holes dead and with good compression has the firing order been messed with? 302's up through 1981 have a different firing order than a 82 and newer 302 and the 351. Usually this type of thing happens when someone puts a 302 HO (later year model) cam in an earlier engine. A 81 or older 302 cam in a 351 will require a different firing order, the early 289/302 order. It will cause 4 cylinders to not be able to fire if the wrong firing order is used. Just a guess.
Have you tried turning the engine over and watching the rotor to be sure its not somehow jumping? I can't think of a lot that wold kill fire on 4 cyl and leave 4 firing. If I am reading you correctly you have no fire on the 4 center wires. The only thing that controls which wires get fire is the rotor and distributor cap. If firing but not in time lots of reasons but no fire at all makes it a puzzle for sure good luck
Yes a mystery..I am starting to think maybe the plug wires are marginal and finally starting to fail. I will let u all know when i figure it out
This makes no sense even as I type it when you mention the symptoms, but have you swapped the condenser? I have had multiple bad condensers in the past few years and one that stumped me for about 6 months since I was sick of messing with it. My car had real poor spark and would hardly run. I thought I was chasing carburetor issues with some old Holley 94’s until I finally noticed the weak spark on a freshly rebuilt distributor. I swapped the condenser, and it ran like a champ for the next 20k miles...
Finally got this problem sorted out. Turned out the original electronic ignition failed...Then when i put the original points in, the condenser was bad. Replaced the condenser and it helped but the spark was just not right. (Probably bad new condenser) as guthiesmith mentioned. Finally installed another electronic ignition and that finally got thing going like new. Well Almost. In the course of all this, if found the shaft in the distributor is pretty worn, so am now waiting for new distributor to arrive and will put it all together again... that should be it. Thanks for the input guys. To many bad/marginal things can make diagnosing tough sometimes
I'm glad you found the problem. Do you mind telling us which electronic ignition you selected this time?
Originally installed Accel points eliminator kit into the original motorcraft distributor. It worked great. I think i probably killed it when i accidentially left the ignition key on for a number of hours. The coil was red hot when i discovered it..The ignition worked fine for about 150 miles then this problem.. The ignition i am puting in is a TFI-IV module from mid-late 80s fords. The module Has internal dwell and is triggered by the points so it makes for an inexpensive conversion. Reason i am going with this is because it is remote mounted heat sink and the modules are cheap and easy to get if i need one on the road. I can mount this inside out of the heat. I decided i didnt want to go with proprietary parts that arent readily available. If anyone is interested in alternative ignition here is a website with some info. gofastforless.com
Might be interesting to show how you wired it in too. So you still have points ? Kind of like the older aftermarket CD ignitions.
Back in the 80’s our company used Ford vans for business. We had so many problems with those modules that I bought a spare for each van and showed the drivers how to replace them. Many were replaced at the side of the road.
Replaced my share of those while I was still working. They were better when they moved the module off the distributor to the remote heat sink like you have there. The ones mounted on the distributor would melt the stator connector they got so hot.
Yep in 77 for sure they were on the front side of the inner fender. In 1978 they were moved to the rear. I was service writer for a LM dealership and the 78’s were nothing but problems. Let them sit with the hood up and 20 minutes all was fine.
I knew about the heat problems, but thought i would give it a try. Thats why i installed inside on the kick panel.. Time will tell if it was a bad decision. I will definately carry a couple spares with me. Thanks guys
Been dealing with those Ford TFI's for years in my turbo cars. Parts store modules are fine but spring for the Motorcraft modules. About $100 but way more reliable. You will be just fine with it mounted to the inside of the kick panel. I'm using one on the roadster. It's mounted to the inside of the frame. No issues. Also had one in a Turbo Coupe. Took it off the distributor and mounted it to the inner fender and used the heat sink from an Aerostar van. Made a S/S cover to ward off heat. Worked great for years.
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