Ignition Troubles

[66Sprinter]

I have a strange problem that I want to post for some ideas on diagnostics.

First...car is well tuned considering the 1101 and the mods. Cold start is instantaneous with the DUI..driveability is also acceptable. No hesitations or stalling, pops or strange anythings. I am using a relay inline with the ignition switch to open the 12V line to the DUI.

Cold days...start run...local trips, start run and park in garage. No problems.

Warm days (80 def F+) Cold start great...run local trips...restart nada. Wait 1/2 to 1hr...(get colder) and starts great. Run 1hr with no problem. pull over and restart nada. Wait again for 1/2 to 1hr and I am back in the garage..scratching the going bald head.

I have replaced the relay...no change. I have confirmed that the reason for no start is no spark from the DUI? Can this be an ignition switch..(I have not replaced the original..so its old) It is temp related...and kinda crazy..but really frustrating.

If you can ...just send me your ideas..heading back to STL on Friday nite.

Thanks...Jim

 

[ludwig]

Use the search function for 'heat soak'. That sounds like what you have. Change the ignition switch. It is cheap: +/- $25. You can check the spark by pulling one out and holding it against the head while the engine cranks. Look for the spark that way (with a helper).

 

[mean_maverick]

if nothing else, maybe the module itself is getting too warm for some reason....?

 

[fordconvert]

If you have power goin in and nothing going out I would suspect the module. Its under the rotor. Its the only thing that is likely to be heat sensitive. The coil is not oil filled so its not likely to have that problem. Modules can be had as low as $15 but I would not trust one that cheap. If you need a car pick something common like a 1977 Chevy truck with a 350, every store should stock a module for that application. MSD, Acell, jacobs, ect... also sell modules, a 4 pin module is a 4 pin module. Davis claims theirs are special, its hard to tell. I guess they do contain a microprocessor so there is in theory some options for tuning.

If it was older I would be suspect of connections and the lead wires from the pickup coil but since its fairly new those should not be an issue.

I have seen people put the button and washer in wrong under the coil. The button goes in the cap first then the washer. All that contacts the coil is that little spring. If its put in the other way the button does not stick through the cap far enough to make contact with the rotor. They will run for a while like that but it makes a mess of things. Good part is the washer and button come with the new cap and it usually does not hurt the coil.

 

[LEROY POLL]

HI JAMMER


.....FIRST BYPASS THE RELAY. ANY RELAYS THAT IS NOT CORRECT WILL ALSO HAVE TO COOL DOWN WHEN OUT OF THEIR OPERATING RANGE. HEAVY AMPERAGE WILL HEAT UP THE RELAY AND NOT RESET BECAUSE OF TOO MUCH HEAT.

.....IF IT IS NO SPARK..... THEN JUMP A WIRE ACROSS THE RELAY. THEIR IS NO MONEY SPENT IF THAT IS THE PROBLEM. THEN BUY THE HIGHER RATED RELAY.

.....SECOND DO WHAT FORDCONVERT SAID.

LIVE IN GRACE

LEROY POLL

 

[66Sprinter]

Guys,

Appreciate the suggestion. I had time today so here is what I did. First, it is about 40 def F here in St. Louis, so there was no problem getting it started.

I pulled the carb. Reason? I had a 1.5 to 1.75 adaptor for the 1101. I had milled the lower side (log side) to 1.75, which left a very thin footprint. I replaced both the carb and manifold gasket, assumption here was that I had a vacuum leak.

Next i pulled another relay and just swapped it out. (It either is or isn't bad) I am using 30amp relays...since it is the power wire.

I did not pull my igition switch. But I did use a VOM and traced all the voltages. Good...no problems. The car started just like always. Kicks by the 1st rev...so I couldnt tell if I made a dent in this or not. I had a can of elec freeze nearby just in case I needed to spray the inside of the switch (like testing diodes) but didn't need it. I have plans to purchase a new ignition switch and try to get it installed over the T-day weekend. (Anyone nearby can come and help - I will be frying two 12lb turkey breasts..so we have enough to spare.)

I also have the phone number to Davis..so next week I give them a call and give them the serial #. I just want to explain the situation and see what they say.

Short of driving to Dallas, (warmer weather) I may not get this resolved till the next real warm day or next summer. Still open for any other suggestions. Thanks for the input...very much kind friends!

Jim

 

[Vin Man]

I had a very similar problem with the motor in my 80 Jeep CJ5. It is a 258 cubic inch inline 6.

After lots of trouble shooting, suspecting a bad electronic ignition module, and lots of other stuff, I replaced the starter solenoid. That turned out to be the problem. Not sure if you have the same root cause as me, but the symptoms are extremely similar. Good luck.

 

[66Sprinter]

I have a new starter...but not a new soleniod.....since I upgraded to a 428 hi-torq starter (small profile for the headers) this may be exactly what the problem is.

I know you said same symptoms...but my car will crank...but no spark. are we sure its the same symptoms?

Jim