ignition wiring problem
Thread Starter
|
New User
Joined: Dec 2004
Posts: 19
Likes: 0
ignition wiring problem
Bear with me here. I have been working on my Dad's '83 F150 with a 302 and dsII ignition. I have had many problems diagnosing this beast. I have replaced all the ignition parts with new, compared all voltage and resistance values to my '86 that I converted to dsII. Now I even put an Accell 300 box and tfi coil on it. All have the same symptom, sounds like it wants to start, but will not.
Put the switch in run mode and use a remote start switch and it fires right up. In case of a short in the starter switch, I've replaced that as well. I know ignition systems and have converted many to Accell and MSD. This one has me puzzeled. Any ideas?
Put the switch in run mode and use a remote start switch and it fires right up. In case of a short in the starter switch, I've replaced that as well. I know ignition systems and have converted many to Accell and MSD. This one has me puzzeled. Any ideas?
Elder User
Joined: May 2004
Posts: 506
Likes: 0
From: Edwards Air Force Base
I don't know DSII but if it is like my old 85 grand marquis and you have a TFI module on the distributor, you likely got a bad one from the parts store if you already replaced it. There is a separate "Start" circuit and "Run" circuit in it.
My 85 did the exact thing you are describing in the middle of a blizzard. I couldn't figure it out back then, finally let a "professional" repair shop have a go at it and they couldn't figure it out either. Finally a dealer told me it sounded like the TFI. I towed it home, swapped the TFI and it started right up. I have seen a few more on friends vehicles since then do the same or the opposite where they start but then soon as you let off the key they stall out because the start ciscuit is working but the run side went bad.
If it isn't that or the DSII is different, then the only thing I can think of would be the actual ignition switch. They are famous for cracking and only having half the switch move. It is up under the dash mounted on top of the column.
Hope this helps.
Lee
My 85 did the exact thing you are describing in the middle of a blizzard. I couldn't figure it out back then, finally let a "professional" repair shop have a go at it and they couldn't figure it out either. Finally a dealer told me it sounded like the TFI. I towed it home, swapped the TFI and it started right up. I have seen a few more on friends vehicles since then do the same or the opposite where they start but then soon as you let off the key they stall out because the start ciscuit is working but the run side went bad.
If it isn't that or the DSII is different, then the only thing I can think of would be the actual ignition switch. They are famous for cracking and only having half the switch move. It is up under the dash mounted on top of the column.
Hope this helps.
Lee
Thread Starter
|
New User
Joined: Dec 2004
Posts: 19
Likes: 0
The dsII also has separate run and start curcuits. The start curcuit is the one giving me grief. The starter switch is good but I replaced it anyway. I guess my next move is to check the power wire from the starter relay to the starter switch.
Fleet Owner
Joined: Sep 2005
Posts: 28,609
Likes: 18
From: Lake Tahoe, Nevada
Your starter solenoid should have a terminal labeled "I" which delivers current to the ignition during cranking. Check for voltage there. If it is hot while cranking, trace that wire to the ignition to see if it's hot there. If it is not hot on the "I" terminal, then the solenoid is at fault.
Thread Starter
|
New User
Joined: Dec 2004
Posts: 19
Likes: 0
I have given up on the harness problem for now and bypassed the whole start curcuit by running a wire direct from the start side of the relay. I also realize this will bypass the saftey switch. I may replace the wire harness next spring. Thank you.
Posting Guru
Joined: Jun 2004
Posts: 1,635
Likes: 0
From: Niceville, FL.
Power to the Ignition Module in "Start" is provided through its white wire. Should be at least 9 volts on the module white wire while cranking.
Trending Topics
Thread Starter
|
New User
Joined: Dec 2004
Posts: 19
Likes: 0
On this truck, the start wire at the module is the red wire with a blue stripe. It runs from the ignition switch to the nuetral saftey switch to the ignition box and the solenoid. This wire is under 6 volts when it's cranking. The white wire is the run mode.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
Posting Guru
Joined: Jun 2004
Posts: 1,635
Likes: 0
From: Niceville, FL.
Red/Light Blue harness (start) wire should connect to White module wire at module connector (C321). White/Light Blue Hash harness (run) wire connects to Red module wire at same connector. At any rate, I think 6 volts is too low. As a test you could disconnect the white module wire at the connector and jumper it (the White module wire) directly to the battery (+) terminal and try starting. If it starts ok then you know the problem is the low voltage coming via the Red/Light Blue wire.
Thread Starter
|
New User
Joined: Dec 2004
Posts: 19
Likes: 0
That's what I did, I went right from the start side of the solenoid to the ignition box and it fires up fine, so I know that the problem is in the harness. I've already replaced everything that the start wire goes to. At a later date I will change the harness. Thanks.