Starting problems

[silver87]

I have a 1988 mustang notch and now have a 351w carb'd engine in it. it was originally an auto but now has a tko600 in it. My problem is I know it has no clutch safety just the jumper wire plug from factory. When I got the car it was efi and I took all efi harness out. The car ran when it was fuel injected. When I try and start the car now it cranks over but I do not get spark. When I jump the starter solenoid I have spark. This happened on my buddies car also, he has a 5 speed mustang now with carb on it and same problem. He had a clutch safety switch installed in his but when the clutch safety plunger was depressed no spark and the only way it would start is by jumping the solenoid. Does anyone have any ideas?
thanks

 

[jrichker]

Electrical problems are common with EFI to carb versions. There is no telling what was cut, crosswired or RKE'd (Road Kill Engineered). There are no standard wiring diagrams for a conversion, and almost no way to troubleshoot the problem over the Internet.

Get out your wallet and find a local automotive electrical whiz... OUCH!!!

Proper way to wire the ignition is a Durspark or similar ignition system with a mechanical spark advance. The EFI ignition depends on the EFI sensors to advance the spark. Rip out the TPS and MAP/Baro sensors and and wiring, then the computer will have no idea of the proper ignition timing for best performance. Running a fixed timing setting is only for test purposes or for a race track only car. Don't try it on the street: the results will not be nearly as good as a properly setup Durspark or equal. Crane makes a really nice distributor for non-EFI applications. . See CraneCams for more information.

Duraspark wiring diagram

Do a google search on duraspark wiring diagram for more help.


Diagrams courtesy of Tmoss & Stang&2birds These reflect the stock EFI wiring

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring Mustang FAQ - Engine Information Everyone should bookmark this site.

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/91-93_5.0_EEC_Wiring_Diagram.gif

Complete computer, actuator & sensor wiring diagram for94-95 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/94-95_5.0_EEC_Wiring_Diagram.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

HVAC vacuum diagram
http://www.veryuseful.com/mustang/tech/engine/images/Mustang_AC_heat_vacuum_controls.gif

TFI module differences & pinout
http://www.veryuseful.com/mustang/tech/engine/images/TFI_5.0_comparison.gif

Fuse box layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

 

[silver87]

I have the msd 6al box with blaster coil.

 

[jrichker]

I have the msd 6al box with blaster coil.

According to the MSD website, the 6AL does not have a means to advance the spark from the inital static setting. That means you need a 70's vintage 351 distributor or one of the aftermarket types like the Crane with the advance built in. No fancy distributor, no spark advance and lower performance.

MSD wiring diagrams

 

[silver87]

but I have spark if jumping the lugs on the solenoid, no problem starting, just No spark when using the key in the ignition

 

[silver87]

up

 

[jrichker]

Follow the diagram I posted showing the wiring coming from the ignition switch. The red/green wire goes directly to the ignition coil. No power to the red/green wire, no spark when you put the key in the Run position.

 

[silver87]

Am I an idiot or is this problem common from doing efi->carb swap with ignition. I will follow and test wires tomorrow to make sure everything is ok. I am just blown away that everything worked before I pulled the computer and efi wiring harness now I dont get spark when using the key but get spark when jumping the solenoid and I havent changed anything with regards to ignition.

 

[hotcobra03]

just a reader

Am I an idiot or is this problem common from doing efi->carb swap with ignition. I will follow and test wires tomorrow to make sure everything is ok. I am just blown away that everything worked before I pulled the computer and efi wiring harness now I dont get spark when using the key but get spark when jumping the solenoid and I havent changed anything with regards to ignition.

when you say it starts when you jump solenoid,,is that with just the key on or are you also jumping 12volts to coil..?

 

[hotcobra03]

my thought is on the starter solenoid,,on the older ones we used to switch the 2 plugs to stop someone from taking our car ,it would crank all day but never start

 

[jrichker]

If you had looked closely at the ignition switch diagram, you would have seen that there is a red/green wire that feeds the ignition coil and computer power relay. It should have power when the key is in the Run position. If it does not, check the fuse link shown in the ignition harness to see if it is open.


Diagram courtesy of Tmoss & Stang&2birds

Hopefully you are not still trying to use the orginal TFI distributor. If you are that is part of your problem.

 

[silver87]

Nope, got the carb dist.


hotcobra03---When you say you used to switch the wires on the solenoid and would crank but not start, what exactly do you mean, it is possible I have the wires crossed on the solenoid, is the a picture or diagrma I could look at to see what wires go to what side of the solenoid?
thanks for the help guys

 

[hotcobra03]

learner

Nope, got the carb dist.


hotcobra03---When you say you used to switch the wires on the solenoid and would crank but not start, what exactly do you mean, it is possible I have the wires crossed on the solenoid, is the a picture or diagrma I could look at to see what wires go to what side of the solenoid?
thanks for the help guys

hey most likely you have things right...reading back and searching thru that crazy wire diagram this is my thought,,,key on car starts when jumped..that tells my on your ingnition switch,b5 to l1 in the run position is closed and you start switch b4 to a4 is good...when b5 to l1 is in the start position a jumper wire by passes power back to l1 to power coil..did you maybe hit something when changing pedals in conversion?i have not located this jumper wire but looks like if it just was on the back of harness plug for ingnition switch

 

[silver87]

everything in the dash plus pedals is exactly how it was when I drove it home, nothing has changed.

 

[hotcobra03]

switch

everything in the dash plus pedals is exactly how it was when I drove it home, nothing has changed.

look at this its almost like yours ..b5 to l1 that is to coil...b4 to a4 is starter..

 

[jrichker]

Starter solenoid wiring for 86-91 Mustang

Starter solenoid wiring 92-93 Mustang or upgraded high torque mini starter.

 

[hotcobra03]

nice pic i will keep that,,, what do you have on the start bypass wire,,,,,from his story i wass looking for what key in start does....he could just ckeck it with test lite at coil ...if his lite goes out when cranking that a good spot to start ..thats when i found bypass wire...

 

[jrichker]

The diagrams are Visio drawings. Photos have too much stuff in the background to be helpful when you are looking at a bunch of wires.

The red/blue wire is the power from the ignition switch to close the solenoid contacts. On an EFI car with the stock distributor, the red/blue wire also connects to the TFI module. It is used to tell the ignition system to add more dwell when cranking the car. More dwell at slow cranking speeds means more spark for starting.

 

[hotcobra03]

jumper

The diagrams are Visio drawings. Photos have too much stuff in the background to be helpful when you are looking at a bunch of wires.

The red/blue wire is the power from the ignition switch to close the solenoid contacts. On an EFI car with the stock distributor, the red/blue wire also connects to the TFI module. It is used to tell the ignition system to add more dwell when cranking the car. More dwell at slow cranking speeds means more spark for starting.

ok looked in all my books and they are all the same..lets use your pic on ignition switch,,,circuit 16 is run next to it is circuit 262...see brown wire goes into red .look closer and you see a small black line that loops from 262 to 16....your pics doesnt show inside of switch like my pick did..your pic i also have in fords book,it tells how to ckeck switch,and notes circuits 37,687,297 are connected internally,than notes about no crank conditions.in start 262 should have continuity...also at tft 3 wires come out of thier ,pin 2,3,4 and shows how to test thier...
i still will look at this more that pic was colorfull

 

[hotcobra03]

tfi harness?

The diagrams are Visio drawings. Photos have too much stuff in the background to be helpful when you are looking at a bunch of wires.

The red/blue wire is the power from the ignition switch to close the solenoid contacts. On an EFI car with the stock distributor, the red/blue wire also connects to the TFI module. It is used to tell the ignition system to add more dwell when cranking the car. More dwell at slow cranking speeds means more spark for starting.

what can you send me on tfi harness...in your pic circuit 16 goes to pin 4 on tfi..the test i have for tfi has pin 3 as start and runcircuit,which goes to positive terminal on coil than to ignition switch. and pin 4 as start circuit.it also goes to ignition switch, than pin 2 is has for neg terminal on coil .