Stupid question but I have to ask.

[stinkydogfilms]

Is there a relationship between the starter solenoid and the coil?

[Brown_Muscle]

They are completely separate systems, if that is what you're asking.

[stinkydogfilms]

Thought I read the coil fires off of the solenoid switch.
My solenoid switch stuck on and after I replaced it
my coil need replaced. It was stuck for about 2 minutes. After about a minute I was able to disconnect the positive cable. That shut the engine off, but the switch and starter kept turning the flywheel for another minute. Thankfully the starter did not grind or get wore out.
My car has one of those amp capacitors and when that ran down the starter quit.

[JeffBoudah]

Kind of if you have a duraspark. Solenoid sends full 12v ignition bypass to the coil durning crank. Let off the key coil gets a ballast resisted 6v.

[mercurygm88]

Kind of if you have a duraspark. Solenoid sends full 12v ignition bypass to the coil durning crank. Let off the key coil gets a ballast resisted 6v.

Unless your duraspark box or crank position sensor fails. Then you have no spark, I learned that the hard way.

[gadget73]

CFI cars also power the ignition system off the I terminal in the starter relay. Those run TFI but there are two power inputs, one for key-on, one for cranking power. For whatever reason Ford ignition switches do not have any terminals that are live in both On and Start. Later cars tie directly into the start circuit for this.

[Arquemann]

CFI cars also power the ignition system off the I terminal in the starter relay. Those run TFI but there are two power inputs, one for key-on, one for cranking power. For whatever reason Ford ignition switches do not have any terminals that are live in both On and Start. Later cars tie directly into the start circuit for this.

If I understand this diagram correctly, the coil would get voltage on RUN & START, even with the I terminal wire disconnected:

[gadget73]

maybe thats an 84 thing then. I see the circuit from "start" feeds to both the solenoid and the TFI like it does 86+.

[Arquemann]

If I'm not mistaken, my '85 CFI has a cranking only power feed from the starter solenoid to the fuel pump relay, even though the primary fuel pump power source is straight from the battery.

[gadget73]

fuel pump feed should be constant hot, the pump relay coil is a ground switch from the ECM. I do see that its got a feed out from the I terminal to something on the ECM page, but no idea what that does. Might be the input for engine cranking. SEFI computers have one at least. They will start if you don't have that hooked up but it starts harder and makes the idle really goofy for a bit. The crank input tells it that the engine is being started so it can do stuff with the idle and timing to help that happen.

could also be what keeps power fed to the ECM relay. The hot side of those relay coils comes from the ignition switch. If its tied to a circuit that drops when you crank it, the ECM will not be powered when the engine is spinning so it won't start.

[Arquemann]

Diagram shows two power feeds to the FP relay, one HOT IN START and the other HOT AT ALL TIMES.
And the car started and ran just fine with the "I" post disconnected.
I can have the diagram tomorrow, just dont have it on my phone.

But we're digressing a wee bit aren't we?

[gadget73]

yea but thats never been a good reason to stop before

possible the pump doesn't run when cranking and it just goes off residual pressure unless that is hooked up? dunno.

[stinkydogfilms]

The gremlins are back.
Friday replaced the 1 year old ECT sensor, the coil and solenoid switch.
It intermittently started. Drove around 15 miles without issues. It started up 5-6 times.....no issues.

SAT am.....long time starting....30 seconds or more..... changed plug wires, spark plugs , distributor cap and rotor. drove 5 miles around the neighborhood....no issues....started 5-6 times ..
SUN am ..today started up....drove 4 miles..no issues.... 3 hours later took my daughter to work 10 miles round trip...last 1-2 miles started to have a miss and want to cut out at stop signs. Would not start anymore.
An hour later Got home took off the TPS and put another one on....no luck... put the old one back on and it started...then it had a fast idle and bounced between a fast idle1500 rpms and normal 800-900 in park.
Putting in gear the idle stayed at 800-999.
Today a new air filter.
Old one was 1 year old.
Put new IAC on....cleaned the MAF sensor. both including the TPS and 65mm Throttle body...are 8 months OLD...car is starting and running...I've cleaned the TB with TB cleaner.. and the MAF with MAF sensor cleaner...
Fuel pump seems to be fine.
I can't get the code reader to pick up any codes and the check engine light has never came on.

Sorry to ramble incoherently, but I'm frustrated and I'm waiting with the negative cable off after replacing the sensors.
Fuel filter? TFI or PIP next?
I appreciate the help you guys have always given me.
THANK YOU

[mercurygm88]

The gremlins are back.
Friday replaced the 1 year old ECT sensor, the coil and solenoid switch.
It intermittently started. Drove around 15 miles without issues. It started up 5-6 times.....no issues.

SAT am.....long time starting....30 seconds or more..... changed plug wires, spark plugs , distributor cap and rotor. drove 5 miles around the neighborhood....no issues....started 5-6 times ..
SUN am ..today started up....drove 4 miles..no issues.... 3 hours later took my daughter to work 10 miles round trip...last 1-2 miles started to have a miss and want to cut out at stop signs. Would not start anymore.
An hour later Got home took off the TPS and put another one on....no luck... put the old one back on and it started...then it had a fast idle and bounced between a fast idle1500 rpms and normal 800-900 in park.
Putting in gear the idle stayed at 800-999.
Today a new air filter.
Old one was 1 year old.
Put new IAC on....cleaned the MAF sensor. both including the TPS and 65mm Throttle body...are 8 months OLD...car is starting and running...I've cleaned the TB with TB cleaner.. and the MAF with MAF sensor cleaner...
Fuel pump seems to be fine.
I can't get the code reader to pick up any codes and the check engine light has never came on.

Sorry to ramble incoherently, but I'm frustrated and I'm waiting with the negative cable off after replacing the sensors.
Fuel filter? TFI or PIP next?
I appreciate the help you guys have always given me.
THANK YOU

When my ‘88 did that it was the pip sensor. I just replaced the whole distributor with pip and TFI module included. The check engine light only illuminates if you lose oil pressure or overheat the engine, it’s pretty much a replace engine light.

[gadget73]

there is a yellow check engine light that most things didn't have until 89 for the computer. The red one is the "replace engine" light. Has nothing to do with the ECM.

Only a few things actually kick the computer CEL anyway. Do you get codes? You can throw parts at it until you get lucky or go broke but diagnosing it stands a better chance for success here. Also would be helpful to know exactly what combo of parts you have since not many of these came with a MAF from the factory.

[stinkydogfilms]

Keeping my fingers crossed.
Yesterday, I replaced the fuel filter, the old one was was only a year and a half old. The fuel in it was very clean.
I bought a new battery, I noticed the old one was 3 1/2 years old. I try to replace every 2 years because Houston is a city you don't want to break down in anywhere, anytime.
I also replaced the fuel pump relay and the ECM relay.
I checked the PCV and noticed the grommet was loose so I replaced the grommet.
While doing this the other end of the PCV hose came loose under the intake.
This one is connected in the middle under the intake. It took a long while and a few scrapes and mild burns but I got it on.

I started the car and let it idle with the AC on in the driveway for one hour and 45 minutes. I then drove the neighborhood for 14 miles and 45 minutes.
An hour and a half later I let it idle for thirty minutes then drove again for 16 miles and for an hour.
Today I'm going to drive around for hopefully 2 hours. I just started it up this morning. Start up seems normal.

I sense that the fuel pump relay was the issue.

My code reader couldn't connect. It kept saying the cables could not connect to the car. (maybe the ECM relay was bad).

I read that a battery can have a cracked plate and still have a good charged output.
My old battery was saying 14 volts on an in dash volt meter.

My car is Bernies old one.
It is a 90 block with HO cam, GT 40 heads and intakes. In May 2021 I swapped the HO throttle body for a 65 mm throttle body and a 67 mm spacer. At this time I changed to a PRO M MAF replacing the PRO FORM MAF.
The conversion to mass air was done by Bernie before I bought the car.
I've put 29,000 miles on it since I bought it in 2015.
All other parts, the remaining sensors, plug wires, plugs, distributor cap, TFI module are Motorcraft. It has shorty headers. It had a Flamethrower coil the last year and a half. Now swapped out to an ACCEL one. (The ACCEL coils are now made in China and not the original yellow).
THANK YOU AGAIN GADGET AND EVERYONE.
I'll post how the 2 hour drive goes.
Again I'm thinking either the fuel pump relay or the ECM relay.
Could the contacts sticking in the solenoid be the initial cause of the relays going bad
I THANK ALL.

[stinkydogfilms]

90 Colony Park.

[stinkydogfilms]

Happy that so far so good.
Cars been running and starting good the past 200 miles and 10 days.
The most miles at one time has been 30.
The idle is still fast at 1500 rpms at startup in park and 900-1000 rpms in drive. I'm not gonna complain.
I'm still think a bad fuel pump relay was the problem.
Thank you all again for your advice and help.

[gadget73]

definitely shouldn't idle that high. Does it drop if you unplug the IAC ? If not, fair bet either the screw is cranked in too far, or the air bleed screw in the throttle body is too big. I've had to plug those before on certain combos in order to get the idle right. The hole is big enough that even with the IAC fully shut it flows enough to make the idle high.

[stinkydogfilms]

Gadget the idle was fine before I started having issues. I did swap an (new car take off) IAC off of a new Lo Po throttle body I've had around.
I did fudge with the TPS. Should I check adjustment with the TPS?