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Topic: PMGR Starter Issue (Read 593 times) previous topic - next topic

PMGR Starter Issue

Hi All,

I installed a PMGR starter on my freshly built 5.0 and am having a strange issue that I'm hoping someone can shed some light on. I'll mention that when I did my 5.0 swap, I also went with a T5 and chose to eliminate the firewall mounted starter solenoid altogether, since the PMGR has a solenoid built onto the housing and I did a wire tuck.

Symptom: Starter only turns over motor sometimes when triggered by ignition switch. Sometime it'll take 20 or so turns of the ignition switch before I can get cranking.

Diagnosis so far:

1) I initially suspected my battery might be low so I charged it, and it now reads over 12.6V

No Change

2) I figured it may be a grounding issue so I installed a grounding strap from the back of the starter to the K member. I grinded the paint away from the K member to ensure a good connection.

No Change

3) I removed the starter from the vehicle, along with all associated wiring. I hooked up jumper cables straight from the - to the housing and + to the positive strap going to the motor.

The motor spun fine

4) I hooked up the + jumper cable to the solenoid's coil.

Saw it push the bendix gear out

5) I installed a new solenoid assembly, thinking the original may only be pushing the plunger out and not closing the contacts for the motor all the way. Truth be told, I'm not sure how the internals of this particular solenoid work so this was kind of a shot in the dark and since the replacement was $15 I figured it wouldn't hurt to try. I reinstalled this in the vehicle.

Made no difference, same issue.

6) I removed the starter again, this time leaving all of the connections hooked up but letting the starter hang freely under the vehicle. I triggered the ignition switch repeatedly.

The bendix gear both protruded and spun at the same time.

7) I did some research to double check that my starter and flywheel are compatible.

As far as I can tell, they are. Flywheel is 157 tooth and the starter was one of the ones recommended on the coolcats website.


I'm kind of at a loss as far as what to do next. I'm having a hard time understanding how the starter can work every time outside of the car but not when installed, especially since there is no adjustment for gear engagement and I believe I have the right parts.

Any ideas?

1988 Mercury Cougar LS
5.0HO + T5 Swap + Suspension/Brake Mods

Re: PMGR Starter Issue

Reply #1
Does the starter spin but just not engage the flywheel,  or does it just not spin at all?

Pretty much every starter has the same tooth count reguardless of flywheel tooth count.

When I did my sn-95 t-5 swap, I found out that there are two different offsets for the nose of a starter, 3/8" and 3/4" length. The first starter I tried. It hit the flywheel but could not pull back enough. After doing some reading. Lot of guys had the same problem and added a 1/2" stack of washers. That when I found out about the nose length difference and I got the correct starter out of a pick up truck.

My thinking. It might be possible that you have the wrong lenth and the teeth don't always make contact.
Quote from: jcassity
I honestly dont think you could exceed the cost of a new car buy installing new *stock* parts everywhere in your coug our tbird. Its just plain impossible. You could revamp the entire drivetrain/engine/suspenstion and still come out ahead.
Hooligans! 
1988 Crown Vic wagon. 120K California car. Wifes grocery getter. (junked)
1987 Ford Thunderbird LX. 5.0. s.o., sn-95 t-5 and an f-150 clutch. Driven daily and going strong.
1986 cougar.
lilsammywasapunkrocker@yahoo.com

Re: PMGR Starter Issue

Reply #2
Did you check the ignition switch on the steering column?  They are a known item to go bad on our cars and act funny working then not working before failing.
1988 Thunderbird TC, 5spd
Stinger 3" single exhaust, Cone Filter, Adjustable Cam Pulley, Schneider roller cam,
'93 Mustang Cobra replica wheels on 235/50R17

'16 F150 XLT 5.0
'17 Husqvarna TX300

Re: PMGR Starter Issue

Reply #3
Did you check the ignition switch on the steering column?  They are a known item to go bad on our cars and act funny working then not working before failing.
This was going to be my question as well.
Mike

Re: PMGR Starter Issue

Reply #4
Haystack - the starter doesn't spin at all when installed in the car. The solenoid just "clicks". Where do you measure from to determine the 3/8" or 3/4" length?

Mickey97D - When I turn the ignition switch to the momentary contact, I do get a full 12VDC to the solenoid coil. I'm assuming this means my ignition switch is doing what it's supposed to do.
1988 Mercury Cougar LS
5.0HO + T5 Swap + Suspension/Brake Mods

Re: PMGR Starter Issue

Reply #5
Cowboy, sorry, I went to edit my post and accidentally cut/deleted almost the whole thing.  Since it was late and I was half asleep, I'll try to throw my guess back at it again after re-reading your efforts to diag so far.

Yes, bad ign switch can cause intermittent or weak voltage to apply to start signal wire causing wonky issues.  The more important thing is it can cause wiring going to it to melt due to resistance/poor contact.  People have had bad dash fires or even lost the whole car to fire due to bad ign switches.  Bottom line, check yours out, dont put it off.

Resistance/length of signal wire to starter should not be an issue since its hardly carrying much current, just needs to be roughly 12v. The factory red/blue signal wire is like a puny 18 guage wire, just for context.

On starter wiring, there isnt much to eliminate before you should have it pretty well narrowed down. Faulty connections are 95% of starting issues.

 If the solenoid at the starter is only clicking, it sounds to me like you have a bad ground connection on ground cable from engine to battery, or ground cable itself is junk.

 Also triple check positive batt cable connections and load test battery to make sure its not just holding good voltage with no load, but experiencing a dead short under the load of cranking engine, just giving enough to click the solenoid.

If these connections are correct and in place, then your problem lies in the ignition switch OR you simply have a bad starter motor.  Because thats all thats left in the circuit.

Re: PMGR Starter Issue

Reply #6
I did install a mains fuse for the vehicle for safety, so I'm not too worried about the accident scenario but that is a good point. I'm fairly certain my wiring is correct. Would it be possible to have a bad ignition switch that is still able to energize the coil of the solenoid? I'm thinking something along the lines of the ignition switch having some resistance and not allowing enough current to the coil of the solenoid to full actuate the motor contact. It's also possible that since I'm sending the switched ignition signal a further distance by going directly to the starter motor mounted solenoid, I may be getting resistance there?
1988 Mercury Cougar LS
5.0HO + T5 Swap + Suspension/Brake Mods

Re: PMGR Starter Issue

Reply #7
I would throw a new ign switch in (under the column plastic, NOT the cylinder where the key goes, just an FYI if you didn't already know), and see if that makes any difference.

As old as these cars are (and there were recalls done just specifically for the switch..) it's very possible it's bad, or failing. Not only that, the design of the switch lends itself to wear...it's like old dirty socks...who wants THAT ;)
'84, '87 Mustangs
'98 Explorer 5.0
'06 Explorer EB 4.6
'11 Expedition EL

Re: PMGR Starter Issue

Reply #8
Disconnect the start wire to the starter, tape it up and run a temporary jumper wire in it's place to the battery area. When all clear, just touch the wire to the + post and see if the starter works.
84 COUGAR/90 HO, 1.7RRs, performer RPM,700DP, equal length shorties, stainless EXH ,T-5,Hurst pro-billet, KC clutch, 8.8/ 4.10s, line-lok, bla ,bla, bla.
71 COMET/289,351w heads, 12.5 TRWs, 750DP, Liberty TL, 9"/6.00s, 11.9x @112 , bla,bla,bla.

Never shoot your mouth off, unless your brain is loaded! ....I may get older, but I'll never grow up!....If you're not laughing, you're not living!  :laughing:

Re: PMGR Starter Issue

Reply #9
Although the starter has a built in solenoid, it will still draw a significant amount of amperage to energize the solenoid. When the solenoid is initially latching, it will draw 25-50 amps and then taper off down to about 10 amps. Your ignition switch and circuit are probably struggling to provide the amperage the solenoid needs to latch.

I would recommend at least a 30 amp relay, with 10g wiring feeding it, and running to the starter solenoid. Either way, it'll save your ignition switch.
It's Gumby's fault.

Re: PMGR Starter Issue

Reply #10
Thanks for the input, guys. I'm definitely thinking it's the ignition switch now. I had my buddy hold the key in the momentary "start" position while I checked voltage to the coil. It was only reading 6V, while not cranking the motor. I'm thinking the contact in the ignition switch may be failing. I ordered a new one and will report back. Interest enough, I removed the column plastics to get to the ignition switch just to scope out how I would remove it, and noticed it had an F2 part number. Looks like it must have already been replaced under recall like Beau mentioned!
1988 Mercury Cougar LS
5.0HO + T5 Swap + Suspension/Brake Mods

Re: PMGR Starter Issue

Reply #11
Hmmm.

Yup, definitely let us all know how the replacement switch fares.
'84, '87 Mustangs
'98 Explorer 5.0
'06 Explorer EB 4.6
'11 Expedition EL

Re: PMGR Starter Issue

Reply #12
Well... I fixed it!

After replacing the ignition switch with a new unit and retesting, same result as before. The switch did not fix my problem, which led me down the path of measuring the resistance in the wire from the ignition switch to the starter solenoid. Barely any resistance. At this point I realized that I had confirmed everything was good electrically, so that only left some kind of mechanical interference issue, like Haystack suggested. I should also mention, I had previously gone down the path of confirming I had the right starter. My next though wast that it was possible my brand new flywheel maybe be machined out of spec, bringing the front of the teeth closer to the engine than normal. This would result in the bendix gear interfering with the flywheel teeth when thrown forward the majority of the time. I added a 1/16" washer on each of the mounting bolts between the starter and the bellhousing to push the starter away from the trans, retested .... and VOILA!

In conclusion:

Based on the fact that many of you chimed in to help and that I did extensive research on the interwebs and had not heard about anything like this, I'm now convinced this was a freak issue. Glad I have this one under my belt for future reference, and glad I could pass this along in case anyone else runs into the same issue.

Thanks for the help guys,

Dan
1988 Mercury Cougar LS
5.0HO + T5 Swap + Suspension/Brake Mods

Re: PMGR Starter Issue

Reply #13
What application was the new starter for?
Mike

Re: PMGR Starter Issue

Reply #14
I bought it off Rock Auto under 93' Mustang GT
1988 Mercury Cougar LS
5.0HO + T5 Swap + Suspension/Brake Mods