Hi all, mechanical issue, Jeep Patriot. Can anyone help diagnose this. I’ve replaced the starter and had a new battery out on. I’m just at a loss. Thank you

[John soderberg]

[V]

Sadly, it is a fact of life in the 21st century that new (or remanufactured) parts can be faulty or with unexpected designed in defects caused when copying OEM parts. You cannot rule out that the new starter motor is not at fault without trying it in another vehicle.

 

However, it sounds like the starter pinion is failing to engage the ring gear. Possible causes in no particular order.

 

1. Insufficient current to energise the solenoid properly due to damaged wiring on the Jeep or inside the starter motor

2. Mechanical problem on the starter pinion shaft or yoke preventing pinion engagement

3. Damaged or missing ring gear teeth

4. Warped flywheel or flex plate causing excessive runout on the ring gear

5. The wrong starter motor with the wrong pinion - too tight to engage.

6. Pinion stuck engaged on ring gear - I don't think a starter would last long with the engine running with this and I couldn't hear it in the clip.

7. Restricted movement of the solenoid caused by poorly fitting reman contactors

 

If possible, swap a known good starter motor from another working Jeep and see if the problem travels to the other Jeep or if it stays with yours.

 

This clip may be useful to watch

[V]

This clip is for the inertia style pinion engagement. The presenter calls it a Bendix but it's not what I recognise as a Bendix from the days before pre-engaged starters.

[Caroline12]

In the video, was that 3 times no start and 4th time engine started, I’m a little bit deaf, last bit was a bit short for me.  Please can you clarify for me, exactly what happened at the end.

1. was the engine actually cranking over when not starting ? Have someone watch the engine for fan belt movement. This crucial. 

2. If cranking, but not firing, it’s the fuel system.  
3. Is it petrol or diesel ? (I know Diesel engines most, followed by gas engines (spark ignition), not worked on petrol engines
4. if not cranking at all, then what V said above. Even new starter motors fail, had it several times. 

can you tell me the vehicles history, had for  it long ? ran before, now doesn’t, last service etc a brief timeline would help. 
 

Im an ex merchant navy engineer - diesel, now mechanical mobile service engineer with industrial 4 stroke gas engines. Worked with engines fault issues for 20+ years.

 

Edited August 25, 2021 by Caroline12
Missed a word out

[V]

Despite trying to visualise what I would do before typing I still managed to miss explaining the most important thing to check first. Thanks for following up.

[V]

This may not be relevant to your Patriot but for those reading with a 2.5L i4 or 4.0L i6, a field repair to get an engine started can often be achieved with a hammer blow to the starter motor's steel casing (Not the casting!). If attempting this the objective is to free a stuck pinion gear or contactor, not destroy the starter motor in situ. You have to get underneath the Jeep to do it but it has worked for me many times on my own Jeeps and on other's during expeditions too far away from parts stores.

[Caroline12]

23 hours ago, V said:

This may not be relevant to your Patriot but for those reading with a 2.5L i4 or 4.0L i6, a field repair to get an engine started can often be achieved with a hammer blow to the starter motor's steel casing (Not the casting!). If attempting this the objective is to free a stuck pinion gear or contactor, not destroy the starter motor in situ. You have to get underneath the Jeep to do it but it has worked for me many times on my own Jeeps and on other's during expeditions too far away from parts stores.

 

also use a multimeter crocodile clips on positive and negative on starter motor, setting DC voltage high/low record function. start the Jeep, if voltage goes below 11 volts, it’s the batteries. Charge or change. Try again.

 

engine turns but not firing.

- petrol/gas check your ignition system is working well HT leads/plugs etc, check fuel pump, any leaks, hoses etc. All electrical connections are clean and shiny, no tarnish. Use contact cleaner.

 

- diesel, injectors check get tested, make sure there is no air in the system. Crack injectors connections, you should get diesel out - good. If air, your sucking air in from somewhere, check hose/connections. 
 

not sure on petrol side of this, but  diesels yes, check non return valve is holding and operational. If non return valve has failed, you wont hold fuel in the fuel line, it drains back to the fuel tank. Will never start. Non return valve normal have a manual lift pump  combined. I’ve had lift pump worked fine, the non return valve had failed - won’t start. 
is fuel pump working ?

is fuel filter blocked ? 
 

sorry just a few things off the top of my head to check.