Intermittent starting issue

[maxbottomtime]

Howdy all,

I've got a 2001 Boxster with intermittent starting issues. I bought it as a project, and replaced the engine with a new (to me) 2.7L from the same year. Car is manual transmission

Before installing I put a new starter (of dubious quality perhaps) on the engine.

Symptoms:


https://youtube.com/shorts/BJ5zQ0wL1Ys?si=jAS6s1e5lSjk0MZD

When going to start, the key turns to the on position, and I hear a "click" from the rear of the vehicle (next time it does it, I'll have my wife turn the key while I locate if it is the relay clicking or the starter).
It only does it sporadically - Since getting the new engine installed/running, I've started maybe 40-50 times (I am doing it now any time I am working on something on the car for a few minutes just to stretch its legs, test the problem). It has "clicked" like this 4 times.

Usually I am able to get the car started, but I am pressing clutch in/out, Shifting between gears, hitting brakes, etc. It may just be coincidence, but fully seating the gear selector into 5th it has started after returning to neutral.

Car runs beautifully, only engine diagnostic currently is passenger side Catalytic converter (testing O2 sensors, then will be replacing if needed - old engine I used them from were high mileage).

Attempted fixes:

1. Replaced starter relay with a Napa branded one
2. Tried jumping clutch sensor (made male to male jumper, plugged into the two closest female spade connectors on the end of the clutch pedal).
3. Replaced ignition switch (electrical connector). I was having intermittent HVAC issue where the fans would only blow in accessory. Once running, if i jiggled the key left they would kick on. After replacing the switch those symptoms are gone.

4. I am in the middle of replacing the back window (stitched it in, gluing seams now). Once that is done I'll be pulling the engine cover, checking power lead at the front of the engine bay, and the lower left (when facing crank) bolt for tightness to ensure the power going to the starter is solid. I just installed the motor, so don't think this is the issue.

It is so intermittent that it is hard to count on/diagnose. I need it to not start while I am about to start a project so I can bust the multimeter out and get to work!


What should i be considering? Likely junk starter/solenoid assembly? I see a Bosch for the same price as my chineseum one.

[blue62]

Could be as simple as the negative battery cable not grounding to the frame properly.
Or any number of other issues.
So go to Utube and look up "Voltage Drop Testing" a Starting system"
Once you understand how to do the tests it will be much simpler to find electrical issues like your having.
All you need to do the testing is a Digital Multi Meter.
The hardest part of the testing is having access to the electrical connections and components.

[maxbottomtime]

Originally Posted by blue62

Could be as simple as the negative battery cable not grounding to the frame properly.
Or any number of other issues.
So go to Utube and look up "Voltage Drop Testing" a Starting system"
Once you understand how to do the tests it will be much simpler to find electrical issues like your having.
All you need to do the testing is a Digital Multi Meter.
The hardest part of the testing is having access to the electrical connections and components.

I got back into the engine bay yesterday (finished up other projects). Ashamed to admit the positive cable nut at the front junction was loose. I had to drop the engine like 3 times as i was reassembling to fit things that could not be done (PS reservoir, parking brake cable, etc.). Fingers crossed that was the issue!

[blue62]

Originally Posted by maxbottomtime

I got back into the engine bay yesterday (finished up other projects). Ashamed to admit the positive cable nut at the front junction was loose. I had to drop the engine like 3 times as i was reassembling to fit things that could not be done (PS reservoir, parking brake cable, etc.). Fingers crossed that was the issue!

First rule of diagnostics:
Always check what human hands have touched first.

[maxbottomtime]

Originally Posted by blue62

First rule of diagnostics:
Always check what human hands have touched first.

No kidding. I'm still going to swap in a bosch starter to replace the chinese one - will make me feel better.

On a positive note, my cruise works with a new brake switch, and I passed the catalytic converter OBDII monitor! It had failed, so instead of babying it, I gave it a few pulls and drove her hard. Ole eye tall ee an toon up.

Just waiting on evap & secondary air injection and I'll get it fully plated.