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If I had possibly let the paperclip touch the metal surrounding the switch, would that have caused it to spark?
Yes of course it would. The metal of the engine/frame are connected to battery ground. The paperclip is essentially bare wiring connected to battery positive. Paperclip touches the metal frame and you have short to ground = heat/sparks. You should have been able to simply set meter to Ohms and test switch. If it showed 0, switch is fine and didn’t need to be bypassed.
You most likely have a short to ground somewhere tripping fuse. ETCG has videos on tracking those down so you can search this forum or his youtube channel. And for sure don’t bypass fuse or put in a larger one. Fuse is there to protect wiring and provide a weak link in circuit. Bigger fuse could move weak link elsewhere and melt wiring / catch something on fire.
So I am a little confused here. Are you saying the starter has been checked out by the parts store as being fine; yet when you install in the car it both gets hot immediately without trying to start car and doesn’t crank the engine?
CordiaMad: there isn’t anything wrong per se with pulling plugs. It’s a valid test in certain situations and I totally agree it is a no cost test. I just think it is much quicker and easier and diagnostically encompassing to do the voltage drop tests first. Voltage drop tests the entire starting circuits (control and starting motor) under normal operating conditions. If both tests yield around 10v on meter we know relay control is functioning, battery is good, and all the cabling from battery to starter and ground back to battery are good. Only thing left is starter/solenoid. If both #’s are the same but low, all wiring is good but battery is weak and needs charged or replaced. If two numbers are different we have a wiring problem. Track it down like I commented before.
EDIT: last possibility is no voltage drop across battery (stays 12.4 v ) in which case we need to go after starter control circuit/relay.
By pulling plugs if starter then turns engine, you still don’t 100% know if you have a wiring/cabling problem, battery problem, or a starter problem. When starter motor is first turning, amperage is high. As starter motor speeds up, amperage draw drops. But by removing plugs, starter motor has a lot less mechanical resistance so less voltage/amperage is needed to turn engine. Which is why I think voltage drop is better initial method.
But of course I can totally see personal experience and style making the decision. To each his own way that works best. Thanks for commenting.
Not to beat a dead horse, but to be clear both tests (across battery, across starter) are performed while trying to crank engine. You need current flow to see voltage drop. No current flow, no voltage drop. Report back the values you get as it will at least get us started on direction.
Personally since it started just fine a few weeks ago, i’m not pulling plugs or any other parts off just yet. Since you hear the relay clicking, don’t think it is park/neutral safety switch either. You said it started once when put in neutral, but not since. Makes it sound like you got lucky and connection was good enough at that moment. The whole thing sounds like an electrical connection issue. Here is from another post i made for similar situation (edited for your situation):
The way I like to test starter is check voltage between battery posts (and i mean DMM leads on posts, NOT terminals. Being on terminals i got wrong diagnosis once) while cranking. If voltage stays above around 10V, then repeat tests across starter. Red lead on main big power feed post (again NOT terminal but on post ) of starter, black lead to starter housing bolt (clear of paint, grease grime etc. need a good ground connection). crank engine. If voltage drop is the same reading as across battery (10v or above), then starter/solenoid is bad and needs to be replaced. (with only possible exceptions to this being a seized engine or seized accessory like an alternator that is preventing starter from turning engine. But since you were able to start the truck a few weeks ago, these are not a factor in this situation. Even less likely since you had starter tested recently.)
If voltage drop is a lot lower across starter – say 6v, then you have a wiring problem. Move black lead you have on starter housing to battery negative post (not terminal) and repeat cranking. If voltage drop goes back to same reading as across battery ( >= 10v), you have a grounding wire problem between battery and starter. If voltage still drops low, problem is on power feed side. From here you trace the path from battery to power/ground connections taking voltage drop readings along the way to find where the unwanted drop is.
Again, hope this helps…
First thing to check is the basics. Make sure the battery is fully charged. Make absolutely sure all the power and ground cables are clean and secure. Be sure to check ground cable from engine block to battery.
If that doesn’t solve it, then you really need to get a meter and start voltage drop testing the circuits. If you are not familiar with basic electrical diagnostic, it can be hard to explain in a post…but ETCG has numerous vids on no crank, no start scenarios like this. Plus this forum has a lot of advice as well if you do some digging.
Hope this at least gets you started.
I know you had said you verified timing – but wanted to put that out there again to be 3x sure.
And really since you have a -10% fuel trim, the computer is pulling fuel away so don’t need to worry about a vacuum leak. If you had a vacuum leak, fuel trims would should + numbers due to lean condition caused by leak. Revving engine would cause the numbers to go down closer to 0. But in this case you have computer pulling fuel away. +/-10% total fuel trim correction is generally considered right on the edge of acceptable.
High negative fuel trim corrections can be caused by MAF sensor problems, high fuel pressure, leaking fuel pressure regulator diaphragm, faulty evaporative emissions components, leaking injectors, defective O2 sensors, exhaust leaks/pinholes before the O2 sensor, coolant temp sensor problems, and base engine issues such as low compression and incorrect camshaft timing. But you have replace most all of these items which is why I was thinking towards timing issue.
Curious to know if you have a plugged cat now….
First thing i would do is leave the batteries alone (don’t unhook that is – just be sure they are fully charged.) and use my DMM to check for voltage drop across the fuses. Set scale to mV and test each fuse. If you get absolute 0.0, then there is no current flowing in that circuit and move on to next fuse. if other than absolute zero at least some current is flowing through that circuit. How much depends on the fuse size and reading you took. Below is link to a chart and directions to guide you. Hope this helps…
If removing the O2 sensors don’t prove out a plugged cat, i agree with ArmedsouthernEr to be really sure about timing. What all the clues seem to point to. And if cat is plugged, need to look into why it happened. if smelling gas at tailpipe, you still have an issue. Cat maybe end result not the original problem.
You say you have a basic scan tool and LTFT is -10%. What is short term reporting after it is warmed up and in closed loop? And can you see the 02’s switching on your scan tool? If so, you can repeat looking for vacuum leaks by spraying around and watching for a reaction on the front o2’s and STFT. If O2’s report rich ( plateaus on/near 1v) while spraying then you have a vacuum leak. STFT should also go negative to compensate.
If you want eliminate the battery as an issue, test battery voltage while cranking which is easy enough. Connect DMM to battery posts (not terminals) and try to start car. Then connect meter across starter. Red lead on main starter solenoid power feed post (again not terminal) and black lead to starter mounting bolt (make sure it is clean for good connection). Repeat cranking test. If both numbers are the same and stay above around 10v (9V worst case), then you don’t have a battery or wiring problem. If measurement across starter is a lot lower, then you have a wiring issue to deal with. If a lot lower, move black lead to battery neg post and repeat cranking test. If new readings = same as across battery (>=10v), then you have a grounding wire issue between starter and battery. If voltage drop stays low, you have a power feed side wiring problem. You may want to pull fuel pump relay during tests to make sure you have time to get good readings.
Out of curiosity what makes everyone think the ECM is bad? throwing codes?
I’m no master mechanic but I do know bypassing it just isn’t gonna happen….unless you wan’t a car that does not run at all…then you can bypass it all you want .
I agree with DaFirnz and ErictheCarGuy. When you say battery voltage and fuel pressure are “fine” what does that mean? can you provide empirical data? What is battery voltage while cranking engine? what is fuel pressure and how does that compare to manufacturers spec range?
And what does “a long cold crank condition (~2-3 seconds before a weak start)” mean? That when you turn key to start it does nothing for 2 – 3 seconds? or does it crank but slowly for the 2 – 3 seconds before firing? or does it crank normally but takes 2 – 3 seconds before firing? Please provide some specifics.
Without some data to start getting some direction we are all just guessing.