I need serious help with "missing spark".......

[cskals]

Hi fellow Rocketeers.
My 05' won't start.

I have had it split apart, except the engine, and when I put it together again, it won't start.

At first, no issue, it started fine, once or twice.
After that it got harder and harder, and now it won't start at all.
I think it has been started 5 times overall, but it got harder every time.

I have found out that it does not spark, I believe everything else if fine.
1. Fuel pump works and build pressure.
2. Plenty of battery.
3. Just put new relays on.
4. Installed new wires from battery, 35mm2.
5. New sparkplugs.
6. Fall sensor ok.
7. Gear position sensor ok.
8. Crank position sensor cleaned, but not sure how to check if it works?
9. Turns fine in the starter, but I have ordered a Toyota upgrade.

When pulling a spark plug to check for spark, it does not spark.
I have measured the following:
Battery: 13.0 V
Battery when pushing start: 10.5 V
Relay: 12.7 V
Coil: 12.7 V
Coil between pins with ignition on: 11.4 V
Coil between pins when pushing start: 8.2 V

The low voltage on the pins concern me, 8.2 V is not a lot, but how much does it require to fire the plugs?

What am I missing?
Thanks in advance.

 

[TURBO200R4]

i would say that the volts should be the same as battery voltage when cranking.
so i am thinking that when cranking you are dropping to 8.2 volts on battery
battery wires barley passible when new. terible when old replace with bigger and soldier terminals.
try with a jumper or charge bat.
hth
you will never get it started with 8.2 volts.

 

[Mongler07]

When cranking you should see a voltage drop as you are pulling amps. i do not know what it SHOULD be but a good check rule of thumb is no less than 10 volts when cranking at the battery. The relay was 8.2? when cranking? humm seems wrong to me but idk

 

[cskals]

i would say that the volts should be the same as battery voltage when cranking.
so i am thinking that when cranking you are dropping to 8.2 volts on battery
battery wires barley passible when new. terible when old replace with bigger and soldier terminals.
try with a jumper or charge bat.
hth
you will never get it started with 8.2 volts.

There will always be a voltage drop when cranking, and it drops to 10.5V on the batteri.
It's on the coils it drops to 8.x

 

[cskals]

When cranking you should see a voltage drop as you are pulling amps. i do not know what it SHOULD be but a good check rule of thumb is no less than 10 volts when cranking at the battery. The relay was 8.2? when cranking? humm seems wrong to me but idk

I´ve heard the 10V as well, and I agree, 8.x is way to low.
I just don't understand what can cause it?

 

[Anthony5900]

quick read on this, i would assume battery cell is damaged but not enough that it shows while sitting, but under load that cell isnt enough to power it !.

aside from the from what you have changed the only other thing in that system to go wrong would be actual coils ! unless ive skipped over that part you have not replaced these?

 

[Journeyman]

I vote that your battery is toast. IF coils, I have some I need to sell. New that I bought when I was diagnosing a problem (turned out not the coils).

 

[TURBO200R4]

There will always be a voltage drop when cranking, and it drops to 10.5V on the batteri.
It's on the coils it drops to 8.x

i am going to guess that the whole system is dropping to 8 volts. if it is just the coils then that circuit has a problem. ps i think that the injectors is on that circuit.
i have a fluke multi meter and was checking mine one probe on bat neg and other on starter nut on starter i would set meter for high and low voltage this is a good place to check
if you are getting enough volts just befre the starter starts to turn motor over.
it was hot after driving and trying to run it down a little with lights on it started with 9.33 volts. will try to check it in the morning.
i have been fighting a cold start with ecu not fireing coils once it starts (automotive charger on hi with crank assist) she starts good all day.
hth

 

[TURBO200R4]

also for a test you could run a jumper from battery positive to the positive coil wire.( the one on the inside terminal.)