miata

Background: work on 80s-early 90s 4 cylinders (Miatas, Fords mostly) and 6 cylinder Japanese imports (Z32, Accords)

Swapped a newer 2006 engine/trans with less than 60,000mi into my 2005 Toaster which had head gasket/piston issues. Engine harness, ECM among many other things switched over as well. This part wasn't so bad.

Currently in the process of getting the engine started. This is where I am having issues. Don't have access to the manual anymore so decided I ask on here.

Below are some important items I replaced due to age or because it was non-functioning.

1 - Replaced fuel pump and fuel sock as it was not functioning after sound test, meter testing, and then bench testing.
2 - Replaced and gapped spark plugs
3 - New Battery
4 - PS / AC belts
5 - All fluids

When placing key into ON all relays function correctly, and all electronic functions (lights, radio, panel) work well. When I turn the key the engine cranks strongly, which is a good sign, but it doesn't turn over.

So far I have narrowed it down to the Ignition system, perhaps COIL PACKS. Below is the process that I have gone through to come to this conclusion.

1 - In-line spark plug tester indicating NO SPARK. (Checked bulb with another car to confirm that the tester functions.)
2 - EFI and Start relays operating normally.
3 - Removed coil packs (non-oem) and checked for resistance with meter set at 2000 OHMS.
All four coils read at 855
4 - Tested OEM Denso coil packs from older engine. All four coils read at 350.

QUESTION #1: I understand that the range is 300 to 1000. Is this correct?

QUESTION #2: What other tests can I use to confirm that the No Spark is due to bad coil packs? Could the coil packs be bad even though it is returning a reading within range?

Moved on to the Crankshaft Position Sensor (under Crank Pulley) since this sends the firing signal to ECM.

1 - Visual Inspection saw that it had oil on the metal end.
2 - Resistance read at 1300 OHMS which is good

I can pull the Cam Position Actuator (above alternator) and the Cam Postion Sensor (facing air box) to check operation, but I have seen the newer 2006 engine running fine
and with no codes before pulling for swap, so it is very unlikely to be the sensors which also confuses me on why the coil packs might go bad (though Engine had sat for a year waiting for swap).

Question #3: Anything else that I might have missed? Already gone over all the plugs and connections, nothing obvious out of place, relied on manual/wiring diagram, pictures/labels before and during swap.

Thanks hopefully I can get this resolved soon so I can drive a super low mileage Toaster again. I promise I'll post pictures after it is running and detailed.

miata

So back at it. Figured I'd continue this in case anyone else has the same issues in the future and so I can keep notes.

Fresh Fuel.
New coil packs installed.
Engine again would not turn over under any condition.

Switched over all interior wiring and sensors from newer 06 XB and it showed spark which indicated wiring and computer issues/incompatibility with 05 interior leading to ECU (which was from the 06).

Engine would now start strong for two separate times, but it would die after about 3 seconds.
Reset ECU.
Engine would now require throttle to start from cold. Adding throttle would keep the rpm high enough to idle, but the idle would then wander and thus would need constant adjustment of the throttle. Engine would die with no throttle.
This time around I was able to pull codes, specifically Random Misfire, Cylinder 1 Misfire, and Cylinder 4 Misfire.
If the engine didn't require constant throttle this would be easier to chase down, but because

Due to repeated starts before having spark and fuel and then after having spark, I would assume the below:
Plugs are fouled (pulling plugs confirmed that engine is running rich enough to carbon foul plug ends)
MAF requires cleaning
ICV requires cleaning
Injectors requires cleaning (less likely)
PCV is clogged (less likely)

Due to codes:
Vacuum Leak
Coil Packs (installed are not OEM)
Weak spark (more likely)
Camshaft Sensor (good operation under cold)
Crankshaft Sensor (good operation under cold)
Fuel Pressure
Injector failure
Wiring Short
Fuel Regulator

I'll have to swap around the coil packs and injectors to see if it follows the part or not. If it does replace and re-try. If not then I would assume the Position Sensors are faulty under hot operation.
I could check compression (and I may do so later) but again right before the swap the engine was strong with only 60,000mi and a good history.

I am also replacing the entire exhaust with OEM as even though it is not throwing any codes, it is very rusted on the exterior, even with it being a full Stainless Borla. (also the only place the 05 has rust). I would assume that the interior of the cat and muffler is clogged somewhat after nearly 300,000mi.

If the engine didn't require constant throttle this would be easier to chase down, but because of this it adds aome more factors. I do know for certain that I am running rich so theres that

ToyotaPower

I’m having rite about the same issue. I replaced fuel pump, nothing. Checked Efi fuse replaced it and it turned over but I shut it off and tried again and wouldn’t start over. For an entire week I’d crank it daily and it would randomly crank and start about 3-4 times out of id say 20 times or so. Replaced ecu 3 different times still nothing. No spark on plugs.

18TTony

Remove the 2006 wire harness.
Remove the 2006 knock sensor.
Remove the 2006 knock sensor stud-mount.
Install the 2005 knock sensor into the hole on the 2006 engine block where the 2006 knock sensor stud was previously located.

Install the 2005 wire harness onto the 2006 engine.

Put everything back together with the original 2005 parts (PCM, harness and whatever else you changed).

The 2005-2006 knock sensors are different.

2005 has 1 wire and this sensor resembles a bolt.

2006 has 2 wires and one is hollow in the center.

1 wire???
2 wires???

What's the big deal???

Big deal is that the one (more) wire on the newer knock sensor changes the pin-out locations in the firewall & at the PCM.