Kugawestie's MX5 SDV Build Thread - Now An Upgrade Thread

[KugaWestie]

I hsve just had a chat with the chap at Autolink UK, very helpful  

He says the missing pin/cable not connected to a pin purely runs the rev counter, so this should not stop the car starting.

He suggested swapping the coil pack over for the other 3 pin one that I have as a spare to see of this gets the engine going, if so, then the coil pack is burnt out.

I still need a 4 pin coil pack to run the rev counter though!

[KugaWestie]

Swapped the coil packs over, and there is no difference, so either both coild packs are whacked, or both are good.

Can anybody tell me what the two connections are on the inlet manifold?

I span the engine with my thumb over the connector at the back of the manifold (LHS of the photo) and there is suction, this also caused the engine to run on for probably 1.5 seconds instead of 0.5 seconds

Off to Maplins to buy a multimeter in a minute!

[Mark (smokey mow)]

The one on the back of the engine is a vacuum for the brake servo.  It needs a cap on it.

The one on the front may have gone to the carbon cannister, and again needs sealing off.

Looking at your pictures is the vacuum hose from the fuel pressure regulator now connected?

[hilux]

I`m not familiar with the Mazda engines but the right hand one might be the vacuum take off for the ECU and the other might be a vacuum take off for the servo.

Oops just seen the previous post - good shout, quite often on engines of that era the fuel pressure regulator has a vacuum pipe off the manifold that momentarily raises fuel pressure when throttling up so as not to lean out.

Does your ECU have a vacuum take off?

[KugaWestie]

The one on the back of the engine is a vacuum for the brake servo.  It needs a cap on it.

The one on the front may have gone to the carbon cannister, and again needs sealing off.

Looking at your pictures is the vacuum hose from the fuel pressure regulator now connected?

So block the two off then, thanks

smokey - it was an old photo, everything else on the manifold is connected  

[Mark (smokey mow)]

The one on the back of the engine is a vacuum for the brake servo.  It needs a cap on it.

The one on the front may have gone to the carbon cannister, and again needs sealing off.

Looking at your pictures is the vacuum hose from the fuel pressure regulator now connected?

So block the two off then, thanks

smokey - it was an old photo, everything else on the manifold is connected  

Make sure all the vacuums are either blocked off or have the relevant hoses attached.  On mine there's some hidden on the underside of the throttle body and manifold.

The ECU controls the fuel to the engine based on the readings it receives from the Airflow meter.  To get the correct measurement all the air entering the throttle body and inlet manifold must pass through the AFM.  If any air leaks in through open vacuum take off's or split hoses etc the ECU wouldn't have measured this and calculated for it when delivering the fuel.  The consequence of this is that the engine would be under fuelled as it thinks it's receiving less air than it actually is.

[KugaWestie]

The one on the back of the engine is a vacuum for the brake servo.  It needs a cap on it.

The one on the front may have gone to the carbon cannister, and again needs sealing off.

Looking at your pictures is the vacuum hose from the fuel pressure regulator now connected?

So block the two off then, thanks

smokey - it was an old photo, everything else on the manifold is connected  

Make sure all the vacuums are either blocked off or have the relevant hoses attached.  On mine there's some hidden on the underside of the throttle body and manifold.

The ECU controls the fuel to the engine based on the readings it receives from the Airflow meter.  To get the correct measurement all the air entering the throttle body and inlet manifold must pass through the AFM.  If any air leaks in through open vacuum take off's or split hoses etc the ECU wouldn't have measured this and calculated for it when delivering the fuel.  The consequence of this is that the engine would be under fuelled as it thinks it's receiving less air than it actually is.

Understood.

I am now in possesion of nice new multimeter, and have the bits to make up the LED light for the diagnostics.

I am off out into the garage again after a mince pie    to do some blocking off and checking  

[KugaWestie]

I have retired hurt for today, fed up with it.

To top it all off, I have noticed an oil leak on the sump  

[Dave Eastwood (Gadgetman) - Club Chairman]

Try not to get down about it, while it can be difficult to walk away with a problem umsolved, viewing it with a fresh pair of eyes tomorrow might make a world of difference!

[SteveD]

personaly i would wait until you have all the dash and other wiring connected

[KugaWestie]

Try not to get down about it, while it can be difficult to walk away with a problem umsolved, viewing it with a fresh pair of eyes tomorrow might make a world of difference!

It has not been the best of days

Engine wont run, need to buy a 4 pin coil pack, oil leak on the modified sump  

Any advice on how to start checking the wiring with a multimeter please?

[Mark (smokey mow)]

Any advice on how to start checking the wiring with a multimeter please?

If all other avenues have been exhausted and there are no fault codes are showing on the diagnostics then start with each engine connector in turn and check the continuity back to the coresponding pin of the ecu.

Do you have a copy of the Rod's manual? If so also use this to check the correct operation of the AFM and resistances of the other sensors.

[Dave Eastwood (Gadgetman) - Club Chairman]

Like I said before though, and Steve commented on, I'd be wary of checking too much without the extra loom and things in place - unless you know for sure they're not required. (even so, I wouldn't want to be going for an engine start with no instruments!)

[KugaWestie]

But likewise I don't want to be too far down the line with an engine that does not run and start having to undo, if that makes sense

[nikpro]

Check for vacuum leaks on the inlet manifold - make sure they are all plugged up.

Check fuel pipes are connected correctly - should go:

Fuel tank > Fuel rail > Pressure regulator > Return to Tank.

and not...

Fuel Tank > Pressure Regulator > Fuel Rail > Return to Tank

Check wiring to MAF & MAF itself

You need guages to check for oil pressure IMO.

Have you got the Lambda sensor Plugged in? (Should run without I think)