Engine Startup Problems

[Paul Quinnell 0]

Hello everybody,

 

First post, please be gentle...

 

I have recently re-installed my 8v engine back in my Pug, after unsuccessfully running an MI16 lump...(another story)..

 

The engine was running fine before I removed it, however on start up it went from zero to 3500 instantly and stayed there with no throttle input before I quickly shut it down...(fortunately I had turned the engine over a lot with decent oil and made sure it had oil pressure before start up.)

 

Before start up, I had checked static timing, replaced the fuel pump with a direct Bosch replacement, and checked for spark and fuel pressure which was all good...

 

1, Has any body any ideas why this is happening

2, Has anybody got a simple color diagram of the brown plug connections and general wiring from the sensors, alternator etc.. 

 

Cheers  Paul

[Telf 224 2 Cars]

sounds like an air leak at the intake manifold. has the bolt on the right hand side ( as you look at the car) that holds the oil filler been fitted and tightened? Is the hose underneath the intake manifold fitted?

 

un metered air will shoot your RPM into the region of 2500-3000 rpm .

[Telf 224 2 Cars]

[Telf 224 2 Cars]

[Telf 224 2 Cars]

^ not mine but on the site if you know where to look

 

[Telf 224 2 Cars]

Lifted from on of my old threads :

 

As per the thread I linked but easily missed :

 

As Anthony stated back in 2007:

 

"The underdash plugs are the same on all Phase 1.5 and Phase 2 cars, with the exception that the starter solenoid (46B - blue) and ignition live (2B - red) are swapped between early and late cars and hence needs to be checked "

 

I've modified the diagram accordingly- not sure but I think my car is in the crossover from phase 1.5 to phase 2

 

[Telf 224 2 Cars]

The SAD pipe connects under the Intake manifold - number 3 on the picture- could be loose or split.

 

[Paul Quinnell 0]

Hi Paul,

 

Many thanks for all the details and your help..

 

Cheers  Paul

[Paul Quinnell 0]

Thanks to Paul's excellent help on the manifold hose, the Pug now starts fine on the throttle...

 

The issue now is it is running really rich and over fueling..

 

• I have discovered the SAD sensors are disconnected but the wiring has been a bit modified before...
• There are three pipe connections coming out of the bottom of the throttle body with no hoses attached to them...

 

Can anyone advise on the above and what color wires the two SAD sensors need to be connected to in the under bonnet loom...

 

The blue sensor wires are grey and white and the black sensor are orange and green..

 

Many thanks 

 

Paul

 

 

[welshpug 1,661]

the SAD does not have sensors,  its a very simple idle bypass valve with a 2 pin black plug connection.

 

the blue 2 pin sensor is a coolant temperature sensor for the ecu, if this is not plugged in it will indeed run pretty rich.

 

the throttle body has two larger takeoffs for coolant, this is often bypassed with the small hose from the thermostat housing returning to the expansion tank instead,   the smaller takeoff is for the Vacuum advance on the distributor.

[Telf 224 2 Cars]

The SAD is just a air supply during cold start. The plug supplies a constant voltage , heats a bimetallic disc that slowly closes over time and reduces the extra air. The engine heat also assists. Its not even fitted on my car as I run a Emerald ECU and none of the old and pretty crap Lucas ignition/management. 

 

The water temp sensor must be operational and wired in or you will overfill massively . The ECU will assume you have a cold engine 

 

 

[Telf 224 2 Cars]

And yes before any one says I know the original engine management was good in its day!

[Telf 224 2 Cars]

Sorry if you're not sure the blue plug is for the temp sensor. It's under the dizzy

Edited March 12, 2023 by Telf

[welshpug 1,661]

2 hours ago, Telf said:

crap Lucas ignition/management. 

 

 

  I think you're ranting on the wrong forum...

 

No prince of Darkness on these cars, all Bosch!

[Telf 224 2 Cars]

Yeah Bosch. Whatever it is mainly worn out crap. I got bored of the whole AFM nonsense when I rebuilt the car a few years back.

[Paul Quinnell 0]

Thanks to Paul's excellent help on the manifold hose, the Pug now starts fine on the throttle...

 

The issue now is it is running really rich and over fueling..

 

• I have discovered the SAD sensors are disconnected but the wiring has been a bit modified before...
• There are three pipe connections coming out of the bottom of the throttle body with no hoses attached to them...

 

Can anyone advise on the above and what color wires the two SAD sensors need to be connected to in the under bonnet loom...

 

The blue sensor wires are grey and white and the black sensor are orange and green..

 

Many thanks 

 

Paul

 

 

[Paul Quinnell 0]

Many thanks for your help guys, my problem now is which wires to connect the plugs to in the loom ?

[welshpug 1,661]

are the wires not connected to the two 2 pin plugs?

[Paul Quinnell 0]

Hi Mei,

 

No unfortunately they were separated from the loom when the engine came out.....the wiring has been altered with the brown plug been chopped and replaced with connecters.

 

I now have the blue and black plugs (2 pin) plugged into the top and bottom of the SAD ..with open tails.....grey and white tail from the blue one and orange and green from the other black one....any idea what colors in the loom I need to connect them too...

 

Thanks

Paul

[welshpug 1,661]

Best approach is to get a haynes manual and a multimeter/test light, unplug the ecu and buzz through from the ecu plug to the wires you are unsure of in the engine bay.

 

Logically though,  just find the same colour wires and rejoin them, neither go through the brown plug in the middle of the engine loom!

[Paul Quinnell 0]

Many thanks Mei, I will have a work through...

 

Cheers

Paul