Weber Carb

[nightracer35]

can ant 1 tell me do i need a stepper motor on my webber carb, if so what does it do?? the reason for asking is i have bought this carb but came without the plug for stepper motor, and the throttle bracket to fasten to the inlet manifold.

 

 

any info greatly needed

 

many thanks ron

[SEgan]

I am no expert but I think it depends on the type of ignition system you are using. ESC 1 type does not have a stepper motor on the carb, if you have ESC 2 some of the connections go to the stepper motor on the carb.

 

Sean

[Simon cooper]

Ditch it!

The stepper motor is a form of idle control and is therefore run by an ecu. if you do not have the ECU and the correct loom, you will not get it to run right. You can bodge the linkage but you have no idle screw. The other disadvantage with that carb is the mixture screw is hard up against the rocker cover and an absolute b1tch to set. Bin it!

Simon

[nightracer35]

thanks for your replies and advise

 

 

 

many thanks

 

ron

[robert cockling]

Ditch it!

The stepper motor is a form of idle control and is therefore run by an ecu. if you do not have the ECU and the correct loom, you will not get it to run right. You can bodge the linkage but you have no idle screw. The other disadvantage with that carb is the mixture screw is hard up against the rocker cover and an absolute b1tch to set. Bin it!

Simon

 

 

Hi I was about to raise another topic regarding Stepper motors and Weber carbs , but I might as well jump in here.

 

Are you saying ditch the whole carb or just the stepper motor

 

I have the electronic plug on my car and it's connected to some ECU (Ford Sierra Circa 1988) and now that I've hopefully sorted my cooling problem(see under another topic) I'm looking to sort out my car performance issues. I noticed that when I disconnected the plug the car seemed to sound better and pull a bit better (although maybe this is wishful thinking!!), and with a bit more popping and banging on overrun (nice!!)

 

Wasn't sure what potential damage this is doing........if any

 

 

Robert

[Longboarder]

Effect depends on what the engine was doing when you pulled the plug. If the engine was off then you will get a slow or no idle as the butterfly will be closed. As simon said all it does is control the idle by moving the idle stop screw a little bit and monitoring revs. No problem running without it connected. May have to fiddle with the idle stop screw a bit. Should not make any difference and the DFTH carb has only marginaly less potential than the DGAV.

Another slight posibility is that you will get some engine run on when very hot.

 

Nigel

Nigel

[salty_monk]

Like that name "run on" you seem to be having on your post??

[Simon cooper]

Robert,

The favorite problem with that carb set up is pulsing of the stepper and poor idle.

The solution is make 100% sure that the stepper pin that contacts the idle linkage has perfect continuity (Electricaly that is). The stepper pin earths through the linkage, this is the way that the ECU knows when to control the idle. If the contact is bad, the ecu sees that the engine is about to stall as it also monitors revs, and pushes the pin out. Then when the revs go up, it retracts it but not knowing how to regulate it as it has no feeling so to speak. Rub some fine wet and dry over the contact area and all will settle down. When the idle is stable at around 900rpm, pull off the plug and set the idle mixture. when right, switch off and re-connect the stepper plug. DO NOT RECONNECT WHEN ENGINE IS RUNNING. This can blow the stepper and/or the ECU. The ECU has to initialise the stepper on power up.

The stepper is also responsible for the fast idle when on choke. You can leave it disconnected all the time but the first five minutes will be spent keeping the engine alive with your foot.

Simon