Thread: idle bypass valve

Originally Posted by mike 90 RR

The valve has the plunger on the RHS of the photo ....


When you installed it into the body ... I suspect that you left it fully extended and when you screwed it into the ali body you have jambed it (the Plunger) against the opening, inside the ali body that it screws into

Firstly ...inspect & confirm that the plunger is jambed / fully closed
... when You take the 3 hex bolts off the Ali body ... have a look inside the body and I recon that you will see the plunger hard up, closing the valve / instead of seeing a 4mm opening of the valve

Discowhite + others would have more experience on this subject ... The other thing is ... If you have jammed the plunger .... then you may not get this thing to work cause it's now internally damaged






What I would do ......
Undo the 3 Hex bolts to the stepper (Idle control unit) body
Unscrew the idle control motor / unit
Grab & turn the plunger all the way in ... so the plunger (on the RHS of the photo) is fully retracted /// Just turn it ... (as a threaded bolt)
Reinstall the idle control motor / unit to the ali body
Reinstall the stepper unit to the plentium
Turn ignition key & wait a bit
Start motor

The above is a guide from my memory only ... But I recon that you may have jammed the plunger against the opening of ali valve body / stopping the idle control valve motor from working


Hope it helps

Mike

thanks for all the help mike i will have a go at it tomorrow after work its a new valve that is in it to, i got it to idle sometimes but it still stalls at times and wont start with out giveing it throttle thanks luke.

Originally Posted by mike 90 RR

The valve has the plunger on the RHS of the photo ....


When you installed it into the body ... I suspect that you left it fully extended and when you screwed it into the ali body you have jambed it (the Plunger) against the opening, inside the ali body that it screws into

Mike

Mike, it wont jam if the plunger is fully extended. As you screw in the unit, the plunger will push back into the unit itself. Its nothing more than a DC motor drive. It is a bit stiff but can be pushed back and even pulled out, but you do it very slowly and dont exert too much force on it.

One side of the plunger has a groove in it and a notch on the body. Once you slowly pull it to its maximum out, you then unscrew the plunger from its home and it will come all the way out. Be careful of the long spring behind it.

Also, there is no need to reset the throttle plate as this has no bearing on the stepper at all. Unless you have pulled the throttle plate out to replace it or have had all the linkages removed from the plenum leave the plate adjustment.

If it idled fine before the stepper motor was broken, then it will be possibly loose carbon deposits blocking the plunger seat or as Mike stated, check the vac hose running to the fuel regulator off the back of the stepper housing.

Removing and replacing the stepper will make no difference to the idle settings elsewhere.
All the stepper does is take a command from the ECU to open or close until the ECU see's the correct idle speed from the tacho. The stepper has no common zero setting and the ECU has no way of telling where in its stroke length it actually is.
It may also be the stepper you bought is faulty if its second hand.

Cheers

Andrew.

Originally Posted by LOVEMYRANGIE

Mike, it wont jam if the plunger is fully extended.

I've never had to repair one ... I've taken them off as a whole and cleaned it / put it back on .... Never had one go Cuput /// But they are pretty basic

But as we are both saying ... check the vac hoses are connected to the stepper body .... a 3mm? small one & a 16mm? large one


The other thing that Spook is not confirming is ...why did he take the Idle control valve off ...in the first place??

Mike

Originally Posted by mike 90 RR

I've never had to repair one ... I've taken them off as a whole and cleaned it / put it back on .... Never had one go Cuput /// But they are pretty basic

But as we are both saying ... check the vac hoses are connected to the stepper body .... a 3mm? small one & a 16mm? large one


The other thing that Spook is not confirming is ...why did he take the Idle control valve off ...in the first place??

Mike

mike i took the valve of to clean it and it cracked when i un did the valve thats why i got a new one, so i took it of today to check if it was jamed but it wasnt it , i didnt need to screw it back in, it was all ready in, so i put it back as you said to do so, have not been for a drive yet but it did idle,but wont start first go takes a second go for her to start.

Originally Posted by LOVEMYRANGIE

Mike, it wont jam if the plunger is fully extended. As you screw in the unit, the plunger will push back into the unit itself. Its nothing more than a DC motor drive. It is a bit stiff but can be pushed back and even pulled out, but you do it very slowly and dont exert too much force on it.

One side of the plunger has a groove in it and a notch on the body. Once you slowly pull it to its maximum out, you then unscrew the plunger from its home and it will come all the way out. Be careful of the long spring behind it.

Also, there is no need to reset the throttle plate as this has no bearing on the stepper at all. Unless you have pulled the throttle plate out to replace it or have had all the linkages removed from the plenum leave the plate adjustment.

If it idled fine before the stepper motor was broken, then it will be possibly loose carbon deposits blocking the plunger seat or as Mike stated, check the vac hose running to the fuel regulator off the back of the stepper housing.

Removing and replacing the stepper will make no difference to the idle settings elsewhere.
All the stepper does is take a command from the ECU to open or close until the ECU see's the correct idle speed from the tacho. The stepper has no common zero setting and the ECU has no way of telling where in its stroke length it actually is.
It may also be the stepper you bought is faulty if its second hand.

Cheers

Andrew.

thanks Andrew but when i got the new stepper not second hand, it did this from new which was a couple of months ago, so i put the old stepper back in just glued the crack up and it idle was spot on with the old valve,but the glue didnt last so i had to put the new one back in so now im have idleing problems. thanks luke..

The stepper is not a powerful idle control like in Motronic.
It depends on the "kerb idle " being correct for it to control idle speed correctly in four steps.
Maybe the old one leaked and someone cut down the kerb idle to compensate.
To check the kerb idle, remove the hose between the throttle butterfly and the stepper and seal both ends with duct tape or similar.

The engine should then idle warm at 550-600rpm. If it stalls then the throttle butterfly is dirty or out of adjustment. Clean the butterfly and the oil ventilator . If still bad the throttle stop can be adjusted by turning the small screw inset into the top of the butterfly housing. AFAIR in is faster but it will be obvious.

Once you have the engine kerb idle correct, then the stepper should work properly.
Regards Philip A

Originally Posted by spook

mike i took the valve of to clean it

Beauty ... There are so many different reason's why they don't idle ... that it's hard to pinpoint with out some background / history on what the problem originally was


Do what PhillipA has written



Taking 2 go's to fire up is not unusual .... Mine is a very healthy V8 ... but first up in the morning ... I start my car in 2 steps /// I turn the key to on, wait 3 secs & start it for with a quick flick & then turn off the key ... Then I return the key to start the motor again ... and IT then fires up (straight up)

The reason for the (Just a quick flick of the key) .. (not much .. 1/4 of a second) ... is that the injector squirts a bit of fuel /// this gives time for it to vapour in the pot, which will fire up the piston the next time I turn the key to fire her up

If I just turn the key when it's cold ... then it takes a long time for it to fire up, and I would be basically, just flooding the motor
If you keep flooding the motor ... then this will kill your spark plugs, Bigtime




Mike

Mike,

Mine also does this but became better when I fitted a new VR fuel pump. The pumps have a non return valve that is supposed to keep the rail pressurised.

I suspect that the fuel pressure regulator may leak a bit and lose pressure overnight and so need 2 lots of priming and if I get keen enough I may repace it to see if it makes a difference.

You are correct in saying that the injectors squirt a little . Also no more fuel is squirted while cranking until the engine fires.

BTW to clear flooding the 14CUX has a feature that no fuel is introduced if the accelerator is held flat to the floor to clear a flood. Just like a carby car.
Regards Philip A