Running Issue 1.9 8 Valve

[smithy 1]

I know there are many running issue threads but i have a specific problem that did not come up on a search

 

i have got no vac from the throttle body to dizzy vac advance so getting no advance at idle and need dizzy advanced too far to keep running,i have gone through the set up in haynes several times and i am 100% it is as per spec,the outlet from throttle body is clear but no vac at all from the outlet.

 

the vac from main hose to servo and sunroof etc is fine.

 

any ideas what to check next??

[Obey_R 23]

Is it the lack of vacuum causing problems or a slit vac advance? I assume you would have checked this as you seem to know most of your stuff.

[smithy 1]

Just no vac from throttle body,must be an air leak on manifold I reckon just cannot seem to find on yet

[oldkiteman 6]

If you have got the vac pipe on the right pipe on the throttle body,there should be no vavuum at tickover and as the butterfly opens,the drilling is exposed to the vacuum and it starts sucking then.Hope this helps.Rob

[smithy 1]

I will put the mitivac back on and give it a try again but fairly sure there was nothing at all yesterday??

[Rob_the_Sparky 9]

If you have got the vac pipe on the right pipe on the throttle body,there should be no vavuum at tickover and as the butterfly opens,the drilling is exposed to the vacuum and it starts sucking then.Hope this helps.Rob

 

Agreed, so there is something else going on here - not the old air leak into the manifold problem? This makes the car run badly or not at all at ildle. Commonly caused by missing the screw that holds the oil filler to the manifold. Done this myself, despite knowing about it!!

[smithy 1]

Agreed, so there is something else going on here - not the old air leak into the manifold problem? This makes the car run badly or not at all at ildle. Commonly caused by missing the screw that holds the oil filler to the manifold. Done this myself, despite knowing about it!!

 

 

it does not run too clever to be fair,got high idle even with air screw wound fully in it is at 1100rpm if i retard ignition timing i can get it to run around the 900-1k mark but it is very flat and hesitant and struggles to rev up even with no load on.

i have done all the checking and setting procedure for throttle stop and the TPS,got different dizzy and AFM but fault still the same,new coolant temp and different ecu.

I have had a good spray round with carb cleaner and cannot find any air leaks.

I am starting to think the rev counter may be inaccurate making me think it is idling too high,gonna have to get a proper tacho to get accurate reading and take it from there.

 

to confirm just as the throttle opens there is indeed vacuum going to the dizzy.

Edited August 16, 2011 by smithy

[oldkiteman 6]

A couple of things to check for a fast tickover that wont slow down is firstly that the SAD device may be stuck open.Check this by getting the engine up to temp and clamping the pipe with long nose pliers.Doing this should not affect tickover.If it slows down,then SAD is faulty.Another thing is to check that you are looking at the correct timing mark.Take out no1 plug and stick a long screwdriver in.Turn engine ideally with a spanner on crank and find TDC.By rocking it back and forth you can get a good feel for TDC.See if this coincides with the mark you are using when timing it up.On my 205,the mark is barely visible and i ended up removing the lower tin plate covering flywheel and painting TDC marks there.Rob

[smithy 1]

Cheers for input the engine has only recently been fitted back in after rebuild fortunately I decided to paint Marlene timing marks on flywheel while out as like you say they are faint.I set ignition timing up static by lining up the mark on flywheel and setting dizzy so rotor points to no1 when no1 piston is at TDC.

I tested SAD on bench connected to battery it closes fully just wondering if the body is leaking like my last one? Will clamp pipe and see. Also going to blank servo barb on manifold see if that makes a difference.

 

Definately got air leak somewhere I reckon it's just being a sod to find.

[oldkiteman 6]

If you are convinced it has an air leak,try to find a garage that has a smoke tester.You disconnect air pipe and connect it to AFM.It pumps smoke into inlet manifold at about 1.5 pounds per sq inch and any air leaks show up very clearly.Its only a 10-15 minute job so shouldnt cost too much.We have got one at work and it is the dogs.Rob.

[smithy 1]

Thanks I will ring round local places see why they say.

Sounds like a cracking bit of kit

[Rob_the_Sparky 9]

Thanks I will ring round local places see why they say.

Sounds like a cracking bit of kit

 

P.S. - just for your sanity - Agreed, you definetly have an air leak, just need to find it now!

[smithy 1]

right had a mess today between rain showers found the sad closes fine but was sucking air in through the little rivet things on the body,covered them with a blob of silicone and it is now sealed up ok so should not draw in air.

servo hose,servo and sunroof vac stuff all ok as there was still vac in the servo and sunroof vac tank,although servo hose is brittle so i have renewed anyway.

 

One thing i have found while poking with multi meter,i was testing the earth wire to SAD and found both wires are 1.0ohms to earth.Checked the drawing in haynes and it seems the sad is fed via starter solenoid signal and then the tachy relay same as injectors,the solenoid trigger is also down to earth. currently ignition is off and battery disconnected is this normal behaviour until the key is turned to start position? think wire concerned is 46