Vacuum Questions

[xzltd]

Hi all,

Got hold of a vacuum gauge and did some testing.

Firstly...
Timing is set to 10 degrees
There are no vacuum leaks (checked by spraying in all areas)
Oil pressure and levels are spot on.

The gauge is reading 16.5Hg at idle and I adjusted the airflow meter for the very best vacuum.

This reading is low and it fluctuates only slightly about 1/2 inch of vacuum at idle

The meter says I could have late ignition timing and other sources say it could be worn rings or poor oil pressure. The car blows no smoke and oil meter indicates pressure is fine but the car has no guts especially on takeoff and it gets slightly better the higher the revs.

Can anyone diagnose the fault?

P.S. readings are exactly the same running petrol or gas.

:???:

[defect-prefect]

Hi all,

Got hold of a vacuum gauge and did some testing.

Firstly...
Timing is set to 10 degrees
There are no vacuum leaks (checked by spraying in all areas)
Oil pressure and levels are spot on.

The gauge is reading 16.5Hg at idle and I adjusted the airflow meter for the very best vacuum.

This reading is low and it fluctuates only slightly about 1/2 inch of vacuum at idle

The meter says I could have late ignition timing and other sources say it could be worn rings or poor oil pressure. The car blows no smoke and oil meter indicates pressure is fine but the car has no guts especially on takeoff and it gets slightly better the higher the revs.

Can anyone diagnose the fault?

P.S. readings are exactly the same running petrol or gas.

:???:
your motor has no guts. have a look at your accelerator cables. my motor was gutless, i took it in for a tune up. the problem was the outer cable had broken, when i hit the pedal to go, the outer cable "folded" over it's self causing me to only have 1/3 normal acceleration. a new/2nd hand outer cable was fitted for me, and it is all go now. this may help, i hope so. regards, defect=prefect. dave

[xzltd]

Thanks Dave,
Cables are ok, I have already replaced the worn ones.

[85ghia]

hey there,

when i was fiddling around with the afm i found-

1 - when you adjust the afm hex screw till the point where the idle wont get any higher, the car will be an absolute pig to drive, gutless at all rpm and uses heaps of fuel. it will take 10 seconds or more to rev out 1st gear (3sp auto). on the plus side it will idle nice and smooth.

2 - when you adjust the afm hex screw to the point where the idle becomes a bit lumpy, it drives really well, does all the things its supposed to. that is until you come to a stop, where itll most likely stall, so too when you put it into gear. when i had my afm adjusted like this, it took about 8 stop start attempts to get into my garage. drove really well on the road tho. maybe you can raise the idle speed to compensate? i didnt try

[xzltd]

Here's the story so far with the airflow meter...

The wheel adjusts one thing either idle mixture or cruise mixture, the hex nut does whichever one the wheel doesn't. I say this because I found opposite information from various sources, however, all sources say that there is a difference.

This explains your experience.

At this point my problem is vacuum, I have a feeling it's a stretched timing chain, but don't know enough to know for sure.

[ZC-Cruiser]

Check for stretched timing chain by having the car out of gear, grabbing the harmonic balancer and try to turn the engine one way then the other.

The crank will turn fairly easily untill the slack is taken out of the timing chain.

If you can move the crank more than half an inch or so, your timing chain has stretched - this is very common due to there being no oil feed onto the chain.

The chain can be replaced without removing the engine from the car.

While changing the chain and gears (they come as a set), drilling a 1/16" hole in the Lifter Oil Gallery plug right behind the Cam Gear will allow a fine jet of oil to spray right onto the chain.

Instead of stretching and needing replacing every 100,000km or so, the chain will then last as long as the rest of the engine does,

HTH

[xzltd]

Thanks mate,

Yep it's stretched about 2 inches i reckon, it'll work out better to get a donor engine i think, as i don't have the tools or knowledge to do it all myself.

330,000klms and it's the retirement home :(

[ZC-Cruiser]

Thanks mate,

Yep it's stretched about 2 inches i reckon, it'll work out better to get a donor engine i think, as i don't have the tools or knowledge to do it all myself.

330,000klms and it's the retirement home :(

Maybe you should find a friend who can help you recondition that engine - then it'll be good for another 330,000 rather than putting in some other suss thing...

[XF0747]

u'll also find its gutless on take off due to the 2.77 gears in the diff, and thats y u'll find it goes like a freight train in the higher rpm range, coz of the gearing in the diff