Really weird timing readings.
#1 _mike_nofx_
Posted 05 July 2006 - 04:45 PM
I can get it to run really good, but then it backfires LOUD, almost like a gunshot, when i turn the engine off. A guy at work nearly shit his pants when i turned my engine off in the carpark. Big flame shoots out too.
Right now ive got it to run pretty good, but it still backfires when i turn it off, but its only small, more of a quiet 'pop'.
Its probably as good as im gonna get it.
Now the problem, when i check the timing with the gun, its all over the place. Sometimes the white line is on the complete opposite side of the pulley to the numbers..?? and other times its around the 9o'clock mark, if you imagine the pulley as a clock face.....
Is it just that my timing gun is stuffed. I use the lead closest to the front of the car.
Thanks
Mike
#2
Posted 05 July 2006 - 05:25 PM
#3 _[BOTTLEDUP]_
Posted 05 July 2006 - 10:49 PM
#4 _rorym_
Posted 06 July 2006 - 08:51 AM
I am with Howard...I bet my left one the outer ring with the timing mark on your harmonic is turning/spinning on the inner bit. Rubber breaks down and allows it to slip.
Rory
#5 _Yella SLuR_
Posted 06 July 2006 - 10:39 AM
Few things to try there anyway.
#6
Posted 06 July 2006 - 12:31 PM
#7 _devilsadvocate_
Posted 06 July 2006 - 12:50 PM
How can you test for this otherwise? Off the top of my head:
Perhaps put car in gear, tighten fan belt and either using fan or screwdriver between fan bolts, attempt to rotate the engine.
Or look at central part of balancer under timing light, not sure what they look like exactly without one in front of me, even a dab of liq paper on the edge of the end of the crankshaft..... if it stays still under the timing light and the marks on the outside dont.....definitely outside and inside arent spinning together.
#8 _jimjet61_
Posted 06 July 2006 - 12:52 PM
#9
Posted 06 July 2006 - 01:41 PM
#10 _torana_
Posted 06 July 2006 - 01:52 PM
Make a mark on your harmonic balancer from the inner to the outer and see if it moves when lit up by timing light
cheers julian
#11 _mike_nofx_
Posted 06 July 2006 - 09:44 PM
This weekend i will re-check the timing and if the balancer is slipping.
In the mean time, how bad/unsafe/dangerous would it be to drive if it IS slipping?
I really only need to drive it tomorrow (friday) to work, then i will check it all out this weekend.
About a new balancer, where can i get one? any auto shop?
If the balancer is tight and has no probs, how do i tell if its a standard or better-than-standard one?
and the backfiring? any ideas there?
Also, a tune is on the cards for the next couple of months. Im guessing they will also do the timing.
#12 _draglc_
Posted 06 July 2006 - 10:02 PM
But for peace of mind, you can just go buy a new one, if your doing timing with a light, and at idle its + or - 30 degrees, its obviously the balancer.
The main concern, other than timing of course, is that it could fly forwards and through your radiator, though ive only ever seen them go backwards towards the engine.
If i were you, id just go find standard one at a wreckers, in good nick and swap it over, will do in the meantime, you can at least set the timing!
If you want to fork out later for a good one, that will handle the rpm you want to give the engine, then by all means do that!
A1
Edited by draglc, 06 July 2006 - 10:02 PM.
#13 _rorym_
Posted 06 July 2006 - 10:12 PM
R
#14
Posted 07 July 2006 - 12:49 AM
other thing to look for is condition of distributer cap etc, can you swap with a known good dizzy to rule out cross fire.
back fire is usually caused by a lean condition.
when you get the timing right and if the problem persists check for main jet blockage on carb model or idle lean and if accompanied by run on check for high idle by either adjustment or idle solenoid, binding linkages etc.
#15 _Yella SLuR_
Posted 07 July 2006 - 06:34 AM
I'm still thinking that the turbo is sending weird signals to the dizzy. I'm also wondering if the turbo sends stronger signal to the dizzy at idle, and therefore if stronger springs not put in the dizzy, or not regraphed, would not be getting full vacuum advance, due to parital advance at idle. Have you ever had the dizzy adjusted to suit the turbo, or have you just put in a standard normal aspirated electronic dizzy (still has vacuum advance). Just thinking out loud, could be a load of crap, but could be checked out by a place that specialises in tuning turbo cars. Those guys are pretty cluey about how these beasties work.
Can check the above by keeping the timing light on while you pull the vacuum line to the dizzy to see if any change in the mark anyways. Should give you a feel for what's going on.
Wouldn't a turbo car go lean when switched off anyway while the turbo keeps spinning while fuel is cut off?
Edited by Yella SLuR, 07 July 2006 - 06:37 AM.
#16
Posted 07 July 2006 - 08:42 AM
Another easy way to tell if the balancer is OK ( on red 6) is that with the keyway at 12 o clock, the timing mark is at 11 o clock...if its anything else the outer ring is slipping...and I have seen them walk forward..on a VK Commodore...the rubber fell out and all that could be heard was a "ting ting" sound of the outer ring rolling and flopping around....I told the guy he shouldn't drive it and that they were cheap to replace....but he new better...and drove it until the crank snapped.
Yours should be ok to drive provided it doesn't come apart.
#17 _dave720gtr_
Posted 07 July 2006 - 01:49 PM
cheers
#18 _Yella SLuR_
Posted 08 July 2006 - 08:20 AM
#19
Posted 08 July 2006 - 03:15 PM
I also think its the balancer....
Maybe check your dizzy cap is ok, it might be cracked and not sitting properly which means it can jump all over hte place and backfire etc...
#20 _mike_nofx_
Posted 08 July 2006 - 09:15 PM
As for the dizzy cap being cracked (Havent checked yet) and sparks jumping, wouldnt that make the car run shit? it runs good still.
I still havent had a chance to check if the balancer is loose yet.
#21
Posted 08 July 2006 - 10:25 PM
#22
Posted 09 July 2006 - 05:19 AM
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