Anyone know of a good write up on adjusting the timeing on a 94 Q? If not, anyone have any tips or do's and don'ts when checking the timing?
Thanks,
Stephen
Timing
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Q45tech
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- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
The easiest way is with the special adapter [$200] which plugs into the driverside ignition harness.The CAS has a wide range in the slot [-25 ---+15] and setting 1.0 degrees resolution is tricky. The normal position shows about 1/5-1/4 of the slot exposed to the right.
Follow the instructions in your shop manual closely as to locking out the IAC, setting rpm and making sure the coolant temp has stablized at 176F [minimum].
15 Deg BTDC [as measured with timing light at crankshaft pulley] is ideal as 17 will cause over activity in knock sensors and limit full advance in summer heat further reducing power.............some run 13 degrees which will only droppower at 4,000 rpm by 1-2%.
The Consult always reads 15 degrees at idle [in park]because it assumes you have set the CAS properly [in drive it changes to 20 degrees].
{{Checking the maximum advance is productive it should be 26-28 degrees under WOT as you exceed 6,000 rpm [lower around 22-24 at 4,000]...............at 2,000 rpm cruise light load steady speed it might get to 40 degrees ......the above requires a Consult}}
Follow the instructions in your shop manual closely as to locking out the IAC, setting rpm and making sure the coolant temp has stablized at 176F [minimum].
15 Deg BTDC [as measured with timing light at crankshaft pulley] is ideal as 17 will cause over activity in knock sensors and limit full advance in summer heat further reducing power.............some run 13 degrees which will only droppower at 4,000 rpm by 1-2%.
The Consult always reads 15 degrees at idle [in park]because it assumes you have set the CAS properly [in drive it changes to 20 degrees].
{{Checking the maximum advance is productive it should be 26-28 degrees under WOT as you exceed 6,000 rpm [lower around 22-24 at 4,000]...............at 2,000 rpm cruise light load steady speed it might get to 40 degrees ......the above requires a Consult}}
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Chally
- Posts: 445
- Joined: Tue Apr 30, 2002 12:17 am
- Car: '94 Infiniti Q45
2002 Nissan Patrol 4.8L
2013 Citroen C4 (economy)
If you don't have the special machine, you can remove the No. 6 coil & connect a hi-tension lead between the coil & plug, then you'll be able to hook up a conventional timing light.
You use No. 6 coil because it's easier to get to than the No. 1 coil. No.6 is the 2nd from the back on the passenger side.
You use No. 6 coil because it's easier to get to than the No. 1 coil. No.6 is the 2nd from the back on the passenger side.
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Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Just rememeber that the least advance that will not trigger the knock sensors is much better than an agressive advance that will........especially when ambient gets above 75F.
One or two degrees won't be felt but a KS retard of 5-10-15 surely will result in significant power loss.
The Q 13-17 BTDC range..............almost a waste to set it at 17 because you will end up back at 15.
Keeping the coolant temperature below 194.99F at the end of the acceleration is very important...........other than a brand new car/rad system------ few can accomplish this.
The problem is how to cruise at 174-176F and have enough thermal reserve to not raise the coolant by 18-20F in WOT acceleration..............measure the coolant difference AC on and AC off at cruise.
One or two degrees won't be felt but a KS retard of 5-10-15 surely will result in significant power loss.
The Q 13-17 BTDC range..............almost a waste to set it at 17 because you will end up back at 15.
Keeping the coolant temperature below 194.99F at the end of the acceleration is very important...........other than a brand new car/rad system------ few can accomplish this.
The problem is how to cruise at 174-176F and have enough thermal reserve to not raise the coolant by 18-20F in WOT acceleration..............measure the coolant difference AC on and AC off at cruise.
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Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
At 5,000 feet the air density is at least 15% lower than sealevel at the same temperature. This means the MAF is reporting 15% less than sealevel normal at each rpm/load.
The ecu has a 20% correction range in closed loop but less at WOT..........I expect the mixture to be even more than the normal rich like super super rich............which would speed the flame burn rate..........but at super rich it slows it down like putting water on a fire
I would guess 15 degrees would still be suitable.......need some data like MAF voltage and injector duration vs rpm at WOT........to know for sure.
In any case the power [torque and HP] would measure 15-20-25% less than at sealevel.
It would be interesting to know the ecu parameters at 60 mph flat steady cruise..........bet the mileage is down by 10% because the engine would need to turn 5-7% faster the make the power need to run [tire/friction losses] 60 mph at 5,000 feet.
Since the air is thinner the radiator is less efficient therefore I would expect your coolant temperature is higher........above 194.999F you start to lose advance across the board [all load/rpm ranges]..........
Didn't think Denver had Real 92 or is that just the labeling as most high altitude gasoline is lower REAL octane because they can get away with it.........they tilt the reasearch upwards and the motor octane lower so it still average 92 but would be very knock prone compared to 92 blend at sealevel.......the higher the motor octane the more the blend cost to refine.
The octane rating is essentially useless unless you know the results of the two different tests.......hopefully the 92 is better than the 89 and better than the 87........at least that's the way it is supposed to work.
You must watch out for oxygenated blends as the lower BTU per gallon makes the whole situation worse by 5%.....that probably half the summer problem plus the coolant temp plus the natural extra decline in density from 30F to 80F [another 5%].
You need a 3 psi supercharger just to breakeven with a sealevel Q.
The ecu has a 20% correction range in closed loop but less at WOT..........I expect the mixture to be even more than the normal rich like super super rich............which would speed the flame burn rate..........but at super rich it slows it down like putting water on a fire
I would guess 15 degrees would still be suitable.......need some data like MAF voltage and injector duration vs rpm at WOT........to know for sure.
In any case the power [torque and HP] would measure 15-20-25% less than at sealevel.
It would be interesting to know the ecu parameters at 60 mph flat steady cruise..........bet the mileage is down by 10% because the engine would need to turn 5-7% faster the make the power need to run [tire/friction losses] 60 mph at 5,000 feet.
Since the air is thinner the radiator is less efficient therefore I would expect your coolant temperature is higher........above 194.999F you start to lose advance across the board [all load/rpm ranges]..........
Didn't think Denver had Real 92 or is that just the labeling as most high altitude gasoline is lower REAL octane because they can get away with it.........they tilt the reasearch upwards and the motor octane lower so it still average 92 but would be very knock prone compared to 92 blend at sealevel.......the higher the motor octane the more the blend cost to refine.
The octane rating is essentially useless unless you know the results of the two different tests.......hopefully the 92 is better than the 89 and better than the 87........at least that's the way it is supposed to work.
You must watch out for oxygenated blends as the lower BTU per gallon makes the whole situation worse by 5%.....that probably half the summer problem plus the coolant temp plus the natural extra decline in density from 30F to 80F [another 5%].
You need a 3 psi supercharger just to breakeven with a sealevel Q.
"The easiest way is with the special adapter [$200] which plugs into the driverside ignition harness.The CAS has a wide range in the slot [-25 ---+15] and setting 1.0 degrees resolution is tricky. The normal position shows about 1/5-1/4 of the slot exposed to the right"
How much shop time would it take a dealer to set the timing on a 95 Q, including warm up and set up of the "special adapter"? Would a 95 Q with 85,000 benefit from this? I asked at my last service visit and was told the Q never needs to be timed. I didn't pursue his statement with discussions of timing chain stretch and such. I'm going in tomorrow(alignment) and may insist on the timing set also if it's considered necessary by this fabulous board.
How much shop time would it take a dealer to set the timing on a 95 Q, including warm up and set up of the "special adapter"? Would a 95 Q with 85,000 benefit from this? I asked at my last service visit and was told the Q never needs to be timed. I didn't pursue his statement with discussions of timing chain stretch and such. I'm going in tomorrow(alignment) and may insist on the timing set also if it's considered necessary by this fabulous board.