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Discussion Starter #1
Hi,
Using a obd II tool my timing advance seems a bit high (+15 degrees BTC at idle) and swings around quite a bit and at cruising speed ~2000 RPM is over
+35 degrees BTC.

According to an tech article I found it seems like +5 degrees at idle is what it should be. It idles 'hard', all cylinders are firing but shakes the truck more than I think it should. Everything I read says that you cannot adjust the timing so...

Any thoughts on the cause? The vehicle has over 212000 miles. No idea what service has been done as I purchased used over 2 years ago.

Thanks,
 

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99 Tracker, 5 door, 2L, 4x4
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Dont fret about the timing, that is the ECU doing its job...

You should perform a basic OBDII live data scan and post the results..

Providing there is no chain noise, there is no need to panic, If there is, beware (chain breaks, valves slam into pistons).

.... Philip
 

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Discussion Starter #3
Hi Aquanaut20,
Not sure what you mean by live scan. I had the scanner running while driving and what I posted is what was being displayed as timing on number 1 cylinder. I never saw the timing go negative but also never under +15 degrees. At times over +40 degrees. I do not think that I have ever seen timing that high. I am using OBDLink app that came with ScanTool and also another app to verify what I was seeing. Sometimes at idle the advance slings from +15 to +25.

Thanks,
 

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Raw static timing is adjustable. Once set per the manual (attached) the ECU takes over the additional operational timing needs, as Phil points out.

Now, having said that and seeing what MAY appear to be somewhat erratic timing swings (in degrees), rough idle AND given the high engine mileage...there may be excessive wear (slop) in either the valve timing chains and / or the Cam Position Sensor. Both of those area components dictate the engine running timing. And if you have never replaced your CPS, they are somewhat known to be problematic in high mileage 2.0's, particularly with "hot no-starts" and "mis-fire" problems, FWIW.

Manual...
https://www.mediafire.com/folder/cvrt1rfoso8t8/Service_Manuals

Previous timing discussion thread...
http://www.suzuki-forums.com/1g-1999-2005-vitara-grand-vitara/107753-set-ignition-timing-without-tech-ignition.html#post662457
 

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Discussion Starter #5
I was kind of thinking that the timing chain components might need to be replaced. I have seen two part numbers, 1 for the cam position sensor and 1 for the cam synchronizer. Should I replace both or wait until after replacing the timing chain components to see whether the issue is resolved?

Thanks,
 

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I'd start with attempting to set BASE timing, observing the resulting test data from that, and then think CPS replacement, followed by an "open and inspect" of the timing sprockets, chain, guides and tensioners, before ordering parts.

Is the front engine / timing chain area noisy? :huh:

Any records showing superlative oil change maintenance? :)
 

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Discussion Starter #7
Ok,

Thanks!
 

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Discussion Starter #8
the timing chain assembly is not noisy. At least not in my experience. I owned an older Toyota with the JDM engine 18RG which is a DOHC 2.0 engine and no appreciable noise in the J20A engine.
No records from before I purchased and I change oil every 4K miles.
 

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Before delving in and changing part, other than service items.. lets get some baseline data...

Since you have not grasped the search function, I include the "Basic, Live Data Scan"

Provided the back pressure test verified the CATs as OK (taken at front O2 bung,<3psi @2500rpm)

time to connect a LIVE DATA SCANNER.

COLD engine, (KOEO)
AIT (air temp)and ECT(coolant temp) must be with in 2% of ambient temperature, verified with IR gun.
TPS, 0% at stop and rise smooth and steady as throttle is advanced
MAF, 0% with no air flow
Battery, 12.6vdc, fully charged.

Start engine.
ECT, must start to rise and attain and hold 180* at idle and 2000rpm
CL (ECU) must maintain at idle and 2000rpm
MAF, small reading at idle and rise steadily as throttle advances.
O2, (B1S1, precat), must start actively switching with no lean/rich bias...
LTFT, (long term fuel trim), close to 0%, +/-2 is allowable, if more, time to investigate fuel delivery/illegal air
Vacuum, at unregulated manifold port, 19-21”hg..with a dead steady needle, investigate jitter or bounce.

If the plugs have not been changed/checked/cleaned/adjusted lately, I recommend this be completed first. Take special note of the coil lances (rubber section between coil and plug). They deteriorate and allow crossfire to ground.(miss fire/shake).. They can be obtained separately from coils...

While the plugs are out, do a compression test, with a fully charged battery, fuel and ignition disabled, post results of dry and wet pressures..

.... Philip
 
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