[aaronstevens]

grand vitara 98 2.0 J20A SQ420
have changed my timing chain, tried to start car, it is winding over but just won't go, it backfires everynow and then aswell.
i pulled the timing chain cover apart again and realigned the timing, same thing has happened again . if it is not timing, any idea what it could be?

does anybody know a definite compatible obd2 device to buy that will work on my car?

[watermouse]

I am presuming you are having another attempt at fixing this


Did you check that there is no damage to the cam shafts or the sprocket keys on both cams, particularly the exhaust cam? (this drives the Cam Angle Sensor)
It sounds like a timing issue.


Pretty sure that with early efi suzukis you only get useful information with the suzuki scantool or this http://www.rhinopower.org/diag/sdl_if.html You might want to ask rhinoman http://www.auszookers.com/forum/memberlist.php?mode=viewprofile&u=3386

[aaronstevens]

Cheers man , there had looked to be no damage , the timing kit went on and I relaligned it all twice !
I had sprayed abit of degreaser over the covers , could I have sprayed it on a plug for a sensor ? Could this cause this problem ?

[Gwagensteve]

OBD won't help unless the car is running.
The timing is out.
I can't help more than that- I'm unfamiliar with the J20, but it's pretty clear something is seriously wrong.

[aaronstevens]

Can I just pull my rocker cover and and look at the cam shaft sprockets and make sure they are still inline with the crank shaft ?

[fordem]

Based on my knowledge of the timing marks for the J20 engine - NO.

The marks you should be using for the cam sprockets are below the cam centerlines and not clearly visible when the timing chain cover is installed.

More out of curiosity than anything else, let's assume that you could see the cam sprocket marks with the cover in place, what exactly do you plan on using as a reference for the crankshaft side of things?

[aaronstevens]

The mark on the top of the harmonic balancer that is inline with the crankshaft key

[aaronstevens]

I guess I could also put a screwdriver in the spark plug socket without the plug in , and rotate it by hand and see if tdc is inline with the crankshaft

[Gwagensteve]

Do you have an FSM?

[VitNick]

Big timing chain has 1 tooth difference between marks on it. Caught me out when hand cranking motor around, almost comes back to all lining up but not perfect. Easy fix if you catch it and correct it, if not probably be close enough to run, but crap and backfire and stutter heaps.

Also if you can do a compression test in case it skipped a tooth or few when the bolt worked it's way out.

Either way you have to pull timing case apart again, that bolt has broken the timing case and rocker cover. Worth checking timing is correct when it's all open anyway, and to torque the cam gear bolt you need good access to it.

^x2 FSM helps heaps and shows everything clearly and how chain is slightly different

[aaronstevens]

I've taken it all apart and realigned the timing since the Bolt issue. Now it just won't start , only wind, it's a pretty monotone wind , I don't know if I'm lacking compression ? Or whether it normally sounds pretty monotone

[VitNick]

Check compression, assuming you have replaced broken covers?

[aaronstevens]

Yeh replaced the covers , will check the compression and stick a screwdriver in the spark plug socket to see if it's still in time when I wind it over by hand

[fordem]

aaronstevens wrote:

Now it just won't start , only wind, it's a pretty monotone wind , I don't know if I'm lacking compression ? Or whether it normally sounds pretty monotone

There is a distinct difference in the way an engine cranks when it's lacking compression - it's faster & smoother - almost constant rpms, rather than the cyclic/rhythmic drop in rpms (of the starter motor) as each cylinder comes up on it's compression stroke.

A compression test would be one way to find out if you have bent valves as a result of the previous bolt incident, or possibly it being cranked whilst out of time.

[aaronstevens]

Okay thanks for the info , so stupid question but I'm not too sure , if the engine is out of time will I still have compression ?

[watermouse]

No, You lose compression if inlet or exhaust valves are open at any time during the compression stroke.

further to Fordems suggestion, you need to be sure that the timing chains are aligned correctly to determine if lack of compression is due to bent valves.

[aaronstevens]

Okay thanks, is there any sensors that I may have bumped or knocked when doing this ? Any vital sensors that will cause the sparking to be out of time ?

[watermouse]

The only sensors that affect spark timing directly are the cam position/angle sensor (CAS/CMP) on the back of the rocker cover on the exhaust cam and the crank position sensor (CKP) which would be on the back of the block behind the flywheel. (note: I have had two transmissions and flywheels out of SQ420 Grand Vitaras in the last few weeks and they both did not have this sensor fitted. Even the FSM says "if fitted")

There is a possibility you may have damaged the exhaust cam, when it fell apart, which rotates the CAS. It is unlikely you would have damaged this with degreaser as it is well back from the damaged area around the timing chain and sprockets.

Here is a long but informative video about timing on these engines.