[feral4mr2]

hello, i've just bought my wife a very tidy 1999 GV auto with the j20a engine in it. condition for it's age is great, everything feels tight and drives well.

but.. it seems to have a lower rpm hesitation when taking off and it can be felt sometimes when cruising at highway speeds. everywhere else in the rev range it goes great.

today i replaced the spark plugs, fuel filter and air filter. no change.

has anyone had this problem before? should i look at the cops and maf?

cheers.

[Built4thrashing]

At what revs are you talking?

[feral4mr2]

from idle to 2000-2500 rpm. at 100kpm/ph is ~2800rpm and feel a slight surging.

put your foot down so it kicks back or once the revs come on after the hesitation it revs cleanly and pulls well.

[watermouse]

Mine did this for most of the time I owned it. J20A manual however.
I changed spark plugs, oxygen sensor, cleaned MAF, checked fuel reg and pressure, checked cam timing, blanked the EGR, checked Intake Air Temp sensor, Throttle Position Sensor, nothing made any difference
Early on I discovered that the old coilpack probes had electrical tape around them. New probes fixed the miss but not the low power/surge from 1800-2500rpm.

The biggest and lasting improvement came from advancing timing at the CAS housing about 3 degrees and running 98 octane.

Sadly I came to the conclusion it was poor engine management, I don't think there was a problem with the engine, just how the ECU was mapping it.

[feral4mr2]

hrmm.. ok. thanks for your input.

it doesn't have a miss, idle is smooth. just that loss of power/hesitation and as you said like a surge. otherwise great little car.

[ozzycouch]

Have a look around the engine bay for cracked hoses, sounds like a vacuum leak.
Had the same thing in a Mazda and a Subaru, both were between the air metering thingo and the throttle body.
Good luck.

[feral4mr2]

thanks. will have another look tonight.

borrowed a obd2 scan tool doobie off my cousin, will see if that works on it and shows me anything.

[watermouse]

It will be interesting to see if you can get the OBD2 to work. From what I understand, although the connector is the same, you need the Suzuki Scan Tool to get any useful information.

paging Rhinoman

http://www.rhinopower.org

If you are looking for CEL/MIL faults you can jump the connector on the RHS under the bonnet to get the Check Engine light to flash any fault codes stored.

[feral4mr2]

thanks! i wasn't sure if it had the old cel blinking method like my mr2 does. i will check that out when the wife gets home.

[Built4thrashing]

So the GV has a OBD2 plug but uses a different program?

Interesting. i was thinking of getting a OBD2 bluetooth transmitter so i could read the engine specs but doesnt sound like it will work
on my phone....

[feral4mr2]

i couldn't even find the connector for the obd2 device.

back at work now so i'll have to wait until i am home again to try the old CEL check. even though the cel isnt on i want to see if the ecu has any fault codes that might help track down the problem.

[atari4x4]

the plug you're looking for to bridge is in the engine bay.

[feral4mr2]

yes i seen that one, ran out of time to bridge it and see if there were any stored codes. i had read about people using obd2 scan devices on early grand vitara's, i couldnt find that plug.

cheers.

[murcod]

Built4thrashing wrote:

So the GV has a OBD2 plug but uses a different program?

Interesting. i was thinking of getting a OBD2 bluetooth transmitter so i could read the engine specs but doesnt sound like it will work
on my phone....

My 2004 XL-7 has an OBD2 plug, but the ECU doesn't communicate in the correct OBD2 protocol. I think it was January 2006 it became mandatory in Australia?

I've got an X431 and that will work, but my generic scanners won't (hand held and ELM327 PC interface.)

Regarding the OP problem, it could be your O2 sensor dying. They get slow to respond with age which will cause surging in closed loop. You can try monitoring the O2 sensor voltage with a voltmeter and check that it instantaneously changes voltage when accelerating/ decelerating. Realistically it would need replacing anyway if it's the original factory fit- they have a limited life.

[feral4mr2]

thanks murcod, i have a new 02 sensor on it's way.

[feral4mr2]

small update. i put the new 02 sensor in today amongst a few other things i had ordered.
pulled the cops off (had to anyways to do cam cover gasket) and pulled the leg off them. couldnt see any carbon thingies i have seen word of but there was rusty philips screw head in the main section of the cop. cleaned them up with a small screwdriver and sprayed with electra clean lube stuff. was a little rust on the surface of the spring that connects to it so gently sandpapered them.

i pulled the manifold heat sheild off as i could hear a noise when revving the other day. sure enough there are 2 cracks in the manifold. i cant be stuffed pulling it off to braze with the oxy so ordered a set of hurricane extractors.

test drive it does feel more responsive then it was. take off was better than before, though i can still feel a very slight hesitation when cruising around 100 kp/h and putting my foot down.

the extractors will be here next time i am back from work in a few weeks so i'll put them on and see what difference it makes.

i know my gt2554r turbo and a aftermarket ecu will solve a lot of issues..... but that will have to wait until the wife isnt using it for work anymore. haha

[Gwagensteve]

feral4mr2 wrote:

i know my gt2554r turbo and a aftermarket ecu will solve a lot of issues.....

[fordem]

I'd suggest replacement of the coil pack "probes" - they are available separately, and are not expensive. Treat them as you would any other spark plug lead - I had no noticeable misfires or hesitation issues, but, a couple of them had torn edges, so I swapped out the lot, and was pleasantly surprised with the difference in performance - the car was smoother and more responsive.

[feral4mr2]

Gwagensteve wrote:

feral4mr2 wrote:

i know my gt2554r turbo and a aftermarket ecu will solve a lot of issues.....

haha.. sorry. i normally put a turbo on anything i own.

[feral4mr2]

fordem wrote:

I'd suggest replacement of the coil pack "probes" - they are available separately, and are not expensive. Treat them as you would any other spark plug lead - I had no noticeable misfires or hesitation issues, but, a couple of them had torn edges, so I swapped out the lot, and was pleasantly surprised with the difference in performance - the car was smoother and more responsive.

what are the 'probes' you speak of? is this the peice that came off with the spring running up the middle?

[fordem]

Yup.