54 replies to this topic

[KNGGSR]

my gsr, is jolting when it gets warm, can't figure out the problem, just started to do it, replaced crank angle, leads, spark plugs, still same issue, what do you blokes think ?

[leadfoot]

ISC.

[KNGGSR]

Wats isc ?

[leadfoot]

idle speed controller it a creamy coled 6 pin square plug on the throttle body to test it grab a ohm meter and check between pins 1 and 2, 2 and 3, 4 and 5, 5 and 6

 

should all ready around 30 ohms if one doesn't you got a dead coil and need to replace the isc

 

pin layout is like this

123

456

pin 2 and 5 are earth

pins 1 3 4 6 are power signal from ecu

[jack be nimble]

Pin 2 and 5 are 12v power from the mfi relay.
1, 3, 4, 6 are switched earth by the ecu.

Or something. ...

Edited by jack of all, 03 January 2015 - 11:21 AM.

[KNGGSR]

my idle speed isn't connected, i run a microtech  

[blackvr]

Aah.. there's the problem ....  You are probably 1 fuel increment out in the light load area... either it's too rich and nice and smooth, or a tad lean and as jerky as all hell ! Good luck !

[leadfoot]

well that pertinent information i didn't have does it have 4 wire ISC control on the microtech?

[KNGGSR]

guys it can't be the tune, numbers don't change on its own, I've been driving the car for 3 years with out skipping a beat, now this jolting occurs, i don't get it, it has to be something mechanical

[Ian91]

Boost leak?

[KNGGSR]

nope , checked all that 

[Ian91]

Got a wideband in it? Maybe the fuel pump is dodgey or something?

[MDK87]

Checked the coolant temp sensor? 
 

Edited by MDK87, 04 January 2015 - 08:46 AM.

[blackvr]

The tuning numbers dont change... but lots of other things do . It's probably a fuel related thing ie injector  base seals gone hard and drawing a little air in while cruising etc. Microtech, like most of the after market ECUs, run a Speed Density setup using a MAP sensor as a load source. They are unable to adapt to any mechanical or fuel change. Microtechs are particularly sensitive to small changes in anything... unless they are setup on the rich side. The tuning resolution is particularly coarse, along with the interpolation between load sites !

 

When specifically does the car jolt ? Cruising, accelerating or full power ? This info will make diagnosis easier .

[Evo-00x]

O2 sensor?

[KNGGSR]

when you want to go full power it starts to jolt, and no I'm not running a o2 sensor 

[jack be nimble]

So it jolts at full throttle?
What about cruise?
Only when hot?

What leak tester do you have? What pressure do you go to? And how long did it hold?

Compression test results?

[KNGGSR]

compression all good, haven't done a leak down test yet, wen i get to work ill do it... 

[jack be nimble]

All good at what? 165psi or all good at 90psi.

Your answers are vague, like you havent really done the test and are just dismissing it.

Like ian asked if you checked for a boost leak. That means did you did a boost leak test with a tester.

If your compression tests are good then a leak down test is not going to tell you anything else.

[evo-gsr]

Lol.