ST185 Slight Surging under load

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ST185 Slight Surging under load

Postby LEAKER » Sun Jan 20, 2013 4:11 pm

Hey guys most of you will have a rough idea of my car by now but a quick rundown of work done to it:
Rebuilt engine
New dissy cap, rotor, leads about 10,000km ago.
Second hand knock sensor
New o2 sensor
New fuel pump
Engine is standard apart from exhaust manifold and exhaust, front mount intercooler, adjustable cam gears (set to 0) and bov.


Ive just taken it on a 3 hour drive and the whole time it was going great EXCEPT for a slight surging from around 1800-1900rpm up to aroun 2200-2300 rpm. It does it in all gears except first and it gets worse under load.

I had been running it on 95 but i put 98 in it for the trip so around $20 of 95 and $60 of 98.

I thought of either trying cleaning the throttle body, cleaning the AFM or adjusting the TPS sensor as i doubt the TPS was adjusted correctly when the useless mechanics that rebuilt it put it back together.

Whats everyones thoughts?

Also the wirings fairly $&#$% but it was consistant and doing it the entire time so i doubt thats got much to do with it.
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Re: ST185 Slight Surging under load

Postby Grrrrrrr! » Sun Jan 20, 2013 4:17 pm

LEAKER wrote: adjusting the TPS sensor as i doubt the TPS was adjusted correctly when the useless mechanics that rebuilt it put it back together.


why the duck would they play with the TPS in the first place? Those things should be left the hell alone unless they test out as stuffed, then replace them and recalibrate as per the toyota manual.

Not sure how you test a knock sensor, but since that is second hand i'd test that to start with. Also check that the TVIS is working properly.
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Postby LEAKER » Sun Jan 20, 2013 4:21 pm

yeah i thought knock sensor but absolutely no engine light coming on and car runs perfectly below and above that rev range. Should probably do a hunt at pick a part. I don't feel like spending $350 on a new one.

Edit* I have had alot of experiance with knock sensor issues in these and everytime its happened the knock sensor has triggered engine light and car goes into limp mode.
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Postby LEAKER » Sun Jan 20, 2013 4:57 pm

$&#$% vacuum leak. All the vacuum hoses are new, and at the tip of one it had a slight nick. Cut end off and now its perfect.
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Postby LEAKER » Sun Jan 20, 2013 10:27 pm

bump, still doing it. Seems to only happen after about 10 minutes driving.
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Postby Crucible » Mon Jan 21, 2013 12:39 am

Plugs and leads
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Postby LEAKER » Mon Jan 21, 2013 1:08 pm

Cracked plug. Will drive for a couple of days and see if that was the cause.
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