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Hesitation/surge when lifting or applying throttle

Posted: Wed Jul 02, 2014 12:03 pm
by Nafe
Heya guys,
recently picked up my 85 exa and it has a bit of a surge/hesitation sometimes. I have been doing some reading that suggests cleaning/adjusting the TPS may help with this. I haven't pulled the TPS off yet to clean though.
What do you guys think? What is the best way to clean a TPS?
Is there any science to adjusting the TPS, or do you simply adjust a bit and test drive?
thanks for any help guys. I am sure I will have more to ask haha.
Will put some pics up in Members Rides soon :)
Nafe

Posted: Thu Jul 03, 2014 6:30 am
by Damo
There is not much to clean. It is just an on off switch to let the ecu know when you first press the accelerator. To adjust it you will need a stubby phillips head screw driver, a timing light and preferably a set of friendly eyes to help. Clean and mark you timing marks with some white-out or similar to make them visable, warm up the engine, back off the tps adjustment screws enough to allow adjustment, have someone check you timing marks while you adjust. When the tps switches from idle to not idle, the ecu will ADD a handfull of timing (5-10deg from memory), you want the tps to switch with just the slightest movement of the throttle.
Re-read that last sentence as it is important to get it correct!

With the tps set correctly, you can now set your base timing to 14deg BTDC (+ upto 5deg for type of fuel used).


Damo

Posted: Fri Jul 04, 2014 10:22 pm
by boosted
welcome nafe,
have you read this?
http://forum.n12turbo.com/viewtopic.php ... highlight=

if you have a ohmmeter, you can see if your contacts are clean enough to give a nice on-off signal.
of course damos method should also show you if the ecu is bouncing between idle and non-idle mode at the switching point.
this was clearly causing my hesitation problems.
cheers