Throttle switch not clicking.

Helping a friend with a 73 Volvo 1800ES. Via email, so a bit cumbersome. He replaced all wire terminals of the FI on the engine recently, now it’s low on power. He cannot get the 20 click on the throttle switch. He had the 4 wire connector to the throttle switch incorrectly connected. The wires were connected incorrectly, numbered wires were reconnected in reverse orientation. #17 wire was at the lower part of the connector instead of the top, as you look at it in the car. He reversed those to the correct orientation and also checked continuity back to the ECU of those 4 wires and has continuity. However he still cannot get 20 clicks.

Any advice will be helpful.

Thanks.

Hi Unknown,
we like to use our First Name here in this forum - this makes the conversation less anonymous.

Welcome to the forum!

Your friend should open the TPS and inspect it. Clean the surface of the board using alcohole or so. Polish the surface. Bend the feelers a little bit sideways so they run on fresh material.
Clean the contacts at the brown swing arm <or, at the former version, the contacts of the micro switch>.
Don't grease anything. Even contact spray can hinder from giving reliable contact.

Adjusting is being described in the compendium here. jetronic.org/en/d-jetronic/tps

There is a replacement for heavy worn boards, but I think it's mostly unneccessary to replace the board. Cleaning will help in at least 95% of the cases.

Best Regards
Norbert

Hi Unknown,

I fully agree with Norbert!

Hello, thank you both for your quick replies. Would it be fair to assume that having the throttle switch connected incorrectly has done no damage to other components such as the ECU?

He has cleaned the board. Any advice on how to bend the feelers? Seems quite fragile, don’t want to damage anything.

Craig

Hi Craig,
there is no risk of damaging the ECU by incorrect connection of the TPS.
One of the leads is 'ground', the others are -or are not - being connected to this ground. This switches the functions.

Yes, the feelers are fragile - but if one isn't able to bend them just a little, little bit sideways he shouldn't work on cars at all... just do it with some caution, isn't a great job.

Regards
Norbert

Hi Craig,

there is no need to transpose feelers if you do not see abnormal wear where the feeler glides. Normally that can happen on acceleration feelers where contacts look like a comb. Mostly it is enoght to clean and polish that area.