When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Having an issue adjusting the tps on my 85 GS. After checking the timing and setting the mixture and idle per Mazda service manual specs, the engine runs very rough when adjusting the tps so both volt meters show simultaneous current flow. When adjusting so the engine runs smoothly, the meters are now out of sync with one another. Any ideas what would cause this to occur would be appreciated.
Correct me if I'm wrong but the tps should have no real affect on how a 12A runs. Try unplugging it, probably half of all Nikki's out there have emissions removed.
It definitely affects engine operation on my 12A. With it disconnected it runs rough, connecting it it runs normal. When making the adjustments on mine per service manual with two voltmeters hooked to the green test plug, the engine is revved to 3k rpm then allowed to drop to around 1200k, the idea is to have both meters to show voltage simultaneously. When adjusting the tps screw in that way, it causes the engine to run rough necessitating to adjust it so they are out of synch for smooth operation. Checked vacuum lines, rat's nest solenoids, and removed and checked the acv (air control valve) for defective diaphragms solenoids, all appeared fine. Am thinking perhaps an issue with the shutter valve and how it's connected to the carb, which was replaced a few years ago. Seems coincidental my tps issue began after its installation and maybe the two hole lever that connects to the carb is in the wrong position. Would someone have info on how the shutter valve should be connected? Thanks in advance!
Last edited by BooBooBear-1; May 25, 2018 at 01:09 PM.
Reason: Added Info
You want current to go to one voltmeter, not both. This is just a regular TPS adjustment? Or are you doing something different? The service manual adjustment doesn't mention revving the engine to do the adjustment. Unless you were testing the sensor itself. But that's done with one ohmmeter, not two.
Last edited by broccolini; May 25, 2018 at 03:53 PM.
You want current to go to one voltmeter, not both. This is just a regular TPS adjustment? Or are you doing something different? The service manual adjustment doesn't mention revving the engine to do the adjustment. Unless you were testing the sensor itself. But that's done with one ohmmeter, not two.
Thank you for your response. Here's what the Mazda service manual states for my 1985 GS.
