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914World.com _ 914World Garage _ 75 1.8 L jet bucking

Posted by: Geezer914 Jun 23 2019, 03:57 AM

Coming home from a friends house last night the car started bucking. Luckily I just made it home. Where to start?

Posted by: jim_hoyland Jun 23 2019, 06:48 AM

Try looking at: http://www.914world.com/bbs2/index.php?showtopic=29931&hl=bucking

BTW-Found this thread by doing a search using +bucking, then selected titles only; a whole page of threads appear with "bucking" in the titles.
Good luck with this one, keep us posted;If I'm the next one to experience bucking, I'll rely on your analysis.....

Posted by: Geezer914 Jun 23 2019, 09:16 AM

Thanks for all the reply's. I'll do the search on bucking.

Posted by: Porschef Jun 23 2019, 09:48 AM

Dual relay, then vacuum leak

Posted by: rfinegan Jun 23 2019, 11:44 AM

when my 1.8 was bucking it was the connector at the AFM. I had a pin or 2 push out of the connector and intermittent contact. ez fix and problem solved for me...

Posted by: jim_hoyland Jun 23 2019, 03:42 PM

My 1.8 L-Jet never went through biking episodes; but if it did, the first thing I would check is the connector at the dual relay. The connector on the left side has 12v in, ground, starter, and fuel pump ( black/red). If that fuel pump connector is not making good contact, the fuel pump will go off/on.
I aventually connected those wires directly to the dual relay.

Posted by: mepstein Jun 23 2019, 03:53 PM

My car bucked off and on for over 6 months. I did a bunch of things but I believe it was overhauling the distributor that fixed it.

Posted by: ClayPerrine Jun 23 2019, 09:40 PM

Check the ground contacts at the rear center of the motor. Broken or loose grounds can cause bucking.

Dropping resistors can cause this also. They have a tendency to break wires in them.

With a 914, it's always the grounds. Except when it's not the grounds.

Posted by: Geezer914 Jun 24 2019, 11:45 AM

Tested the coil it read 9380 ohms from the negative post to the center. My spare coil read 8500 ohms. I think the coil over heated. I swapped out the coil and replaced the plugs, cap, and rotor. It has a Petronics ignition module. It ran great, but I need to take an drive for an hour or so to let things get hot and see if the same symptoms develop.

Posted by: Geezer914 Jun 29 2019, 04:27 PM

Took a 45 minute drive and everything ran fine. Ordered a CHT from 914 Rubber to install for piece of mind.