93FD3S

My Fd seems to be suffering from the bouncing idle sickness between 1k and 600 rpms. But only on cold starts in the morning. Does it for about 2-3 minutes and goes away. I'm not running the ISC, and 02 feed back is turned off. Fuel set up is 850cc primary and 1680cc sencondary, fuel pressure set at 40psi on SX regulator. I had the bouncing idle problem before on all startups warm or cold and adjusted the screws and solved that. Strange thing is that the cold idle bounce just started happening recently. I haven't changed any settings on the PFC since I last adjusted the idle screws. I'm gonna try throwing in a fresh set of plugs to see if that helps. Its a new motor with about 1k miles, maybe fouled plugs. Oh I'm also running the FC leading coil with the Jacobs 1000 ignition and 4 NGK 9s. Any ideas....? THanks.

cewrx7r1

iTrader: (2)

How about screwing in the adjustment screw for the AWS hot wax rod cold start assist cam or whatever it is called? The lever with the screw under the TPS.

93FD3S

Chuck I tried adjusting wax rod screw and it didn't seem to help . It was already screwed in pretty much all the way, so I tried unscrewing and it didn't seem to help. Any other ideas...? Thanks.

cewrx7r1

iTrader: (2)

There are too many variables to determine the problem unless one knows them and tries them all.

PFC idle speeds and cold start settings(extra fuel). O2 control on or off. Throttle body idle and air bleed screw, hot wax rod can go bad and it has two adjusting screws, one for temp set point where it disengages, and the previous screw which sets how much the throttle opens when cold.


Even my engine requires diffferent idle tuning for winter than summer. That's what happens when we heavily mod these engines with their finiky idle control settings. With my old Weber street ported 12 1st gen, I just had to adjust how much choke I gave it until it warmed up. Same with my old Alfa Romeo with twin Webers. Sometimes simpler is better.

93FD3S

Thanks for the feed back Chuck. I often think that I should of just left my FD all stock.......well in another lifetime maybe. :-) Once you start you can't stop..!! Its a sickness I tell ya..!! Chuck do you think if I adjusted the Rev/Idle settings on the PFC it would help? I might have to try it. Thanks again Chuck.

cewrx7r1

iTrader: (2)

With the cold start assit hot wax rod not engaged(same as full warmed up), adjust the throttle idle set screw 1/4 turn open from fully closed. Screw in the air bleed screw all the way then back out 2 turns.
My idles are: 850, 900, 1000 with all fuel cut points at 1500.

Start from there and play. Have you taken off your AWS solenoid which when stock was responsible for the 2500-3000rpm start up. If not do so. or block off it's pipe so it can't get air.

93FD3S

Chuck you say to adjust the throttle idle set screw 1/4 turn open from fully closed. Now is that the screw which you use an allen wrench to adjust with the lock nut on it? The one that runs horizontal on top of the throttle body. Or the one that thats vertical which you use a screw driver to adjust, located on the side of the throttle body next to the oil filler neck. Oh my AWS is removed with a block off plate. Vacuum reads 15 at about 850 rpms so I don't think its a vacuum leak. Thanks again Chuck.

jeremyb

With a PFC my cold start now jumps to only 2k and will ALWAYS go there... with my stock ecu my my engine has a little fluid in it the engine will just bog at low RPM... does the ECU disable the wax rod in ayway?

cewrx7r1

iTrader: (2)

That one adjusts the close limit of the secondary mechanical throttle.

I think you need to get the Mazda manual and study section F!

93FD3S

Got the Mazda manual, I'll take a look....Thanks Chuck...!!