Idle surge and running rich. Input please

[Dog5ohfun]

Well as my profile states I have a DSS 331. It runs fine but I can't seem to get it to idle smoothly. It will hunt from 600 to 1000 rpm and sounds like it is going to die. I can smell the unburnt fuel out of the exhaust. Occasionally when I shut it off it diesels a little. I am running 8.5:1 compression, should I lower my fuel pressure from the usual 38psi? I am running 24lb injectors. Is it possible that I am flooding the engine because of the low compression? I can tune it with the throttle plate adjustment and the tps monitor but then it changes the tps voltage range and the problem doesn't go away, so I am curious if it is something else. Should I go to a hotter spark plug? Any thoughts or ideas would be greatly appreciated.

[goodyear1984]

when u have bigger injectors u dont want to lower the fuel pressure...with the 24's u should be around 44 psi...did it just start to do this or did u change something and then it changed ....is the maf calibrated for the 24's? the tps voltage should be around .9v at closed throttle ...did u check for vacumm leaks?is the check engine light on?

[goodyear1984]

hey just thought of something is that cam has like 218/228 duration it should run a bit rough .idk if u just installed the motor or what

[Dark_5.0]

Your fuel pressure should be at 38 psi with the vacuum off.

To set idle and TPS.

Back off the idle adjustment screw until you can fit a .10 feeler gauge between it and the plate. Then turn in the adjustment screw 1/2 turn. Now adjust the TPS voltage to .93-.99.

If the bad idle persist you may have a vacuum leak or a bad mass air meter.

Pull codes if all else fails and post back up.

[USMC302]

Seems like I always bring up the same things in these forums, LOL......What's your timing set at? And yes I have to ask, what size and type of Mass Air Meter are you running, does it have the right tube in it for the 24lbers?

[Dog5ohfun]

Hey everyone, thanks for the input so far. I haven't had a chance to spend time with the car. Yes they are always the same answers to the same question. I will try to baseline the throttle plate. I know the mass air meter is correct for the injectors as I bought them together as a set. Timing is at 14 degrees. I am leaning towards the possibility of a vacuum leak. Will keep you posted.

[Dog5ohfun]

Just a quick post to thank all you of for your help and input. About a week ago I finally had some time to work on the car. Changed the upper intake gaskets (yes plural I have two 1/2" phenolic spacers). The car seemed to idle fine in the driveway. I haven't driven it as it is not a winter car, no heater. I will eventually re baseline the throttle body and see how it goes from there. As for the TPS it is always at .98 volts as I have the digital TPS monitor installed. Thanks again and Happy Holidays.