2nd Generation Specific 1986-1992 Discussion

runs horrible under 3600 RPM

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Old 04-16-2006 | 10:14 AM
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i have a 1988 convertible that is have a horrible bogging problem under 3600 RPM. the car barely moves but when the tach reachs about 3600 it is like a switch is flipped and they car runs perfect. ive changed the coil packs and put in new plugs and wires. ive also ran the vacuum line that opens the secondary butterflies directly to the manifold port (eliminating the vacuum temp switching device) and i removed the cats none of this made any difference. could the 5th and 6th ports be stuck open? or the secondary injectors? the car almost feels like it is loading up or flooding. ive checked the computer for codes using the 2 LED device and there are no codes. any help would be great
Old 04-16-2006 | 06:14 PM
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75 Repu's Avatar
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try improving the grounding straps on the car.. some people say this helps alot..



look here :

https://www.nopistons.com/forums/ind...howtopic=48183



and here :

https://www.nopistons.com/forums/index.php?...69&hl=grounding
Old 04-16-2006 | 06:27 PM
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under 3500? maybe bad primary injectors? o2 sensor reading too rich or too lean, um its kind of an odd problem, usually it would be the other way round
Old 04-16-2006 | 07:06 PM
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yes. from what ive been reading most people have a bogging problem over 3800 RPM. but this car runs great from 3500 all the way to the redline. it idles like **** and bogs and has no power below 3500 RPM.
Old 04-16-2006 | 08:53 PM
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Leaky or cracked primary injector maybe? Any trouble with it flooding when you try to start it?
Old 04-16-2006 | 09:19 PM
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it does have to crank a little long to fire up but it always starts. the exhaust does seem rich. it definatly feels like it is loading up or flooding. what exactly turns on the secondary injectors? perhaps they are on when they shouldnt be? i have a parts car so i can switch out the primary injectors to see if that is the problem. are these injectors known for being problems? i dont really know a hell of a lot about rotary engines. ive always liked the simplicity of the engine's design. too bad it has all this complicated junk bolted on. i would really like to simplifly everything. ive read the FAQ on removing the air pump and rats nests and would like to do that but i dont want to cause even bigger problems
Old 04-16-2006 | 09:41 PM
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It probably is a leaky primary injector, it wouldnt be the first time i have seen it. If you have replacements i would definately swap them out and see if that helps. I assume you know the cars have to be the same series for the injectors to be compatible? The secondaries and primarys are the same so as long as you have the correct spares it doesnt matter which of the 4 you use.



Removing all the extra crap usually helps make the cars more reliable, at least in my experience. There are less things to leak, crack, break, or malfuction and when something does go wrong you can narrow it down faster. It all depends on how far you want to go, but i would remove all the emmissions stuff if inspections arent a problem for you.

My TII didnt have A/C, pwr steering, omp, or any of the things that i could get block off plates for on the intake mani. I had to let it warm up before i drove anywhere and i had to premix, but other than that there was nothing out of the ordinary i had to do. The heat didnt bother me too bad in the summer and it was still really easy to steer, i actually liked the steering much much better w/o the pump.

I would read through that FAQ a few times and do a search on this forum or some of the others about removing all this stuff and see what people have to say, the more you know about it the better. And you dont have to do everything i just said, but it sure does clean up the engine bay alot.



Also i would get one of those $100 flex-a-lite electric fans from summit, that makes for tons of room too and i dont car what anyone says, i swear there are power gains even if they are small, and it definately affects throttle response.
Old 04-16-2006 | 09:56 PM
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thanks. i will try the injectors next. both the convertible and my parts car are the same year so they should interchange. i already have an electric fan on the car. ive also been reading about the infamous 5th and 6th ports. is it possible these could be jammed open? from what i read some people wire them open so i dont think this is the problem. right now i have them disconnected because i cut off the cat and havent yet welded on a bung for the vacuum hose but i will do that this weekend when i switch out the injectors.
Old 04-16-2006 | 10:36 PM
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Nah, the 5th and 6th ports being stuck open wouldnt do that. the engine wouldnt have as much torque down lower, but it would still run smoothly. People wire open those ports sometimes if they dont open on their own, and the only downside is a bit less low-end torque, but not the problems you are describing. The car is supposed to run a little rich on start-up, but if it smells gassy for more than like, a minute max, then it really sounds like your primaries are leaking. the "like a switch at 3500" behavior doesnt exactly fit, the car should run progressively better and better as you approach 3500, but the drop in fuel pressure due to the secondaries coming on may decrease pressure on the primaries to mitigate their leaking problem. That and the increased engine speed (and thus fuel consumption) may explain the switch-like behavior.
Old 04-23-2006 | 04:59 PM
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took my injectors out today. and sure enough one of the primary injectors was junk. i blew compessed air into them and 1 primary and the 2 secondaries would hold back the air, but on the other one the air would just blow right through. now i have to find the stupid little plastic air bleeds that disintagrated when i took them out. swell!



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