Hey guys ive been searching and asking questions before about this, but to no avail. No matter how fast i get it there, whether redlining all gears or slowly accelerating, i cant get past 100 mph! i have posted on this before, but everyone just got off topic and started talking about totally different things... i just need like one person who knows what he/she is talking about to give me some help and advice. with that said, heres the setup and situation. when i first got my car, i had it up to about 110(just once) in a secluded area. was fast enough for me. since then, i have had my cats removed and gone to straight pipe. so i wired open my aux ports to make everything work. then one night took it out on some back roads and wouldnt go past 100! i tried to redline 4th... went to 100, shifted into 5th, tach went down to 4k and mph was at 100, even with me holding the accelerator all the way down. wouldnt do that before..... so i asked some questions and it was suggested to me to fix my aux ports. made sense to me, so i picked up some used parts (one of my actuators wasnt functioning anyway) and rigged it up with a valve setup(works just like one from an 89 model and up) and ports open right at about 3500. took it back out... not past 100... got there quicker cause of the ports, but no faster than 100. my question is could it be some kinda problem with the egr system, or maybe my exstension manifold(vdi on 89+). I know the computer is limiting my speed to 100, but for why??? i just cant figure it out. thanks for the help in advance. By the way, i have an 88' base n/a.

 

I doubt it's your ports if they are working (or even wired).

Have you done a basic tuneup? What condition is your cat-back? How's compression? Any other weird (seemingly unrelated) problems?

 

i havent checked the compression myself, but the guy i bought it from said it was good, and it pulls pretty good, up until 100mph... not really any seemingly unrelated problems, just the minor electrical crap like my idiot lights, wipers, and such. im going to reground my ecu today hopefully, i dont think that will help this porblem, but ive heard its a good thing. also, when the cats were removed, the guy cut off the tube from the old cat to where it comes out on the acv, the one with the vacuum line in it that connects to my aux ports. i was wondering if this was used by another system in the car, like extension manifold or egr or something. its just hanging there behind my exhaust manifold doing no good. could the be the problem??? im still learning and trying not to be stupid about stuff... but if thats the problem ill kick myself. and the rest of my exhaust looks to be in good shape, but hopefully the wife will let me get a new full racing beat system or somthing like it in the near future.

 

o ya, and i havent really done a tune up yet, besides changin fluids and plugs and stuff, but i dont know what else i can do here, and theres not really anyone in my area that knows anything about rotaries... thanks for the reply also.

 

That tube is not the problem. It's only purpose are the ports.

If you haven't, you should start with a full tuneup and go from there. Especially, replace the air filter (and make sure the airbox is not full of leaves, mice, etc.).

 

i have replaced the air filter with a cone filter, and changed all fluids and plugs. i think the plug wires are fairly new, they look good on both ends. what else could it be? when i replaced the filter, i noticed the plug going into the afm was pretty loose. not knowing that it wasnt a "plug" i unscrewed it and took a look to make sure everything looked ok. but when i pulled it out, some of the wires inside(i think there were 4) came undone. i spent about an hour figuring out which one went were, and i eventually got it started, and it ran fine... could this be a problem?

 

If it runs, you're probably fine. But you should get a service manual and make sure everything is connected properly. If the car is in good tune, and your exhaust is not clogged, I would start with a compression test...unless you're running oddly sized tires or something...

 

i havent had it compression tested, i guess i need to do that. but i need to find someone around here who can do it ... i dont have a clue... but still it seems like it would be something to do with electrical stuff, i mean it feels like its the cpu limiting it or something, but i dont know, im still learning about my 7...

 

got any wings, spoilers, etc? you might be reaching your aerodynamic limit...im pretty sure thats what my car does..it will go to 130-135 and wont get any faster...still has lots of power..but it just wont speed up any more...i can even get it to go this fast on a signifigant uphill incline..in fact..i got it to go faster uphill then i ever have on a flat.... did get to 145 on a downhill one time...

so... im interested to hear an answer to your problem...im not sure if there is such a thing as aerodynaic limit..i think so..sort of... but thats the only thing i can think of to explain mine...

Good Luck!!
Pat

 

huh, i thought that limit thing you're talking about is broken by having more hp. i dunno

 

it is..but its a exponential scale..so..the faster you go the more hp u need to accelerate. but...that doesnt really explain whats happening to me or him..so i dunno

 

Definitely the ports! My 88 SE wouldn't go over 100mph when the ports weren't working.

Check the split air pipe and make sure there aren't any cracks decreasing back pressure in the tube. I beliee you need about 3 PSI to actuate them.

 

He said he also tried when the ports were wired open. Therefore, the ports are not the problem.

 

i have already solved the port problem, so thats not it. unless theres something screwed up in the extension manifold(vdi on 89+) actuator, i dunno, although i did read another story where a guy pulled apart his afm and when he put it back together nothing worked. this happend to me, but i thought i got it back together, and everything seems to work. i have gutted the cats, cut of the split air pipe, rigged the ports to open via a vacuum between the air pump and acv(and they work fine) but before i fixed all this, i had to replace one of my port acuators, it was frozen. that could mean the ext. manifold actuator thing could have been frozen also, which could be a problem, but why then before i got my exhaust work done could i go faster than 100? could it be maybe the cpu is dying??? i have noticed a few other things, seemingly unrelated, but the cig. lighter just stopped working all of a sudden(i need it for my rader detector..) and my shift buzzer stoped working. idiot lights never did work right, and my wipers' intermittent setting doesnt work.... everything else seems ok.... and yes i do have a spoiler... but why could i go faster before???

 

It just occurred to me: your secondary throttle plates are stuck closed or sticky.

 

have them check the ecu and see if somehow it didnt set its self to limit out at 100mph, also btw does it strain to make 90? or does it just go there.

 

No amount of wings or spoilers could stop him dead at 100 if everything is working fine. In a word without air resistance a car could go as fast as it is geared to go over time. Most cars theses days have govenors that stop a car at cetain speeds, but the other reason cars have top speeds is because the HP is not great enough to overcome the air resistance.

 

yeah but the 2nd gens had no such thing. right?

 

No govenors, stock they typically topout at around 135-137.

 

when you put the cone air filer on how did you mount
the air flow meter? is it level?

matt

 

secondary throttle plates?? your not meaning aux ports... something else? i looked in my haynes manual but it doesnt say much.. how would i fix the throttle plates? if i have to take the throttle body off to do it its gonna be a while. and i wasnt under the impression that you had to have the afm level for everything to work properly.. is this true?
i guess it wouldnt hurt to have it all nice and level and stuff... ill go fix that in the morning...

 

secondary throttle plates own you.

my car was a SLOW POS and would not go past 100MPH (but I have a TURBO!)... this was the reason.

the AFM needs to be nearly level for it to work properly, yes.

ok.. in your throttle body there are two sets of throttle plates.. one set of three, and one set of two infront of that. The three are the main throttle plates, they're controlled by your right foot. The two are the secondary throttle plates, they're controlled by your right foot, and the vacuum system, and a damper. In my car, something in the vacuum system had broken and it was holding them closed. I took the vacuum line off, removed the damper, totally decarboned the intake manifold (I don' t think this did much aside from screw up my idle even further) and now the car is a rocket. I can't keep the tires behind me in 2nd gear. There was seriously a HUGE difference in power. The car that wouldn't do 100 before is now hard to keep below 100... hehehe Just move your throttle by hand and see if eveyrhting is opening right all the time every time.. You shouldn't need to take the throttle body apart to fix the problem. I'd be willing to bet that this is your problem.

 

ok thanks guys ill look at this today...

 

May the force be with you!

 

wierdnesssss. I replied to another thread and it got put here...