top speed 85!!!???

[honda_eater]

hey ive got a 1989 240sx (s13)its all stock 156,000 miles. usually when I'm highway drivin i get to about 85 mph (maybe my speedo doesnt work)or 3500rpm (5th gear) and my car stops accelerating completely and with no throttle control i coast down to about 2800 rpm and the engine kicks in feels normal until i go back up that high in rpm. somebody told me to change my fuel filter and i did and it didnt fix problem. usually my car does this but sometimes it just doesnt and i can go above 3500 in 5th gear. does anybody have a clue y it does this or how to fix it.

[float_6969]

Well what your describing sounds like the govener, only it is kicking in way to early. See if you can borrow an ECU from someone and see if this fixes the problem. If not, I would look at the fuel delievery system. Fuel pressure regulater, fuel filter, fuel pump, and injectors. Also, see if you can find anyone with a FSM that is the same year as yours and see if you can get any codes from the computer. I know how to do it for the 91-94 ECU, but I don't know about the 89-90's.

[float_6969]

Also.... does it only do this in 5th, or will it do it in 4th also?

[honda_eater]

yeah sometimes in 4th gear around 4500 rpm it will do it

[float_6969]

so do you think that it seems to be more of a RPM based problem, or a speed based problem?

[NISMO24096]

ok if your speedo does not work than more than likely one of the plugs on your transmission has come out or loose, it sounds like what happened to me one day when i was trying to remove my speed govener on my old 98 back before i new how to do it, just a thought check and make sure all your plugs are intact on your transmission....

[float_6969]

I don't think that he was saying that his speedo wasn't working, I think he was saying that he thought that maybe it was off. If it isn't working, then he definatly needs to check his speed sensing circut.

[Turbo_Nismo_EC]

My buddy has a 97 Nissan H-Body p/u and it does the same thing. I thought he a BSing me until I actually got in it and got on the freeway and it absolutely WILL NOT go past 86 MPH, even when going down hill drafting another car. I know the motor has enough power to go faster since I have drafted a Z28 going down the freeway up to about 130 mph(until I chickened out and let off). If you guys figure this out please let me know. Also, his ECU is ODB-2, it changed from OBD-1 to OBD-2 in 96.

[Ceptos]

i know this isnt the problem, but i thought that the last gear in a transmission will not reach top speed because it is the overdrive gear?

[leper421]

There is a switch that screws into the transmission that tells the ECU you are in 5th, also one for 4th. As far as I know their only purpose is so the ecu can limit the revs in those gears. The 5th gear limiter kicks in at 5100 rpm though.

[Mike09]

The exact same thing is happening to me in 5th at around 3600rpm my motor kicks out then kicks back in when it drops back below 3300rpm. What the FUC*

[Emperor240]

im havin kinda the same problem, sometimes my car will stop at about 3500 in 5th, and my speedo connection is loose. but when it was connected i got it to the 115 displayed speed and a lil over. so what you sayin is that i need to fix my speedo connection to get the governer to work right. holla

[honda_eater]

im giving up on my fixing of the actual problem and now im tryin to just pull the plug on the whole rev limiting system, unfortunately after following the FAQs info on how to do that it still didnt do anything....im boutsta feed my car to a hungry mule

[ItzGenX]

My 89' does this. When I bought the thing (180k miles), it never had a working speedo to begin with(burnt circuit on the gauge cluster), but I drove it around and around. It went whatever speed it wanted til one dreaded day it started to cut on me. You guys all describe the same symptoms, but as of yet I never figured it out because the car is now a back yard prune. I, however, did narrow it down to the fuel pump or some part of the fuel system. If I revved past 3500 in 5th, it would cut. What I did was quickly press the clutch and depress it and keep holding the gas, ONE time by using this method I made it to 5k RPM. Also this problem not only happens in 5th, but it happens in every gear, just at different RPMs. The lower the gear for example 1st gear, the less of a chance of it to happen til even higher RPM. So all in all, it wasn't my speedo doing it. I narrowed it down to fuel delivery, just gotta figure out exactly what part of the fuel system. Like the thread starter said, the fuel filter wasn't the problem (I changed mine too). I think its either A) the fuel pump. B) fuel pressure regulator. C) injectors.

[honda_eater]

souds good ill give that a try

[ninjak84]

ouch, 85 is terrible news!perhaps a change of nickname is in order mr. "honda eater" jk, jk

[honda_eater]

haha tru, I can dream cant I

[honda_eater]

At last I think I may have found my problem. My back fuel injector is soaked with gasoline which means its proly leaking like a mug. It looks as though its been goin on for a while so MAYBE thats why my car is so slow and MAYBE thats why it cuts out at 85 and MAYBE I should get it fixed so my car doesnt explode:angryfire

[Mike09]

has anyone who posted here fixed there problem. I'am still curious because i havn't.