5sfe slow take off!! help

[skyteq]

hello! i have a 93 mr2 n/a with some serious acceleration problems, when first taking off on low rpms it feels sluggish till it hits 3000-3500 rmps after that the car just takes off. this happents on all 5 gears, when up shifting and downshifting.
i already did the full tune up... plugs,cap, rotor oil change...i also did a seafoam treatment and i've been putting lucas injector cleaner every time i fill the tank...
funny thing is that it doesn't happen all the time, sometimes is worst that others... when it gets the worst it seems like the gas pump broke.. but if i let it sit for a few hours it simply goes back to the drivable slow acceleration and irregular idle... please help!!!!

UPDATE !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
ok so I still have the same problems. boggy acceleration until hitting 3000 + rmps, at times so boggy becoming undrivable, lots of misfires, erratic idle sometimes as high as 2000rmps others stalling at 1000rms... but now check engine light on giving codes 14 and 31
here is what i've tried with no results...
tried 3 different map sensors, changed the igniter, i even tried a different distributor.. nothing i still get the same codes and i car still accelerates like crap and dies sometimes.
Im trying to check the wiring to see if I its bad ground or a bad ecu but all i have is a 91 repair manual to do this and the ecu terminals are different that the ones on my ecu.. so am suck..
does anybody have a 93 manual or knows the differences of the ecu terminals.

[MR2Jedi]

You didn't mention plug wires. How old are they? Did you check ignition timing?
Also, whens the last time the fuel filter was changed?

[TheEngineer]

my first thought would have been plugs, but i agree with mr2jedi, i think the wires is also a very good bet.

[skyteq]

all of those things replaced when i did the tune up wires, fuel filter, pvc etc... but the issue continues and its driving me crazy!

[MR2Jedi]

Check for a vacuum leak.

[skyteq]

ok based on this diagram where should i focus my attention for leaks i already checked the EGR VM and the EGR valve. but i have no idea where the EGR vsv and the Bimetallic vacuum switching valve are?? and yes i live in cali..

[ModifierMR]

A vacuum leak in the TVIS system could cause your issue. I would run tests on your TVIS runner to make sure there are no leaks.

[skyteq]

the TVIS system, excuse my ignorance but how would i go about testing this??

[not12listen]

have you checked the condition of the timing belt, and have you checked the timing with a timing light?

[mrturrari]

The 5sfe doesn't have TVIS so don't worry about that. The problem is probably something with the ignition system or timing. A vacuum leak would probably not make it act like you describe unless it was huge and then you would have a really high idle. Check your base timing to make sure it is at 10 degree. You will need a timing light and to jumper the diagnostic port between E1 and TE1. If that looks good then you might want to check mechanical timing by turning the engine to TDC, pulling the valve cover and checking that the mark on the intake cam lines up with the mark on the head.

Have you done any recent work to the engine? Timing belt change or removing the distributor? Many times when stuff like this happens it is because of something that was recently done. Start with the simple and obvious stuff.

[skyteq]

wow no tivs on mr2s na and here i am panicking haha .. yes i' ve done some work on the engine like i previously said i did the full tuneup on the car(plugs,wires,cap and rotor, oil and gas filter,pvc) i did it precisely for this reason... but nothing seem to improve. now i heard about the timing...but am still wondering if timing would cause the car to run like this on low rpms...i unfortunately dont have a timing light or the know how to change timing.. i wonder tho if by completely replacing the timing belt will this resolve my issue?

[Russell D]

I dont think it would be a vacuum leak or anything like that, because if it were it wouldn't do it periodlically, unless when you say "doesn't happen all the time" do you mean it does it when the motor is warm but not cold?

I would guess it would be more of a fuel issue, I say that just because my truck started doing the exact same thing about a month ago, and a few weeks ago I started smelling gas around the motor, now gas starts dripping under the motor if it sits running while I scrape the frost off my windows.

I would try letting the car idle and unplug a plug wire, see if the idle changes, if it gets worse plug it back in and try the next cyl; do this for all four and if you get one that doesn't change the idle when unplugged you have a problem cylinder, then you just diagnose parts of that cylinder. When removing the wires, remove them from the spark plug, you may get a little shock removing it from the cap(I've done it before, it doesn't hurt, but I jumped and it scared the sh*t out of me)

[Jason.MZW20]

Originally Posted by skyteq

wow no tivs on mr2s na and here i am panicking haha .. yes i' ve done some work on the engine like i previously said i did the full tuneup on the car(plugs,wires,cap and rotor, oil and gas filter,pvc) i did it precisely for this reason... but nothing seem to improve. now i heard about the timing...but am still wondering if timing would cause the car to run like this on low rpms...i unfortunately dont have a timing light or the know how to change timing.. i wonder tho if by completely replacing the timing belt will this resolve my issue?

Invest in a timing gun. They're relatively inexpensive.

You'll also need a fuel pressure tester.

And yes, timing can cause poor acceleration, but so can lean running. The 93s have the 2nd gen 5SFE, so it has a knock sensor.

[skyteq]

i think more that lean is rich.. not too long ago i tought my gas pump had failed because it wouldnt accelerate even with the gas pressed all the way in...you could hear the engine going but there was crawling acceleration and i was burning gas like crazy and again as soon as i hit 3.5k rpms the car would take off....
i just realized something, this problem is more prominent when the car is been running for a while not to say that when is cold it doesnt happen, but when the car is hot/warm its simply scary to drive it...

[skyteq]

ok i finally had the car taken to a mechanic not by me tho(work schedule not flexible) mechanic found no problem with timing. but as i was told, the issue seems to be with some kind of sensor.. now i wonder if anybody had an idea what kind of sensor can cause this???