pynikal

i just bought a 93 civic sedan lx d15b7 i believe. 125k. and when im at half throttle and accelerate the car seems like it hits a flat spot like i boggs down thans goes again after it falls on its face. its almost like a early vtec crossover (no vtec here) it also does this when im in it all the way in 3rd and 4th gear.

t-belt was done 10k ago>>>could it be out of time???
no known tune-up has been done>>>could it need plugs, wires, cap, rotor?

or is it something else??
i did search this and found info on swapped cars but nothing really on a stock car.

thanks for your help H-T

Murk 'EM

check the timing of the dizzy... check the tps, map.... do a check on all of hte sensors..

pynikal

will do tomorrow.
hope there are some answers there.

pynikal

well i check the tps and map. tps was fine but map is not reading any voltage at all??

philosofy1

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pynikal &raquo;</TD></TR><TR><TD CLASS="quote">well i check the tps and map. tps was fine but map is not reading any voltage at all??</TD></TR></TABLE>

voltage varies when testing the map. if running under no load (on idle) it should read 1v or slightly less. under a heavy load it should read 2.5-2.75 volts.

BryanM.

iTrader: (1)

An exhaust leak may also make it run funny.

philosofy1

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mcvtec &raquo;</TD></TR><TR><TD CLASS="quote">An exhaust leak may also make it run funny. </TD></TR></TABLE>

so would a vaccum leak. he stated that the map didn't read any voltage. just posting the voltage levels he should be looking for.

pynikal

i checked the map at the yel/grn(ref) had 5v all the time.
at the grn/blu (input) i had little or no voltage with car on or off.

if i had a vac leak wouldnt the car idle like ****?? it idles and runs fine untill half throttle and it feels like it cuts quickly than get into the gas burbs a little than its fine?????

pynikal

listened for an exhaust leak as well and there is no evidence of there being one.
so..............

pynikal

anyone on this???

El_Capitan

O2 sensor??

pynikal

how would the o2 affect this??

not trying to be an *** just dont know how this would affect it.

scbmx87

Clogged fuel system maybe? I know when my old Mustang had a clogged injector it would hesistate under heavy throttle, then clear up just fine. Try that and let us know...

pynikal

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by scbmx87 &raquo;</TD></TR><TR><TD CLASS="quote">Clogged fuel system maybe? I know when my old Mustang had a clogged injector it would hesistate under heavy throttle, then clear up just fine. Try that and let us know...</TD></TR></TABLE>

ive given that some thought and it makes sense. that would be great if that was the issue. that would be a real cheap fix. tune-up probably wouldnt be a bad idea anyway though.

scbmx87

Yeah man, try a full tune up...cap, rotor, plugs, wires, oil and air filters, fuel system cleaner, then let us know what's up man.

El_Capitan

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pynikal &raquo;</TD></TR><TR><TD CLASS="quote">how would the o2 affect this??

not trying to be an *** just don't know how this would affect it.</TD></TR></TABLE>

If it isn't reading correct voltage back to the ecu it will cause the a/f to swing wildly back and forth causing the bucking or hesitation you speak of, and it will only do it under load. Dead spots in the TPS can do that too. But you know, the more I think about it the last time someone I know had this problem it ended up being the distributor. (poopy reman)

pynikal

dizzy's cant be that much for this motor can they???

im gonna do the tune type stuff and see what that does. and check the timing on it.

El_Capitan

Nope shouldn't be that expensive. there is ways of checking the parts of the distributor (pickup, coil and the module) check the manual if you have one, and a tune-up wouldn't hurt

pynikal

ill put a scope on the o2 tomorrow and see if its telling the truth.

and mess with the dizzy too.

pynikal

check timimg and thats ok