Saigon_Bob

iTrader: (2)

First off where are the O2's or O2 supposed to be on a 91 305 5spd?? BTW this is my other car, not the 357 automatic in my sig...

I bought the car and realized the cat has be replace with a straight pipe and i don't think the O2 is there anymore.

Every now and again while driving my car will start to idle funky ( roughish) and the SES will come on... after i park the light goes off so it makes it hard to check on the scanner....

When i do check it there's no history or current codes...???? wtf

Next up is how does the TBI register incoming airflow... like a carb?
My car is running super rich to the point of giving black smoke and a headache lol. I know i need to clean the Air Filter that's on it.

One last thing I have one in an old ECU from a 92 305 automatic and I'm thinking of putting it in my 91 305 5 spd....


is this a bad idea. will i benefit from a performance gain? what kinda gas shoould i use.

dimented24x7

iTrader: (2)

The O2 is, or should be in the drivers side manifold/header.

The TBI doesnt see the airflow directly like a carb. It would be nice if it did, but it doesnt. Isntead, the airflow, or air in each cylinder, is indirectly calculated from the manifold pressure. With nearly all FI systems (MAP/MAF), a dirty airfilter will have no effect on how the engine runs, itll just make less power.

As for the rough running, it could be due to fuel leaks at the TBI, a bad MAP or disconnected MAP hose, blocked return line, bad CTS, among other things. It could also be a bad O2 reporting low or grounded O2 signal wire. That will trick the computer into thinking the O2 is lean and itll add lots of fuel in closed loop, and then throw a code after some time.

Saigon_Bob

iTrader: (2)

hmmmm ya i found the o2 by accident today fussing around the engine bay at work this morning. The scanner says the codes are 32 EGR and blah blah O2 lean....

look into the datastream and the car goes into closed loop but the o2 still reads lean, the voltage doesn't move far from .32 to .43 or so.. maybe a lazy O2 im thinkin... i'll buy one at cost at work for cheap and slam it in and see...

i also figured out that the car had a MAP sensor.. sheesh this is my first try at EFI and boy my other thirdgen was carb when i bought it and wayyyy easier. Oh well. The speedo worked through a whole tank of gas finally ( was intermittant b4) so i'm guessing at around 15MPG at most that im getting. Sure is way off from the 35 mpg i was used to in the Honda.

oh well still more to go to fix up the car to reliable... lol tune up, cooling system, etc. Shoot i raced two RSX's the other night ( one b4 dinner, one after) and they beat me... who woulda guessed lol 170hp vs 200hp. Now 3rd to 4th grinds unless i granny shift it and 5th to 4th alway grinds.

dimented24x7

iTrader: (2)

You should be able to average 25 mpg during normal mixed driving.

The stock EFI system does have alot of useless junk, but as far as EFI goes, its as simple as it gets. I ripped out all the useless garbage exept for a few sensors in mine so its as easy as a carb to work on. Cant stand all the junk, either.

As far as the VSS, it could be a faulty pickup in the trans or a break in the wiring somewhere. It also sounds like its time for a rebuild for the T-5. Also, dont forget to check for exhaust leaks. Does it still have all the factory AIR emmissions stuff, or did somebody remove it and just leave the one-way valves?

Saigon_Bob

iTrader: (2)

wtf damn i was about to settle for 17 or so... shoot if i knew i could get 20+ mpg i'd be doin alot.

The A.I.R system is chopped up. The pump is intact but not connected to anything, driverside manifold tubes are removed and plugged with huge bolts. Passenger side tubes are there but goes right around the bellhousing and are pinched shut. There are two things on top of the tubes... beats me what they are.

The exhaust is stock manifolds and y pipe then a straight pipe where the cat was to i'm guessing a flowmaster rear section ( axle hump and back )


Knock on wood the VSS is working fully now. I need to throw a clutch in the car soon. I know it slips and i think my throw out bearing is going out. Every now and again i get a grinding noise while the clutch is pressed that goes away if i let the clutch out. But it only happens when the car is in gear sitting stopped and if i put it in nuetral the noise either goes away or gets quieter.

dimented24x7

iTrader: (2)

If the grinding felt in the pedal and heard as well then is definatly a bad throwout bearing. Sounds like its time for a complete clutch job.

Id say if your driving is split between highway and street, and your easy on the gas and good on the clutch, it can get good fuel economy. V8's get around 30 MPG out on the highway, but probably only 20 or so in the city. Thats about how mine is.

If the AIR is that butchered, then it might be easier just to remove all of it, but mind you your emmissions may suffer as the car has a 3-way cat. It also sounds like you need to put some NPT pipe plugs on the AIR manifolds. 1/2" IIRC. The one way valve there can suck air in with manifolds due to the exhaust pulses. Plug them and see if your rich issues improve.

Edit: I see you live in florida. Ditch the AIR and forget about it.

Saigon_Bob

iTrader: (2)

I feel the grind i wanna say everywhere... not bad but i feel it. esp in the shifter.

I'm slam the clutch in it just cuz it needs one, hopefully that helps some problems.

as for the one way valves, would they be on the passenger side manifold? and if so would they still affect O2 on the driver side.


Oh and theres no cat and the smog pump is there but not plumbed, dont worry my other 'maro lost it too so i know how to ditch it.