ECU doesn't match chassis

[JLP]

First post, thanks for reading!

92 Geo Tracker LSi 2D 4WD 8V 5MT FED has been hacked on extensively by previous owners and a little myself.

I've put about 4000 miles on it in a year and a half and it runs great. At least I think so, it's the only one I've ever driven. Starts and runs smooth, will run 80MPH down the highway. This is my daily driver but only about 5 miles a day. Despite running well it gets an estimated 10MPG which now concerns me since my commute will be going to 60 miles per day shortly.

The driveline and suspension are unmodified and it has 27x9.50 tires on it now, most of the miles I put on were on 235/75's. I've been searching and reading for days and have identified some key contributors to the poor gas mileage.

#1- No cat and an oversize short exhaust. It has a header with EGR tube. I suspect the lack of back pressure is causing the EGR to not function properly.

#2- The EGR valve was plugged up. I cleaned it up as well as the ports although I didn't have a way to get any more than a couple inches into the exhaust port. It passed the stall test after clean up. Live test shows the diaphragm moving a little but I suspect not enough due to the lack of back pressure. No bark with valve installed.

I have no CEL not even when forced on by jumping ECU pin B13 to chassis ground. I suspect the bulb has been removed, will verify. I need to do that so I can check codes. There are a couple things I need help figuring out before proceeding.

#1- Am I in fail safe mode? Warm idle is 800, runs smooth, plenty of power, no RPM limit, no hesitations or stalls, no black smoke. Winter weather cold idle would rev up and down between 2000 and 3000 RPM until warmed up, then 800. Terrible exhaust fumes and terrible gas mileage.

#2- The sticker on the ECU has P/N -56B60 and says FED-AT. I see that P/N described as being for a 94 with auto trans-I'm 92 with manual trans. I don't know how many doors or valves that ECU is for. Anyone have further details on this ECU and/or any input on how badly wrong it is for my application?

Thanks again for reading!

[fixkick]

First off you Odometer will not show correct miles with huge tries, IT CAN NOT.
that means MPG is impossible to do , unless donen with GPS logs. OK?
80mph in 2door is crazy Idea on this 2000 lb box kite. wildly dangerous for sure in any crosswind or worse buffeting winds, and 10x on any bridge.
80 is 84on this car wrong tires, wow.
end rant
LIMPHOME = FAILSAFE = limp mode, etc.
The engine ECU is in limphome?, is the CEL lamp glowing at key on? then turns out? running.
if stays on that is limphome and 15mpg is what it does like that.
and is not running good. sure it runs but is only burning 1/2 the fuel the rest goes to the atmosphere (smog)
with big tires, the prop drive shafts turn slower, and speedo reads slower. and that causes miles to be way shorter that REALITY. (gear ratio facts)
the error is about 5% my guess,. if I knew your tire circumference i can compute true error.
http://www.fixkick.com/part-time-test.html#SPEED

so if you drive 300 miles on 10 gallons fuel (averaged fill ups)
the the true miles is 285 miles and 28mpg.
if the odometer shows 150 miles and 10 gal, then that is 143 miles and 14mpg. Not 15 using corrected speedo or GPS total distance.
the missing CAT renders EGR dead for ever, so forget EGR it will never work lacking CAT backpressure stock ,sorry.

the CEL lamp is dead, well that is first. it needs to work , many of these cars, have it removed by nasty PO's, that hide faults. (classic)
the #18 lamp is sold in stores.
http://www.fixkick.com/CEL/CEL.html

if the cell is on, that means limphome mode, code 51 may or may not trip LIMPHOME mode.
if the good lamp is dead that mean the ECU is in BACKUP mode, and will do 10mpg easy in that mode, horrid MPG,

that B60 AT ecu will run ok, i got 28mpg with wrong ECU like this in 91 MT 5 speed car..
the only issue is the A/T park pin input to the ECU needs to be correct. (make it work like the clutch switch did)


how do you measure MPG, ?
filling up tank 100% same gas station even same pump and never top off, or force past out shut off?
then average 3 tanks,
then only use GPS total miles,?(Garmin GLS or ? tom tom or >? some why)
the key to good MPG readings is full tanks driven to 1/8th full, then repeat and averaged. (and use GPS to end the uselss speedo errors)


are the spark plug tips white or jet black.????
with no cat the exhaust on your car will be rich in nasty toxic NOX (nitros oxide stench from hell) keep the windows up. GRIN.

that is all for now good luck to you on your old kick.

First post, thanks for reading!

92 Geo Tracker LSi 2D 4WD 8V 5MT FED has been hacked on extensively by previous owners and a little myself.

I've put about 4000 miles on it in a year and a half and it runs great. At least I think so, it's the only one I've ever driven. Starts and runs smooth, will run 80MPH down the highway. This is my daily driver but only about 5 miles a day. Despite running well it gets an estimated 10MPG which now concerns me since my commute will be going to 60 miles per day shortly.

The driveline and suspension are unmodified and it has 27x9.50 tires on it now, most of the miles I put on were on 235/75's. I've been searching and reading for days and have identified some key contributors to the poor gas mileage.

#1- No cat and an oversize short exhaust. It has a header with EGR tube. I suspect the lack of back pressure is causing the EGR to not function properly.

#2- The EGR valve was plugged up. I cleaned it up as well as the ports although I didn't have a way to get any more than a couple inches into the exhaust port. It passed the stall test after clean up. Live test shows the diaphragm moving a little but I suspect not enough due to the lack of back pressure. No bark with valve installed.

I have no CEL not even when forced on by jumping ECU pin B13 to chassis ground. I suspect the bulb has been removed, will verify. I need to do that so I can check codes. There are a couple things I need help figuring out before proceeding.

#1- Am I in fail safe mode? Warm idle is 800, runs smooth, plenty of power, no RPM limit, no hesitations or stalls, no black smoke. Winter weather cold idle would rev up and down between 2000 and 3000 RPM until warmed up, then 800. Terrible exhaust fumes and terrible gas mileage.

#2- The sticker on the ECU has P/N -56B60 and says FED-AT. I see that P/N described as being for a 94 with auto trans-I'm 92 with manual trans. I don't know how many doors or valves that ECU is for. Anyone have further details on this ECU and/or any input on how badly wrong it is for my application?

Thanks again for reading!

[fixkick]

5 miles a day is 60days of driving on my 91 8v. or in city, 48 days 10 gallons.
hell someone can steal your gas in 60days, had that done to me 2 times, one time with ice pick to my tank.
MPG is best done during and after a long trip, total miles and total gallons

and oops is this USA gallons? or those funny ones up in CANADA, ? 1.2 timeS larger that USA gallons !

AT 80MPH THE CAR IS IN WIDE-OPEN THROTTLE MODE AND USES 12;1 FUEL RATIO NOT 14.7:1 AND USES WAY MORE FUEL FOR THAT AND THE RAW SPEED,(DOUBLE HIT TO Mpg)
the energy used is the cube of velocity, in cars, on the ground at sealevel where the air is thick, and at high speeds you are not only force AIR out of the way you compress it.
this uses huge energy and fuel at 80mph.
see this marks super answer,
https://www.quora.com/Why-is-air-resista...e-of-speed


the fuel consumption is based on the engine tune (and in this case 5th gear overdrive friction) and at 80mph the air friction is a BIG DEAL.

I can drive my car at 45-55mph and get 28mpg at 60mph actual
all other speeds are less. every car made has magic speed that gets max MPG, and 80 mph is never it.
some are 45mph, other 55. and is easy to discover, if car is 1996 or newer, hell my jeep shows this in the cluster 2008

If the MPG is bad at 60mph, get new 02 sensor. (and make sure the CEL turns on, key on, and stays out driving (just like new cars do)

good luck to you !!!

[fixkick]

". No bark with valve installed"
that mean the EGR modulator is missing? if yes, you have the EGR hooked up very illegally ,(not law) but now the vacuum of the EGR port is direct to the EGR and will cause horrible economy like that.
more simply said how man vacuum lines are missing now.?

the EGR TV porting on this car is NOT linear from idle to WOT (not in the least)
it is like SWITCH, and the modulator does all the modulating (save with the port is turned off by ECU via VSV solenoid valve)

[JLP]

Thanks Fix!

Roger that on the 80 being unsafe. Guess I should have said it CAN do 80, think I maxed out around 70 indicated with room to grow one time. The point was that it's not limited to 2500 RPM or maxing out at 35 MPH. It runs good minus the fuel burn and smelly exhaust. So this sounds like Limp Home to you? What about Back Up? From what I've read I would expect the car to be barely driveable and chugging black smoke in Back Up mode.

Four times a day I drive a 1.4 mile route maxing out at about 50 MPH with one stop sign halfway through the drive. I'm in 5th gear by 35 MPH. Not ideal for USA MPG but it shouldn't drink like a big block.

Sounds like the incorrect ECU may not be ideal but probably won't hold the injectors wide open because it's in the wrong chassis. I will correct the other issues, change the CEL bulb, and check codes.

Are there any known CATS that will bolt up to the aftermarket header?

I know that no gas is being stolen or leaking. I don't really track the mileage but I always reset the trip odo and I put about 9-10 gallons in every 125 miles or so. NOT GOOD! Not even close!

Thank you!

[fixkick]

the ECU has many modes, not just 1, back up mode is like limphome insane mode, it knows the ECU is bad so goes to backup mode, (like a lawnmower with no spark advance)
OK 80 MEANS ONLY CAR HAS FULL POWER,
since the cat is missing then that smell issue is not possible to know what that means, rich fuel or NOX or both, for sure NOX , nox burns eyes and nose, rich fuel is black /gray exhaust is is only nasty smelling not NOX PAIN MAX> burning eyes, nitros oxide is nasty stuff.
if the MPG in the car is good the engine is running good but doing MPG correctly is not easy on any HACKED car. but using GPS (tomtom) or GPU tools for distance traveled cures that.
let me do limp again.
the car you key on, CEL glows, if not the lamp is bad or the ECU is in backup mode. take your pick buy a lamp or live with backup mode and high fuel bills.
then you start the engine, above must work, and the CEL lamp goes out , when it goes out that means its not in limpome mode : BTW this is all covered in my CEL page. read that?
the B60 ECU is not really wrong, its just for AT car. it will burn fuel perfectly , it will. the MT will cost you $400 to learn that. 56B30?
you just said injectors that is wrong this car ONLY 1 injector, TBI is 1 . not 4.

t 9-10 gallons in every 125 miles or so (OMG BAD that) horrid bad,.
why not buy a GE #18 bulb and put it in the CEL lamp socket and end all the drama????? you have no scan tools for this relic (non sold) so only that lamp is your salvation OK?>??????
why in the world run any pre 1996 car with a dead CEL lamp, I am so amazed this? why do that/?


yes the ecu for 4doors may have better tuning for way heavy cars
again my web page has your correct ECU pages. here.


look here. 1992 MT 2door, 4wd fed.
as you can see the correct ECU ends in Dash, 56B30, the B60s is 1994/95 only.
the 95 runs unique EGR parts.

http://www.fixkick.com/ECU/EPC-ECU96-98/...9-95NA.pdf


buy the lamp #18 put it in and get the Flash codes.


posted yesterday for 91 kick.
1: in limphome mode ECU, CEL flash codes not 12 flashes. (or if CEL lamp dead, horrible BACKUP MODE and 10 MPG even less) 15mpg is limphome , 28 i s normal at 60mph steady.
2: fuel pressure out of spec, not is not wrong, 34-41 psi. is spec., and only changes by ALTITUDE.
3: injector leaking or hacked wires to it to gawd knows what.
4 :any of 2 injector 0-rings leaking on actual injector in TB. ( can be seen with eye on on it ask?)
5: O2 bad, or exhaust cracks near it cause it to go NUTS (sets o2 max lean 0volts and ECU goes MAX rich)
6: if the Distributor bad , MPG will be low.
7: Map bad or hose to it clogged or cracked. map never fail only vacuum to it fails for all the reasons, even the nipple source vaccum clogged or susuki silly filters on this hose clogged up.
8: spark timed wrong, or spark bad , coil bad, wires HV bad , spark plugs bad. cap rotor bad.
9: vacuum leaks are no it, well except to MR, MAP. sensor and its hoses. the hoses to the MAP must be perfect, no clogs ,cracks end to end.
10: cam belt slipped. or was timed wrong last service 60k point.
11: CAT melted, if car has full power this is not it. (you have no cat , ouch)
anything else would be super obvious air filter packed in crap or critter nets from end to end, air intake.
12 :compression very low. 150 par wide open throttle.
13: ECT bad, reads 10,000 ohms hot engine, not 300 and will burn a tone of fuel ever time. I call this stuck in ALASKA mode.

this list makes NO assumptions, it's regardless of any tests done already or parts replaced. (ok, a list is good to have, and work from , in total)
the list gets longer with A/T slush pump transmissions, for sure.

I do not know what parts on your car are missing for sure hoses, and for sure connected WRONG.
with the CAT missing the EGR is useless, for a fact, so ID defeat the EGR by pulling the EGR main nipple, vacuum hose and plugging up the hose with Golf TEE. so it can not suck air.
the 95 ECU will not like anything about 92 EGR parts nor missing CAT, the 95s some do odd things, with EGR dead, in USA< (in canada it is all different) but the EGR in the CALIF car will also not like EGR bad.

one of the reasons it does this is to end NOX>
if EGR is dead, The more modern EGR car (94 up) may go to limphome, due to 1 fact, that fact is, that rich AFR hides the NOX,
hiding the nox saves peoples lives and lungs.
nox rips lungs up, and causes horror smog and is the worst of all
when it does that it goes rich and combustion temps drop vastly and NOX ends. this is common starting in 1995 and up.
the raw fuels is burned up by our SUN and does not make NOX doing so and thus saving man kind. SEE?

why did I say that well the 95 ECU can do tricks that 1991 B30s never do.... ok?

[fixkick]

yes
any 3way cat made for say 1600 to 2000 engine will work here.
there is no rear 02 sensors to make happy, 1996 up./
the closer the cat is to the 8v manifold collector flange the better (makes cat get hotter faster, all good)

[fixkick]

btw we will find MPG 10.
it will be easy,. once the #18 bulb is inserted back home.

[fixkick]

here is 1s stage, FPR test, remove the vacuum nipple if the FPR leaks raw fuel from the nipple the PFR is bad.
cracked diaphram inside it.

[fixkick]

stage 2 FPR test is fuel pressure testing,
this ECU can not correct bad fuel pressure for sure is 50,60 ,or 70PSI. The ECU gets lost. (means loses control) and for sure accelerating or WOT)
by lost that means fuel trims gets lost (on a 1996 + car we can scan this and see this live even while driving)
fuel trim has limited scope (range) and if it can not get the O2 to read right , it is lost and burns fuel like a PIG.

that and limphome mode cause RICH, (as sumps spark is perfect)
on your car , fix the CEL lamp dead first
then we do tests to find cause, 1 by 1.