Please help cold start/emmisions jtgh?

[DJB1981]

Well i have replaced everything now from my old vit apart from the throttle body itself lol Just thought i would give you a quick update.

Checked everything again and it was all working when removed from old car, gave IAC a quick clean and it run same (engine warm) let car cool down... Turned key and car started !!! It was rough though and as soon as i touched throttle it over fuelled. Seemed to be a little progress and a lot less black soot on floor from rear exhaust pipe so i have removed plugs and cleaned them (dreaded black soot) and let in a bit more air at iac hex , will try it again in morning.

Interesting thing was when it started roughly it was about 1000 rpm for 30 seconds then the IAC? seemed to kick in it revved upto 1200rpm then dropped to 900 when warm.

Oh well see what happens tomorrow , do you think a head gasket failure could cause a cold start problem. Exhaust is blowing bad now where exhaust meets the manifold so i need to get that sorted 2

Hope everyone had good holidays

[jtgh]

hello mr 92-8V
I forgot to ask, is car stock (all origional OEM suzuki)?
your CAt is installed and not rodded out?

your OXYsen will never work with fresh air hitting it ,
fresh air hitting oxy = piles of oxygen , so the sensors yells WAY too LEAN , the engine (hot only) programs RICH MIXURE and black smoke. ( this ECU is too dumb to figure it out)
no cracks, no bad gaskets in the exhaust from the valves all the way to the far end of the CAT.

many things can cause too rich cold and
too rich hot.
the Map and TPS are important to cold start and warm up.
The ECT, IAT and OXY , map are very important to warm run.


just found my ECT sensor 5x off , and my IAT sensors both off same. bought new ones , they are perfect.
THey both aged in the same direction and the same amount.
(both reading low in temprature)


Your Cat if fresh(new) might even hide a sick engine.
( no easy way to check that , at home)

keep in mind the choke in your car is the ECT and software tables.
The engine can also go rich if any of the three IDLE control device
go closed (1 inside TB, 2 Dash pot on side of TB and 3 IAC ON T
if any of these 3 malfunction and stop air from lowing the engine will go rich.

good day and cheers.

[DJB1981]

well im about to give up , changed everything other than o2 sensor, it starts first time now but is so rich it chokes up within 20 seconds. When its warm and you rev it there is black soot all over road below tail pipe exit. o2 would be last thing to change but im not convinced its that and i already spent too much time and money It seems to be getting air but running way too rich even tried another ECU!!!

Thanks for all the help

[jtgh]

lets start over. (what are you driving) 1.6L or ?
you said VIT, vitara , is it a v6 like some have down under?

what engine is this: 8 valve or 16v. Since you havent mentioned the MAF , it must be 8valve engine.

Blowing exhaust, does that BLOW , happen to be forward of the rear of CAT or behind cat.
???
Any blow is always accompanied by a suck, (put paper tissue on end of tail pipe and see it suck. (back and forthy) ( intake and exhaust valves over lap and presure waves bounce)

Exhanging bad parts for bad will make you pull your hair out.
my ECT was bad,so was my spare. New one works perfect.
an open ECT , forces ECU to be stuck in Siberia for ever. see? (cold and rich,and retarded)
The key is to test the sensosr and get the bad ones out.

on your car , ECT , TPS, MAP an OXY.

on my car the IAT sensor was bad , and in the exact same way as my ECT.
I suspect they last 10 years and that's it.

when your enging gets hot)( does it?) the ECT will read 300 ohms (there abouts)
The TPS wiper can be checked with a volt meter, the wiper will very that voltage from
1-2v (idle ) up to and close to 5v with full throttle, (no jumpiness allowed during the pressing of the throttle, smooth and linear ramp with same on right foot)

15mins work those sensors or off the list.

map is probably good ( do you have one? on the fire wall with a hose on it )?

NO EXHAUST LEAKS ALLOWED forward of the CAT rear CLAMP !!!!!!!!!!!!!!

Some cars with V6 , have many sensors in the TB, very strange but you got tell us.

Cheers.

[DJB1981]

Sorry its a 1.6 8valve Spi

Changed all sensors in intake inc MAP IAC EGR TPS Injector etc and checked (including spares) Only sensor not changed is OXY but not sure how quickly this comes into play?

I do have a slight blow in exhaust between manifold and exhaust, tried sorting that twice but it keeps getting better of me!!!

Car start but cuts out when cold due to overfuelling , on its test emmisions were way way too high but unplugging map sensor dropped it to 0.3 not sure why unplugging MAP sensor dropped emmisions so much (over 10 on machine) Once car is started it will tick over 1200 dropping to 800rpm

When car is hot or cold and you rev there is a black sooty deposit on drivewat/road from exhaust pipe. Spark Plugs same

[jtgh]

hello 92 8v (A/F rich all the time, exhaust leak)

exhaust problem will kill hot run and HC a/f (rich)
OXY sensor only comes into pay as engine gets warmer than 150deg F.
when this happens ,it is called closed loop (servo action between ECU and OXY ++)
And only if Oxy heater is working. and sometimes only when going over 1000 rpm.
most modern cars hit CL and stay when hot.

cold start and run are completely different matters. (modes)

Map is either bad or its being lied to. ( i bet it is the latter)

on cold start there are 3 air supplies.
1- IAC (isc) idle air valve with 2 wires connected top of TB.
2- remove cover plate front bottom of TB , this is Air valve #1 it must be open when
cold ,if not it is dirty or bad.
3- on the butterfly valve is a Vacuum Diaphargm drivice on the back of TB .
This device must be pushing the throttle open during cranking then it must release to run cold or hot. it has a gap adj. that measures at a #25 drill bit diameter.
this device has a spring inside the pushes the trottle open ,KEY OFF.
spring could be broken ,jammed or anything.

it is calibrated at the factory this Diaphragm servo.

The MAP has a tiny device just in front of it that could be clogged.
when ou say "changed" does, that mean new or used parts.


my manifold did the same.
had to remove it and replace 2 bad studs and re-machine the surfaces on the collector
so they made an AIR TIGHT seal. ( then she hit closed loop and stayed )

First , get an ohm meter (dmm, dvm, multimeter) put it across the ECT.
the value on the engine coolant sensor must be 2500. ohms and drop to below 300 when the engine is hot,
if the wires are missing or the device is open circuited in any way, the ECU will read -40 degress F. ( it that happens , the ECU will flood then engine when cold or hot)
temp-sensors

see test 1 2 , you already pass step 3.
you probably already did that . but code 12 is important.


These problems are difficult, after measuring every sensor hot and cold some people
discover the ECU is quite insane.

does your ECU send out code 12 when commanded to do so.

if not it is bad.

Keep in mind, all cars, (most) have 2 ECU's inside, one is the full ecu and the other
is a fail safe device that will run the engine, and make lots of black smoke.
BY DESIGN. Suzuki calls it , Failsafe. (others called it LimpHome).
If your car is stuck in Failsafe, it is not tunable.

too bad they didnt put a light for that.

I can tell you this, fix cold run A/F mixture.

The is one more element to this ( tad more difficult ) and that is that pesky
little Fuel pressure regulator, if it is stuck wide open car will be rich all the time.

it can be tested with a fuel pressure guage and a vacuum tool or with out vacuum tool
one can just pinch the vacuum hose and watch pressure sky rocket.
if it doesnt modulate with vacuum the car will never run correctly.

you will need to do step 1 and 6
here:
http://carfix.stufftoread.com/INJECTORS/pump.htm

there is a test port on the left side of the Fuel filter, 10mm screw head.

cheers.

[jtgh]

a more condensed analysis.
1- ecu is insane ( you replaced it , so mybe not )
2- Sensors are lying to ECU.
3- fuel pressure is way too high into the TBI injector .

I dont think you have an air loss problem at start, because it idles ok, hot.
800 RPM is controlled vigorishy by ECU via IAC flutter valve. seems to be ok by your great discriptions.

hope that helps.

Cheers,