CEL out, cannot pull OBD1 codes. How to fix?

[fixkick]

you are the man! Without even mentioning it myself...you mentioning checking ohms to determine temperature etc and i stumbled across your "temp sensors" page as well as another suzuki forum that where someone with my same vehcile had a similar problem..it idles perfect at 800 and everyrhing like his..but it made sense to me.

My linear gauge for engine temperature never goes past the bottom slit near C. I thought at first because of the other lights being out that it could be a cluster or fuse but we have determined it is not. Plus when i get the car warmed up for sure it goes from below C to slightly above C.

not to mention last winter when i got the car before i did my.fixes to it..i noticed white sludge on the top of the oil dipstick and thought "oh god..head gasket" but it turns out the car wasnt getting to operating temperature in winter and the (old..since changed) oil was full of water and fuel that didnt evaporate off. yes white sludge = never gets hot to burn off all water, so oil goes bad real fast not good that.

I thought to myself (assumed..sigh) that ill just check the thermostat after summer because maybe the PO was overheating so he either put a low temp (160..or none at all) thermostat in it. Point being tho thst i planned on addressing..and will need to address..thermostat and likely ECT before winter. All levels remain high and no leaks..50/50 mix isnt dirty or have bubbles in it. No overheating issues and radiator/pump is flowing water but i dont think its hitting opersting temperature or at least is "too cool" ..  lacking an IR thermal gun here is the test, all mech used for 100years,  the hand test, hot engine drove 10 to 20 miles until fully hot.,hood up, hand lays on top rad hose (g16 only) and hand flies off,  fast, ouch, bingo 180f + bingo.! good.


Which everyone (bah) ive bounced this off of says its no prohlem at all and surely better than too hot but comes with its own issues..
yah but if too cold the ECU runs in the WRONG MODE< rich and can get as low as 15mpg.  and all the carbon dumped everywhere ! and burned up cat as a door price.
180 to 195f is good, way below bad. (this is no CARB engine it is dumb EFI)
The ECU runs in many modes, cranking 1,  just started 2, cold running 3,  at 150f goes to warm running and more all are AFR and spark advanced tables, and more.
AFR=air fuel ratio, 3D MAPS inside ECU and no way ever to change that.  what will be , will be, inputs wrong the table maps are indexed WRONG.
GIGO, in all comptures, garbage in = garbage out. (hard logic)



From what ive deduced reading..improper operating temperature can cause a rich condition as well. I checked the o2 sensor and its been replaced fairly recently: the pigtail on it was brand new looking and even scotch locked all nicely onto the connector with what looks like new zipties.
good that baby can run.

Id guess its been changed within the last 3 years. Plus its not behaving like a bad o2 sensor would ..i just havr the white tip plugs and fuel smelling exhaust indicating rich condition. It can go 100,000 miles easy , 80k is spec on 8v but 100k if engine runs great, that long.

I even read that if it never goes above 158 then it stays in warmup node and Never goes to closed loop which would make perfect sense of the cold conditions i have as well as the gauge and the winter prohlems as well as the fuel smelling exhaust..just everyrhing makes sense if there is too low a thermostat or none at all in there..or faulty ECT?   (if the stat is wrong ETC good causes wrong ECU mode, The ECT is just thermometer, that is all it does, but at IAC closure at 150f the ECU sees that act
and goes to warm running mode and tries to see if 02 works now if does uses the O2 for fuel trim and does, at 14.7:1 AFR, closed loop.

What im.guessing now..and.i need tools to.confirm..is that the ECT may have been bad before..it may have been overheating on PO so he (by the look of the blue gasket maker around thermostat..ugh) replaced thermostat and put in an o2 sensor trying to fix problem . what i think based on all of this is that he may have missed a faulty ECT causing the whole thing and then "fixed symptoms instead of disease" if you will by replacing thermostat with a lower rated one or none at all..which of course leads to further issues. (you do know right any thermostat and ECT put in a pan of hot water from cold to hot on burner (stove) shows if it works right. easy easy test out of car. no tools but  thermometer) On car get engine hot, fully , hand on top rad hose flies off and DMM ohms on 2 ECT pins (conn pulled)reads 300ohms 300= 180f.
easy stuff here only DMM, if the ohms is wrong we find out why next.  just  knowning it reads wrong is every thing here. and is a "first order failure" !

What im going to do FIRST THING so i can do what u have told me..is get myself a DMM and an IR thermometer. I can also check my cat with that and ..with ur manuals i can read ohms with our thermometer to see what the ECU is saying.
2 weeks ago..this would be rocket science to me but now i am reading and getting deep into your math for ohms to temperature and voltage read by ECU etc.. And my god man ur a genius on this car and a godsend to me. The ECT IS only a resistor no magic no electronics at all just thermistor that is really a THERMOMETER.
Im not genius all EFI cars from 1988 to 2020 work like this , on topic;....nothing new under this SUn.

Im getting in there this weekend to check ECU caps and ordering #18 GE bulb but i am.now at a point where i need some more tools to diagnose this right But thanks to you i have the knowledge and have a fundamental.understanding of the car itself which i could never repay you for. You own me zero, I help anyone for free. Im retired now. 100% for 10 years.(early) I am glad to help and have no problem showing ways and means all ways to do the job, and some tricks too, like hands fly off above.


Only one question (besides the update and other symptoms i didnt mention but once i made sense of what u were asking it clicked for me). What is OEM (or recommended) thermostat? Once i get in there and look ofc..when I looked it up i got conflicting info:on my 1993 8v tbi does it take the 180* or the 195* (I saw rated 192?) thermostat? also which gasket does it take? I read that auto parts stores will gige u both LOL is it The 1 mm or the 4-5mm rubber o ring?

OH yes, 180 to 195 works, hotter even cools better, yes sounds strange but does. (air and water temps far from each other is more cooling(Carnot laws)
yes 92 to 95 has 2 intake manifolds one with old 1mm thermostat lip and one 4mm, the later uses a huge 5mm Oring, if  not there the stat floats and engine runs super illegal cold and is really  a hard failure here, the lip must  be seen and measured, first.  type frigid kick in search box fixkick.com  even a TSB covers this little horror.

Thanks to your help i am.going to save hours upon hours of labor and have myself a new tool set to work on this myself!  (dad told me.for every hour of labor saved you can buy 4 tools..rip to him I lost him too soon before he could teach me more and wished id listened more when younger.)
He is right tools are why cheaper that $100/hr labor that adds up fast.  in a shop.
trick 2: drain only little water out of RAD and the thermostat goes dry, and pull housing ,read stat rim, stamp 150f, and measure 4mm on lip. aluminum pit wall.

I'm sharp but still need to be exposed to the material..so i thank you so much again or answering my directly and in detail while I also cross reference your manuals. 

I have the answers and am.on the right track i am sure of it. Im buying the tools this weekend and will update you again after i have performed the tests and/or replaced snything found faulty

P.S. it still has the ORIGINAL FUEL FILTER on it. New muffler..new shocks and struts all.on rear end and they never once replaced the fuel filter. How this car ran when i got it..ill never know.
yes the ECU will run  with vast things busted, it does that but burns lots of fuel to do LIMP,  in 1996 les
I am fixing that this weekend. Also i noticed that the EVAP CANISTER is bypassed and has a hose with a cap.on the end coming up beside it (im guessing to preserve the vacuum for the VSV?
the Canister does have  a hose to nowhere, it is only vent hose to not let water get into the vent say fording a stream, in 4wd offoard,  alxe and trans vents do that too.
hose to nowhere,  but high.
the VSV only sucks are from the canister moving, driving, that way vacuum, at idle is not , weak.
make sure all VSV hose to all VSV on the plenum vacuum intake side are not missing or cracked,

i havent read up on that YET but it almost seems like my a/c is bypassed and i need to look again to see if it is or not) i have a slight belt squeak on startup that isnt any bearings or pulleys..due to a seal.in power steering pump being broken and dripping ATF from p/s onto belt. Doesnt affect vehicle at all and im losing 1 reservoir every 6 months so im putting that one off until i have the parts car. ( this makes since)

Also per your site and instructions i am changing multiple hoses- the return hose for the fuel pressure regulator is noticeably gritty and old..

I may have fibbed so only one more question- do i need fuel system depressurized to replace FUEL REGULATOR RETURN HOSE? (not not VACUUM ever)

only the fuel lines removing fuel line rear TB and TB front FPR removed it will blast fuel into your face is not. (some FPR do not leak at all key off and hold pressure or 5minutes or more,  not 1 hour but Id not wreck you eyes on my guess on max. nobody knows max hold , depends on FPR quality or even worn in better to seal better.
some valves close better with age.
its open running, and regulating at 38psi.



I found instructions on how to from you and will be doing that while fixing fuel filter ofc)
to remove fuel pressure start engine, pull FI fuse see engine slowly stall as the fuel burns off. and bingo your are safe. (from flying fuel breached lines)
not only that you learn how a dead fuel pump acts as it fails running, engine. fun no?

Again i cannot thank yoy enough for all of the help. Im long winded and apologize for all of this text but I want to relay as much into as possible cuz it being internet etc.

hey man it is car and is old not a toaster.  cars are very complex and ECU more.

At this point tho until i do the tests..relaying anymore info is pointless so I'll get in there and come back hopefully with good news but if i run into anything elae and cant find it on here then I'll ask for sure.

Hello Partner.
your brain is wired like mine (EX NAVY  GUY , trust NOTHING! and live:", I have the same thought processes, and what you said makes sense. (all)
cheers to you and happy trails !

I'd make sure the thermostat is stamped 180f +up.
and that lip.