idling issues

[edc55]

I am from the philippines and i have a 1997 suzuki vitara.
I've replaced the following:

timing belt
tensioner
crankshaft pulley
spark plugs
distributor rotor and cap
iacv
fuel pump and filter
alternator
all the rad hoses
thermostat

Here is my problem sir:

My vit starts ok and idles ok when i start it in the morning. It revs at around
1t rpm and gradually goes down to around 800rpm. when i turn on the ac the idle goes up a bit. The car works perfectly.
After using it and start it again immediately the idling is ok. The problem is, when i switch off the engine and let it rest for about 5 to 10 minutes and i start it again, the idle becomes rough! If i step on the gas hard. it becomes normal idling again.

What do you think is the problem? pls help

[ranger88den]

What size engine, what kind of trans? Any computer codes? Air cleaner filter? Fuel pressure test? Do you have an EGR system?

[edc55]

It's a 1600 16valve engine auto tranny. I forgot to mention that i also replaced the air filter with a new one. I tried to get the cel code. 4 short blinks. so is this cel no.4?
Everything seems to work out fine. except for the initial rough idling when you start the engine after switching it off and letting it rest for some minutes.Rev it hard and the idling normalizes.But if you start it immediately after switching it off, the idling is ok. And also if you start it from cold the idling is ok
It has no egr and the fuel pump is new.

Here's a pic of my engine

[jtgh]

hello: mr. HOt Soak restart problem. 97 PHIL.

you didnt mention spark plug wires.
year 97, vitara, ok. but what engine, 4cy. 1.6. 2.0L or V6. tranny, body type 4wd?
A+ for telling location !
3 doors or 5 doors?
16v for sure.

the CHECK engine lamp must be on, key on, no start.
then it must go OUT, after starting.does it?

sounds like it is running rich under these condtions (no egr ).
so check your fuel pressure. make sure it is proper values.
when it does this ,pop the hood and rap the Fuel pressure regulator with the back side of a screwdriver, rap ,rap , rap,
if they stick , fuel pressure goes way high and will cause real rich condition.
also , you can view the data , live with any obd2 full scan too.
you can make sure hot restart is not super rich, by watching the ShortTermFuelTrim STFT parameter and if the Oxygen sensor is swinging or dead.

could just be a bad Oxy sen.
VID:
the metal plate lable on the engine bay fire wall top.
it has 5 lines of data.
one line can be:
TA0 or TD0 ........
or
JS........................
the the last line
had 9 digits, this line , at the end last 2 digits tell the market type.
eg: LPN675T22 <<< see T22 this is Market E22 and tells lots of important info about car.
this plate is very important , when you need parts.

[jtgh]

here is fuel test proc, out of FSM.. ( if the pressure is too high FP reg. has issues)

Remove gas cap at thank.whooosh.
releave line pressure by pulling fuel pressure relay while running.
Install gauge to rail test port at front.
put back Relay from above.

Turn the ignition switch ON for 3 seconds (without starting the engine), then turn it OFF. Repeat this three
or four times, then check the fuel pressure registered on the fuel pressure gauge attached to the fuel
delivery manifold. The fuel pressure should be 35.6–42.7 psi (250–300 kPa) for 1.6L engines, or
38.4–44.0 psi (270–310 kPa) for 1.8L engines, and should remain above 28.4 psi (200 kPa) for one
minute after the fuel pump stops.
If the fuel pressure is within the specified range, skip to the next step.
If there was no fuel pressure, jump to Sub-Test 1.
If the fuel pressure was initially within the specified range but dropped below 28.4 psi (200 kPa)
within one minute after the fuel pump stopped, skip to Sub-Test 2.
If the fuel pressure was too low, skip to Sub-Test 3.
If the fuel pressure was too high, skip to Sub-Test 4.
2.
Start the engine and allow it to reach normal operating temperature3. .
Allow the engine to idle and observe the fuel pressure on the gauge. The fuel pressure should be within
29.8–37.0 psi (210–260 kPa) for 1.6L engines, or within 31.3–37.0 psi (220–260 kPa) for 1.8L engines.
If the fuel pressure is not as specified, the problem is most likely a clogged vacuum passage for the fuel
pressure regulator, or a faulty fuel pressure regulator. If the fuel pressure was within the specified range,
the fuel pump and fuel delivery system is functioning normally.

[edc55]

Ok i will bring my vit to the local dealer to do the tests.

The check engine lights when i start it and turns off right away. As i mentioned in my previous post, i tried getting a ecu reading... the check engine shows 4 consecutive short blinks. Ist this the TPS?

(By the way its 4wd, four door, 1600 cc engine, auto tranny and i havent replaced the plug wires cause they are still ok)

I'm just wondering how come when it idles roughly upon restart when hot and i rev it hard, it immediately idles ok. If i dont rev it and just leave it idling roughly (as if it wants to die on me) (and the exhausts smells bad) after a few seconds it normalizes by itself. So i just rev it hard right away so that it stops the rough idle. But this isn't normal right? And it's a waste of fuel! lol

[jtgh]

the hot restart is rich , very rich.
it could be caused by a bad , and intermittant ECT. (engine coolant sensor)
intermitants are hard to find.

do you have an OBD2 16 pin connector under the dash. (not square , not rectangle OBD1 but D Sheel shape and fat.
i have no idea what ECU you have.
if it is OBD2 compliant you can look at all the sensors at once and see why it is rich.
but the ECU can not measure fuel pressure.
so if you dealer can scan you car ( many cant) and you see all senors read pefect and
the O2 is vastly rich (during failure mode)
then the next most logical is the Fuel pressure.
keep in mind it might be ok , that pressure if you take it in and it is working perfect.
they will charge you to say, it all looks perfect.

you could have an exhaust leak that gets worse , when hot soaked.
but that is in left field.

what is the last line on you vehicle tag. ?
this tells use what the exact model car you have, what ECU , what smog devices and what EFI parts.
every country has different models.

USA /canada has the fancy OBD2 in 1996, the UK anD EU 2001.
vast differences exist.
that last TAG line and all lines really . tell people what you have.

cheers.

[edc55]

I was finally able to bring my Vit to the largest and oldest suzuki dealer in our country the other day. They hooked it to their engine analyzer and adjusted everything that was not into specs like the tps, iacv etc.
The ecu was throwing a 12 cel code so according to them all was ok now. Fuel pressure was ok.everything was as per specifications. But the problem was still there!!!! Left the car for them to work on it and just told them that i'll return the next day.
Day 2...No luck. problem was still there!!
If you let the hot engine rest for about 2 to 3 minutes and you start it again the idling gets rough but the engine doesn't die. If you let it just rough idle for a few seconds it corrects itself and idles smoothly! But if you want to hasten to smooth idling, i just step on the gas hard and viola, the idling becomes smooth.
If you turn off the engine when hot and immediately start it again, idling is smooth.It only idles rough when you let it rest for a few minutes. And also if you start it from cold, no rough idling in the beginning.
All the mechanics were baffled. They cleaned the throttle valve which was clean in the first place cause i cleaned it already. results still the same
They said that plug wire number two was showing weak connectivity so they replaced it plus the number 2 spark plug. still problem exists.
They did compression test and they said that no.3 was low comp. reading was 8 or .8 i'm not sure anymore but they said it was low. So that was the culprit and they want to tear down the engine for an overhaul!!
and i almost forgot... they also adjusted the valve tappets.
My question is, are they right? How come the car works fine once it overcomes the few seconds of rough idling? wouldn't the performance be affected if there was indeed low comp on a single cylinder? The car doen't overheat. And it performs well. Nice acceleration etc. And now they want to do an overhaul??
one of the mechanics told me that it could probably be the cylinder head gasket. Is that possible. No traces of oil on the radiator water though.
By the way, i looked at the id plate on the firewall and these were the figures i saw...

TYPE SE416
TDO1V PH002228 i think this is the chassis number
and another number for the engine. G16B......

What else do you think should we check to solve this idling problem? Pls help

[jtgh]

97 1.6L
i suspect it will get worse.
it could be a slow head gasket leak.
a violent restart clears it ! common.

i bet the dealer didnt scan the ECU while it was failing (running rough)
A+ for dealer checking basics.

low compression , what standard you using there BAR? please say whitch?
8bar = 116 psi, that is a cyclinder that is Very sick.
IT WILL GET WORsE fast.

mechanical:
head gasket,slow leak to water jacket.
bent or sticking valve.
collapsed rings.

EFI;
fist of all , the EFI is NOT designed to run engine perfect if there is a gross mechancal problem ( although it does wonders, and tries very hard to)

you either have 1 problem or 2,
engine is sick,#1
and you might have a sensor problem. (maybe not)
neither will go away by themselves.

please ,when ever you pay money for a compression test, demand a report.
1 = 150 psi
2 = 160
3= 116 (8 bar)
4: 160
see, i can see there that #3 is not leaking in to #2 nor #4 .?
when paying , demand a full written report. tell them you want all data in the report.
scan tool data if they can print it.

alternate tests:
you dealer stopped short , (imho)
he did not ask you to do a Radiator leak down.?
and a Radiator combustion gas detection test ( $40 tool and not having one in a shop is silly)
and he did not ask you for the cylinder leak down test.

he also did not tell you the effect of putting 1 teaspoon of oil in the #3 to see if PSI
raises or does it stay same , raises show ring leak. during the compression test.

and advanced shops , have a bore scope.
he looks in and sees anifreeze, BINGO.

all these tests are easy and obvious to any tech who finds #3 low.

keep in mind if you have antifreeze invasion on #3 you are killing the CATCON.
more $$

did he check Vacuum for 19 inch HG (64-kpa) , at idle and not bouncing like crazy.?
that is a basic check too. never to be skipped, on sick motors.
IMHO.

That is the best i can do , not hands on.
cheers,

[edc55]

Thank you very much for taking time to reply to my problem. One last question, will changing the cylinder head gasket solve the problem? by the way i also forgot to mention that i usually have to add water to the radiator at the start of the day. Cant find leaks tho.
Can a slowly leaking head gasket be the reason for the low comp on one of the cylinders? if so can changing it remove this pesky problem?
I suppose i didn't ask just one question. lol. my apologies sir.
EDC55