98 Daewoo Leganza Hesitation - Coil Specs?

kurnia_2 · Post by **kurnia_2** » Tue Mar 21, 2006 10:12 am

Hello all,

I'm a freshly registered newbie.

I'd like to ask for your directions.

I'm a Toyota technician, but the used car department has a traded-in Leganza with a problem. So I don't really know about the history of the car.

It is a 98 Daewoo Leganza with Automatic Transmission.

This car has a hesitation and stumbling when 1st accelerating. After 3-5 secs, it doesn't stumble anymore.

It also has a miss that I noticed when scoping the ignition. It does this every time, hot and cold.

Pulled into the workshop, checked for fuel pressure - 38psi. Max pressure @ 60psi when return line is blocked.

Scoped for ignition pattern. #1 & #2 had a descent pattern, but #3 & #4 had some dropouts.

No check engine light. I noticed that oil vapor has slowly made it's way to the air ducting just before the throttle body.

I checked the coil resistance on the secondary towers. It's got 5.5 and 5.4 Kohms.

I don't know how to check the primary ones, but I did check the 4 terminals at the bottom (ABCD).

AB got 11 Kohms, CD got 11 Kohms.
AC, AD got 20 Kohms
BC, BD got 30 Kohms.

It looks weird to have this specs when usually the secondary has higher resistance.

Please help, I need your advice before spending money on unnecessary replacement parts.

Thanks,

Bob

cpd · Post by **cpd** » Tue Mar 21, 2006 10:20 am

<offtopic>

How good's this? Professional mechanics asking for help!

</offtopic>

MMamdouh · Post by **MMamdouh** » Tue Mar 21, 2006 10:57 am

well... i am not too sure if this is easy to do or not but in a similar situation i'd use another coil pack for testing, beats the hell out of any diagnostic that can be done.

those engines do spit oil vapor through the crank case breather so it is normal to have oiley TB... i clean mine with GUNK carb medic every 5k kms. TB and IAC cleanup helps with rough idling... check the how to section for detailed instructions.

keep us posted with what you do.

MMamdouh

MMamdouh · Post by **MMamdouh** » Tue Mar 21, 2006 10:57 am

cpd wrote:<offtopic>

How good's this? Professional mechanics asking for help!

</offtopic>

every body needs help even the very knowledgable ones.

MMamdouh

kurnia_2 · Post by **kurnia_2** » Tue Mar 21, 2006 11:16 am

MMamdouh wrote:well... i am not too sure if this is easy to do or not but in a similar situation i'd use another coil pack for testing, beats the hell out of any diagnostic that can be done.

those engines do spit oil vapor through the crank case breather so it is normal to have oiley TB... i clean mine with GUNK carb medic every 5k kms. TB and IAC cleanup helps with rough idling... check the how to section for detailed instructions.

keep us posted with what you do.

MMamdouh

Thanks for the quick and pro response and recommendation. I'll try to clean the IAC too.

The unfortunate thing is I only have 1 car to work, no spares, so no other coil pack I can use to test.

Do you by chance have any specifications on the resistance? And the testing procedures from factory manual?

And I also have a problem getting to the injector connectors. How do I take the plastic cover of the injector wirings off?

I need to get to the top of the injectors.

Thanks and I'll keep you updated.

Bob

MMamdouh · Post by **MMamdouh** » Tue Mar 21, 2006 11:34 am

i never tested my coil pack for resistance so i got no idea... their is a link to a lanos manual in the general section, the coil pack is the same on the lanos and leganza so you can check the lanos manual for coil pack diagnostics and apply it to the leganza coil.

the cover on the injectors is only available on the leganza - i got a lanos - so again i have no idea but most probably it is a pop up thingy... i never saw screws or clips holding it on the few leganza engines i saw before.

MMamdouh

BosnianLanos · Post by **BosnianLanos** » Tue Mar 21, 2006 8:58 pm

If the sputtering goes away, I doubt it is a coil pack. Generally, when the coil pack goes bad, you misfire badly on the affected cylinders and just have an overall painful ride, no matter what gear or speed.

My guess would be to check the TPS sensor and the Camshaft Position Sensor for correct operation. The Camshaft Sensor had a recall and is quite poor quality.

The engine should have thrown a CEL, but maybe the bulb burned out. Hook up a OBD scanner just to check.

Aneab · Post by **Aneab** » Wed Mar 22, 2006 1:30 am

If i remember right, you don't have to take off the plastic cover on the wiring, and if you absolutely have to, you have to try and go around the snap ons one by one... If you take out the fuel railing It's easier to work with the plastic cover (theres two bolts near the rear of the fuel rail, and those hold it to the motor) What i did to remove it was simple, i took off the intake, to allow more room to work, undid the two bolts, pulled off the rail and went from there... I dunno if that helps at all, but the plastic cover is connected to the fuel injectors, and if you take off the rail you can get to the injectors unplug them ect...

~Kyle

daewoomofo · Post by **daewoomofo** » Wed Mar 22, 2006 1:46 am

i recently had the same studdering problem on my lanos, i put a can of spt fuel system cleaner in the gas tank ran it for a week (about 200 miles) then i put some new spark plugs and plug wires in and bam! no more studdering, i also had horrable fuel economy and now it back to normal! id say try the stp then the wires amd plugs. good luck and as always keep us posted.

kurnia_2 · Post by **kurnia_2** » Mon Mar 27, 2006 7:27 am

BosnianLanos wrote:If the sputtering goes away, I doubt it is a coil pack. Generally, when the coil pack goes bad, you misfire badly on the affected cylinders and just have an overall painful ride, no matter what gear or speed.

My guess would be to check the TPS sensor and the Camshaft Position Sensor for correct operation. The Camshaft Sensor had a recall and is quite poor quality.

The engine should have thrown a CEL, but maybe the bulb burned out. Hook up a OBD scanner just to check.

Thank you all for the replies.
The car is still in the workshop and left alone for now because we've been busy.
However, I did take a bit of time every now and then to continue diagnosing.
I did find a way to undo the plastic cover on top of the injectors. Thanks, they are snap ons indeed.

I was thinking of the coil pack just because of the resistance reading I got from metering it. I don't like it, but it looks like the coil pack is firing alright.

I checked the EGR valve because I thought that it might be stucked open. The result was good.

I did injector balance test, all injectors tested ok.

I checked TPS, reading looked good.

I checked MAP sensor, reading looked good.

Check engine light bulb works.

Still no check engine light.

One other thing that bothers me is that the O2 sensor reading doesn't fluctuate lean to rich to lean and so on.
I read the signal right from the O2 sensor and it read 0.5volts or below (lean) and it was a flat line on my scope.
As soon as I shot carby cleaner into the throttle body, the reading went up to 0.9v (rich) and came back down to below 0.5volts and misfiring. So, it was a lean misfire.

I think the computer should have richened up the fuel supply as soon as it saw a lean signal and cut down the fuel supply as soon as it saw a rich signal.

I checked for vacuum leak visually, couldn't notice any leak.

I haven't checked the cam or crank sensor though. I can't find them.

I'm leaning toward the ECU now, but that would be the last thing I'd condemn.

The bad thing about this is it doesn't throw a code.
And if it does throw a code, I don't have a compatible scanner to read the code or live data stream.
Also the manual I downloaded from this site is awesome, but it's not for leganza.

Do you guys know what other GM cars that use this DTEC Engine?

More input?

Thank you,

Bob

kurnia_2 · Post by **kurnia_2** » Mon Mar 27, 2006 7:58 am

daewoomofo wrote:i recently had the same studdering problem on my lanos, i put a can of spt fuel system cleaner in the gas tank ran it for a week (about 200 miles) then i put some new spark plugs and plug wires in and bam! no more studdering, i also had horrable fuel economy and now it back to normal! id say try the stp then the wires amd plugs. good luck and as always keep us posted.

I forgot one thing,
I did replace the plugs and wires.

Aneab · Post by **Aneab** » Tue Mar 28, 2006 4:36 am

The nubira uses a 2.0L DTEC engine that has almost all the same parts as the 2.2L that are probably in that leganza... So a nubira manual might also help a bit.

The cam sensor is on top of the block near the timing belt (should see a wire leading into it) just gotta take off the spark plug cover... no idea where the crank is though sorry... My cam sensor was bad, but it threw a code though so i'm thinking this isn't your problem...

woo · Post by **woo** » Tue Mar 28, 2006 4:45 am

my 98 leganza has a 2L in it. I have the workshop manual on my computer for the 2L leganza. PM me if you are interested

kurnia_2 · Post by **kurnia_2** » Tue Mar 28, 2006 7:24 pm

woo wrote:my 98 leganza has a 2L in it. I have the workshop manual on my computer for the 2L leganza. PM me if you are interested

How to send a PM?
I did try it and I see it in my outbox, not sentbox.
Has it been sent?

Aneab · Post by **Aneab** » Tue Mar 28, 2006 7:26 pm

That 2L is the same one in my nubira correct?