Car Running Poorly/Dead ECU? *UPDATE: 1 PROBLEM SOLVED*

BosnianLanos · Post by **BosnianLanos** » Thu Jun 05, 2008 7:38 pm

The green car is back at it...giving me problems. Car ran fine for 60 miles with only a slight shudder in idle. Parked it overnight, tried to start it up the next morning...it started after a few trys (it used to start right up). Ran VERY rough...tried to drive it, instantly bogged down. Back into PARK, and revved it, would bog until maybe 2500 RPM and then run smoothly, let it back into idle to rev it up, bogs down again. Coil, plugs, wires, injectors, pump all OK, fuel pressure OK. Compression even across the board. Not even 10% difference. Not burning oil. Coolant is fine. Belts are fine, Battery is fine. Let it run in idle to further diagnose, shifted to reverse, STRONG jerk and clunk from the engine/transmission, same when shifting into Drive. TPS, IAC fine, no vacuum leaks. Transmission fluid level fine

My guess is ECU...what do you guys think? My indicators are these: While the car is running, I pulled the #1 Cyl. plug wire. Very loud electrical popping noise coming off of the tip (as it should). Replaced it. Pulled Plug #2, the engine began to shudder, but there were no sparks coming off of the wire. Same with #3. #4 popped like #1. I have weak spark on the 2/3 bank. It's not the coil/wires, I swapped the test coil onto the Red car and it ran fine. Also, the VERY rough jerks when shifting were totally reminiscent of when I put the Manual ECU into the Automatic car...the car didn't know how to shift.

I reset the ECU overnight thinking that maybe it picked up some sort of new parameters due to faulty timing. Nothing ran exactly the same. Very badly.

What do you guys think?

buddha102 · Post by **buddha102** » Thu Jun 05, 2008 9:10 pm

maybe its the fuel, becuase as i remember i had my fuel near red light, and my car stayed in the sun and i start it after few hours and it was barely ruining so i fill my tank up with best fuel and added additives to my tank and i had to take it for a "spin", after few minutes it was working fine :P

daewoomofo · Post by **daewoomofo** » Thu Jun 05, 2008 9:23 pm

its easy enough to swap the manual ecu in to it so give it a try. i know you cant drive it with the manual ecu in there but it will tell you if there is a problem with the auto's computer. even put the auto in the manual to see if it does the same thing.

Post by **PrecisionBoost** » Fri Jun 06, 2008 12:05 am

Well... the simplest fix is to have a button spray nitrous when it boggs down

But seriously... there are so many different issues that could cause that problem.

So.... have you replaced your fuel filter lately?

Perhaps do so and split the old one open to see if there is any crap inside plugging up the filter.

Perhaps you have some crap in the bottom of the tank and once in a while it's getting sucked up into the filter.

How do you know the fuel pump and injectors are ok?
What kind of testing was done to ensure they are working within specification?

BosnianLanos · Post by **BosnianLanos** » Fri Jun 06, 2008 3:41 am

...Well I do have a half-full nitrous tank sitting in my closet. No sense in wasting the NO2!

Fuel filter is brand-spanking new. Not even 100 miles on it. I disconnected the feed line to the fuel rail and ran the pump with the car off but Ignition set to "ON" to prime it. Fuel was totally free flowing, took the filter off to inspect...no clogs.

The oldest portion of the fuel HAS been sitting for quite some time now, maybe a year, but it was partially filled in November. I pulled a sample of the fuel from the tank with a siphon pump and it looked clean.

Pump and injectors were a pain in the ass to test. I took the injectors and pump off of my Red Lanos (not even 50K miles on it) and swapped it with the green Lanos. The red car ran just fine, but the green car exhibited the same problems. I suppose they could still be faulty, but the Red Lanos ran like a top.

Like I said, I'm fairly sure it is a spark problem... there is simply a weak spark on cylinder 2 and 3. But like I said, I took off the plugs, wires, and coil and put them on the Red car, and it ran fine.

I have a spare manual ECU laying around, I'll throw it into the green car to see if that clears anything up. If it does, off to the junkyard for a auto ECU.

I wouldn't be surprised if it was faulty...205,000 miles, a hydrolock, a blown gasket, a valve job, several batteries, it's fair share of shorts...

I'm just hoping it's that!

Spider · Post by **Spider** » Fri Jun 06, 2008 5:59 am

_______________________________________________________
" I have weak spark on the 2/3 bank. It's not the coil/wires......"
___________________________________________________________

You swapped the coil pack on to another engine (with it's wires???) and it ran fine.
The best (visual way) to check for good spark is to pull the plugs than snap the wires back on and ground the threads (one cylinder at a time) have your helper crank the engine and observe (in shade not bright sunlight) the spark. You want to see a healthy bright yellow/orange/blue lightning bolt jumping the electrode. All 4 should be the same.

Good Luck !

BosnianLanos · Post by **BosnianLanos** » Fri Jun 06, 2008 12:31 pm

I just pulled each wire from the plug individually to see what was up. Like I said, cylinder 1 and 4 gave off a loud electrical popping noise with a visible arc that jumped from the end to nearby metals. While pulling 2 and 3 DID make the engine run worse, there was no popping noise or bright arc that sparked from the ends of the wires. While doing the same experiment in the Red Lanos, all four wires sparked with the same intensity.

I've had an undiagnosed "Misfire Cylinder 3" CEL for 4 years now. At higher speeds 65+ under WOT, it would begin to blink. But the plugs, wires, coil, injectors, pump, and all other sensors were fine. It really could be that my ECU was getting sick all these years.

But like I said, tonight we either implicate or rule out the computer.

jak4calibrah · Post by **jak4calibrah** » Sat Jun 07, 2008 1:56 pm

test/change your coil pak, reason is cause on my calibra my dad degressed the engine and it the ran on 3 cylinders then not long after it ran on 2. changed the coil pak and all was good.

Post by **PrecisionBoost** » Sun Jun 08, 2008 5:03 am

This is a waisted spark system were talking about..... so it fires 1&4 and 2&3 together.... so if it's a coil pack issue then it would definitly make sense if 2&3 weren't strong.

I don't see it as a possible ECU issue... the ECU is sending a simply 5V positive pulse to the coil..... there is a driver board imbeded into the coil pack that does all the high power switching of the coil.

One thing you could do is swap the two trigger wires (involves cutting) and it all of a sudden 1&4 don't work and 2&3 do then it's definitly the driver inside the coil pack.

I personally wouldn't be checking the plugs by the method you did.... I would use a spark plug to check the spark.... since the spark plug is resistive and needs to be there to get a proper impedance match with the coil pack.

If you want to check for spark strength then you can insert a plug into the wires and hold it a 1/16" from a ground source ( it should arc)

Then you simply pull it further and further away until it stops arcing.

I don't remember the formula but the air gap jump is directly proportional to the voltage potential.

For some reason I seem to remember that 40,000V will jump 1/2...... which is approximatly the voltage put out by your automotive coil ( I use to fool with Tesla coils )

Post by **PrecisionBoost** » Sun Jun 08, 2008 5:07 am

As far as the fuel pump, it must be under pressure ( 3bar ) for flow measurements...... free flow is not an indicator of pump condition.

It might work just fine at 0psi resistance but you might find that the flow at 3 bar is close to zero.

Yes..... testing injectors is a huge pain in the ass..... I would check the spark first.... but my logical second choice is the fuel pump.

Can you pull the fuel pump out of the other car to give it a try?

BosnianLanos · Post by **BosnianLanos** » Fri Jul 04, 2008 4:21 am

Ok, I bought a datalogging program for my laptop and have been able to diagnose the problem. It was due to a faulty TPS. I had a spare lying around, and while that problem was repaired, a new one surfaced. It's a problem that has been present since I did my timing belt change myself, but it's been getting worse

I keep getting code P0304...Cylinder 4 misfire. And boy, did I check EVERYTHING!

Compression is great, plugs are good, wires are good, injectors are good, coil is good, vacuum is good, fuel pressure/pump/filter are good, electrical lines to the injector are good, and the ECU seems good. Everything was twice checked manually, or checked on the software via laptop.

It seems to me that the LAST thing it can be is that my timing is off. Listening to the exhaust note, it sounds as though the exhaust valves open during the compression stroke, as there is an strong PUFF from the exhaust every few seconds (engine cycles). Granted, there isn't any smoke or strange smell from the exhaust, so who knows.

Literally the last two things I can think of are ECU and Timing. I'm going to completely re-do the timing belt tomorrow...step by step, to 100% rule out timing. I can always figure the ECU bit out when I get my red car back.

Do any of you have any idea why #4 would keep missing? Sensors all check out, and like I said, everything that would traditionally cause a misfire has been ruled out.

Help!

Post by **PrecisionBoost** » Fri Jul 04, 2008 5:11 am

I have a boroscope I like to use to go in and look at the piston/valves via the spark plug hole.... it's great for looking at build up.... and to see if coolant or oil are making their way into the cylinder.... and to see how well the rings are seating ( you can see pattern changes in the honing of the cylinder )

Have you ever thought about the idea that #4 might be filled with massive amounts of carbon?

If you get it to TDC you might be able to partially see inside with a small bright flash light

Did you switch injector #1 with #4 to see if they are balance equally?

If you continue to get a misfire on #4 then you know that the injectors are just fine.

If the misfire switches to #1 then it's an injector problem.

I can't imagine your timing is off..... with the DIS it's nearly impossible to screw it up and if you were off by one notch on the timing belt all four cylinders would have the same problem.

BosnianLanos · Post by **BosnianLanos** » Sat Jul 05, 2008 5:17 am

Didn't get much chance to do anything with it today. I did start it and run it for a bit, and the same problem persisted. Tomorrow, I'm gonna run down to the local yard and pick up a spare ECU. I'm nearly convinced it's that problem. The more I reasoned it, the more I became aware that there was no smoke or odor coming from the exhaust, so my timing guess was off.

I do have a new set of NGK V-Grooves to throw in (Bosch Platinums are in the car now), and I have a new, freshly flow-tested set of injectors to put in. Also, I will fill up the gas tank tomorrow and throw in some injector cleaner. All that + the new ECU could HOPEFULLY solve my car issue. If it doesn't, I'm gonna put the car back together and start looking for a seller...It's sad, but It's my last option.

BosnianLanos · Post by **BosnianLanos** » Sat Jul 05, 2008 8:46 pm

No Daewoos at the lot...so no new ECU. Again, not much work happened on the car today, I spent most of the day fixing the bumper on my sister's Civic.

Again, I'll throw in some new plugs and injectors, and hopefully that'll aid the issue.

BosnianLanos · Post by **BosnianLanos** » Sun Jul 06, 2008 6:35 pm

Disconnected the battery, put in new injectors, new plugs, and a full new tank of Shell V-Power 93.

Nothing. It even stalled on my way to the gas station. Still ran rough. I have no idea what the hell is going on.

I came back home and hooked up the code reader and it stated that it could not detect ODB Protocol. I double checked all of the connections, and everything seemed ok. Then I switched the reader to my Civics, thinking it was faulty, but they started right up.

What the hell is going on?!

Could my ECU be so dead that it can't even accept a reader hookup?

The original daewootech forum

Car Running Poorly/Dead ECU? UPDATE: 1 PROBLEM SOLVED

Car Running Poorly/Dead ECU? UPDATE: 1 PROBLEM SOLVED