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I replaced the cyl. head on a 2000 Daewoo Leganza because ...
Sent to Car Experts November 10 09:10 PM

I replaced the cyl. head on a 2000 Daewoo Leganza because the timing belt idler pulley broke. Compression is good, but when I had the plugs sitting on top of the engine to test for spark, I turned on the key, got the spark plugs to fire and I'm not cranking the engine, also the fuel relay switch is clicking at the same time. Vehicle will not start, good psi from fuel rail, ECM has been changed also, I did go by VIN when I switched it. What is going on?
Please help.....Tim

 

Optional Information:
2000 Leganza 2.2

Already Tried:
replaced ECM,

Customer (name blocked for privacy)
Status:  Closed   Value: $15
Answer
November 10 10:37 PM (1 hour and 26 minutes and 12 seconds later)
         
REPLIEDCheck Mark

The ignition system works in the following manner;

The ecm gets a signal from the crank and cam sensors, reads them, and calculates the pistons' position and rpm. Ecm then sends a signal to the coil driver which sparks the coils. The coil driver is powered by the ignition relay. Now, if your coils are sparking when the engine is not running, you can have the following problems; ecm thinks engine is running, the coil driver is faulty, or the ignition relay is doing something funky. Here are a few wiring diagrams to help you out.

Images available only to Customers.

Images available only to Customers.

Now as you can imagine, tracing this can be tricky. So, when the engine is sparking, disconnect the crank and cam sensors and see if that stops the spark. If it does, the ecm thinks the engine is running (bad sensor). Next, measure the voltage going to the coil from the ign relay. (12v +/- is good) . Next, measure the voltage out of the ecm to the coil (both wires) and see if it's right (you must have a scope to test this). If that is good, a bad coil drive is your problem. The coil driver is part of the coils and must be replaced as a coil/driver assembly. I would suspect the coil driver or the sensors since you replaced the ecm. The coil driver would be my guess. Test both well and don't try to cut corners. Good luck and let me know if you have further questions.



Edited by rmldaytona on November 10 2006 at 10:38 PM
1 Other Expert Agrees with this!
rmldaytona -- ASE technician -- 99% Positive Feedback on 497 Car Accepts
ASE Certified. Aerospace engineering studies. Drivebility.
Reply
November 13 2:15 PM (2 days and 15 hours later)
         
Reply to rmldaytona's Post: Replaced the coil pack on this Daewoo and it still is doing the same thing. Checked fuel PSI and it's good but it won't hold. Could a bad fuel pump or fuel pressure regulator be the problem? All other components tested out fine. I'm thinking maybe a bad ignition switch...

Edited by Customer (name blocked for privacy) on November 13 2006 at 5:00 PM
Customer (name blocked for privacy)
Answer
November 13 7:08 PM (4 hours and 52 minutes and 44 seconds later)
         
REPLIEDCheck Mark

If you are asking me if a bad fuel pump or a bad pressure regulator can cause a no start; absolutely. However can a bad pump cause a coil to spark without the engine running; no way.

As for a bad ignition switch, well... IF the ignition switch is telling the ecu that the engine is cranking, then yes. Your injectors would also turn on and off. Do you hear them clicking? Unfortunatley, Deawoo has not released any diagrams which tell you what is the wire the ecu uses from the switch as a "start" signal. You can access the wires yourself and see if you have any "trickle voltage" from the start wire OUT of the ignition switch.

By the way, after you installed the ecu, did you relearn the crank/cam sensors? This will give you a drivebility problem, but says nothing about coils sparking with the engine stopped.

I still say you MUST have a problem, eithe in the coil driver, ecu, or the relay. One at a time, unplug the cam+crank sensor, the ign relay and tell me if the car still sparks with the engine off. Next unplug the ecu and tell me if it stops. See if your ignition switch is leaking voltage in the start wire.

I know I sound repetative, but the car can't spark with the engine not running.

Make sure all your connectors are hooked up correctly. Some connectors look the same, therefore are easy to crosswire. If any connector looks the same, make sure they are hooked in to the right component. This has happened before. Look for the coil connector and see if you can find one that looks the same on the car. Maybe a connector mishap is all this is.

Good luck and please let me know how it goes. I'm really curious now.

rmldaytona -- ASE technician -- 99% Positive Feedback on 497 Car Accepts
ASE Certified. Aerospace engineering studies. Drivebility.
Info Request
November 13 9:36 PM (2 hours and 28 minutes and 13 seconds later)
         
Check IAC connector and the coil connector, do they look the same?
rmldaytona -- ASE technician -- 99% Positive Feedback on 497 Car Accepts
ASE Certified. Aerospace engineering studies. Drivebility.
Reply
November 14 12:44 PM (15 hours and 8 minutes and 16 seconds later)
         
Reply to rmldaytona's Post: We are frustrated, you have been a great help and I'm willing to pay for your expertise. So far we tried everything you recommended and still the same, ignition switch has low voltage drop in one wire, unplugged ECM turned on key, car does nothing, the clicking rely is not there and there is no spark or injector action.....Tim
Customer (name blocked for privacy)
Answer
November 14 1:14 PM (29 minutes and 58 seconds later)
         
REPLIEDCheck Mark
I have a feeling that if everything you checked is good, then there is something that can't be picked up with a voltmeter. You might need a manufacturer specific computer and a scope to figure this out. There must be a signal that is not to specs, a connector in the wrong place or a faulty component that will be found only with more advanced diagnostic equipment. I'm sorry I can't be of further help to you, but without looking at the car, it's difficult almost impossible to follow a steady diagnostic track. Good luck and let me know if you need anything else.
rmldaytona -- ASE technician -- 99% Positive Feedback on 497 Car Accepts
ASE Certified. Aerospace engineering studies. Drivebility.
Reply
November 28 11:53 PM (14 days and 10 hours later)
         
Reply to rmldaytona's Post: Hello..remember the Daewoo problem you tried to help me solve...just thought I would get back to you and let you know I got the car running, it was a bad ground in the wiring harness....Tim
Customer (name blocked for privacy)
Info Request
November 29 8:05 AM (8 hours and 12 minutes and 14 seconds later)
         
Cool. How did you find that out?
rmldaytona -- ASE technician -- 99% Positive Feedback on 497 Car Accepts
ASE Certified. Aerospace engineering studies. Drivebility.
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