Quad Driver, ECM question
Drifting
Joined: Jul 1999
Posts: 1,337
Likes: 0
From: Brighton, MI
Hate to hijack this post but it's interesting because I've been dealing with the same issues, sort of. The car has thrown code 28 since I got it, but this does not turn on the SES light. The previous owner installed a manual fan switch. Center position is supposed to be automatic (ecm controls fans). Left position is one fan always on, right position is both fans always on. I usually keep the switch in the center. Could this switch be suspect for setting code 28? How long does it take to toast the ecm in this condition? Is it mileage based, time based? Because of my "other" issues, can a bad ecm continually toast the opti-spark, but still run the car ok if you replace the opti? This car eats opti's as much as it drinks fuel.
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
The fan switch would be a good candidate for the code 28. depends on why he put the switch in. If it was because the fan did not come on that needs to be checked. I doubt it has anything to do with the opti. What kind of failures does it have? If it is the rotor you might have too much play in the drive gear for it. Just a WAG on this one.
Drifting
Joined: Jul 1999
Posts: 1,337
Likes: 0
From: Brighton, MI
He put the fan switch in to be able to have manual control of the fans for cool-down at the track. You can run the fans without the car running. I'm not suspecting that the QDM is causing the opti to go bad, but I'm reading in this post that the QDM fault can cause the ECM to flake out, and maybe I have a bad ECM that's causing my opti problems. That's my question.....can a flaky ECM kill the opti? I have some sort of electrical issue where I can't get opti's to last at all. My last one was purchased direct from GM lasted about 3k miles and died with code 16. Now granted I don't drive the car a lot so that was about 3 years time. Car never sees water so no water issues w/ the opti.
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
Have you taken a failed opti apart to see what the problem is? I doubt the ECM is causing opti failures. If a car eats optis my first suspect is wobble in the rotor caused by play in the drive gear. It will show up as a loose rotor and/or broken rotor. There can be electrical issues that cause this to but I look at the obvious( mechanical) stuff first. You can use one of the screws from the TB plate and a pair of channel locks to remove the opti cover screws if you do not have the proper socket.
Safety Car
Joined: Jun 2006
Posts: 3,629
Likes: 28
From: FL
with Redeasysport, as stated I know my fan switch sets my code 28, this causes no other problems and like your car the DTC does not turn on the Check Engine light. I don't doubt that some quad driver circuit failures can take out the ECM,as others have indicated. However if you look at the wiring diagram in the FSM you will see the fan switch does exactly the same thing the ECM does, providing it is wired correctly. It grounds terminal "F" of the fan relays to close the relay coils sending power to the fan motors. It just does it at a different temperature or in your case when manually switched.
To check your fan switch wiring leave the switch in the off position and see if your ECM can run the fan once the engine temperature reaches 228, it should be able to do so. This will also verify if the manual switch is causing the code 28. If you clear the code with the switch off it should not reset until you again use manual control. For what it is worth my car has had the fan switch and code 28 for two years with no ECM failures.
I don't know if a bad ECM can take out the Opti, but suspect it could if the 5 volt supply voltage was too high, the FSM details the procedures for checking that and using it to do so makes way more sense than throwing parts at the problem, good luck.
Drifting
Joined: Jul 1999
Posts: 1,337
Likes: 0
From: Brighton, MI
Thanks guys. I went through the diagnostic procedure in the FSM today for code 28. Everything checks ok and leads to the "intermitant" path in the chart. Which isn't really true because it's always there. The ecm can activate all the relays on it's own, and the currents are within spec. QDM 3 only involves the fan and A/C that I see.
Ironically I ran the car for a while today in the garage and it did fine. A couple weeks ago it died with code 16. Not today, so it's intermitant. The last couple times I tried to drive the car (6 months ago) it didn't come home under it's own power (due to the opti I think). Wasn't brave enough to take it for a drive today. Going to check it every day until DTC16 shows up again. Then go through the FSM procedure for that code. Have to wait until the DTC to show up really do due much about it.
Ironically I ran the car for a while today in the garage and it did fine. A couple weeks ago it died with code 16. Not today, so it's intermitant. The last couple times I tried to drive the car (6 months ago) it didn't come home under it's own power (due to the opti I think). Wasn't brave enough to take it for a drive today. Going to check it every day until DTC16 shows up again. Then go through the FSM procedure for that code. Have to wait until the DTC to show up really do due much about it.
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
Intermittents suck. I much prefer it just dies then you don't have to worry about being stranded.You know code 16 points toward the Opti and it may just be a matter of time till 36 appears then you will definitely know. I had a H16 code on mine when I got it a few weeks back ( checking for codes was one of the first things I did no ses light though)and never had a problem yet. Don't know when it was set but it makes me paranoid.I reset it. Car runs great though till......
Drifting
Joined: Jul 1999
Posts: 1,337
Likes: 0
From: Brighton, MI
Yeah, last one died with code 36. Forgot to mention that yes I did take apart one of the previous opti's more as an experiment than anything. I didn't see anything abnormal. I don't know how there would be an wobble in the drive gear. The opti drive shaft came new with the opti, and the cam shaft gear is new. This is on a 383 stroker with about 5k miles on it. I've considered maybe that it's an rpm issue, but I don't run the car that hard and I'm not seeing rpm's that much higher than stock anyway. Engine runs cold too so not a heat build-up issue.
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Racer
Joined: Sep 2007
Posts: 393
Likes: 0
From: Bartonville Illinois
On that intermittent DTC 16, on a 1993 the Opti cable has another connector under the fuel rail cover about 18 inches away. You might check it to see if its clean and plugged in good. This is where mechanics can check the opti easily, they could possibly leave it loose or not put it back on its hanger.
Thread Starter
Racer
Joined: Mar 2007
Posts: 326
Likes: 0
From: McKinney Tx
I used another scan tool and it said it was specifically quad driver 3.
Also said my right o2 sensor wasnt working properly.
As for the retard control (thats supposed to retard once 5lbs of boost) I dont think is working, I was on LIVE monitoring and gave her all she has got (with setting to 20degrees retard) 1 degree of retard...
Also said my right o2 sensor wasnt working properly.
As for the retard control (thats supposed to retard once 5lbs of boost) I dont think is working, I was on LIVE monitoring and gave her all she has got (with setting to 20degrees retard) 1 degree of retard...
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
Like I said it sounded like 2 different issues. O2 ( if wire is not grounded) looks like it needs replaced. It should not be an issue at cold start as the car goes into closed loop. You never did respond on the hard start issue as to wether there was any difference between cold and warm starts. That is important. Did you reset the codes and check again? Just what "sensors" did the first mechanic change?
Thread Starter
Racer
Joined: Mar 2007
Posts: 326
Likes: 0
From: McKinney Tx
Like I said it sounded like 2 different issues. O2 ( if wire is not grounded) looks like it needs replaced. It should not be an issue at cold start as the car goes into closed loop. You never did respond on the hard start issue as to wether there was any difference between cold and warm starts. That is important. Did you reset the codes and check again? Just what "sensors" did the first mechanic change?
I dont know what sensors where changed, but the scan tool seemed to show they were all fine except the o2 sensor.
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
Try cleaning your TB if cold starts are harder.It might be starving for air through the IAC there is a hole in front of the butterfly that gets junk in it.Do a leak down check with the FP gauge on the rail turn key on then off and watch the pressure. It should hold for a little while or drop slowly. Check your FP and see if it is around 40.
Try a reset and check codes. You do not need a scanner
http://www.c4guru.com/articles/CCMCodePull.pdf
Have fun.
Try a reset and check codes. You do not need a scanner
http://www.c4guru.com/articles/CCMCodePull.pdf
Have fun.
Thread Starter
Racer
Joined: Mar 2007
Posts: 326
Likes: 0
From: McKinney Tx
I really appreciate all the help so far, you guys have helped me hold in a little hair on my head and little strands of hope.
Im going to take your advice and im also going to replace that o2 sensor then get back with you.
Im going to take your advice and im also going to replace that o2 sensor then get back with you.
Melting Slicks
Joined: Feb 2005
Posts: 2,135
Likes: 0
From: Sebastian Florida
St. Jude Donor '06
Try cleaning your TB if cold starts are harder.It might be starving for air through the IAC there is a hole in front of the butterfly that gets junk in it.Do a leak down check with the FP gauge on the rail turn key on then off and watch the pressure. It should hold for a little while or drop slowly. Check your FP and see if it is around 40.
Try a reset and check codes. You do not need a scanner
http://www.c4guru.com/articles/CCMCodePull.pdf
Have fun.
Try a reset and check codes. You do not need a scanner
http://www.c4guru.com/articles/CCMCodePull.pdf
Have fun.
Hard starting can be a symtom of the IAC being not properly set or a dirty IAC. I had a hard starting problem and thought it was the new injectors, but I had replaced my IAC at the same time. After checking and rechecking my injectors, I reset my IAC and it still does not start up as good as when I first got her, but it starts a whole lot faster now.
Thread Starter
Racer
Joined: Mar 2007
Posts: 326
Likes: 0
From: McKinney Tx
Hard starting can be a symtom of the IAC being not properly set or a dirty IAC. I had a hard starting problem and thought it was the new injectors, but I had replaced my IAC at the same time. After checking and rechecking my injectors, I reset my IAC and it still does not start up as good as when I first got her, but it starts a whole lot faster now.I dont know this IAC or drip down check. Someone guide me?
Melting Slicks
Joined: Feb 2005
Posts: 2,135
Likes: 0
From: Sebastian Florida
St. Jude Donor '06
I will go look for my instructions and post them for you.
Instructions on iac:
It doesn't sound like you reset the minimum air setting.
Turn on ignition
Wait 10 seconds and disconnect IAC connector
Start engine
Adjust Idle screw to minimum idle speed (550rpm)
Turn off engine
Reconnect IAC
Start engine.
Instructions on iac:
It doesn't sound like you reset the minimum air setting.
Turn on ignition
Wait 10 seconds and disconnect IAC connector
Start engine
Adjust Idle screw to minimum idle speed (550rpm)
Turn off engine
Reconnect IAC
Start engine.
Last edited by Randy93; Apr 10, 2008 at 03:11 PM.
Thread Starter
Racer
Joined: Mar 2007
Posts: 326
Likes: 0
From: McKinney Tx
I will go look for my instructions and post them for you.
Instructions on iac:
It doesn't sound like you reset the minimum air setting.
Turn on ignition
Wait 10 seconds and disconnect IAC connector
Start engine
Adjust Idle screw to minimum idle speed (550rpm)
Turn off engine
Reconnect IAC
Start engine.
Instructions on iac:
It doesn't sound like you reset the minimum air setting.
Turn on ignition
Wait 10 seconds and disconnect IAC connector
Start engine
Adjust Idle screw to minimum idle speed (550rpm)
Turn off engine
Reconnect IAC
Start engine.
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
The leakdown is just charging the rails with fuel and watching the gauge to see how long and how much it drops. Too fast indicates either a bad FPR or stuck injector or bad check valve in the Fuel Pump( which is not going to cause a whole lot of problems)
The idle screw usually has a cap on it on the backside. If the cap is there it means no one ever played with it (in theory) because you have to sorta pry the cap off to get to the screw. If you car idle at~550rpm with the IAC unplugged it is good. BE CAREFUL the plugs are very brittle I broke mine with very little lift on the lock clip. Do not even try it till you thoroughly clean the TB.The IAC motor plug is the square one under the TB in the front just above the WP.
The idle screw usually has a cap on it on the backside. If the cap is there it means no one ever played with it (in theory) because you have to sorta pry the cap off to get to the screw. If you car idle at~550rpm with the IAC unplugged it is good. BE CAREFUL the plugs are very brittle I broke mine with very little lift on the lock clip. Do not even try it till you thoroughly clean the TB.The IAC motor plug is the square one under the TB in the front just above the WP.
Last edited by Redeasysport; Apr 10, 2008 at 04:35 PM.
