The latest on the problem when hot
Thread Starter
Melting Slicks
Joined: Nov 2005
Posts: 3,323
Likes: 142
From: Green Valley Arizona
The latest on the problem when hot
Connected an O'scope to the wires between PCM and OptiSpark. From the beginning the low resolution pulses shows a varying pulse width on every other pulse (4 per camshaft resolution), the other pulse has a constant pulse width. This does not seem normal??????
EDIT: This is normal. Found Figure 39 which shows the pulses have a different width to identify cylinder number. So appears that OptiSpark is good.
Okay, finally got the engine problem to show-up...while monitored the low and high resolution pulses and the +12V from PCM to OptiSpark. The engine finally stalled. The DTCs were as follows: 16, 42, 36, 48, 33, 51. While getting the codes, the tach needle was bouncing around, rad fans were coming on and off, some relay was clicking away.....lots of odd things going on.
I think the 51 is the real error. What you guys say????
EDIT: This is normal. Found Figure 39 which shows the pulses have a different width to identify cylinder number. So appears that OptiSpark is good.
Okay, finally got the engine problem to show-up...while monitored the low and high resolution pulses and the +12V from PCM to OptiSpark. The engine finally stalled. The DTCs were as follows: 16, 42, 36, 48, 33, 51. While getting the codes, the tach needle was bouncing around, rad fans were coming on and off, some relay was clicking away.....lots of odd things going on.
I think the 51 is the real error. What you guys say????
Last edited by LannyL81; Mar 24, 2009 at 07:05 PM.
Thread Starter
Melting Slicks
Joined: Nov 2005
Posts: 3,323
Likes: 142
From: Green Valley Arizona
Has anyone else put an 'Oscope on the pulses from the OptiSpark? I am curious about the varying pulse width on the low resolution pulses...the FSM figures that I have seen do not show this pulse varying. Makes me think that the OptiSpark might not be good afterall.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
"I am curious about the varying pulse width on the low resolution pulses"
Slow it way down, time wise, is the wave nice and square and not dirty looking...with just the voltage variation?
At what point in the wiring did you tie the probe in?
I'd say you have some loose wires or wires grounding wires somewhere. Check the ground points for the engine, PCM/ECM all the way to the battery when the engine is hot.
Slow it way down, time wise, is the wave nice and square and not dirty looking...with just the voltage variation?
At what point in the wiring did you tie the probe in?
I'd say you have some loose wires or wires grounding wires somewhere. Check the ground points for the engine, PCM/ECM all the way to the battery when the engine is hot.
Thread Starter
Melting Slicks
Joined: Nov 2005
Posts: 3,323
Likes: 142
From: Green Valley Arizona
Must have mis-read something....it is the pulse width varying; the voltage level is solid.
I did adjust the time base and trigger to view a single low resolution pluse with the engine at idle. The edges are good, but the width is varying.
I opened the insulation just past the connector on top of the intake.
I have checked and wiggled and tightened ground connections...nothing makes a difference. It appears to be the ECM and I will be getting a different one this Friday as I am at a loss as to what else it could be.
EDIT: See initial post for edit.
I did adjust the time base and trigger to view a single low resolution pluse with the engine at idle. The edges are good, but the width is varying.
I opened the insulation just past the connector on top of the intake.
I have checked and wiggled and tightened ground connections...nothing makes a difference. It appears to be the ECM and I will be getting a different one this Friday as I am at a loss as to what else it could be.
EDIT: See initial post for edit.
Last edited by LannyL81; Mar 24, 2009 at 07:05 PM.
Instructor
Joined: Jan 2008
Posts: 118
Likes: 0
From: Austin Texas
For some reason i can't get my car to do this again, not unless it is really hot. I start it up and move it around, and idle it around my apartment. It fires up immediately and runs perfect, all up until the problem starts, then same symptoms as yours 0.o
Thread Starter
Melting Slicks
Joined: Nov 2005
Posts: 3,323
Likes: 142
From: Green Valley Arizona
Is yours reving-up several times and then finally stall? This is what mine does. Have replaced the OptiSpark unit twice...no change. Have had the ECM checked and possibly I have a different one...not sure. Will be putting in a different one is about two weeks from now as I still think it is the ECM. If not, then I am going to have a fire sale.
Instructor
Joined: Jan 2008
Posts: 118
Likes: 0
From: Austin Texas
Yes it surges hard several times then stalls, but never quite the same, whatever it is cuts spark though, not fuel. It stalls like it was never on, but only when hot (10-15 minute drive at 220). This is insane, and it drives perfectly fine otherwise...
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Thread Starter
Melting Slicks
Joined: Nov 2005
Posts: 3,323
Likes: 142
From: Green Valley Arizona
Yep....about the same. I have always shown a good fuel pressure when the problem occurs. Although have not put a noid light on the fuel injectors or a timing light on a plug wire when the problem occurs.
Either way to me, this points to the ECM. Will know in two weeks when the replacement ECM is returned from being flashed.
Either way to me, this points to the ECM. Will know in two weeks when the replacement ECM is returned from being flashed.
Thread Starter
Melting Slicks
Joined: Nov 2005
Posts: 3,323
Likes: 142
From: Green Valley Arizona