Time to play "Which sensor's broken?"!!!

[SVX10]

I couldn't find a mark, but I did find a picture of the pulley, and the key is opposite of the lettering, which would make the lettering TDC, correct? It would make sense to do it that way.

Should have the sensors by Sat. Still gonna check and ensure that the spark plugs are the right ones. Hopefully they are...that'd be nice It's still the front runner since the OBD1 reader pulled that as a code.

[SVX10]

Dug back into everything tonight. Started by checking plugs. Turns out that they're an NGK R, but they are a different model number. By visual inspection, they have a larger gap as well. So, I replaced all the plugs with the OE plugs.

While I was investigating the plugs, I found this:




That's just 1 coil, but both rear coils looked like that, and the DS front boot is starting to look like that. I would imagine that both of those coils are grounding out, at least intermittently.

So, I'm going to inject some epoxy or insulating material where the wires are exposed on the coils and try everything again. I'll see how it runs with just the plugs and coils addressed, then I'll continue with checking the sensors.

[SoCal LS-L]

Yike! This is making me want to pull my coils again, I didnt inspect the wires that closely when I did my plugs.

Whats the number on your old plugs?

[SVX10]

I'll look when I get home. They were definitely different, though. The gap was larger, and the tip/electrode construction were different. Even if it was inconsequential, I feel better knowing I have the exact right part in there

[SVX10]

the old spark plugs were NGK R BKR6ES11

Even with replaced plugs, repaired coil wiring, and Tom's cam and crank sensors, it's still doing the same things as before. Warms up great but won't stay running once warm. It seems to start misifiring when it gets warm. I hear more and more "puff, puff, puff" sequences from the exhaust right before it cuts everything. grrr

On the bright side, can change plugs and cam/crank sensors in like 20 min now.

[SoCal LS-L]

Thats ok man, you have narrowed the problem down immensely now.

I was about to condemn the IAC/BAC valve but I read through the entire thread again and you stated that it will still stall while being revved up to 2K, thats a different story.

To sum it up, its a misfire type problem, which only happens when warmed up, and happens both at idle and revving the engine, which manifested itself only after sitting for a few months correct?

You have done the CTS, crank and cam sensors, checked the timing, did the plugs and fixed the coils, switched MAF's, and fixed a fusible link problem with the alternator, + whatever I forgot in the last 3 min yes?

This is a tough one.... besides what YT suggested, I can only suggest trying running the car on battery power, with the alternator disconnected completely from the battery, to eliminate your high 14.4 voltage from being a culprit.... then,

You may have to get nitty gritty and probe each sensor wire @ the ECU while the engine is running or at least on and compare all of the values to what the service manual suggests. This is a PITA especially with a stalling issue, but I have no further ideas besides combing through all of the under dash and hood wiring to make sure it wasn't gnawed on, especially since the problem came directly after the car sat for months.

Keep us posted!

[SVX10]

Originally Posted by SoCal LS-L

To sum it up, its a misfire type problem, which only happens when warmed up, and happens both at idle and revving the engine, which manifested itself only after sitting for a few months correct?

You have done the CTS, crank and cam sensors, checked the timing, did the plugs and fixed the coils, switched MAF's, and fixed a fusible link problem with the alternator, + whatever I forgot in the last 3 min yes?

And when I unplug the CTS as it begins to sputter/die, the vehicle will recover and run indefinitely

[sowise]

I know in older carburated cars when the idle would slowly decrease (you could adjust the carb to keep it running which we can't do) the PCV valve or the vacuum hoses going to the valve becoming clogged or plugged could cause this. I really dislike emissions stuff so I tend to replace as much as I can when I have to get in there. Also you say it runs rough when it does run with the CTS unplugged. Just curious but is this 6 month old gas still in the tank you are running it off of? May have a high water content in your fuel too, have you checked your fuel filter? Just giving you more options. Oh and stuck open EGR valve will function like a vacuum leak and can cause stalling engines too. Good luck

[SVX10]

Can you explain the EGR further? I'm pretty sure I have an issue with either pipe #2 or #3 in the image below...it's cracked right where it goes into the exhaust manifold...could even be broken clear off by now. Would the EGR issue cause misfiring also? At idle and while revving?



The old fuel should be through the system now, and the fuel filter has been replaced.

[SoCal LS-L]

The EGR system recirculates exhaust gasses into the intake under partial throttle to allow the inert exhaust to take up space in the cylinders, therefore allowing the engine to be ran with a smaller air/fuel charge, increasing efficiency and decreasing emissions.

An opening in the EGR system can absolutely stall you out and cause lots of problems, its basically a huge vacuum leak if your pipe is broken. I would fix this first before trying any other diag on the car..

[SVX10]

Wow...it'd be awesome if that were it, but it would suck, too, because I've known about that all along

[SoCal LS-L]

Originally Posted by SVX10

Wow...it'd be awesome if that were it, but it would suck, too, because I've known about that all along

Better late than never

[sowise]

Sorry if this ends up looking screwy I'm on my blackberry.

That was a good explanation! I would just add that it uses the exhaust gas to help keep the combustion temperature controlled by using the inert exhaust. This improves the efficiency of the engine. If the valve is blocked I believe it can cause higher combustion chamber
Chamber temps which is not as good for our efficiency and the engine. If it is stuck open (w/o) leaks then you will have too low of combustion chamber temps and your engine will run like poo and will require more fuel and air I.e. More throttle/rpm's. With a leaking line or tube it will definetly cause problems
With cool air going into the combustion chamber and could stall you out. Definitely make sure your emissions set up is clean, clear, and connected. If in doubt change it out or atleast remove and try cleaning the valve. Should be able to find how to on .

[SVX10]

Well, tube 2 from the diagram above was most definitely cleanly severed and not going into the EGR valve. the exhaust gas was just venting into the engine bay, and the opening on the EGR valve was probably 3/4 open to the atmosphere (there was maybe 1/4 overlap between the tube and the hole still.

So, I've got the JB weld curing right now so I can at least re-install it and see if that fixes my issues. Here's to hoping...

[SVX10]

Originally Posted by SoCal LS-L

Better late than never

hahaha