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Hey! I had a really long thread on here about my 1989 E-150's lean issue. If anyones interested here's a LINK
Basically shortly after my last post in that thread the cold start stalling issue went away, seemingly on its own so I've kind of just been waiting for it to return. So far it hasn't been stalling on me but today I took it in to get smogged here in California and it failed! The technician told me it just barely failed due to unburnt fuel levels in the exhaust. He suggested I get a tune up done, specifically spark plugs, cap and rotor. His thinking being that the spark might not be igniting as much fuel as it should.
I'm going to go ahead and put new plugs, wires, cap and rotor on since I am due for it in 1000 miles or so but I'm curious if anyone has any other advice. My van has often had a lean trouble code so I'm wondering if the computer is compensating by dumping more fuel into the mix causing it to fail smog? Should I be going deeper than just a tune up here or is that a good place to start?
Yes do the plugs and pay close attention to the color of them, they should all be a consistent tan color but if one is black,sooty, or even wet while the others are pale or white that suggests the injector for that cylinder is stuck open.
It looks like you have done a lot to search out this problem. Can you read data? The computer will use the O2 sensor to determine if the engine is running rich or lean. The O2 sensor won't affect your starting issue but is something I haven't seen that you have looked into. With all the other vacuum leak chasing you have done, I didn't see that you have verified base engine condition. Maybe you have an intake leak? Something very small. Generally, if the ignition system is an issue you would run rich, and set a code as such, with the computer pulling fuel and causing other potential emissions issues at a smog station.
What do I need to read data? All I have is one of those little OBD1 code readers and a multimeter.
I actually just ordered a motorcraft o2 sensor to throw on just in case since its something I've wondered about ever since I first got the lean code (code 41 which my book states is the sensor voltage low/out of range). I used a multimeter to test the values coming from the current o2 sensor while idling and while giving it some gas and the numbers I got indicated it was in fact detecting a lean mixture. I can't remember the numbers exactly now but it gave me the impression the sensor was definitely doing something.
Intake leak is possible. At one point I replaced the intake manifold gasket when I had the plenum removed to clean the injectors. I replaced other gaskets while I was at it (throttle body, egr, IAC). Is there somewhere else I should be looking for intake leaks? It is around the service interval where I'm supposed to re-tighten to intake manifold bolts to spec so I'll go ahead and do that.
So, you're thinking it's not very likely an ignition system issue because the code would be showing a rich condition?
I'm not sure if there are any consumer friendly, easily available tools to read data for OBD1 vehicles. I have an old Snap On MT2500, but I used to be a mechanic and they were readily available as they started to age out. The ability to read data is pretty important, I think, because you can tell more about what is going on. The O2 sensor could be fine, data will tell you. You can also, as you have indicated, use a meter to read the voltages from the sensor. The oxygen sensor in particular can be doing "something," but be slow to react (because it is worn) and set codes. Regardless, it will not be functioning on a cold start so it is not the only problem and may not be a problem at all. I think you should look elsewhere, first, but keep it in mind.
You could use something like a propane gas canister or starting fluid to check for seal imperfections. Just remember that these are flammable. The best option is to use a smoke tester, but I don't know how available these are for consumer purposes. A smoke tester will allow you to test so many things that could contribute to this, and do it visually with the engine off. No flames! Anything that bolts to the intake manifold, hoses to the manifold, and the manifold itself, is worth checking. Sounds like you have already done good work on the vacuum system.
If you are do for a tuneup, it is worth doing. I personally would wait to find the other issues OR do it and confirm you still have an issue. How many times can you run through the smog test?
So I got distracted by other projects while I waited for the parts to arrive but finally got around to working on the van again today. I replaced a faulty check valve on the secondary air system that I discovered a while back. Not sure if its related but since it has to do with sending air to the cat I figured it couldn't hurt to make sure its working properly. I also replaced the o2 sensor, air filter, cap, rotor and will be replacing the spark plugs and wires tomorrow but first I'll be doing a compression test while I have the plugs all out. Here's a look at the plugs that were in there
#2 gap looks a little wonky because I had to knock it loose from my socket. They have about 10,000 miles on them. They don't look too bad, seems like they're running lean if anything which is the code I've been getting but the smog test said I had high HC so I'm curious if its running lean why is there too much unburnt fuel coming from the tail pipe? Can anyone think of anything else I should look into before I take it in to get tested again?
I have heard changing the oil can help if it is getting close to time to change it. I'll let someone else comment on the plugs except that they do all look about the same and the oil on the end of the threads on #8, that is from oil around the plug hole?
I had a 1990 Town Car with a 5.0 an AOD. I went to get the emissions done once and it just barely failed. The guy told me to take the car and drive it up the interstate and back for about 10 to 15 miles and come straight back to be tested. I did and it passes.. Now the test site was only a mile of the interstate.. I am not sure what that did for the emissions but it passed.
I tried to look up the plug number but wasn't sure... I use copper core plugs. I have heard those are best for our older 5.0's
Yep I've heard the same thing about getting the engine hot before you get the test done. Catalytic converters work best when they're hot so driving on the highway for a while before getting the test done is a smart move. The place I get it tested is a half hour drive away on the highway so that shouldn't really be my problem.
I'm not sure about the oil on #8 actually. I'll check on it tomorrow in the daylight to see why that one looks a little dark.
Engine oil from the PCV dumps into the rear of the upper intake and cylinder #8 gets most of that. Installing a catch can and re-routing it to the vacuum tree would reduce the injested oil quite a bit, that may be enough to get a pass.
Im thinking that perhaps the oil on the threads of #8 may just be where you took the plug out and there was some oil that had seeped in around the plug due to a valve cover leak.. I replaced my valve cover gaskets with the fel-pro perma-dry that are rubber molded around a metal frame and stops to keep you from tightening the cover bolts too far down. I found a couple of bolts that had worked loose..
Hopefully its that simple..
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