Cadillac Seville / Cadillac Eldorado Forum Discussion, WTF is up with this Eldo? in Past Cadillac Vehicle Discussion; Ok, still haven't found the cause of the misfire in the car and it still keeps throwing the E046 and ...
Ok, still haven't found the cause of the misfire in the car and it still keeps throwing the E046 and the E048 codes. Seems the solenoid the controls the EGR doesn't work, as it doesn't seem to get vacuum to the EGR.
Could the EGR cause the "right to left bank fueling difference" (E046)?
Still have the ground fault which I do believe is directly related to the misfire, but trying to locate it is about to drive me to drink I know the old school method of finding the shorted circuit, but since it's in the ignition system somewhere, pulling the fuse will do me no good.
Well, maybe not the start circuit, but the run circuit anyway...
As a side note, a new code is showing up (B440) which is the "Air Mix Door". Its not switching and it's become quite HOT in the car. Seeing as how it's vacuum activated, could I have a vacuum leak in the mix also?
EGR will not cause fuel trim errors, particularly if you don't think it is working. It could if it was stuck open but that doesn't sound like the case here.
The solenoid blocks vacuum from getting to the valve unless you are in gear driving and even then only under certain conditions.
You cannot do a "static" test without engaging a manual override or performing a special test.
Ok, I got a check list for the E046 Code, which in part says check both O2 sensors (both new), check ECM (also new (yes I replaced the computer about a year ago, but have only driven the car about 3 months in that time frame)), check the injector flow (A-5 B (don't know how)) and an A-5 A possible power imbalance.
What is this? Power imbalance maybe from a direct short? If so, I might be able to chase down the circuit related this issue.
I think I see the chart you are looking at on alldata.
We had some special test tools for injector balance testing. The tester would pulse the injector a certain number of times for a certain duration and you would measure the pressure drop from KOEO pressure and look for a low or excessive drop to identify a bad injector.
Without the tester you are limited in what you can do as far as checking injectors. You can test the resistance of each. Most SFI engines (I am a bit rusty on a 91 Eldo here) I think are around 12-16 ohms.
What you are really looking for is consistency. They should all be close to eachother, anything that varies a large amount is suspect.
From there you can check each to see if it "clicks" when running to make sure they are all working.
A power balance test is basically robbing something required from a cylinder to see if it is working or not such as fuel or spark.
You can do this by using a method I described recently in another thread with old spark plugs and some vacuum hose or you can unplug one injector at a time. You are watching to see something similar to the other tests, you are seeing if one cylinder drops less (or not at all) rpms than the others. This would identify a suspect cylinder for further testing like a compression test or something of that nature.
Wow this chart says block learn values have to vary from one bank to another by 15 counts, that is huge!
If you have a miss like this you need to pin it down to one cylinder and go from there.
Run some of those tests and tell us what you find.
Found the dead cylinder. I'll give you three tries, but I think you'll only need one.
Sorry about the big pic, but I can't resize where it's at.
Anyway, I don't get what could be doing this. The cylinder is getting some spark, as the back side of the electrode is actually clean, but it doesn't seem to be enough to ignite the fuel. Broken injector maybe, drowning the cylinder? E046 only tells of fueling imbalance, not too rich or lean...
Do you have access to a compression tester? You need to do a compression test on those cylinders while you have all the plugs out.
Disable the ignition, block the throttle wide open and crank the engine for about 8-10 seconds per cylinder and read the gage, write down each number and make sure they are all close to the same amount.
If those all agree then we can go back and look at the fuel system but you will need a pressure gage and some other tools.
I tested cylinder 5 4xs with the first test being the best one. The second test yielded me 180 psi and the 3rd, and 4th was 175 with no drawdown. I did not test any of the other cylinders more than twice.
I don't know if my inability to shut the fuel system off had anything to do with why I was losing psi on 5, but I couldn't find the fuse for the fuel pump just the injectors. Although in hindsight, pulling the injector fuses should have shut them off, not distributing fuel in the cylinder at all.
If I remember correctly, there can be a 10% difference between cylinders; putting me right where I need to be. So I think it puts me back at my fuel system possibly being the issue. Since I didn't have an injector tester, I switched the #5 injector with #7 to see if the #7 cylinder would wind up fouling out the plug like #5 did. I'll have to drive it a few days to see...
I'll test the injectors with an ohm meter, but what is the definitive resistance I need to look for? If you don't know for sure, I do have another mechanic friend I could possibly ask.
The fuel pressure gauge I have is quite old and has seen better days, which brings it's accuracy in question. I may need to buy another one.
Now, I don't know if this makes a difference (if there is a fuel pressure switch or something), but I've replaced the fuel pump, screen, filter, lines out of the tank (rubber), and wiring harness. Dropping the tank was a pain, but it needed to be done.
By the time I gt this car back in order it'll be new and I'll want to burn it, but don't tell the wife; it's her car...
Usually SFI injectors are in the 12-16 ohm range but with the testers we have available to us I rarely use resistance to identify a problem.
It isn't really the best way to check them but it can be a good starting point if you don't have other means.
As before what you are looking for is consistency. If #5 is way higher or way lower than the others then it is a good indication that it could be bad.
You have to trust your pressure gage or you are wasting time, true.
The best way to check them is with a pressure drop test but that can be hard to do.
I remember years ago there was an output test you could do with the on board controls but I can't remember what year it was I did it on.
I am not so sure a 91 would have it. If you get desperate I can dig out the book but I can't promise I'd have time for that.
I just want to chime in here, I recently had similar symptoms with my '90 Eldo. Misfire that felt like one cylinder and the E046. I ended up tracking mine down to a intake gasket leaking vacuum above the affected cylinder... I would consider this after you eliminate a fuel problem since you already took care of spark and compression.
True, I don't see many of those but a leaking gasket could cause that.
A can of brake or carb cleaner is good for sniffing out things like that.
Get it running and spray it near suspected leaks and see if there is a big rpm change.
Taht's the recommended method for most, but difficult on a 4.X since the head/manifold mating surfaces are under the valve covers. I recommend exhausting all other options before considering this as it will take some dis-assembly to confirm diagnosis.
Ok, my mechanic friend (not that I wouldn't consider you one with the time you've spent ewill3rd, but he's not a Caddy specialist, he works on BMW, Mercedes, and the like) told me that the ohm range for the Eldo fuel injectors was from 15.8 to 16.6 ohms.
drewsdeville, your words give me hope and at the same time despair . It would definitely make sense though, because at wide open throttle this car doesn't give the impression of stall or a dead cylinder (in fact it just about melts the tires), but at idle to a gentle takeoff, this car shudders, and fumbles (but doesn't die). I've considered a vacuum leak before, spraying EVERYTHING I could find, but to no avail
Now the other thing this car does while rolling (say 65 or so) is it "shudders" like a misloaded washing machine, but it happens in cycles. I'm wondering now if this isn't because of the (possible) vacuum leak throwing the rotation of the engine off I don't think it's suspension as I have already replaced the struts, done a front end alignment, and put new tires all the way around.