99 Continental blowing fuse

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velocityboy

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:( Specifically, fuse 34: AC Clutch cycling pressure switch; AC Clutch relay Sensor; Intake Manifold Runner Control; Backup Lamps; and Console Shift Illumination (although strangely, this last one still works even with the fuse blown).

I can stick a new fuse in and start the car without it blowing; back the car up (with backup lights working), stick it in drive and get about 100 yrds before the thing goes pop. Doesn't matter if the AC is on or off at the time.

I'm disinclined to think it's the backup lights, as they'll stay lit no problem for as long as I care to leave it in reverse, so long as the fuse is good.

I've had a pretty good going over of all the grounds and connections I could find, and everything is nice and tight and corrosion free.

At one point or another I've had all the connections for the AC unit disconnected, and the fuse blows anyway.

I THINK I disconnected the IMRC, and the fuse still blew anyway. ( when I say THINK, it's because I've had a hell of a time finding any consistent info on where the IMRC is on the 99 Continental, or indeed what it looks like).

Before I go any further with this, I'm curious if anybody here has ever had an issue similar to this; or if there's a common problem to the 99 that might be at the heart of this.
 
I should also note that, with a new fuse in, the car throws no codes (whether turned off, or idling).

After fuse is blown, I get the code for the "wide open throttle sensor". I assume this is tied into the AC system; but suspect it's only throwing the code since the sensor (along with the rest of the AC) is disabled by the blown fuse. I certainly haven't gone anywhere near WOT since the car has developed this problem
 
Since last update the fuse now starts blowing as soon as I turn the key to the ON position.

Went through and sanded down, cleaned and tightened every single ground on the car.

Inspected the entirety of the under-hood wiring harness. Short of unwrapping the entire thing, I couldn't find any obvious damage anywhere.

Also cleaned every under-hood connector with electrical cleaner, and added some di-electric grease. Top and bottom side of engine. (If nothing else I'm hoping this might help prevent future problems).

Pulled the relevant relays from the relay box under the hood. Fuse 34 STILL BLOWS. I assume this means the problem lies between the relay box and the ignition switch.

Replaced the ignition switch. Still blows.

I'm running out of options here. Something in the ECM perhaps? Maybe the fuse box itself?:confused:

I'm also annoyed by the fact that the Console Shift Illumination is still apparently working. Seriously, it lights up just fine at night. Makes me question the accuracy of the owners and service manuals (at least as they pertain to this particular car's wiring). Its been in the family since it was only two years old, so I know it hasn't been modded in any way relevant to this prob.
 
Could be a bad ECM or one of the wires connected to it is bending on a bad angle. Can you unplugged ECM and see if the fuse still blows. I have never had these prob so I'm just trying to brainstorm. This part of the forums is a ghost town so don't hold your breath.
 
Yeah, I've sorta noticed that. Still, I plan on posting updates here just in the off chance anybody else ever has a similar problem and is trying to find answers.

I definitely appreciate ANY input. Sometimes the smallest suggestion can lead to new ideas. For instance I really hadn't thought of trying to turn the car on with the ECM unplugged. Innately that just feels like something you shouldn't do; but I suppose it wouldn't hurt since I'm not actually STARTING the engine.

I'll give that a go next time I get the chance.

Thanks.
 
It could possibly work meaning it probably is the ECM that has gone bad. Yea, unfortunately post can go answered for weeks or just go unanswered period. Do to the continental being a fwd car, it just makes it less desirable to own for most people on here. Definitely keep updating on your progress and good luck.
 
Well, personally I prefer RWD cars too. Not just for their sporting pretensions, but they're just generally more mechanically friendly for your DIYer like me/us. Still, this car was a gift so I'm not gonna complain about it; and other than this horrid fuse problem, the thing's just flat out a nice car, no matter which wheels move it.

Update:

Unplugged the ECM. Inspected/cleaned wiring harness and connector. Fuse still blew.

Even though the Shift Illumination is working, it is listed on that fuse, so I disassembled the console, unplugged, cleaned, inspected wiring. Fuse still blew.

Traced and visually inspected the entire wiring harness leading from under dash to inside the trunk/rear lights. No probs detected.

Unbolted the under-dash fuse block and inspected the backside where the wiring runs btwn the firewall and the back of the fuse block. No problems detected.

Disassembled the Power Distribution Box under the hood, inspected/cleaned the wiring leading into the underside of the relays/fuses/diodes. No probs detected.

After reassembling PDB, removed EVERY SINGLE relay/fuse/diode other than the fuses for the ignition switch (maxi fuses 3, 4). There was literally nothing in there except for "Maxi Fuse 4" and the under dash fuse 34 still blows.
Just for the hell of it, also pulled every single fuse from under-dash box, except 34, so literally nothing in the car would get power except PDB Fuse 4, and fuse 34; fuse 34 still blew.

All of this is leading me back to thinking the problem is in the ignition switch (which I've already changed), or somewhere in/around the steering column somewhere. But I really can't find anything wrong going on under there. Of course given all the masses/bundles of wires and connectors, it's not impossible that I've missed something I suppose.

In the back of my mind I'm also still concerned about the IMRC. It's looking like that thing I disconnected that I THOUGHT was the IMRC was actually the EGR Pressure Feedback Sensor. Still have not found any info (not even in the service manual) about where the IMRC is on this car. Can't even visually find anything where the mani meets the heads. I'm wondering if it might actually be UNDERNEATH the body of the manifold, as I can see space in there behind the alternator.
It's my understanding that the ECM controls the IMRC, so if the fuse is still blowing with the ECM unplugged, I assume the IMRC is eliminated as a problem as well, but I'd still like to know what/where it is.

Any new ideas Mr. Doe or anyone else?
 
OK. IMRC update:

Further digging online has hinted that the '99 Cobra and '99 Continental DON'T ACTUALLY HAVE an IMRC, as they have a tumble port head design that eliminates the need for IMR valves. Taken on its own, I'd be hesitant to accept this, however there is also:

A- I have yet to find anything in the service manual referencing the IMRC.

and B- Despite the impression you might get by reading this thread, I am neither blind nor an idiot; and given the amount of time I've spent under the hood as of late, I should have found some hint of that god forsaken thing's existence.

So this morning I performed a practical experiment, and for the first time in the brief period I've owned this car, I goosed the throttle wide open on the drive to work. Now, assuming the car did have an inoperable IMRC (as it should be with fuse 34 blown), I should have noticed some sort of stumble/hesitation/flatness in the engine somewhere above 3k rpms. Instead she pulled strong and smooth all the way through the rev range. Heck, even with the T/C on I got a bit of torque steer at around the 4k mark.

Considering all of the above, and until someone wiser can prove to me otherwise, my new official opinion is that my '99 Continental doesn't have an IMRC. And its listing in the owners manual is just an error (perhaps left over from previous editions).
 
I went and looked it up and YES, the 1999 motor does not have IMRC. The 1999 motor uses an 'airflow spacer' where the 1997 motor has the IMRC assemblies. Very interesting.

The IMRC are a set of butterfly valves to open the second set of intake runners starting at 3000 rpm. These butterflies would impede airflow somewhat, even wide open. Therefore, an open spacer gives one a better airflow to all intake valves all of the time making more power. This is probably the power rating difference between the two motors and may be an upgrade for 1997 motors, power wise not economy wise.

You should be able to do a visual to verify. Look for a set screw below the intake runners on each side. I had found one of my screws had fallen out and I put it back in. I do have a 1997.
 
Hey thanks for the confirmation. Yah, your link essentially quoted the link I had, but the mustang forum had more input in it too, so cool. THAT question is answered.

As for the fuse problem, not much more I can add.

Pulled the front driver fender liner off so I could access the wiring harness (turns out there are three) going from the firewall to the power distribution box and engine compartment. Pulled all three plugs, inspected, cleaned the wiring and re-plugged. Fuse still blows.

So far as I'm concerned there's nothing much left for me to do. State inspection is coming up in a month, and I'm gonna need those back-up lights working in order to pass. So I'm probably gonna have to take it to a proper mechanic. A tall order for a poor jerk like me when one considers the potential to run into some REAL $$$$ for someone to spend the time/labor chasing a problem like this. Either that, or they'll find it super quick and it'll be something small and stupid that I should have found immediately. Not sure which I'd like less- loss of $$ or loss of dignity.

Anyway, however the end comes, I'll post here.
 
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