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IMRC won't close, P1518, HELP!

S

sjones

Be Gentle I'm New Here
Joined
Dec 27, 2007
Messages
4
I have a 1999 CSVT that keeps tripping a CEL with a P1518 code. I replaced the IMRC with a new unit including the cable. The LIM linkage is intact and working.

When I clear the CEL and start the car, you can manually operate the throttle and the IMRC will open the secondaries the first few times and then stick open. Once the CEL is set, it will go full open as soon as you start the car. If I clear the CEL and start the car, the IMRC will do the same thing all over again (work for the first few blips of the throttle and then stick open). The IMRC cable checks out with correct voltages and no shorts to ground or other conductors. I've reset the PCM after clearing the CEL and P1518 code by disconnecting the battery. The PCM obviously sees the feedback signal from the IMRC when the secondaries are full open or it would not be setting the P1518 code. The secondaries close when the car is turned off or you disconnect the connector to the IMRC.

I've looked through the archives and all posts and I've seen this problem but none of the solutions (bad IMRC, cable, etc) seem to apply. Anyone have any idea what the problem might be?
 
It appears as though I may be having the same problem, I have found very little advice on how to solve this and I'm not about to buy a new IMRC (this post supports not buying one as well), I did however find a PDF about troubleshooting the IMRC at cougarv6.de

http://www.cougarv6.de/imrc_transistor_check_en.pdf

See if any of that checks out, I came up negative on all the tests so I'm not too sure which direction to go in now... :(
 
The secondaries are so built up with carbon the butterflies are sticking! Refer to the UIM/LIM rebuild.
 
^ and that would apply to them opening upon start up from a closed position?

I think everyone is quick to state the obvious.

OP i had the same issue as well, I believe the previous owner of my car was struggling with the issue before he took out the CEL bulb and sold it to me. :nonono: Twas not too happy with that.

I have tried IMRC's all with the same results. After I covered everything I could on my own, i went to a Ford Tech.

First he responded " Carbon build up". However after seeing how it was responding, he took that back. We did a live read on it and the PCM was not recognizing the open IMRC upon start-up. He was quite baffled.

He said the onlything that could be done is a pin point test, and with labor being so high I decided to past. I personally blame a faulty PCM, however I know they tend to be pretty reliable.

Never figured out what the cause was/is. Please keep us updated.
 
todras said:
The secondaries are so built up with carbon the butterflies are sticking! Refer to the UIM/LIM rebuild.
Click to expand...

As I mentioned in my original post, unplugging the IRMC or turning off the ignition causes the IMRC to close the secondaries. If it were sticking due to carbon, this would not be the case. The car only has 90K miles and I cleaned the LIM @ 68K miles (thoroughly in a parts washer, along with the throttle body assembly).
 
sjones said:
As I mentioned in my original post, unplugging the IRMC or turning off the ignition causes the IMRC to close the secondaries. If it were sticking due to carbon, this would not be the case. The car only has 90K miles and I cleaned the LIM @ 68K miles (thoroughly in a parts washer, along with the throttle body assembly).
Click to expand...

Not actually so.

If the resistance (when closing) is high (from carbon build up causing the ports to be smaller than normal) then the IMRC could trigger a "stuck open" code to PREVENT the motor from attempting to close all the time, burning it out.

As stated, refer to the UIM/LIM how-to.
 
Ray said:
Not actually so.

If the resistance (when closing) is high (from carbon build up causing the ports to be smaller than normal) then the IMRC could trigger a "stuck open" code to PREVENT the motor from attempting to close all the time, burning it out.

As stated, refer to the UIM/LIM how-to.
Click to expand...

Where do I find the UIM/LIM how-to? I looked but cannot locate it.
 
Well, you own a Duratec (v6) and you are wanting to do some Maintenance on it, but you're probably wondering where you should read first on this site, so you'll probably want to read the UIM/LIM rebuild how-to with pics.


Follow the bolded words.. :D :D It's like a scavenger hunt!
 
Ray said:
Not actually so.

If the resistance (when closing) is high (from carbon build up causing the ports to be smaller than normal) then the IMRC could trigger a "stuck open" code to PREVENT the motor from attempting to close all the time, burning it out.

As stated, refer to the UIM/LIM how-to.
Click to expand...

You don't need the motor powered to close the secondaries. If you unplug the IMRC with the secondaries open, they close instantly because the spring is what closes the secondaries.
 
After poking through the wire harness recall installation documents I noticed that the 2.5l V6 still has an IMRC solenoid, I went and confirmed this at my local ford dealer, 95-00 has this solenoid, right under the DPFE. You should see a wire harness connector right under the DPFE, this should be the solenoid. My only hunch now is that the solenoid failing make be what's causing the IMRC to stay open.

I haven't gotten around to getting my hands on the solenoid as it's hard to get to, I will how ever get to when I start my overhaul of the SVT, I'll let ya know how it goes.
 
Of all the engine swaps I've done I've never seen this that I recall. If you can take a pic that would be great.
 
Are you sure you're talking about 95-2000? and not just 95 (vacuum operated secondaries)??
 
I still need to try and attack my P1518 CEL some more.

So far I've done (on going for 3 years)......

3 IMRC replacments, PCM swap, complete UIM/LIM rebuild, 3L swap :laugh:, and just recently replaced the injector harness. None of these made any changes to my problem.

Like the OP said, you can start the car and rev it a few times and watch it open and close no problem. After no more than 10 secs, touching the throttle or not, it opens and remains open until the car is shut off.
 
Thats right, you were having similar problems that you posted in one of the threads I started a while ago.

I just dont understand.
 
Ray said:
Are you sure you're talking about 95-2000? and not just 95 (vacuum operated secondaries)??
Click to expand...

The recall documents where vague, listed 2.5l 95-00, so I went into a dealer and looked at the fiche and it showed a different solenoid then what you would see on the 95. The solenoid in the fiche was quiet small and mounted under the DPFE not directly to the IM secondary boss on the LIM.

Any how, I finally ripped the UIM off my SVT last night and was able to get a clear look below the DPFE and you can see the mount for the solenoid but it's not there, so it turns out it's not there on the SVT (not sure about other 2.5l models).

At this point I'm leaning more towards a fault in the harness or a sensor...

Thanks Ford for having such detailed fiches. :@
 
My secondaries are stuck open as well but I'm not getting the CEL. Once I have time to pull off the UIM I should be able to determine if the cable itself is broken or if I can just do the transistor fix. I'll be watching this thread to see what you guys come up with.
 
The typical CEL P1518 is because the IMRC cable broke. Simple check is to remove the "actual" IMRC plate cover and check it.

The next reason is your LIM is full of "gunk" and is literally stuck. All too common on the oil ingesting 2.5L engine. :blackeye:

Another reason is you broke the actual mechanical linkage or linkage bushing. Harder to check. You can see it from the side (with intake piping removed) but best bet is to pull off the UIM.

It seems to have been mentioned but only 96+ (OBD-II) cars have the electric IMRC versus the 95's vacuum operated unit.

The PCM only see's the IMRC open when the cam trips the switch inside the actual IMRC. It will trip the P1518 code only when the engine is started with this switch closed. (i.e. tripped) With this is mind the switch "HAS" to be tripped to get the P1518 code.
 
My P1518 problem and solution

My P1518 problem and solution

I had a similar problem, got the 1518 code and was dealing with the rough cold running startups for a couple of days.

Toronto was about 8 degrees today (47 far) so I had some time to take a look at her. Not sure what thread I read this on, but when I start the car, the IMRC engages right away. When I unplug the IMRC I can see the secondaries close. When I plug it back in, the secondaries are pulled wide open and stay there.

I tested this when the car was showing a p1518, and remembering what RAY said about the PCM keeping the secondaries open when the code is active. So, I cleared the code and went through the plug unplug sequence. Same effect, it instantly opens the secondaries while the IMRC is connected.

I happened to have another IMRC around, when I plugged it in it engaged and would have opened the secondaries if it was fully connected. So, I thought I had a complicated problem in a ground, solder connection or TPS or another sensor related to the IMRC.

Thinking about RAY's thoughts one more time, I cleared the code and tried the new(used) IMRC on the car once the P1518 code was cleared.

it works so far. The new one is plugged in, code is cleared, and when I pull open the TB I can see the secondaries open as expected.

I've got a spare transistor for the IMRC, I'll be replacing it so when the one in the car blows I can swap the other one in.

One more thing, I didn't have the correct materials but I did have some 1/4" thick rubber that I cut up and used to keep the IMRC off the engine. We'll see if this helps.

Thanks for all the posts, this is the best.

Pete
 
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