P1516 code keeps coming back...

[98cobrawilsonville]

So I have this new to me 98 Cobra with 60,100 miles. Obviously the car sat quite a bit given the low miles. I have a code reader and all I find is this due to imrcs not opening properly. This is what I have done so far:

- Cleaned iac valve, it sure had carbon in there, car runs smoother for sure
- Cleaned mass air flow sensor
- Replaced pcv valve
- Replaced a hose that looked too cracked around the intake
- Brand new K&N filter
- Lubricated the rear actuators and cables for both imrcs behind the engine

I have put sea foam both in the engine and the fuel (quite a bit in the fuel). The car pulls like a beast both under 3K rpms and over 3500. My understanding is imrcs open after 3500 Rpms, again the car pulls like crazy as everything works as it should. Yesterday I drove the car for 2 hours hard after lubricating the cables and no light and I thought well must be good now. Well today I drove it 20 mins and boom light came back, checked code and same code. What do you suggest? Should I just take it apart and clean the imrcs? I was also thinking of doing the old sea foam trick, have the car suck a bottle of sea foam from the intake, turn off the car, let it sit for 20 to 30 minutes and then start up and idle it for 5 mins and then drive it... Looking for feedback and advice.

Thank you guys!

 

[projectslideway]

More than likely the IMRCs are gummed up. You can:

1. Remove the intake manifold, mechanically inspect the IMRCs and clean them. If that doesn't fix it replace the controller.
2. Delete them by gutting them and epoxying the holes since 98's are plastic, 96-97 are aluminum and can be welded. I used MMR IMRC delete plates. Ideally you will also need a tune if you go this route.

 

[rzimmerl]

I went thru the same issue with my 48k mile 98 Cobra last fall. I ended up doing IMRC delete as the control box failed and they are obsolete. Accutach can repair the control modules for $100 but I opted to delete and go with a tune so I don't have the issue again. If you do decide to clean the IMRC plates or the delete also look at cleaning the intake manifold and the valves as they will be pretty gummed up, adding PCV catch can will help. I have a post that showed how gummed up my intake valves were before and after cleaning.

 

[98 svt]

Yup, open it up and delete those mofos.
Or you can reach back behind the intake, find the 2 cables, and zip tie them open for a temporary repair. Either way you'll still have the CEL til you get a tune.

 

[hotcobra03]

Go thru pinpoint test HU for air intake system.
I can't share this section so you need to go in Ford manual

Chilton Library

Open scroll down to resource link.

Select yr make model hit select

New page click Repair

Menu opens.

Click Diagnostics

Next page click On board diagnostic II A

Than click pinpoint test.

 

[98cobrawilsonville]

Thank you guys, question, been really thinking about the delete plus tune my only concern is the loss everyone talks about for bottom end, with the tune will I still feel a loss of bottom end? The car has the original hearing for now.

Thanks!

 

[98cobrawilsonville]

Go thru pinpoint test HU for air intake system.
I can't share this section so you need to go in Ford manual

Chilton Library

Open scroll down to resource link.

Select yr make model hit select

New page click Repair

Menu opens.

Click Diagnostics

Next page click On board diagnostic II A

Than click pinpoint test.

So what pinpoint test would it be? I don’t see one for imrc

 

[98cobrawilsonville]

So what pinpoint test would it be? I don’t see one for imrc

Nevermind found it thank you

 

[rzimmerl]

I had a buddy custom tune mine, and I feel no noticeable loss of bottom end. Though it does need a full dyno tune I feel as there is a still a slight blurp at the point the IMRC's were to open. Not sure what would get with mail order tune.

 

[98cobrawilsonville]

Manual says: “P1516 or P1517 indicate the IMRC plates were open or closed longer than expected.” My car pulls hard as they are working okay but I bet they are gummed up and either no opening fully or maybe stuck open all together - will have to open up. I take it the sea foam system nobody recommends? Thx!

 

[98cobrawilsonville]

Last, how would I know if my imrc control module is bad?

 

[98 svt]

Reach back by the firewall, and locate the 2 IMRC cables, at the throttle body bring the RPMs up past 3500 and you should feel them move.

 

[Tillerman77]

I had a similar problem with my 97 a few years ago. I didn't want to do a delete, so I opted to do a thorough cleaning of the plates, tested the actuator box while it was apart and added a catch can after reassembly. It has been working fine for the past 3 years.
As information, the actuator boxes are often blamed for the problem, but in most instances, are functionally fine. The plates being gummed up is what is most likely causing your code. Sticky plates can still work, but as someone already mentioned, will open or shut slower than the ECU is programmed to accept.
Also, it is unlikely that you will get any improvement of this issue by running Seafoam through the intake. It really requires disassembly to actually clean what is gummed up.

 

[98cobrawilsonville]

Yeah I’m thinking I will just get this cleaning done. I ordered new gaskets to do the job right and will replace plugs at the same time. I got NGK V-Power 3951 TR55 I assume they are good?

 

[Tillerman77]

Yeah I’m thinking I will just get this cleaning done. I ordered new gaskets to do the job right and will replace plugs at the same time. I got NGK V-Power 3951 TR55 I assume they are good?

No experience with the plugs, as I used Motorcraft plugs and wires (OEM), which work fine on a stock motor. Stay away from the FRPP wires, as they seem to have poor quality control.

 

[hotcobra03]

Trouble Code: P1516 (4.6L V8 VIN X Std)
Intake Manifold Runner Control Input Error (Bank 1)
Print this code data
Number of Trips to Set Code: 2

• MIL Details

Trouble Code Conditions:
Key on or engine running; and the PCM detected the IMRC Monitor signal for Bank 1 was outside of its expected calibrated range during the Continuous self test.

Possible Causes:

• IMRC mechanical fault - the linkage may be bound or seized
  
  
• Inspect for binding or improper routing. The cable core wire at the IMRC/IMSC housing attachment must have slack and lever must contact close plate stop screw
  

 

[hotcobra03]

its on my 03 but still

during work I had my intake off

my runners were baked black oil

runner and valve stems

I tried cleaning them
it laughed at every thing

I had use stp fuel treatment 1 bottle every tank for a couple of tanks real fast

I was back in again for recheck of work and this is how it looked

I was floored

 

[rzimmerl]

When I did the IMRC delete I was able to clean the ports and valve stems with carb clean, a tube brush, and using shop vac to suck out the dirty fluid. Took about 8 cans and couple hours but they came out spiffy clean. Heres my post:

https://www.svtperformance.com/threads/imrc-delete-and-what-else-to-do.1190845/#post-16502623

 

[Tillerman77]

No experience with the plugs, as I used Motorcraft plugs and wires (OEM), which work fine on a stock motor. Stay away from the FRPP wires, as they seem to have poor quality control.

If you do the cleaning of the plates, make sure to bench test/inspect the IMRC actuator while it is out. As mentioned above, Accutach can rebuild them if needed. Accutach = @mwolson on this site.

 

[98cobrawilsonville]

I was going to clean them this weekend but then my gf wanted to get out of town so next weekend it is...

On another note, do you guys recommend Screaming Demon coil packs? Should I even bother with the car having 60K? Should I replace plug wires?