the head

Well after searching and reading (mostly with the SL55s) I think my I/C pump might be going out. I took the car (05 SL65) to the dragstrip and ran a 12.89@105.8 and then after about a 45 minute cool down went back out and ran a 13.04@105.7, making the guy in the paper plate CTS-V's night I'm sure after he practically peeled the paint off the SL blowing past it.

So some info: runs great around town, half or quarter throttle pins you in the seat. At the track I noticed right around the top of second gear and into third gear (about 80mph) you can feel the power noticeably drop. I even put some 104 octane unleaded race fuel in it after the first run to make sure it wasn't detonating. On the trip home after driving along for about 5 minutes it would pull much harder in the 80mph or so range to 100 with ease. It felt like a totally different car from a 40mph punch. No check engine lights and it idles and runs perfectly smooth at partial throttle. I have warranty so can the dealer figure this out without an error code? Engine temps are at about 100C. Thanks for any input.

maxabo

You can be sure of this;
Either the pump is a gonner, or you have air pockets!

What acctually makes one uncertain if there really is a failure or not at times, is that the immediate punch when you throttle it, still feels pretty good..!
But the IAT builds up reeeaally fast, so already in a couple of seconds, you have an SL500...

So get the pump replaced (or the system bled), and you will have a car that PULLS in a veeeery different way..!

And then get it tuned with a little ECU (with the torque curve more horisontal, instead of dropping), and the car just keeeeps pulling ALL THE WAY to red line...

jmf003

Yep, you've described the symptoms of a failing intercooler pump.

You may or may not be successful getting the dealer to replace it before it fails completely. The local dealer here in Ann Arbor is terrific but wouldn't replace mine before it failed completely.

It's not an expensive part and it's also a DIY project if you're inclined to turn a wrench, so you can have it swapped out even if your dealer won't replace it under warranty.

Good luck!

cal1

This is a good point. I had the same experience with the dealer here in Indy. They said my IC pump has greatly reduced flow rates, but is still within spec so would not replace under warranty. I went with a Renntech pump and HE instead.

NEMES1S

Isn't there a temp range for your iat that is normal? my 600 seams super doggy after it gets completely warmed up and I want to borrow a scan tool to check it out. I wish I had one of those infared thermometer things as it would be faster to check the temp on both sides of the HE

the head

I have no issues spinning wrenches, but I'll see if they will take care of it first. If not then the Johnson pump will be on the way. Well, I say that or is the updated replacement pump better/cheaper? Also, how do you tell if the system is full? Is that the radiator cap in the rear center of the engine? I opened it up and I can see some water but it isn't to the top either. Thanks for the feedback!

FLSL55

Your car should be running around 120+ at the end of the 1/4 mile in stock form.

tommytom11

i am having a similar problem with my SL55. can someone please post the recommended johnson pump to upgrade to

maxabo

I haven't done that mod myself, allthough I have already bought 2 pumps, in case of any future malfunction!
I bought CM30, but I've also heard that CM50 is even better, but is a bit bigger, and takes therefor a few mods to make it fit...

tommytom11

thank you

the head

They apparently had to replace 4 sensors. I was told 1 was an airbox pressure sensor and the other 3 were pressure sensors on the engine. Sounds like too many pressure sensors to me... But if it's fixed I'm a happy camper. Getting it back later today.

sound 8

Get your cats checked.
I had a similar problem with my CL65, and then they phoned me and told me
there was a recall, apparently sometimes they de-laminate and cause
an obstruction. Might be worth a try cos my car got noticeably slower
when used hard.

the head

Will do.

Some other details on the invoice were that the "pressure sensor downstream in the intake faulty - SDS test code P20E1 and P2007 pressure sensor downstream faulty replace sensor in intake and 2 sensors for air box"
Also under cause it lists:
541011 short test, perform
2 005-153-50-28 sender unit (thinking these are the air box sensors)
1 005-153-72-28 sender unit (intake)
152177 Knock sensor, rear right cyl head -
ignition system, R&R

So I'm also guessing they replaced a knock sensor.

Anyway, I just wanted to put info in the thread in case it helps anyone else down the road.

cal1

I'm hoping you run into that CTS-V at the track again.

NEMES1S

I just want to check as I am pretty sure I know the answer, but can't you have a dying intercooler pump and not have a CEL?

jmf003

Yep, you are correct: a failing or failed intercooler pump will not trigger a CEL.

NEMES1S

I need to find a polite way to say you are to the service advisor so I don't get hosed on any of the warranty, without the i/c pump, my tab was at 6,000 for warranty claim....I am sooo glad I got that thing.

the head

Well I think I still have issues. I put a scangauge 2 on it and the IATs are at 190 degF at idle and going down the road it would eventually drop to about 168 deg. If I punch it, by the time it hits 3rd gear it jumps to 220-230 and boost falls off. Once I come to a stop it would go back up to 190 or more. It seemed like the more throttle w/o boosting it would drop the temps. So I took the cover off the bottom of the car and still couldn't quite get to the pump like I wanted to so I removed the front bumper cover and tried to feel for any flow by cycling the key and pinching the hose and feeling the pump body. I also started the car but I couldn't feel any flow in the hose then, either. The hoses also never got hot at the pump even after idling for about 5 minutes. I've read that the pump isn't always on when the car is running but I think I should have felt something.

jmf003

Yeah, those temps are way too high. Hope you are able to sort it out without too much more work!

NEMES1S

that is iat and not coolant temps right?

the head

Yep. Coolant temps were in the 200deg range pretty steady - maybe +/-5 degrees.

the head

Pump is bad. I'm switching to a Meziere. They have a very good racing pedigree (drag racing). FYI, you can mount these horizontally. I called two different techs there and got the same answer. There is another thread on the forum that states you cannot, so I thought I would clarify that. You just have to make sure the weep hole is facing down. I'm wiring to be on with key-on power. Also discoverd some inner bumper cover damage on the lower lip that was repaired. That and some of the bumper filler 'frames' seem to be cut to fit around the foglights. I ordered a replacement for the driver's side because it's a major hack job ($111).

the head

Got it all in. Wow, bleeding it takes a while and I can still hear a little gurgling near the heat exchanger outlet (why couldn't they put the exit at a higher point?). It took several fills, and cracking the lines at the pump inlet to bleed air at the bottom. It wouldn't bleed anything out of the top until the pump would actually work. Even with the cap off, it still wouldn't drain to a lower point. Pump does make some noise, but with it idling it's not noticeable. Only with the key on and the engine not running is it noisy. Let the car warm up to about 182 deg and the IAT never got above 135 deg. I still have the bumper cover off so no test drives yet but I know it's working correctly now since before the IAT would creep up almost exactly with the engine coolant temps (190+). My method of getting it in there is not professional quality by any means so forgive me if I don't take pics.

the head

Driving around it gets to about 120-130. At idle it drops below 120. We're at 76 degree ambient now. Punching it a few times, it pulls harder (could be the air temps being about 15 degrees cooler) but it seems to be pulling hard in 3rd - a first in this car. IATs would still get to about 155 degrees in 3rd, still not quite a 1/4 mile. So I think there is still some air in the system. But at least the temps drop pretty quickly when I let off the gas, dropping in the 130 range within about 10 seconds if not quicker. I just really wish the outlet for the stock heat exchanger would be at the top of the core and not the middle. I think that alone pretty much forces you to have the system bled at the dealership or something. Not quite ready to throw an aftermarket cooler on it but it's bugging me. But all in all at least the cooling system is working.

B R

I took my car out for it's first real drive today. I noticed intermittent very weak acceleration under various conditions. I tried changing trans. settings, esp on & off, but still had real weak acceleration on & off. So it sounds like my pump may have a problem too. Couple of questions.

Would it be normal for a pump to go out with only 16,000 miles on it?
Where is the pump located, how much of a DIY project is changing it out?