1999 S70 idle issue

Post by **Grantkat** » 11 Mar 2024, 11:31

Good afternoon all. If have an intermittent issue with my S70 GLT. Occasionally (maybe once every 3-4 weeks, maybe less often than that) I run into an issue. After a longer drive to store, say 30 minutes or so. I turn the car off. Upon return (usually no more than 15-20 minutes later) I start the car and run it again for about the same time. On the return run, usually more toward the end of that 2nd leg, upon letting off the gas the rpms drop below 500. If i stop at a light and dont give it gas it will stall. Also today there was some surging, jumping from low RPMs to higher ones like below 500 to 1100/1200 and then back down. If it is in gear the car to jump as if i gave it gas. If in neutral or park the RPMs just jumped back and forth but also just stalled. If it stalls it starts right back up. Today it had the issue after starting.
I fully anticipate that upon leaving work today, it will start and run fine for the trip home.
At this point this is very intermittent. It happened today, but before today maybe 4-6 plus weeks ago and it is always a single event. If it happens on the way home its fine the next day.
I have read some similar threads but mine isnt consistent so im not sure where to start on the troubleshooting. I will check for codes

Any thoughts?

Post by **Grantkat** » 11 Mar 2024, 16:41

Here is an update. I had 2 CEL codes P0455 and P01238. I had decided to clean the MAF, while I was waiting to borrow the scanner. While I was doing that I saw a vacuum hose disconnected. Its the one down towards the back on the air intake. I reconnected, and started the car but it still acted up. Once I got the scanner, I recorded and then erased the 2 codes. Once the codes were erased, the engine ran fine, actually better than it had. No codes reappeared. However I will take it on a farther test tomorrow.

Post by **MoVolvos** » 11 Mar 2024, 18:22

Grantkat wrote: ↑11 Mar 2024, 16:41 Here is an update. I had 2 CEL codes P0455 and P01238. I had decided to clean the MAF, while I was waiting to borrow the scanner. While I was doing that I saw a vacuum hose disconnected. Its the one down towards the back on the air intake. I reconnected, and started the car but it still acted up. Once I got the scanner, I recorded and then erased the 2 codes. Once the codes were erased, the engine ran fine, actually better than it had. No codes reappeared. However I will take it on a farther test tomorrow.

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If it acts up again clean the ETM.
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Post by **Grantkat** » 11 Mar 2024, 19:13

BKM,

thank you. Once you remove the ETM and clean it, is there a way to test it while its out?

Post by **MoVolvos** » 11 Mar 2024, 19:31

Grantkat wrote: ↑11 Mar 2024, 19:13 BKM,

thank you. Once you remove the ETM and clean it, is there a way to test it while its out?

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Mine being an NA the intake pipe is different. I only needed to remove it to have direct access to the butterfly of the ETM. If possible can you angle a longer straw and just spray some cleaner into it and check to see if it helped?
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Post by **scot850** » 11 Mar 2024, 19:54

Be careful just spraying in the ETM wildly with cleaning products. You could kill it. Clean with clothes and cotton buds soaked in Carb or sensor cleaner.

Neil.

Post by **MoVolvos** » 11 Mar 2024, 20:16

scot850 wrote: ↑11 Mar 2024, 19:54 Be careful just spraying in the ETM wildly with cleaning products. You could kill it. Clean with clothes and cotton buds soaked in Carb or sensor cleaner.

Neil.

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Yes, definitely allow it to dry well also before testing again.
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Post by **Grantkat** » 12 Mar 2024, 06:13

I have a decent commute, about 40 miles to work. Combination of 2 lane (55 mph) and 4 lane (70 MPH), so it gets a good run. Ran like a champ this am with no variation in RPM upon stops etc. I still believe cleaning the ETM is likely called for.
So if i understand the prior posts, I can clean it as it sits installed, by using some sensor soaked long Q tips etc. I have a bunch of wooden shaft Q tips typically used in detailing. would that be appropriate? I also currently have MAF cleaner and electrical contact cleaner. Do i use either of them or get something different?

Post by **scot850** » 12 Mar 2024, 08:42

MAF cleaner will probably work. The issue is to get all the carbon off around the butterfly flap. Long cotton buds should work. Hardest part is getting access to the ETM. On a turbo there is not a lot of access at the front of the engine and you have to access from below the ETM which means you cannot see what you are doing.

Personally I would remove the ETM. My method is to disconnect and remove the top intercooler hose.

Accessing the clamp for the intake charge pipe is a pain. It is hidden under the RHS when viewed from the front of the car. A 7mm socket on a small ratchet will be needed.

Loosen the clamp enough to allow the pipe to rotate back toward the engine.

Disconnect the radiator fan. There are 2 Torx screws at the top and 2 at the bottom on the rear of the fan. Lower ones just need loosening. Remove the uppers and the fan can be lifted out. This will give better access to the ETM. If you need more room, then you can remove the 2 small bolts and 2 Torx screws that hold the fan frame in place and lift it out. I remove the whole fan assembly as one but it helps to have 2 people (I do it myself but 2 will make it easier) as you have to push hard backwards on the charge pipe to give room to remove the fan assembly.

Lastly there are 4 bolts on the bottom of the ETM. They are 10mm head bolts. Remove the rears first as is harder to get them out once the ETM is loose.

The ETM can now be moved to give access without removing the starter motor and it's connector. You can now see it much better to clean both sides of the flap for cleaning. No new gasket should be needed unless you tear it.

Neil.

Post by **MoVolvos** » 12 Mar 2024, 14:54

Grantkat wrote: ↑12 Mar 2024, 06:13 I have a decent commute, about 40 miles to work. Combination of 2 lane (55 mph) and 4 lane (70 MPH), so it gets a good run. Ran like a champ this am with no variation in RPM upon stops etc. I still believe cleaning the ETM is likely called for.
So if i understand the prior posts, I can clean it as it sits installed, by using some sensor soaked long Q tips etc. I have a bunch of wooden shaft Q tips typically used in detailing. would that be appropriate? I also currently have MAF cleaner and electrical contact cleaner. Do i use either of them or get something different?

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Not sure how much room you have to (CIP) clean in place? Regardless, do not leave any lint / fiber from the cotton especially around the butterfly pivot areas. The goal is to clean throttle body walls and the butterfly edge where it seats so it doesn't stick. Should also push open the butterfly to clean the back.
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: S70 ETM.png (2.81 MiB) Viewed 386 times

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