"limp" Mode!?

[Asinine]

In the past few days (maybe a week now) i've had a serious complex with my car (94 850 Turbo). I had a problem with the tube that goes from the throttle body to the idle motor popping out leaving a serious gap in my air system. It happened about 3 times but i have finally siliconed the mo fo into place.

Now, the last time it popped out (full boost put too much pressure for the improperly secured tube) i was doing like 110 and had to drive for about 2km (taking it real easy) to get off the hiway and re-insert it.

I was real easy on the car on the way home (no heavy foot to prevent and boost and keep the tube in place). I got home permanently fixed it, and since then it feels like i've lost some serious power.

My stock boost gauge (i know - don't trust it) used to fill right up, now only 1/2 into the shaded area. And more reliably, i used to get kicked back into my seat when i'd punch it no matter at what speed - now, not so much.

I posted this problem on swededspeed and something that came up was that the car seemed to be in "limp mode" - that the ECU retarded it's performance. I would have thought if that was the case the "check engine" light would come on.

Does this "limp mode" make sense to anyone - is my missing boost as simple as having my computer reset? I hope i hope i hope!

Thanks

[merlin390]

Have you tried disconnecting the battery and let the car sit a while. Then reattach everything and let the computers relearn everything? This will take a couple of drive cycles

[Asinine]

I have not tried that, but will consider it.

My good friend is a tech. at the local Volvo dealer so i want him to take a look at it, but when i first got it, he told me a code to reset the little diagnostic computer - will doing that code 'reset' everything for me, or will i need to take it in?

Oh my radio presets!! :(

[theunderlord]

patrick, be sure and fill out your signature, so everyone knows what Kinda car you have, year, model, mods... etc..

[theunderlord]

Oh my radio presets!!

←

be sure you havet the radio code! if you have a OE Head Unit!

[VolvoT5]

In the past few days (maybe a week now) i've had a serious complex with my car (94 850 Turbo).  I had a problem with the tube that goes from the throttle body to the idle motor popping out leaving a serious gap in my air system.  It happened about 3 times but i have finally siliconed the mo fo into place.

Now, the last time it popped out (full boost put too much pressure for the improperly secured tube) i was doing like 110 and had to drive for about 2km (taking it real easy) to get off the hiway and re-insert it.

I was real easy on the car on the way home (no heavy foot to prevent and boost and keep the tube in place).  I got home permanently fixed it, and since then it feels like i've lost some serious power.

My stock boost gauge (i know - don't trust it) used to fill right up, now only 1/2 into the shaded area.  And more reliably, i used to get kicked back into my seat when i'd punch it no matter at what speed - now, not so much.

I posted this problem on swededspeed and something that came up was that the car seemed to be in "limp mode" - that the ECU retarded it's performance.  I would have thought if that was the case the "check engine" light would come on.

Does this "limp mode" make sense to anyone - is my missing boost as simple as having my computer reset?  I hope i hope i hope!

Thanks

←

I don't think you're in limp home mode. Limp home mode literally means limp home, it feels like someones swapped the engine for a 1.0L 50hp unit.

1/2 to 2/3 on the stock boost guage is normal unless you're chipped / overboosting deliberately. I've never seen a stock boost to the full area, and I've got three T5's and been in tonnes of others.

Sounds (to me) like you've got a air leak somewhere, the 854 T5 was not boosting as high as it usually was and it turned to be a small leak.

[JDELUNA]

Well maybe "Limp Home Mode" is not the correct term, how about "Safety Boost". When I had a Nissan 300ZXTT if the ecu ever detected something that would be bad for the engine like engine knock, bad gas, etc. it would go into Safety Boost, this is where it would limit the max boost pressure from a stock max of 9.5pounds to 3 pounds, saving the engine. Maybe our Volvo's have something like this ??? God Bless. :)

[prasamin]

disconnect your battery for 10 minutes....reset your codes first! replace the PNP, and check the connector for your TPS.

[merlin390]

start checking vacuum lines and elbows, and might want to upgrade to the samco hose kit

[Asinine]

Wow thanks fellas - i posted this problem on swedespeed and it took forever to get a single helpful response.

I'm not the most mechanically grounded person, but i will pass these pointers on to my friend next time i see him.

However, just for my own knowledge - how would i detect leaks in the system?

Limp mode or not - the car doesn't have as much get up and go as it should/did a week ago - and that's just not cool in my books!

[merlin390]

remove the throttle body cover and there is a vacuum tree down there. find an empty port and hook a vacuum guage to it you are looking for 18-20" of vac. I do not have a turbo but I would pull each individual Intercooler pipe off clean it good and reattach everything. remove the bottom intercooler hose and you can probably flush it with large amounts of brake cleaner or engine degreaser. If you use degreaser then flush the intercooler with lots of water and let it dry. It might surprise you at the crap that will come out. Pull each vac line off and try to blow through it. If you cant then you need to replace that line. elbows. there are several the one on the end of the intake closest to the power steering pump and under the top radiator hose is bad about cracking. Also check your flame trap make sure its not clogged. how many miles are on the car and have you done stage zero yet? Do a search on stage zero its been talked A LOT!! there is a vacuum diagram on the hood of the car I think. Stage zero is very important. Check your diag box for codes, record them if any and clear them. in the maint. section of VS, Rich (bay13) has done a great job of listing the codes for us all.

that should be a start. you can use a band clamp to hold the hoses on the IAC motor if you need to. I would also take it off the car and clean it really well too.

[icefalls]

I'm pretty sure that the battery disconnect is the long way round to reset the adaptives. Just run the car and disconnect the electrical connector to MAF, which will set a check engine light. Resetting this will then reset everything in the ECU. Not sure on newer models, but this is the case on '94s.

[S70 R]

i've been in safe\limp mode before, on a road trip and my check engin light came on and it was a miss firre, i could only bost 6 psi instead of 15 psi! its just hte cars way of saving itself!

[Asinine]

I'm hoping that it's just a mode problem, when the tube from my idle motor to the throttle body (or vice versa) popped out at 120k and i had to keep the car going for about a KM to get somehwere safe to have a look that would been a open gap in the air system, and in fact would have let a small amount of unfiltered air into the system.

However, now that it's fixed i would have hoped the the car would have noticed that the problem has been rectified and be back to it's merry tire turning way.

Also, the check engine light never came on!?

Oh well, i've definitly got enough ammunition here to tackle a number of aspects of the problem!

[Asinine]

I was saddened to find today that it isn't an ECU problem, but i do in fact have a tear in a tube.

It's right under the branch off of the tube running into the throttle body - the branch heads to the idle motor.

So, i'll upgrade to the Samco silicone set to put a positive spin on the situation, but in the time it takes to arrive i've duct taped the hell out of the area - won't do anything but maybe give a bit of piece of mind.