Ok well car has been running excellent for a while then out of the blue I had a new an weird problem happen. I do nto have any leaks that can be found using a smoke test ... and i have used new gaskets with sealent everytime I remove the supercharger. I have tried a new 82mm TB to see if it was something that happened when I messed with the throttle shaft of the old one with no change so the TB is fine. I did find out that my MAP sensor was not in the best of shape so got the newest one and made a huge improvement to the way the drives and such. I have checked everything that I can think of off top of my head.

So heres the one annoying problem going on ..... it hasnt done this ever and I dont know what I need to do to fix it. Ive had the 82mm TB on for over a month and half with no problems. Just a few days ago this new problem reared its ugly head. I noticed its only freeway driving it happens on so far other than that the car is great around town and part throttle and WOT is amazing cars awesome!! But on the freeway if I get on and cruise in the 70 to 80 mph range for a bit it will have a small hiccup ( sounds like the 82mm hiccup prob ) but from that point on it goes lean as hell and stays that way til I shut the car off. I have verified this 4 times so far .... its always freeway .... always 70 to 80 mph .... goes away when you cycle the key and it goes back to being perfect after Ive turned the car off and then back on.

To me it seems something happens under the above conditions on the freeway and the car for some reason goes into a differing map in the computer, until its cycled off and back on. I only get a p0106 and sometimes a P0456 code the 0106 is almost everytime but ive only got the 456 once and then hasnt come back on. I may replace the purge valve and gas cap for preventative maintence with 133k on it as I have replaced almost everything on the car thus far. I have checked for gas leaks under seat .... nothing its bone dry and the tanks and all were just done in march of this year with all new parts. I just need to get this figured out as its ruining the driving experience for me I do everything I can to keep my car perfect and if this is a tune thing I need to know where to lead my tuner. I have a tune by Tony and so far he doesnt see any reason for this and hes amazing at what he does so I believe him. I heard that there is a few places in germany that know what this problem is and how to fix it if we can figure this out id be willing to pay whoever for the info.

I will offer up a reward for anyone being able to help me get this fixed properly I did so on the last weird problem I had and I was a man of my word but the guy declined the reward but i was willing to pay. So anyone willing to take the time to help I will be willing to pay.

Thanks everyone

 

have you used the smoke machine yet to detect leaks?

 

Yes had the smoke test done by a buddy at his shop twice and he cant find any leak at all so dont know what to do

 

if you can create that condition every time then maybe try a MAP clamp to try and see if problem goes away ,, also maybe remove SC belt and cruise at 80 see if its a boost related issue ? I am guessing its a vacuum related some how -- pinhole, cracked hose connecter -- get a vacuum gauge and test

alsoyou may have bigger issues (this is not specific to our cars -- just general ,, but you get the idea for potential problem diagnostics )Run the engine at idle, low cruise (1800 to 2200 rpm) and high cruise (2500 to 3000 rpm). Note the vacuum readings, and any fluctuations, at each speed. Next, hold engine speed steady at about 2500 rpm for 15 seconds and read the gauge. Now release the throttle and watch the gauge as the speed drops. The vacuum reading should jump as the throttle closes, then drop back to its normal idle reading. If vacuum doesn't increase at least a couple of inches when you release the throttle, you may be looking at worn rings, cylinders or valves.Idle vacuum for most engines is about 18 to 22 in.-Hg, but some may produce only 15 to 17 inches at idle. If vacuum is steady and within these ranges, the engine and fuel and ignition systems are operating normally

keep us posted

 

Check the metal vacuum hose that goes in the back of the left-hand (us driverside) surge tank I had similar issues to you, when the car would drive fine but running in certain low throttle situations, idling or cruising it would randomly go into +25% fuel trim mode and shake like crazy while idling. This slowly would happen more and more often until I took it in. Like I said they found a vacuum leak in the surge tank. If its not that one (the metal hose goes over the US driverside valve cover) you might have one elsewhere as your 'triggers' for the ECU going into spastic mode sound like they might be slightly different from mine. The only conclusion I could come from this was that if the ECU was getting unexpected readings it would crash or go onto a weird map like you said.

 

what MAP sensor if you dont mind me asking? bosch and if so does part # end in 191? i have had the EXACT same issue as you so ears are open to what anyone has for suggestions. good luck

 

Im not quite sure which MAP sensor it was but this was going on with the 15 yr old one an the brand new one but its the latest one from MB for my VIN. But i dont see that as being the cause.

i have checked the metal line many times goin to the back to the supercharger an its fine i have added very good.gates hose between in an the hose goin to the purge with nice fuel injection clamps. I have looked for pin holes not finding anything. I even took off the surge tanks an checked them for uneven mounting surface an they both looked a bit off with a true edge so i took out my sander a made them as true as i could.

It would be nice to see some better gaskets maybe some MLS type that have some thickness an sealing surface to take up inconsistancies in the surfaces. I was thinking of getting gasket material an 2 sets of steel gaskets an making a paper gasket an sandwiching it between the 2 an seeing how that worked.

i will be tracing the purge line an looking at the charcoal canister just for peace of mind i dont smell gas nor am getting the p0456 anymore so i dont know

 

Needswings sells a thick set of gaskets. The hiccup poll thread has the explanation about turbulence around the map sensor. I think it's on the last page. I thought about a metal shield with holes in it to smooth out the pressure fluctuations.

 

Well i did talk to Tony an he said he has seen this a couple times an he is gunna look into the ecu an see what he can find an try an remedy this for the guys that are plagues with it. Cus other than this small annoyance.the car runs amazing!!

 

this issue is the plate opening to long and the ecu is seeing to much air ..

 

so why does it go to that weird new map thats so lean an stay there til its cycled off??

 

After shutting the car on and off it resets it! the stock ecu is very finicky pos it’s not use to seeing that much amount of air coming in.


I would check your tps % idle and in drive and while crusing and off throttle .If the values are not like your stock tb ,that will trigger it too.

 

well what a pita ..... lol .... well i dont know what they were with the stock TB an not ripping it all back out when its finally sealed to fjnd out the 82mm makes a big difference in power so want to keep it just have to figure out this stupid lil thing. Ugh i dont like this ecu already making me want to get that aftermarket ecu from speeddriven or something.

 

welcome to a 1998 ecu with garbage Resolution

 

you'ld think they would changed that at some point haha oh well


Just on the advice of a good friend, who thinks I still have a air leak somewhere even though smoke test showed nothing he said the smoke test doesnt have enough pressure, adn this guy knows his stuff so cant hurt to listen. So I removed the supercharger again this time going through and thoughly cleaning every surface and making it spotless ,,, which I did before but still ,,,, then got all new gaskets and new bypass to charger seal, i used mercedes sealant on the supercharger to intercooler, lubed the seal on the bypass to make sure it went in smooth and without kinking or binding, used sealant on the bypass to intercooler gasket to make sure it was sealed, used a little sealant on the supercharger to snout gasket, and used copper spray on the surge tank and intake manifold gaskets. I have torqued it all to spec and bled the intercooler system and filled with new fluid. I have cleaned everything and so I will also go in and redownload my tune an at the moment I am waiting as I dont know how much time to give the sealant before starting and driving the car.

 

Yeah mate definitely is a small leak it was how I got onto that lameo lean map

 

fully cured 48Hours to be really safe !

 

Well ill only be able to wait 24 then have to wk

 

How crispy are your valve cover breather hoses? Mine look like they fit, but theyre old and don't seal as well as they should. I zip tied them to enhnace the seal around the ports and the problem was resolved.

For reference, I had an 82mm TB that was giving me problems and I fixed it by going to an 80. Later on the problem returned and that was the only variable left so it did the trick.

 

It seems like there is never enough time to do a job completely right. At least with a daily driver.

 

I bought a brand new pcv tube and i will probably ziptie or clamp the hoses to the valvecover even though they seem tight.

an your right ecmexchange never enough time when its your daily driver but i dont see any shortcuts since im letting it sit in a warm garage for just over 24hrs .... i used the stuff for the valve covers an it was nice a dry after 6 an not a leak at all. Just being over cautious this time.

 

So did a complete tear down, cleaning of all parts, bought new gaskets and seals, an even let the sealant dry for just over 24 hrs to make sure it was sealed. Car is running excellent .... cant say any better than before i checked ... rechecked, an even triple checked to find any leak an make sure its sealed. So unless its so small i missed it im 99% sure its sealed extremely well. But havent been on the freeway long enough to see if the prob comes back. But seems to drive as well as before i did it.

 

Keep us posted either way. I'm following this closely since I'll be doing the same thing soon.

Also, pay attention to whether the problem gradually comes back. I have been wondering if it has something to do with the adaptations that the ECU makes.

 

No worries brother Im gunna drive it some more here soon and see what she does, still have a feeling that its just some weird glitch that some of us with 82mm get and some dont. Tony is hard at work tryin to help us out

 

Many don’t reset Adaptions correctly to accept this tb .i know this car like a book and little odd and ends to make it happy