Re: [MBZ] 1991 turbo questions
Lisa Strang wrote: I am hoping one of you can shed some light on a problem I am having with my 124 1991 300 2.5 turbo diesel. The turbo works but not all the time- so it is just a dog when it decides not to work.(especially when trying to pass the tourist that is seeing the sights and you are late to work.) I have tried the following with no success: blocked off the EGR valve, by passed boost controls(emissions), no results from trying this. I did notice I have many little holes in the rear muffler which I plan on replacing this week. I know the car runs life a gas engine when the catalytic converter is a mess so maybe this will help. I am hoping someone else has had a similar problem and has another answer. Any help graciously accepted. Thanks Lisa Any attempt to defeat the EGR system disables the turbo! Turbo failures in OM502,96 engines are VERY rare. Most failures characterized as turbo failures are actually wastegate, pressure line or EGR failures. Get the EGR system working as it should and the turbo will work as long as the pressure line from the intake manifold to the ALDA is not occluded. Marshall -- Marshall Booth Ph.D. Ass't Prof. (ret.) Univ of Pittsburgh School of Medicine [EMAIL PROTECTED]
Re: [MBZ] 1991 turbo questions
Howdy, I believe the ALDA lines also can become clogged with buildup - actually IIRC, this is common on older engines using dino oil and seeing lots of around town driving. My 91 300D 2.5 seemed to do the same as you describe when it was new to me (last year) but many miles of my wife driving to work (110 mi RT) ay speeds of 55-75 have gotten rid of the problem One other thought - if the AT is not downshifting properly when you are accelerating hard expecting the turbo to be called on, the car will bog dramatically if lower gears are not selected. I also have full synthetic in the AT and engine. Not sure what controls the shift points on these cars - likely a combination of kick-down switch, accelerator position and vacuum. Larry T (67 MGB, 74 911, 78 240D, 91 300D) www.youroil.net for Oil Analysis and Weber Parts Test Results http://members.rennlist.com/oil PORSCHE POSTERS! youroil.net Weber Carb Info http://members.rennlist.com/webercarbs Porsche Road Test http://members.rennlist.com/roadtest/ . - Original Message - From: "Peter Frederick" <[EMAIL PROTECTED]> To: "Mercedes Discussion List" Sent: Monday, March 05, 2007 8:06 PM Subject: Re: [MBZ] 1991 turbo questions Lots of possibilites: Stuck waste gate, so the turbo isn't generating pressure sometimes Leaking pressure line to ALDA and overpressure valve, or leaking overpressure valve Leaking transmission control amplifier so the boost signal doesn't get to the ALDA Dead turbo bearings. This can be checked by removing the intake hose to the turbo ENGINE OFF and spinning the turbo wheel by hand. Any stiff spots, back to front play, or roughness, it's time for a turbo cartridge. Peter ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] 1991 turbo questions
Lisa, unless you have a Mity vac, you might not be able to test them, but I have found the vacuum transducers that control Alda etc. can develop a hole and leak pressure, which can give "mixed" performance. Excuse the question, but is there a clean pre and main fuel filter on there? John Peterson 1991 300D 2.5 81k Miles Kingston RI Kaleb C. Striplin wrote: on the 2.5 turbo, you cant bypass any of the emmissions stuff or it will go in the limp mode and you will have no power. All the vacuum lines, etc also have to be leak free or it will reduce power quite a bit. Lisa Strang wrote: I am hoping one of you can shed some light on a problem I am having with my 124 1991 300 2.5 turbo diesel. The turbo works but not all the time- so it is just a dog when it decides not to work.(especially when trying to pass the tourist that is seeing the sights and you are late to work.) I have tried the following with no success: blocked off the EGR valve, by passed boost controls(emissions), no results from trying this. I did notice I have many little holes in the rear muffler which I plan on replacing this week. I know the car runs life a gas engine when the catalytic converter is a mess so maybe this will help. I am hoping someone else has had a similar problem and has another answer. Any help graciously accepted. Thanks Lisa ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] 1991 turbo questions
Lots of possibilites: Stuck waste gate, so the turbo isn't generating pressure sometimes Leaking pressure line to ALDA and overpressure valve, or leaking overpressure valve Leaking transmission control amplifier so the boost signal doesn't get to the ALDA Dead turbo bearings. This can be checked by removing the intake hose to the turbo ENGINE OFF and spinning the turbo wheel by hand. Any stiff spots, back to front play, or roughness, it's time for a turbo cartridge. Peter
Re: [MBZ] 1991 turbo questions
on the 2.5 turbo, you cant bypass any of the emmissions stuff or it will go in the limp mode and you will have no power. All the vacuum lines, etc also have to be leak free or it will reduce power quite a bit. Lisa Strang wrote: I am hoping one of you can shed some light on a problem I am having with my 124 1991 300 2.5 turbo diesel. The turbo works but not all the time- so it is just a dog when it decides not to work.(especially when trying to pass the tourist that is seeing the sights and you are late to work.) I have tried the following with no success: blocked off the EGR valve, by passed boost controls(emissions), no results from trying this. I did notice I have many little holes in the rear muffler which I plan on replacing this week. I know the car runs life a gas engine when the catalytic converter is a mess so maybe this will help. I am hoping someone else has had a similar problem and has another answer. Any help graciously accepted. Thanks Lisa ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com -- Kaleb C. Striplin/Claremore, OK (2x) 91 300D 2.5 Turbo, 90 420SEL, 89 560SEL, 87 300SDL, 85 380SE 5.0 Euro, 84 190D 2.2, 81 240D, 76 240D, 76 300D, 72 250C, 69 250 http://www.okiebenz.com