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#1
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1993 300E 2.8 Saga
Here's what's been going on with this car in case anyone is following.
Bought the car running badly at idle, the usual idle surging but otherwise running great at loads. I knew nothing about the HFM-SFI system at the time. I mistakenly thought this would be an easy repair..Boy, was I wrong. Step 1 ![]() Step 2 ![]() Step 3 ![]() Step 4 ![]() Step 5 ![]() Step 6 ![]() That's where I'm at so-far with this step child of mercedes(300e 2.8HFM)..I'm still wondering about the maf, and also the throttle servo, since this is drive by wire, and now that it's out of limp mode it's in play. Last edited by my6.3; 07-08-2010 at 08:36 PM. |
#2
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If the throttle is responding, it's not in limp home. Limp home means the mechanical rod is all that's opening the throttle plate. You'd know if you were limphome because you'd be pressing on the pedal like king kong and getting 15mph out of it.
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Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold) |
#3
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OVP?
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1989 300ce 129k ( facelifted front,updated tail lights, lowered suspension,bilstein sports, lorinser front spoiler, MOMO steering wheel, remus exhaust,stainless steel brake lines). (Gone) 1997 s320 154k (what a ride). Sold with 179k miles. Replaced with Hyundai Equus 1994 e320 Cabriolet 108k ![]() 1972 280se 4.5 153k Owned for 12 yrs, sorry I sold it [/SIGPIC] |
#4
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Try replacing it....instead of fixing it
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1989 300ce 129k ( facelifted front,updated tail lights, lowered suspension,bilstein sports, lorinser front spoiler, MOMO steering wheel, remus exhaust,stainless steel brake lines). (Gone) 1997 s320 154k (what a ride). Sold with 179k miles. Replaced with Hyundai Equus 1994 e320 Cabriolet 108k ![]() 1972 280se 4.5 153k Owned for 12 yrs, sorry I sold it [/SIGPIC] |
#5
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Any codes?
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#6
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Have you checked codes for the throttle assembly? Pin 14, I think (search is your friend here).
I have the same car, and it had the same symptoms you originally posted. Turned out to be a dead MAF and aged O2 sensor. I had pin 8 code 4, and another - forget the exact code - that implicated the o2 sensor. A fresh MAF fixed code 4. Driveability was perfect, idle was improved but still a bit lumpy. A fresh O2 sensor delivered a perfect, seamless idle. What does "falls on it's face" mean - does it not respond to the throttle at all? Or is it slow, or what? |
#7
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Update: Thanks for all your suggestions. I Apologize for the delay, It's been hot here so I haven't been in the shop much and this is a spare car, but I rewired the throttle servo and that took care of the hesitation in the car. It passed emissions now too on first try. Here are the results: HC-0.38 out of 1.00,CO-2.29 out of 12.00,NOX-0.57 out of 2.50. The car runs pretty good now too, just one problem left..the idle speed sometimes drops low enough at a stop sign to kill the engine. I haven't had time to look into that.
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