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+--- Thread: rough acceleration (/showthread.php?tid=4428)
rough acceleration - HyperUniverse - 03-18-2013
Hi,
Two weeks ago I have bought a Mercedes 300TD OM606, and the seller has said it has fitted a "Fuel pump is from om603 fully rebuilt by herlevi finland with 7mm pump elements to deliver 120-140cc".
The car has got few problems, and I am trying to understand where are they coming from, so I can rectify them.
1. there is a lot of white smoke when I first start it in the morning.
2. idle RPM = 880 when engine temp = 90 degrees (measured by a digital laser meter) (how do I adjust it down to 650?)
3. ....and the most annoying problem is that the car is jerkying.
I can not use the full power of this car (supposedly 275hp), because as soon as I put my foot down on the accelerator pedal, the car starts jerkying. If I keep my foot down on it, the jerkying is becoming more and more powerful, and it feels like the car is going to break into pieces..... but in the end it disappears (at very high revs of the engine).
Surely something is wrong.
To successfully accelerate (without getting the jerkying), I have to take it easy (as easy as I would have only 50hp in my engine).
If I keep it steady at the same (any) speed, is running smooth.
But as soon as I accelerate a bit is jerkying again.
Even when the road has a very little incline going up.
I was wondering if this problem is from the modified injection pump?
there is no black smoke, even the white smoke goes away 30 seconds after starting.
the engine seems powerful and responsive (only the jerkying doesn't let me use the power),
(the seller has said the pump has been fitted to 15degrees, and the engine & gearbox are reconditioned too.)
Can anybody give me an idea of what's going on?
Thank you,
RE: rough acceleration - larsalan - 03-18-2013
jerking? Like starving for fuel?
RE: rough acceleration - Simpler=Better - 03-18-2013
Sounds like fuel or the transmission slipping. Is it an automatic transmission?
RE: rough acceleration - HyperUniverse - 03-18-2013
manual transmission with a brand new sintec clutch that doesn't allow any slipping (or so I've heard)
RE: rough acceleration - Simpler=Better - 03-18-2013
Shoot. Timing or fuel would be my guesses, unless there's a major ploblem
RE: rough acceleration - willbhere4u - 03-18-2013
White smoke on cold start usually is a bad glow plug! or possibly low cylinder compression!
RE: rough acceleration - Druk - 03-18-2013
(03-18-2013, 10:27 AM)HyperUniverse 3. ....and the most annoying problem is that the car is jerkying.
I can not use the full power of this car (supposedly 275hp), because as soon as I put my foot down on the accelerator pedal, the car starts jerkying. If I keep my foot down on it, the jerkying is becoming more and more powerful, and it feels like the car is going to break into pieces..... but in the end it disappears (at very high revs of the engine).
Surely something is wrong.
To successfully accelerate (without getting the jerkying), I have to take it easy (as easy as I would have only 50hp in my engine).
If I keep it steady at the same (any) speed, is running smooth.
But as soon as I accelerate a bit is jerkying again.
Even when the road has a very little incline going up.
I was wondering if this problem is from the modified injection pump?
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I'd be very interested in which manual gearbox you have and what type of propellor shaft? Also if you know if you have a dual-mass flywheel or not?
In the W124 Haynes workshop manual 3253 chapter 4D-2 mention is made of an ARA 'anti-jerk' system fitted to the rear of the rack on the IP. The quoted purpose of this is to 'eliminate the tendency for the vehicle to jerk during part load acceleration and deceleration on certain manual transmission models'.
I have a 606TD/manual car which is a few weeks away from it's first run. I've previously read about the ARA in Haynes but put it to the back of my mind. Your plight has awakened my fears that this may happen to my own car.
I would be interested to hear from the Norwegian and Finnish guys who have the 606 tuned engine fitted to a manual box as to whether they have experience of their cars 'jerking' and what they do about it?
.
RE: rough acceleration - HyperUniverse - 03-19-2013
Druk, that is the problem I have.
I've never heard of "an ARA 'anti-jerk' system".
I will surely explore this route, as it describes exactly my problem.
Transmission is getrag dogleg from 190e cosworth
Flywheel is lightweight solid type from 190e cosworth (can anybody give me an idea of what that is?)
Clutch is special made sinter clutch by Techniclutch
I don't know about the propshaft....is there a number on it I can read?
You have to tell me more about that ARA 'anti-jerk' system, Druk.
I have just bought a Haynes manual, but until it arrives I'd like more info please.
I couldn't understand where it should be equipped this system?
Druk, I see you're in Scotland.
On Easter holiday we'll be going to Lake District for a short brake.
If you're close enough, you can come and see my car and see the problem; I don't think I'll be fixing it by then.
Well I hope I will fix it, but now my van died and I want to ressurect it.
So I concentrate more on the van.
Regards.
RE: rough acceleration - willbhere4u - 03-19-2013
The problem could be with the light weight flywheel! These Engines like some weight behind them I know a 240d flywheel on a 300d will cause this problem on the 5cylinder diesel because it is to light!
The fly wheel I got for my 300sdl weighs nearly 50 pounds with clutch disc and pressure plate
RE: rough acceleration - HyperUniverse - 03-19-2013
(03-19-2013, 09:26 AM)willbhere4u The problem could be with the light weight flywheel! These Engines like some weight behind them I know a 240d flywheel on a 300d will cause this problem on the 5cylinder diesel because it is to light!
The fly wheel I got for my 300sdl weighs nearly 50 pounds with clutch disc and pressure plate
I was inclined to think that the problem comes from the clutch assembly.
Anyway I want to replace the sintec clutch, as I want to pull a caravan, and this sintec one doesn't allow any slip.
When I'll be pulling the caravan I will need some slip, especially when starting driving uphill from still.
How hard is to replace the clutch?
I've done it on other cars, but not on a Mercedes.
Do I need to remove the engine?
Or can it be done just removing the gearbox from underneath?
Which clutch shall I go for?
dual mass / or single mass?
anybody got a suggestion?
Anyway the clutch is a must replacement...even if it fixes the problem or not.
Regards.
RE: rough acceleration - willbhere4u - 03-19-2013
If your transmission is set up for a single mass you will have to stick with that!
Dual mass flywheels have the pilot bearing in the flywheel so the transmission has a shorter input shaft
I would get a heaver single mass flywheel from a w124 300e 5spd It's got a 9" disc and then make an m5 pressure plate fit that to get some clamping force on the disc. Then it should work like stock and handle the power all day long
RE: rough acceleration - HyperUniverse - 03-21-2013
someone mentioned that I could fit a Sprinter flywheel with its clutch kit in my arrangement.
but he only mentioned an older than '98 Sprinter.
he didn't specify any engine size or anything else.
Can anybody comment on this?
thanks
RE: rough acceleration - Mark_M - 03-22-2013
My pump has the ARA fitted to it but I haven't seen any others with it. Its basically a similar unit to the unit used to keep the idle steady and fits bellow the idle one. I have no idea what it acts against though and haven't a clue how to control it. The Idle one would be reasonably simple to control because its fairly slow changes but the jerking or nailing I think they call it in the US can be quit rapid so working out the PWM could be a task. There is next to no information on the net about it, the only reason I found anything was via the part number. I wondered what it was so googled the number and found maybe 2 or 3 results that said what it was.
This engine has obviously had the fuel and turbo changed so maybe something isn't set-up quite right. You see mention of the jerking but its usually on larger power engines and usually when they come onto boost hard due to a lot of lag.
What turbo do you have and what's your boost set at?
RE: rough acceleration - Druk - 03-22-2013
Mark.
According to Haynes it takes it's signal from the same ECU as the idle-up. Inputs are crankshaft sensor and engine temp.
.