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Ko Ko
Regular


Registered:
May 2003
A symptoms needs a diagnosis Mon, 24 October 2005 12:05 Go to next message
hey there,
I have a 4ac engine in my sprinter and it has been running well for the last 4 years or so. Anyways recently when i rev the car past 2500rpm or a bit higher the car startes the shutter and I feel a huge loss in power. This occurs when accelerating conservatively and when its pushed a bit harder. Any sugestions on what it could be? Possible Carby from what others have said

Thanks for the help
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allencr
Regular


Location:
tallahassee FL usOFa
Registered:
May 2002
Re: A symptoms needs a diagnosis Mon, 24 October 2005 14:24 Go to previous messageGo to next message
what's the compression?
what do the spark plugs look like & how old & how many miles on them, and the plug wires?
was anything done BEFORE this started happening?
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Ko Ko
Regular


Registered:
May 2003
Re: A symptoms needs a diagnosis Mon, 24 October 2005 21:44 Go to previous messageGo to next message
No nothing was done before this. It just started to occur lightly to the point when u can really notice the power loss and the shuttering of the car/engine above 2500 rpm.

Im not sure what the compression is but Ill check it out at a mech today
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spirokeet
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Location:
London
Registered:
July 2004
Re: A symptoms needs a diagnosis Mon, 24 October 2005 21:53 Go to previous messageGo to next message
Could be coil too?
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Ko Ko
Regular


Registered:
May 2003
Re: A symptoms needs a diagnosis Mon, 24 October 2005 22:00 Go to previous messageGo to next message
Whats a coil sorry?
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spirokeet
Regular


Location:
London
Registered:
July 2004
Re: A symptoms needs a diagnosis Mon, 24 October 2005 22:13 Go to previous messageGo to next message
Sorry, ignition coil:
http://autorepair.about.com/cs/generalinfo/l/bldef _340.htm
maybe check distributor also

[Updated on: Mon, 24 October 2005 22:18]

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SilverGhost
Forums Junkie


Location:
Sydney
Registered:
September 2004
Re: A symptoms needs a diagnosis Tue, 25 October 2005 08:42 Go to previous messageGo to next message
general rule of thumb with diagnosis is:
First check Electrics i.e. plugs, coil, leads, cap, rotor button, dizzy
Then fuel i.e. carbie, fuel pump (if applicable), filter, leaks in the lines
Then mechanical i.e. compression, leak down, sticking valves, unusual noises, blown head gasket etc.

the reason for this is most that is the order of most likely faults to least likely...

In addition, the basics an engine needs to run is:
Air
fuel
compression
spark

the above order will let you determine which of these is not doing its job.... Smile
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Ko Ko
Regular


Registered:
May 2003
Re: A symptoms needs a diagnosis Tue, 01 November 2005 12:09 Go to previous messageGo to next message
Hey,
The engine just recieved an major service and everything was fine . Although once i filled up with a full tank of optimax last tuesday my engine started to rumble (like a wrx) on acceleration and it was unsmooth with alot of jerking. On idle, the engine is still sound rough and the engine is idling like it is going to stall but isn;t if that make sense.

Could my engine need a carby tune and service or is my engine just had its time.
Thanks
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tricky
Regular


Location:
Canberra
Registered:
July 2005
Re: A symptoms needs a diagnosis Wed, 02 November 2005 02:54 Go to previous messageGo to next message
the rumbling says to me that it would be missing. The most likely cause is ignition, so give your HT leads, dizzy cap, plugs and coil a check. Corrosion is bad.

Another possibility is the compression could be gooorne on one of the cylinders. While it is not the best guide in the world, the oil consumption is a good guide. Are you blowing lots of white smoke?

Less likely (if it is inconsistent) is the carb.

As said above, chase the electrics first.
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Ko Ko
Regular


Registered:
May 2003
Re: A symptoms needs a diagnosis Wed, 02 November 2005 04:31 Go to previous messageGo to next message
HT leads, dizzy cap, plugs and coil a check was replaced during the service so I doubt that is the problem. Possibly compression has gone down in one of the cycliners since power levels are dramatically losted

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Steve M
Forums Junkie


Location:
Adelaide
Registered:
June 2003
Re: A symptoms needs a diagnosis Wed, 02 November 2005 05:03 Go to previous messageGo to next message
If the symptoms started after you filled up with petrol, you might have got a shitty batch of petrol.
Shell are good for that.

We've had this before.
It clogs up your fuel filter.
The more fuel the car requires, the more shit it will runas the lines are partially clogged.
Hence the rev problem.

Check to see if your idle mixture screw is grotty and your fuel filter.

Get rid of the fuel that is in your tank and swap it for something BP, they are usually good.
Change your fuel filter before you start the engine on the new fuel.
You will most likely have to change the filter again soon after, as the crud that was in the hoses will now flow into your new filter.

Another option might be your ignition timing, if it is over advanced it can run like shit.
Check to see that the vacuum advance is working by sucking on the tube and seeing if anything moves inside your dizzy (take the cap off first). Things should move.

These things should be checked in addition to the electrical stuff that the other guys said.

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love ke70
Regular


Location:
brisbane
Registered:
September 2005
Re: A symptoms needs a diagnosis Wed, 02 November 2005 06:08 Go to previous messageGo to next message
also check to make sure ur jets are flowin proper in the carb
i took mine off, and when it got put back on she idled like a ho, and died on revs
i advanced the timing to get it to a mate who is a mechanic, and on the way she almost died up a hill so i planted it and dropped to first, hit the redline and she was fine. machanic said it was likely a bit of shit in the jet
its worth a look as the filter mite have missed somethin
~andrew~
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mic*
Regular


Location:
Brisbane
Registered:
July 2005
Re: A symptoms needs a diagnosis Wed, 02 November 2005 06:54 Go to previous messageGo to next message
You posted on Tues 1.11 that last tuesday 25.10 was when you filled up and car and it had been serviced before this already yeah?

You started this thread on the 24th so your car must have had this problem BEFORE the fuel went in???

It also means you must have had a major service just before your problem??? What date was service and how long did you have normal driving for before this issue?

There are usually few coincidences i find. Rather than think "HT leads, dizzy cap, plugs and coil a check was replaced during the service so I doubt that is the problem" i would be thinkin the opposite, they were all touched recently so which one could be the problem?

From what you have described it sounds like you could have a problem that is localised to one cylinder, or else its the cleanliness of your fuel system.

To eliminate a cylinder specific problem, with the engine running, pull one HT lead off, note the difference at idle (hopefully it wont stall) and at a small amount of revs compared with before you pulled it off. Repeat this for each cylinder. If one causes less of a drop than the others, then it wasnt running properly with the lead on - bad lead, plug, connection, compression...

It can take a keen ear but its an easy test which will have you looking in the right place whether it ends up being a cylinder or your fuel.

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jeffro RA28
Regular


Location:
Tamworth
Registered:
August 2004
Re: A symptoms needs a diagnosis Wed, 02 November 2005 07:24 Go to previous messageGo to next message
i found a chewing gum wraper in my fuel tank the other day!

Blow backwards through ur fuel lines into the tank and then see if the car runs any different for a moment.
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Matt-AE86
Forums Junkie


I supported Toymods

Location:
Perth
Registered:
October 2003
 
Re: A symptoms needs a diagnosis Wed, 02 November 2005 08:05 Go to previous messageGo to next message
No Message Body

[Updated on: Wed, 02 November 2005 08:12]

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Matt-AE86
Forums Junkie


I supported Toymods

Location:
Perth
Registered:
October 2003
 
Re: A symptoms needs a diagnosis Wed, 02 November 2005 08:10 Go to previous messageGo to next message
When I had my 4AC something like this happened but on the primary jet in the carbi. This meant I had to rev its head off for it to drive smoothly so the second jet would function as well. A combination of fuel filter, changed a few times cause of a shit batch of petrol from some shit place, distributor points, leads and carbi.

1) Replace fuel filter

2) Replace Leads / Spark plugs

3) Get the points changed in your Distributor and have the timing readjusted.

By now you should be experiencing a smoother ride by now, if not..

4) Carbi Cleaner. Clean out the Carbi with Throttle Body / Carbi Cleaner. You will have to take the Black filter box of to do this. Also reeving the engine then holding your hand over the inlet of the carbi can help, and holding the accelerator down just after you put your hand over, use a rag but don't let it get sucked in, for safety. By doing this it floods the engine, and just before it dies take your hand of. This can remove crap and free sticky valves/jets up etc.

After I changed all these the 4ac was ready for some action, and it ran particularly well !

I hope this can help you with your problems.
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drifthax
Newcomer


Location:
Seated
Registered:
November 2005
Re: A symptoms needs a diagnosis Wed, 02 November 2005 10:27 Go to previous messageGo to next message
Have you actually pulled the plugs out to check if their ok?
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Ko Ko
Regular


Registered:
May 2003
Re: A symptoms needs a diagnosis Fri, 04 November 2005 13:48 Go to previous messageGo to next message
Hey guys,
I fixed my car today. The problem was the HT leads which were replaced this morning. Car runs real well and smooth now.
Thanks to those who helped!

[Updated on: Sat, 05 November 2005 00:06]

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love ke70
Regular


Location:
brisbane
Registered:
September 2005
Re: A symptoms needs a diagnosis Sat, 05 November 2005 01:44 Go to previous message
Rolling Eyes
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