john_p_b
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| posted on 6/8/07 at 05:26 PM |
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holding back/missfire under load over 4000rpm
as title really,
thought it was a fuel pressure problem so fitted electric pump and set pressure accordingly. can't see it's because of running weak either
as at idle it starts choking up in no time really.
still getting the problem though, 1st gear is fine, 2nd seems ok but 3rd gear onwards once it hits just under 4000rpm it's like hitting a
limiter.
could i be looking at a ignition problem? running bestek electronic non vacum set up. under no load it revs up fine all the way to the red line but as
soon as i load it up it's terrible.
once again thanks in advance for any advice.
built a car, built a home, had a family. lost the family, lost the home, still got the car.
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john_p_b
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| posted on 6/8/07 at 07:51 PM |
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anyone? 
built a car, built a home, had a family. lost the family, lost the home, still got the car.
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MkIndy7
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| posted on 6/8/07 at 08:03 PM |
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What was the original problem or what has changed in the setup?.
I've been watching this because I have a similar problem. I've swapped from Megajolt to Megasquirt (to be closely followed by
ITB's), and have a new sports injection cam that brings the power in lower down.
It pulls like a train upto say 3-4K but is then extrememly hesitant, the MS has 2 maps loaded and switching these does make some diffrence but not
enough.
I suspect our problem is either because were running the injection cam with the carb still till its run in, or most likely because the power comes in
lower down the ignition doesn't advance soon enough.
Could possibly be your problem?
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john_p_b
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| posted on 6/8/07 at 08:54 PM |
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got a kent fr31 cam in and engine is out of a 1983 carburated model anyway so don't think cam is gonna be the problem but i'm thinking
along the same lines with the ignition advance. just doesn't make sense for it to be anything fuel related anymore?
built a car, built a home, had a family. lost the family, lost the home, still got the car.
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MkIndy7
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| posted on 6/8/07 at 08:58 PM |
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Is there any way to change the bestek system, or is it already set-up for that cam?
Has it been running fine before or just developed this problem?
Just plucked this quite from another site:
"The two main causes of any hesitation are rich part throttle fuel tuning and too little ignition advance"
[Edited on 6/8/07 by MkIndy7]
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flathatmat
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| posted on 6/8/07 at 09:10 PM |
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Very interested in the outcome of this as i have a very similar problem.
I run a Lumention system and have just fitted a Newman cam, the result is as you describe. The engine hits 3800rpm and then misbehaves and struggles
to pull through it if at all. Free revving all is well.
The only difference i have is that on inspection of the plugs no 4 is running very very weak and no 3 is similar but not as bad, so i am looking at a
possible air leak now as i have been through all the fuel system and was heading next to the distributor atfer changing all the plugs, leads etc.
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MkIndy7
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| posted on 7/8/07 at 09:55 PM |
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I've advanced my map as much as 5 Degrees throughout the whole rev-range tonight and its made it much better.
If it wasn't for the oil pump packing up or the oil going so P*ss thin! stopping me playing even more, then i'd say it had definately
cured my problem.
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