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bbqjackson

Car Wont Rev Past 2,000 Rpm

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Hi Guys,

 

Looking for a bit of advice / help with my l26

 

My car was running quite well for a period of time, and after a drive up to the shops the following problem ensued.

 

Car struggles to start when previously it didn't. Once started, it is able to rev freely and drives up until it reaches operating temperature. Once there it seems to hit a flat spot and won't rev past 2,000 rpm

 

Done the following,

 

* Replaced the points

* Distributor cap and rotor

* New spark plugs (one was fouled) 

* New fuel filter

* Tank has been flushed

 

It has been to 3 different shops (not sw motorsport yet) and still no luck. The last shop said there was a bit of dirt/rubbish in one of the carbies and charged $300 for a clean. 

 

Has anyone had this problem before (i'm not too mechanically savy).

 

Cheers

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What condition is your distributor in? Any major vacuum leaks?

 

Distributor look to be in good condition, the button appeared to have abit of wear and the contact point on the rotor was a bit black.

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A couple of possibilities to check,
 

1. Spark plug leads, particularly coil to distributor, but if the car is missing it may be down on one spark plug lead. Not uncommon that the issue will only show up under load. You mentioned one spark plug was fouled, this may be because that spark plug lead is shot.

2. Fuel pump, might deliver enough fuel to idle and rev with no load but not under load. If mechanical the diaphragm may be shot.

 

When you have issues like this always change one thing at a time, check to see if the issue is rectified then move onto the next. Don't make 6 changes then test. For one you wont know what the problem was, and secondly you may end up chasing your tail.

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I would also look for inlet manifold leaks.

 

If all else fails do a compression test, well two of them actually - One when cold and the second when hot.

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Float level height shutting fuel off under load?

Last mechanic cleaned the carb so I'm assuming they checked that.

 

It sounds like a fuel delivery issue though. Check out fuel pump as Billy (WA240Z) mentioned. Not sure whether this explains the starting issue... Hmm. Fun and games.

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fuel or vacuum. i had a lot of leaks when i put mine back together. my dizzy is also worn and wont rev part 4k but runs fine under that.

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Thanks alot for the feedback so far fella's

 

 

fuel or vacuum. i had a lot of leaks when i put mine back together. my dizzy is also worn and wont rev part 4k but runs fine under that.

 

This one is interesting as the car is fine under 2,000 rpm ... hmmmm

 

Going to start with the fuel pump and as wa240z said, knock them off 1 by 1.

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Hi Mate

 

If the fuel system checks out I would be looking at things that are effected by heat or expand when hot.

 

Gaskets, coil and leads for starters

 

Love these more challenging ones.

 

Cheers

 

PB

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Hi Mate

 

If the fuel system checks out I would be looking at things that are effected by heat or expand when hot.

 

Gaskets, coil and leads for starters

 

Love these more challenging ones.

 

Cheers

 

PB

 

He said:

 

"Car struggles to start when previously it didn't."

 

Do you think that's a separate issue then?

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I overlooked that comment :-\

 

Sounds more and more like a intake vacuum leak to me.

What impact does the choke have on the engine when it is hot ?

 

But without having the car in front of me I am only guessing

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But without having the car in front of me I am only guessing

It's hard enough with the car in front of you isn't it? Haha.

 

On that note, and sorry to go off topic slightly, have you heard of the podcast Car Talk? Couple of ex-mechanics who happen to be a riot to listen to take calls from car owners with issues and they try to diagnose them. They have a really high success rate at both solving the issues and making you laugh. Very entertaining and educational.

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Sorry fellas, havent been able to respond to many questions as i won't get to check out/ try some of the above until Saturday. 

 

PB - The choke has no effect / funny enough, Im not too sure its doing much on cold start either but cant confirm. My apologies as i'm not to mechanical and any work is normally handled by Steve at quickfit

 

Nat0 - Clutch fan still working normally and no noise until it hits 2,000rpm which then feels like it just bottoms out. soundwise, like it is sputtering 

 

George - Been abit of a learning exercise, first carbie vehicle. May revist the fuel pump as i believe they have a filter inside (correct me if im wrong)?

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George - Been abit of a learning exercise, first carbie vehicle. May revist the fuel pump as i believe they have a filter inside (correct me if im wrong)?

 

All you need is a Phillips #2 screwdriver. Give it a go, it's dead easy.

 

Check for cracks as per photo #2 and other gunk. Clean everything and replace filters/diaphragm if necessary. Careful with the filters though as some types are secured to the cast making it impossible to replace. You most likely will not need to replace them - just a good clean with an air compressor.

 

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It's hard enough with the car in front of you isn't it? Haha.

On that note, and sorry to go off topic slightly, have you heard of the podcast Car Talk? Couple of ex-mechanics who happen to be a riot to listen to take calls from car owners with issues and they try to diagnose them. They have a really high success rate at both solving the issues and making you laugh. Very entertaining and educational.

Never heard of them, will have to check it out.

Thanks

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Sound to me like its running overly rich - hole in float / sunken float / needle & seat faulty / dirt in needle & seat / etc.

 

You would think a mechanic would have picked it up if its been to a couple, but perhaps not.

 

Is either carb leaking fuel out of the overflow on top of the float chamber ?

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Hi guys,

 

Just an update. My apologies as i will try to describe the issue coherently

 

The issue seemed to have been caused by a blockage in the line leading up to the front Carburetor; as some did mention, it was getting enough fuel to idle and rev but not under load. 

 

I had some reservations, as a few weeks earlier to this problem, we went out on the zed cruise and she did well for the few hours. But one of the things i didn't account for, during all this. Is that the car had been sitting for sometime and although the fuel tank and other pieces were in good nick, or replaced some of the hoses ect must have built up dust/dirt.

 

thanks for all the help and advice!

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So fresh fuel and a clean and all good?

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