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Guest Message by DevFuse
 

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"Fuel cut" TYPE feeling in 87 GL W/Weber (SOLVED)


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8 replies to this topic

#1 Flowmastered87GL

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Posted 01 October 2004 - 12:28 AM

I dont know how else to describe it... I installed a 32/36 DFEV (the backwards one) about 9000 miles ago. It ran perfect at light throttle and full throttle.

Now... it runs good at light throttle, but if I really floor it I seem to hit at like 4000 RPM or so what almost feels like a fuel cut, a wall if you will, the acceleration ceases. No odd noises come from the engine, no smoke or anything, it just feels funny.

Some thoughts of what maybe could be going on... comment PLEASE!

Fuel filter clogging?
Air filter clogging?
Coil crapping out, cant handle the volts of high engine load?
Same deal, but with fuel pump, cant handle high load?
Timing off?
Vacuum line repluming messing stuff up ( changed FROM a vac line between the base of carb and the intake TO a vac line coming from the carb and going to the disty advance)

Its carbed so I know its not a real fuel cut... but something is up... maybe it just needs adjusting though...

I've been getting like 20-21 MPG city.

#2 Flow

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Posted 01 October 2004 - 12:58 AM

My guess goes toward a failing fuel pump or maybe an incorrect float level setting in the bowl. Snowman was having similar problems awhile back. He put on a aftermarket pump with a regulator and it seemed to clear things up. Are you running a return line to the tank?

#3 VaporTrail

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Posted 01 October 2004 - 02:07 AM

I had the exact same thing happen on my Brat. it was because the snorkle I had on was restricting the airflow at high RPM's

to test this, take the air cleaner off, and take it out with the carb open and see what it does. mine ran awesome, so I went and got a round chrome air filter that worked with my snorkle base. problem solved.

if you run okay open, then your filter probably needs a cleanin'

#4 edrach

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Posted 01 October 2004 - 09:17 AM

If all else fails, run your vac line to the distributor from a manifold vac port. I think the vac line on the weber is a delayed vac.

#5 Flowmastered87GL

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Posted 01 October 2004 - 11:48 AM

Ya the weber one IS delayed... it comes on about when the disty is supposed to advance is what I was told...

Anyway I used to have the weber vac run straight to the manifold... maybe this confused the vac system I dunno, but it idled at like 1200 there.

It idles at 8-900 plumbed "correctly" with NO OTHER changes performed on the car.

Oh, one more thing... when I first had this stuff installed I blew a coolant line and got coolant over EVERYTHING before a rallycross... so therefore I had a nice soggy air filter, never cleaned it after that so it COULD be gummed up with coolant and dirt.

I'll try chaning the fuel filter and cleaning the air filter and see what happens.

#6 Flowmastered87GL

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Posted 03 October 2004 - 10:26 AM

Problem solved:

Air cleaner removal actually made things worse!

So I changed the fuel filter. All is good all the way up to 6750 RPM :cool:

I wanna cut open the old filter and see how nasty it is inside. Its all muddy so I cant see through the plastic. My guess is the brief time I ran arco kinda messed up the filter though.

#7 Scoobywagon

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Posted 03 October 2004 - 02:12 PM

That's what you get for running Arco gas! Actually, I have learned a few interesting things about gas over the past year or so. First is that the refining process to make the base gasoline is the same for everyone, so they generally all keep their base fuels together in one big tank at the fuel farm. What differentiates one brand from another are the additives they use. Those additives are added in the truck just before delivery. There is ONE exception to this. Nobody will let Arco mix their base fuel in at the tank farm because the quality of their base stock is so much lower. They try to make up for this by using high levels of methanol. Its corrosive, so it cleans things, but it also eats up your valves and exhaust.
(/HIJACK)

Ok, I'm done hijacking. Glad you got your problem solved.

#8 Snowman

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Posted 03 October 2004 - 09:49 PM

Wow! I gotta change my fuel filter! Mine does EXACTLY the same thing that you describe. I've got a new fuel pump and regulator set to 4 psi, and it pulls pretty well up to 4,000 then falls on its face. I actually felt it completely drain the bowl a few times on the last trip, in which case it would ping and miss all over the place until I went to a lower throttle setting. The other thing is that if I'm using a high throttle setting for long periods of time, it just starts to bog out, again like it's running out of gas in the carb.

I changed the filter a year ago, but it's possible that it could have gotten clogged again. There is only one filter on the ea82 cars, isn't there? I haven't seen another like on the ea81's.

#9 Flowmastered87GL

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Posted 03 October 2004 - 11:02 PM

Carbed EA82 = only one filter, its in front of the passenger rear tire up with the fuel pump.


The car lurched ONCE today... right after I started it to drive out the driveway. Only did it that once though... some of the junk may have made it to the carb though :(

It still runs way better though, like 99% perfect for now...




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