38 dgas running

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mfw898y
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38 dgas running

Post by mfw898y » Tue Dec 18, 2007 6:53 pm

Hi, all. Just fitted a 38dgas of an old scimitar to my 2.0 pinto. I've cleaned it up, but the thing is, it'll start and idle which gets progressively worse, but it wont rev. As soon as you try to go from idle to rev it dies. The only exception to this is when you hold the choke flaps closed which I would think means either too much air or too little fuel. As the carb came off a 3 litre I would of thought, if anything, it would over fuel but should still run. Any ideas??????????? :shock:



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Post by Coops » Tue Dec 18, 2007 7:03 pm

are the float bowls filling with fuel ok?
and have you the fuel pipes round the correct way,
with engine off, look down the top of the carb and see if when you open and close the throttle you see fuel squirting in,
Regards Tony C (COOPS)
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MS2 V3.57 Ecu mapable efi and wasted spark ignition.
Rotrex C38-91 supercharger and Cossie RS500 Intercooler @ 14psi of Boost.
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Post by mfw898y » Tue Dec 18, 2007 7:15 pm

Cheers. Got plenty of fuel flow. I'll check to see if fuel squirts in tommorrow. Its just strange that it revs ok if i hold the flaps shut.

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Post by Coops » Tue Dec 18, 2007 7:48 pm

did it run ok on the other car?
by closing the flaps it draws more fuel,
sounds like one of your circuits are dirty or blocked mate,
Regards Tony C (COOPS)
Image
MS2 V3.57 Ecu mapable efi and wasted spark ignition.
Rotrex C38-91 supercharger and Cossie RS500 Intercooler @ 14psi of Boost.
Sponsored by: www.extraefi.co.uk & www.interpart.biz & www.caprisport.com
Web site: http://www.capriracing.co.uk

mfw898y
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Post by mfw898y » Tue Dec 18, 2007 8:06 pm

I'll take it to bits again tommorrow as i'm thinking the same. It came off a car that can't have been run for a while. The float chamber and jets were scaled up although i cleaned it the best i could. The holes are so bloody small though i suppose they are easily blocked. Gone through two cans of carb cleaner already (although i used quite a lot as easy start :lol: )

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Post by Coops » Tue Dec 18, 2007 8:20 pm

the carb relies on vaccuum to draw the fuel through, under acceleration the accel pump gives a squirt through the two squirter jets in the top of the carb to eliminate bog when you mush the throttle, once its squirted the carb relies on a vaccuum again to draw the fuel through,
so by closing the flaps your causing more of a vaccum, the same as if you put your hand over the top,
have you changed the idle mixture screw? at the base of the carb, i think theres one either side on the dgas,
as a rule of thumb i screw them both in and back off 2 turns as a base for setting the fuel mixture up.

what do you mean by fuel flow is good?
do you mean from the pump to the carb????
double check you have the flow and return pipes the right way round (seen this many a time, including myself doing it) and double check the float bowls are deffinatly filling to the correct level with fuel.
Regards Tony C (COOPS)
Image
MS2 V3.57 Ecu mapable efi and wasted spark ignition.
Rotrex C38-91 supercharger and Cossie RS500 Intercooler @ 14psi of Boost.
Sponsored by: www.extraefi.co.uk & www.interpart.biz & www.caprisport.com
Web site: http://www.capriracing.co.uk

mfw898y
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Post by mfw898y » Tue Dec 18, 2007 8:49 pm

Well i have flow from the pump to the carb and it will rev all day provided i shut the flaps so i'm assuming the float chamber is getting enough fuel although the level is questionable as i didn't check (it could be me but the haynes way of setting this seems open to interpritation).
There is no fuel return on the carb.
I have messed with the mixture screws starting at 1 , 1.5 and 2 turns out with only very slight alterations to running. Nothing near what i'd call an improvement. Regarding the 2 mixture screws, i'm assuming they should be adjusted the same.

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Post by Coops » Tue Dec 18, 2007 8:58 pm

Regards Tony C (COOPS)
Image
MS2 V3.57 Ecu mapable efi and wasted spark ignition.
Rotrex C38-91 supercharger and Cossie RS500 Intercooler @ 14psi of Boost.
Sponsored by: www.extraefi.co.uk & www.interpart.biz & www.caprisport.com
Web site: http://www.capriracing.co.uk

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Post by mfw898y » Tue Dec 18, 2007 9:03 pm

and its much appreciated. I shall be putting this to good use at first light....give or take a couple of hours :)
I''ll let you know how i get on mate. Cheers!!!

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Post by mfw898y » Wed Dec 19, 2007 1:07 pm

OK. Cleaned it again. Followed the instructions. Put it on car and its drivable but has a flat spot when you take off (you have to feed in the throttle very gently-if you floor it, it dies). After reading a few threads on various sites, this seems indicative of a lean condition. How could a pinto be running lean on a carb that is jetted for a scimiter? Odd! I have also covered it in easy start with apparent vacuum leaks :?
If i squirt easy start in to intake when i throttle up...no hesitation...it revs as it should.
Booked it in for a tune up on Friday morning :D

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