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-   -   edelbrock carb. still too rich! (http://www.hotrodders.com/forum/edelbrock-carb-still-too-rich-22354.html)

TVR383 09-01-2003 02:51 PM

edelbrock carb. still too rich!
 
I've asked many ones and tried many things but my edelbrock 1405 still runs too rich! I didn't have a fuel pressure regulator before and recently installed one and that did fix a problem of engine running on after having shut it down....I guess the electric fuel pump was exceeding the 6 pounds and that was responsible.

I was hoping to see the mixture leaning down from the same pressure correction but that did not change one bit: the O2 sensor reads too rich and the black sooth on the exhaust shows it!

I had lean it down somewhat (stage one lean) by replacing jet and rods but not enough. When I try the stage two lean as edelbrock recommendation well then my O2 sensor goes all erratic from too lean too too rich looks like there is no mid-way....anybody can think of something to try ??Suggestions?? Edelbrock answered me to check the pressure not to exceed 6 pounds but here it's done and still the same problem..

Thanks, Ronald.

That is a 383 stroker,10.25 compression,268 comp cam, brodix street heads,headers,...would be so sweet without that stinky/messy sooth!

DoubleVision 09-01-2003 03:02 PM

have you checked the float level? have you made sure there is no trash in the needle and seat? you say you have a regulator, but do you have a fuel pressure gauge? if so what`s the pressure? with no gauge it`s the same as flying blind, there`s no way to know the pressure without one. your problem to me sounds fuel pressure related, lastly, what`s the spark timing set at?

TVR383 09-01-2003 04:35 PM

Double Vision,

Floats check-in= o.k.,trash?...less than 800 miles on the carb and with" out of the box" or step one lean runs rich but at least the O2 sensor shows steady "too rich" lectures then. MSD electronic dist. with mechanical advance,total of 36 I think and initial set at 10 BTC....

Now that pressure regulator....brand new 13205 from aeromotive....this reg. is sold as a 5 to 12 pounds one. My fuel gauge,wich could be faulty shows 9 pounds...and this with the fuel regulator adjustement nut backed-of so it even doesn't exert any pressure on the spring. The same regulator solved my problem of dieselling I had everytime I would shutt the engine off BEFORE the regulator installation so this shows me that some pressure reduction has been accomplished. The pump is an electric one that is supposed to put out 7 pounds according the ex-owner...The Autometer fuel gauge seems new and I have one spare so I'll check the pressure issue...Gee I wish that's all I have a faulty fuel regulator!

The engine,for undetermined reasons yet, consume oil at the rate of about 1/2 quart for 700 miles...could this influence the fuel mixture and the O2 sensor readings?

thanks. Ronald.

DoubleVision 09-01-2003 06:08 PM

9- 7 PSI is too much fuel pressure, the edelbrock carb can`t handle over 6, set it at 4 1/2 - 5 psi and it`ll be fine.

Centerline 09-02-2003 12:52 PM

Quote:

Originally posted by TVR383
Double Vision,

The engine,for undetermined reasons yet, consume oil at the rate of about 1/2 quart for 700 miles...could this influence the fuel mixture and the O2 sensor readings?

If you're motor is consuming that much oil you must be blowing a huge cloud of blue smoke out the exhaust everywhere you go. I suspect your probably leaking oil somewhere rather than burning that much but yes if you are burning a lot of oil it may effect your oxygen sensor and will probably effect your fuel mixture readings as well.

Does the sensor read rich just at idle or at all RPMs? If just at idle try changing your step rod springs. Carter and Holley make idle step rod spring sets with different tension springs for varying engine idle vacuum conditions. If you're running a big cam then chances are your springs are too heavy and you're feeding the engine too much fuel at idle.

Centerline
http://www.hotrodsandhemis.com

troy-curt 09-02-2003 03:01 PM

Like stated 4 1/2 lb. is plenty.

You could be washing the cylinders down with excess fuel.

Troy

TVR383 09-02-2003 05:44 PM

Centerline here's some answers to your questionning:I have smoke at starting only mostlikely worned valves seals. There are no leaks this I'm sure as initially I've fought with an intake leak that I've fixed now. Initially I was consumming much more oil like a quart at 250 miles....I then had edelbroc Unbaffled valve covers and it was sucked-in by the PCV. Now with the Billet baffled valve covers plus the PCV valve adapted into the Billet specialty breather the consumation reduced dramatically but I still burns around a quart/700 miles...so this,as I've always suspected should have an influence on my O2 sensor's reading but up to what point??

The higher the revs. the better is my mixture but even at 4000rpm I'm still too rich (according the sensor). I've changed the spring from the standard 5HG to 7HG this according to edelbrock to avoid lean spot under harder acceleration...I didn't noticed a big difference. At idle it depends how I settle the idle mixture screws so I can get anything from extra lean to extra rich. The cam is very mild 268.

So here I am contemplating all avenues without beeing sure where to go!! I'll get a third fuel pressure gauge to make sure i'm in the right pressure bracket first.

Changing these valve seals won'nt hurt anything . The oil consumation bugs me somewhat....it's a recent rebuilt with around 1400 miles but the rings are the type who should seat within 30 minutes of use (molys I think) so what else could cause this if not my pcv still sucking in?? Running without the PCV I am told will just keep me replacing gaskets...humm..

Eventually it will be all sorted-out!
thanks, Ronald.

Centerline 09-03-2003 10:24 AM

Since your rebuild only has about 1400 miles on it I would be taking the heads back to whoever did them for you and demand they fix them. (Unless you did them yourself in which case you have no one to blame but you anyway). Freshly rebuilt heads shouldn't have faulty valve seals.

You do need to run the PVC system. You have to have some way of evacuating blow-by gasses from the crankcase and a PVC system beats the old breather tube hands down. It's more environmentally friendly as well.

I think I would temporarily install a mechanical fuel pump, disconnect the electric one and see if it makes a difference. If so then your problem is definitely the electrical pump.

Centerline
http://www.hotrodsandhemis.com

TVR383 09-03-2003 02:55 PM

Thanks Centerline,

The motor was rebuilt but the heads were not redone. I just had a three hours session in it and took a compression test to see if there was something obvious there and with even 205-210 pounds square inch on all cyl.it seems the cylinders are thight. The engine has 10.25 compression ratio.

I've checked more closely the blue smoke and it does puff blue mainly at starting and under decelaration....would this limits the possible damage to the seals only?? Under rapid acceleration it doesn't seem to puff blue .

More I advance in my research I tend to blame the presence of oil into the mixture to be responsible for the too rich situation. While I understand the PCV is good to the engine I keep suspecting it for sucking oil in. I've pulled out the Billet breather with the PCV incorporated to it and there was oil at the base of the PCV and I could see oil on top of the baffles inside the cover...normal is it? For whatever reason the vacuum is high: (there is a vacuum gauge inside and at cruising rpms 2800 it's around 20 and idling it's closer to 23-24..again is this standard or really high and can I blame it to suck-in so much oil as about 350 miles=1/2 quart??

A mechanical pump cannot be installed the v-8 is too thight into the TVR frame!

I'll try to run for a while without the PCV connected and see if that change anything..but I'm not expecting miracle there!

To get the heads off the engine has to come out so I guess if it comes down to the evidence of the heads to blame well I'll wait few months when we'll be in the snow again...

Again thatnk you for your ideas I appreciate.
Ronald.

troy-curt 09-03-2003 03:27 PM

The smoke sounds like valve guides or seals. However that would not affect fuel mileage. You need the pcv system if you can make it work without sucking any oil out.

Good Luck
Troy


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