Got the electric choke mod installed on the Q Jet after 4 yrs of no choke and after reinstall on the car I seem to be losing power at or slightly above 4500 RPM. I had 2 directions of thought on this. One was that I had a vac leak in the secondaries that was making it have a very lean condition once the RPM's got up that high or 2 the fuel pump was now for some reason not keeping up and she was nosing over due to low fuel pressure. Acts just like it runs out of gas. Comes back for a few sec's and then falters again until i get back around 4000. Hadn't done it in the past. Replaced the base gasket but no change. I have a S1 mechanical pump I can put on there or thinking maybe go electric. Thoughts?
I've had that problem and it does sound like a fuel starvation problem if it is like an on off switch being flicked pretty quickly. I have a Stage 1 pump and a pusher electric in the back and I've not had that issue below 6,000 RPM until I turn the electric fuel pump off. A couple of other things to check, the float level. Is there a chance that when you changed the gasket that anything got moved around? Second, no chance the choke is partially closed and restricting the amount of air it can pull?
It is the Stage 1 pump. This new gas is killing the pumps. You might want to try an Airtex 40664 since these are still in production, and probably have a better diaphragm.
Good things to check. I was going to mention the choke closing, or not fully opening, on acceleration. It ran well before, and the choke was the only change.
If the car leaves good going to full throttle and pulls hard up to about 4500rpm's, then goes flat, lays down, looses power, or engine shuts down, 9 times out of 10 it's going to be the fuel bowl going low or empty on hard runs. This is most often fuel delivery, but can also be caused by too small of a fuel inlet seat in the carburetor.....Cliff
If it's the fuel pump. Get a Robbmc set up with a half inch sending unit unless you have one or a fuel cell already. Go with a 550 or 1100 pump. The 1100 is overkill but it can be turned down if you only need 550 or so. If you make more power later you can open it up. Just my thoughts. Good luck. Jesse Z.
I just came to see what that click bait was all about. o No::laugh::spank: I have the robbmc fuel pump, as many others on this site. haven't run it yet but the brochure looks nice.
What's the condition of the fuel lines Steve ? Just asking 'cause my Riv did that, and it was caused by the old rubber gas line and methanol fuel - just a thought. The original fuel line was also located in close proximity to some metal patching that was done in the trunk area, and the old fuel line would simply collapse at high speed, or high rpm's, resulting in a fuel starvation situation. o No:
Make sure that choke is opening all the way was my 1st thought. If it is partially closed it will increase fuel consumption rate.
Yes the choke was the only change. Prior I didnt have the rod or butterfly installed on the air horn Pretty much exactly what it does. Its a basic stock over the counter mechanical pump. Worked well enough till now. I have a S1 pump but that will require me to re work the new stainless hard line running to the carb. Good question. I replaced all the rubber up front when I dropped in the new engine 3 yrs ago. replaced the lines on the tank when I first got the car. Something to look at for sure. After I first bolted on the carb upon return after the choke install I watched it slowly completely open then adjusted idle. As to staying open at speed... That will be hard tell.
Since you added an electric choke did you put the propper chock pull off . Thats the one with the long slotted thing that the diapram pulls the long awkward shaped usually green rod that opens the choke so it cant close. It goes on the rear side of choke. I put an electric choke on mine too, I modified a plastic secondary pull off to fit , then you have to put the one in the rear of choke that pulls it open ounce you start motor, and it doesnt let go till you off the motor. Im surprised Wizzard didnt mention that to you.
Yes and after your done with this fun cause and affect learning expiearance , and electric pump would be the way to go. ,mallory and adjustable regulator, liquid filled fuel gague in line so you can adjust pressure, return line, a fram fuel can type of filter, i think G25 is the pt num for replaceable cartridge filter, Then u need to modify your sending unit with bigger lines in and out. Do Not use rubber anyware, double flare , single works too but tend to split if your one who likes to over tighten everything , like i do.
And i forgot.... YOOOOOOOO ! BRIIIZZZZZZZ!! Whats shakin mannnnn!!. Long time, I decided to look for another hood to cut open instead of mine. So i have TA stage 2 SE heads with shortys 3 in to the back and B4B. Spherical dish pistons, and all the other goodies. I take it your doing the electric pump deal, now that your motor is too strong for the mechanical pumps, mechanical pumps are for grandpas chevy. I ran the performer before, im going for B4B this time. The single plane would be nice but thinking about it , im not looking for power above 6000 rpm, i think thats ware the open plumem intake is better, the nums from what ive seen are pretty even below that. For a street car anyways.
After I first bolted on the carb upon return after the choke install I watched it slowly completely open then adjusted idle. As to staying open at speed... That will be hard tell. With the choke pull off as it goes to manifold vac, your choke should never close ounce runing.
Anson, Id like to go with an in tank pump. Wondering if any sending units avaiable with 1/2 lines for other cars will fit our tanks ?
No, I tried a few trucks ,at wreckin yrd got tired of dropping tanks, the hole is smaller than most with electric pumps, u still need to modify one if u find if cause I never seen a 1/2supply 1/2 return unit, I ended up brazing in 1/2 return and next size down for supply. I double flared everything and used in line female flare fittings. Mounted in the trunk to make filter and pump replacement easy. I went bigger on return line to make it easier on pump. I take it ur runing 1/2 up to ur regulator then reduce to carb size. Wat happen wit ur choke ? Were u missin the pull off ?
There are a few companies that make custom fuel tanks, that look stock, with whatever size lines you want. Some offer them with electric fuel pumps already installed. Rick's Stainless Tanks & Rock Auto are a couple.
It's a sickness. Smokey, our late Labrador lived 15 years. Wife & I met on July15. Married on May 15. And, NO!, she was NOT 15 at the time.:laugh:
Its never had a choke since I rebuilt the engine. Once I put the B4B on there and tried to fab up a GS air cleaner that would fit under the stock hood. The top of my drop base air cleaner would hold the butterfly closed so I completely removed it. Now that the 4" cowl is on there I got room so put a choke back on it. As for the fuel system goes. I aint messed with it yet. Got many projects going on around here to be completed before I jump into this one.
