Dan_s_young

iTrader: (1)

Hey guys,

Well im gonna attempt again to get my car back on the street with the help of a local rx7 racer. I am running full racing beat exhaust, carter fuel pump, holley fpr, with a weber 45dcoe right now the fuel is at about 1psi I know its too low. I have the float levels set for the top position = 1.5 cm below the top of carb and the at rest setting is at about 3.5cm.

The engine only started once and would die if it went under 3000 rpms. We kept it alive like that for a minute noting massive amounts of white smoke coming out of the tail pipe. Just for the record this is a new to me rebuilt engine in the car. The gas does have a small amount of premix mmo in it, 1/4 of a quart bottle to be exact and I put about 2 tbsps of it into each rotor housing and turned the engine over by hand while it was out.

Im just curious as to where to start, float levels? Fuel pressure? Carb mixture settings? I just pray we can get her going so it can get painted at some point. So far I have had nothing but troubles with the weber 45dcoe, which I find to be pretty strange since most people have found the weber carbs to be a bulletproof setup.

And ideas or suggestions are appreciated!
Thanks!

Rotor13B

fuel pressure is to low. It is throwing off your other adjustments too.

paulied3

Sorry but get rid of the weber and put a holley on it. Webers are garbage and much less
reliable than a holley and are habitually tempered.

Rotor13B

You are definately in the minority on this one.

trochoid

iTrader: (6)

I put a Mikuni in my 12a and it was bolt on and go with minor tuning for the idle.

Put the same carb on the 1/2 bp and it fired right up, way to lean of course. I then put the Holley on and it is going to take conciderable tuning time and the use of a wideband. That is even after changing jets and the power vavle plug, just to get it started. I spent more time just opening up the Holley and modifying than it takes me to do a full install on the Mikuni.

The Webers and Mikunis are by far easier to set up and tune than the Holleys. Plus they have that look like they were made for the engine, instead of some huge dichromate lump sitting there.

For your 1st post, I would say you put you foot in your mouth.

Dan_s_young

iTrader: (1)

ok guys heres an update,
We got her to fire up, we adjusted the dist. shaft 1 postion and the car fired up after a second.

Heres my next problem, the fuel pressure declines the longer it is running for some reason. Im almost clueless about this but im going to redo the whole wiring for the fuel pump to make sure its getting good juice. I also need to get larger idle jets. Besides that though the car is gonna rip with that carb, we revved her up a few times and oh my god awesome.

Another thing I am going to bypass the fuel relay thing under the dash, I was talking to a local rx7 guy and he said it talks about doing this in the haynes manual, has anyone seen it hiding in there before?

Hopefully with just a little more tuning the weber will be a badass streetable setup.

Elysian

the holley i put on my FB was pretty much bolt on and go, i only had to adjust idle...

trochoid

iTrader: (6)

If you are still running the oem fuel pump, it probably won't be enough. An after market pump and fpr will make a huge difference.

Mine was supposed to be. Bought it off eBay. Supposed to be a 600, not, it's a 650 with 65 primary and 73 secondary main jets. I now know why the guy sold it. It had never been opened up or modded for a rotary. They are a pain to open up for the first time and clean all off the origional factory gaskets.

But it does have center hung floats, so cornering and boost should be easier.

Dan_s_young

iTrader: (1)

Ok so just to clear you up im running a carter pump and the holley FPR. Anyways on that topic im having all sorts of problems, It doesnt matter to where I change the FPR the gauge reads the same number, but after about 5 minutes of running the fuel pressure gauge shows 0 PSI but it clearly has fuel (I have a inline filter). What could cause this? Its a summit 0-15 psi gauge.

Also I was reading about bypassing the one Fuel pump relay, I was reading this thread: https://www.rx7club.com/showthread.p...uel+pump+relay
But I need help, I looked all over under the dash and can't find the clip that has the same pattern as that.

Also with rewiring the fuel pump where does the wiring go from anyways, Im going to use some heavier 16 gauge wire all the way back to the pump.

Thanks lots guys!

trochoid

iTrader: (6)

Back to addressing your concerns, sorry for getting off topic.

I haven't had problems with relays, but I have had several problems with rust and contamination in the fuel system, especially the tank and fuel pickup tube in the tank.

What I would suggest is check your fuel flow and see if it remains constant. Take off the fuel line, jumper the pump and let it run into a gas can. This should give you and idea if it is the pump or a restriction.

I just recently clogged a fuel filter, in less than 3 hours of idle time, because apparently I didn't get everything out of the tank I had just refurbished.

Have you done any maintinance on the tank itself? i.e. drain and flush. Do you still have the stock fuel filter and how fresh is it?

Dan_s_young

iTrader: (1)

I have not drained the fuel tank, the fuel filter is 6 months old.

Elysian

i don't got any cornering issues with mine, and i got the side hung floats, brass ones... and i've taken some absurdly hard corners...

Elysian

i wired my fuel pump directly to the battery's positive terminal with a switch and a fuse in line with it, it works perfect, don't got to worry about any kind of relay...

trochoid

iTrader: (6)

I would start with those 2 items first before I rewired anything. They are probably easier to find than the relay anyway.

Well that's good news. From my reading it sems to be a problem on the long sweepers.

bliffle

Maybe there's a vacuum buildup in the tank. Does it hiss loudly if you remove the gas cap after it dies?

B

cpa7man

iTrader: (2)

Is the fuel filter before the pump?

Siraniko

iTrader: (13)

first, set your fuel pressure.
remove the air filter, start the car and let it idle. then slowly increase the fuel pressure. forget about the pressure reading for now. if it floods (gas actualy dripping in the venturies), then adjust the float.

then you do the tuning.

Dan_s_young

iTrader: (1)

I would do this but I don't want something that I have to switch on everytime, I would like it if it was a hooked up to a ignition source. The fuel filter is before the pump, and we took the gas cap off and there is a small hissing noise but nothing drastic. Is there some sort of ignition only power source I could hook into???

As far as the fuel pressure goes I have no idea why it would lose a rating on the gauge after about 5 minutes of running, it deffinately is still getting fuel when it does this. The thing runs like a bad out of hell, it just barely starts and won't idle less then 2000 rpms, so now I need to replace my f855 idle jets with some f960's and hopefully that will help. But wow this car has great throttle response!

Siraniko

iTrader: (13)

have you taken this carb apart? I suspect a clogged idle circuit. but before you do anything, remove the fuel filter in the carb's fuel inlet. ****, if i were you, buy the weber carb book and study it; besides, its a good bathroom reading material.

Dan_s_young

iTrader: (1)

yes I have taken the carb apart, it was just replaced like 2 weeks ago and hasnt been used for more then 20 minutes with it.

Elysian

having the switch makes it so i never flood out when starting heh... makes for easy starts every time

31rx7

I have a similar setup - Weber 45 DCOE with 38mm venturis, Racing Beat exhaust, Carter pump, Holley FPR. I believe I run around 3 lbs fuel pressure.

For getting it to run correctly and tuning, I did a search on this board using terms like "Weber 45 DCOE tuning" and "Weber DCOE jets", etc. I also read one of the Weber tuning books out there. Short story is that it required some reading, thinking, and messing with jets and emulsion tubes to get it where it runs strong. Some of the posts give a good starting point for jets, and I was fortunate I didn't have to spend too much on spare jets. But, I could see where it might cost a small fortune.

If you spend some time on the phone with a good rotary shop and purchase the parts through them, they may be willing to assist and guide. Also, see if there is a local racer that really understands Webers and is willing to assist. There are a lot of variables associated with the Weber as pretty much everything is easily adjustable. For most people, it is not a simple bolt on and go.

I don't think I have my set up optimally tuned, but it runs strong and smooth, pulls way past 8,000, and starts even when cold outside. I auotocross it, and have no problems in corners or anything. Gas mileage on the street is even reasonable.

Spend some time: research, read, tune. Repeat.

Siraniko

iTrader: (13)

if the car runs fine after 2500 rpm, then your fuel is fine. but if there is a problem with starting the car and idling (assuming that timing is set right), then there is a problem with the idle circuit. With the idle jets, it will IDLE no matter what size you use. Will the car start on its on? Do you need to step on the pedal multiple times OR will it start with the help of starting fluid? PM me instead with complete details as searching for issues is a PITA sometimes,