eViLjAy

I have searched for the last 3 hours and it seems I am the first with this problem. I recently dropped in a new engine. It did not come with a carb so I am using the one that ran perfectly fine until the previous engine got old and spit out an apex seal. Granted it sat from November last year until about 2 weeks ago.
The engine starts beautifully. Idles fine. It makes plenty of power as long as the secondaries do not open. Jets are stock as they were fine with the other engine. Dropping the pedal results in a horrible bog that does not go away no matter how long it is held and makes no power. I suspected lack of fuel so it got a new filter with no change... Seems the problem is WAY too much fuel.
It seems as if the secondaries are slamming open then a second later gas just pours in. Still running vacuum secondaries. The only way I can go WOT is 4th gear and very slowly pushing the pedal till it hits the floor(as in 4th or 5th are the only gears long enough to accept the slowness required). Even the cruise control is opening it up too fast! WTF is going on here?
The rats nest has been removed along with all the stupid emissions garbage. It is entirely possible that vacuum lines are not in the correct places but ALL rats nest removal threads I can find are so old that none of the images still work. Does anyone have a WORKING rats nest link? Does this sound likely to cause this kind of problem? Any help would be greatly appreciated!!

eViLjAy

oh ****. not a good sign when ya have that many views and no replies....

Vashner

There should be a rats nest sticker on your hood. There are threads on it. And your shutter valve is working? Stock exhaust?

Rx-7Doctor

iTrader: (13)

Damn I am sick of seeing threads on the rats nest! LOL

Seems like almost everyone one that removes that **** winds up posting a thread having an issue. My advice to everyone is leave the **** alone and leave it stock unless you are putting on a "Aftermarket" carburetor.

You searched with the term "Rats nest" and did not come up with this 1 month old thread?

https://www.rx7club.com/showthread.p...ight=rats+nest

eViLjAy

rx7doctor, yes I came up with this link. http://maz_tutorials.ten15.net/Tutorial_1.pdf and downloaded it. I get repetitive error messages so linky no worky in essence.The thread itself that you suggested had no useful info. Now if you had a rats nest removal thread with still functioning pictures that would be very useful.
The engine had the rats nest removed and worked fine for over 2 years until the apex left the block. New engine had no intake or rats nest so how would you suggest not messing with it and leaving it stock? If your not going to read the whole thing before commenting than just stfu.
Not trying to be rude, I am looking for people with knowlage of nikki carbs to explain what could possibaly be causing said issues.
Shutter valve has been eliminated and the exhaust is a thrown together bunch of crap but it did work fine for the last couple years before the previous engine crapped out. Its an unknown header to two oddball presilencers to a monza catback. I am positive this is a carb problem. It wouldn't start this easily if it was ignition. It wouldn't idle so smooth if it was a vacuum problem. This was a low miles short block with all the old(emissions removed) parts transferred straight over. It should have been a bolt in and drive scenario...

kutukutu1

iTrader: (5)

k op, i had that same issue, first it was the fuel filter, but since you changed it, lets rule that out, now the only thing that you need connected for vaccum is the first nipple from left to right that t off into both diaphrram in the dizzy, then the other one that is not capped is the fuel boal vent, which is next to the fuel return in the carb, its about 1/4 in in diameter, thats not capped everything else cap it and make sure you got no leaks, i was having that problem and no matter how much you press the throttle it just bogs until you let off and go slowly and that was my problem, hope it helps.

Oneiros

Leaving the carb sitting that long, chances are something got blocked up, sounds like the secondary fuel jets could have crud stuck in them. Rebuild time.

Vashner

Yea maybe something sticking. You might try some techron fuel additive. This is fresh fuel right? You drained or burned off the oil gas?

eViLjAy

Ok cool. Will tear her down and see if I can find any more gunk hidden in there. Isnt it necessary to also have something hooked up vacuum wise for crankcase ventilation? Those are the ones I was unsure about having correct.. It appears all others are as suggested, plus I am still running the cruise control, and this is working properly. Yes the fuel was drained and replaced before the first startup so that should be good. I will take her apart today and update this post on what happens.

BandDButton

rats nest removal.

http://maz_tutorials.ten15.net/Tutorial_1.pdf

eViLjAy

This is a bad link yo. Already downloaded it and one page shows, no text and half of one picture.....

kutukutu1

iTrader: (5)

I have to check my car but if I remember correctly I t off from a line that goes into the charcoal canister, ill take a pic and make sure

BandDButton

It took my computer a good two minutes to download the whole tutorial.

eViLjAy

I also downloaded it 4 times with the same results. Half of one pic and no text past the opening page.

Rx-7Doctor

iTrader: (13)

Sorry i don't know what issue you guys are having with down loading this link but it took a little over a minute to down load and all pictures are 100% functional at this link?

http://maz_tutorials.ten15.net/Tutorial_1.pdf

I gave you the link in my original post because it was to the above link that is fully functional. Anyone else having issues with down loading the above link? My computer is even old being that is is almost 9 years old!


This is a link to a thread from sterling the carburetor guru that may or may not give you some insight.

https://www.rx7club.com/showthread.p...light=sterling

In case you need some pictures to identify components while working on it.

http://intertron.com/ron/carb.html


Other thing to check is fuel pressure. Are you running a stock or aftermarket fuel pump?

Rx-7Doctor

iTrader: (13)

One more very useful link-

http://sterlingmetalworks.com/the_nikki_carburetor.htm

eViLjAy

Well heres an update. I tore the carb all the way down and cleaned absolutely everything as well as switched it to mech secondaries. It is bogging just before they open up, and if I push it till they are open (above 4000rpm) it now dramatically loses power. Like it nearly stalls out completely. If it is sitting in neutral and I peg the throttle I have a new way to kill the engine altogether. Pissed off and tired of playing with it tonight.
Tomorrow it is going back to vacuum or i am making it into a 2 barrel so it is at least drivable. Looking into replacing this damn carb now.

RxDoctor I am still not able to open that first link up, guess my computer is failing. I will read into what Sterling has to offer though so thanks.

perceptionproblem

I am having this exact same problem. But I have not removed the rats nest.

I have found out that one of my plugs only fires when the engine is turning over, but once it gets to idle (or above) it stops sparking.

Once I had replaced my fuel filter and pump, checked fuel delivery and cleaned the carb, I thought I had nowhere else to look for this lack of power. So I started checking my timing, which ended up with me looking into the wiring. (reading this thread I realized I need to check fuel pressure)

Are you backfiring? Have you checked your cat/muffler to see if they are clogged?

Oneiros

With mechanical secondaries, you can't flat foot it from idle. That is what you have to live with. It will most likely stall. You have to press the throttle slowly and learn to control when the secondaries open with your foot, around 3KRPM is good but you always have to press the throttle slowly to smooth out the transition.

As for your other problems it sounds like one or both of the secondary fuel jets are blocked.

eViLjAy

Yeah I know stomping on it at idle wasnt going to work but really didnt expect it to stop the engine completely. The carb was completely torn down and thoroughly cleaned yesterday so I am positive the jets are clear... Now I am starting to question the pressure regulator or pump of not supplying enough flow, or possible plugged return line. Pressure is good for sure, I can crank up the fpr enough to flood her out, flow though may not be there as it was a cheapo pump. I have an extra factory pump I am going to try out today.
As for the cat being plugged, Iowa is a non smog state so that bastard was scrapped when I got the car.
Will post updates as they happen.

eViLjAy

Well I took the carb back off and returned it to vacuum secondaries as I didnt like the feel of mech. Deciced to check that the return line to the tank was not kinked or plugged and found that the one way valve was backwards (dumb me) so I thought I had found the issue.
Went for a drive and nothing has changed. The more I think about it I dont think it is the pump or it would fall on its face more gradually. The bog happens almost immediately as the secondaries open. I dont think the bowls are just instantly empty as I can turn off the fuel pump and back out of the throttle and power returns.
Now I am completely baffled and about to just take the carb out and smash it to bits. Or now considering selling the whole car so it can be someone elses problem. I do not have the money to replace the carb altogether and nothing seems to fix or even improve the problem.

Kentetsu

When you tore the carb down, did you actually remove and inspect the fuel jets? I ask because this was not listed in the rebuild steps when I did my carb years back. Blocked fuel jets definitely fit your description.

If it were a pump or filter (fuel delivery issue) then there would be times that it would work fine (fuel bowls filled), then would later show symptoms (as the fuel in the bowls was depleted).


P.S. You came in here looking for help, and when a well respected member offered advice you snapped at him (telling him to stfu), then said you weren't trying to be rude. If you can't/won't treat the people trying to assist you with some common courtesy then I (and probably many other sources of information) will not assist you in your threads. Please keep this in mind...







.

Oneiros

Hmm. I would be checking the secondary fuel jets (in the bottom of the float bowls). Also check the emulsion tubes and transfer jets, basically anything on the secondary side, for blockage. You may have done some of this already.

Another issue could be the accelerator pump not operating correctly. This is critical to a smooth transition to secondary throttles. Look down the barrels and check for a clean stream and no leakage around the pump cover.

These carbs can be very frustrating to troubleshoot as they are fairly intricate and complicated. Hang in there.

IanS

iTrader: (4)

Update for OP

I have been helping him the last couple days troubleshooting. A couple things were found/noticed:

Checked timing. Leading is dead nuts accurate to the leading mark. Trailing is also dead nuts on to the LEADING mark. The trailing will not adjust enough to get to the correct mark, only about half way.

Lots of guys run zero split, I dont think this would cause this problem but just to make sure we swapped in a different good dizzy from a different engine. EXACT SAME TIMING. Crazy, I know. Problem still present.

Next thing was we thought possibly a bad plug fouling or just being stupid, so new leading plugs went in and also we decided to change the wires (I had a spare brand new set). No change.

Then decided to disable the trailing ignition since the timing was weird on them. Again, no change.

I checked the resistance of the coil as per FSM and is supposed to be 1.35 ohms +- 10%. Leading was 1.4 and trailing was 1.3. Should be good.

Next we thought maybe the secondaries were the problem, so we disabled the vac diaphram arm that makes the magic happen. No change.

SO THEN we thought maybe the carb itself is the issue (somehow). So then we mounted my Sterling nikki on his engine and although running richer than it should, the exact same problem persists.

We thought then that possibly the fuel pump is the issue. We know that the pump keeps up at idle. His fuel pump is wired up with a switch so we thought that if we simply turn off the pump and see what happens. Same problem. (Personal note - the pump, if it couldnt keep up would simply cause the engine to fall on its face when the carb runs out of fuel in the bowls, because to my knowledge all the pump does is simply keep the bowls filled).

The problem ALWAYS HAPPENS if more than about 1/3 throttle and starts around 3500 RPM and OCCASIONALLY "works itself out" if you get it past 5000 RPM but its rare that it works right. In fact, it has never worked "right" only "better"..




OK, so theres the story. Feel free to throw out some ideas...




Kentetsu - Dont worry I already smacked him around and then told him to not tell people to STFU when asking for help lol.


Edit number 12 lol - I cant remember what Jeff20B has said about running timing 90 degrees off. I want to say he says 180 off is ok but thinking this may be an issue. This is me thinking that previous owner/s removed the timing pulley at one point and didnt get it back on correctly. I really am out of ideas right now so honestly someone help me before I freak out...

Oneiros

Hmmm. That eliminates the secondaries as the cause of the problem. Have you tried disconnecting the vacuum advance altogether?