1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Dellorto Carb Help

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Old 01-04-10 | 11:42 PM
  #26  
pinoyremix's Avatar
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oh i think the needle they put in the kit is the 300 so see if your original one is still good before using...mine was..
Old 01-05-10 | 11:19 PM
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Well after cleaning the carb and what not I've concluded that the carb aside from the fuel pressure issue is not the cause for my idle problems, I've taken off the lower manifold, the gasket was soaked in gasoline but otherwise in good condition, inspected all the gaskets and blockoffs and nothing was blatently leaking or anything so I'm still not sure what the cause is but I will be ordering/making a blockoff plate for the omp within the week and getting the correct bolts to block off the injectors and hopefully that might help with the blow-by issues as well as possibly this idle issue from perhaps a worn out injector or something.
Old 01-09-10 | 08:33 PM
  #28  
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Finally got my block-off plate in from Pineapple as well as got the bolts required for the injectors, got those teflon taped and installed, re-rtv'd my emissions plates and put everything back together, gonna let it sit over night and hopefully tomorrow I can get the car started.

I've been reading about premixing oils and which ones are best and it turns out MMO is not supposed to be used as a premix on its own, now my OMP was working and tied up to about half to full flow but I still don't have confidence it was doing a job and this might be some of the cause of why my car is having lung mustard issues and it hasn't before.

Would replacing a quart of oil with the Lucas Oil Stabilizer and correcting my premix [O'Riellys carries Master Pro 2 Cycle, any good?] regiment possibly help slow the blow by issues? I've done most everything I can to get the oil filler neck and center iron ventelated, I currently have vaccum lines running from both nipples to connections on the back side of the air filter mounting plate so it does draw a bit of vaccum at all times.
Old 01-10-10 | 11:01 AM
  #29  
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One more small update.

Got the car started today, managed to get it to run for about 2 minutes nice and smooth then it started acting up again, low and behold the main jets are again dumping fuel into the barrells which is flooding my motor. gonna check the fuel pressure AGAIN today and possibly get a different little gauge as I'm not sure this one is entirely accurate, lower it down to 2.5psi and see if it will work then.

Other problems I have discovered:
Brake Master Cylinder is leaking so thats gonna need a rebuild/replace.
Exhaust flange gaskets.
Old 01-10-10 | 01:03 PM
  #30  
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http://mrcmfg.com/catalog/product_in...roducts_id=163



Great fuel pressure gauge I use it on the REPU. Dell will run on 2.5psi.

Do you have a return line for the fuel line? That'll allow the fuel pump to live longer, keep it cool. Fuel pumps don't like to be dead-ended.

Are you absolutely sure the floats don't leak and fill with fuel? And are set at the proper height?
Old 01-10-10 | 04:13 PM
  #31  
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According to my current gauge the mallory will only go down to about 3psi once Ive actually taken the adjustments screw out of the regulator.

I checked the ignition, MSD and spark plugs, all checked out.

I took the plugs out and had my mum crank the car and there were no noticable dead sides though the rear rotor felt stronger than the front on all 3 sides.

Short of compression testing the motor I'm pretty lost. Ive checked and checked and checked again and again and again and the car still will not run right. I took it around the block and part of the way it was fine but I get on it a little and it sputters and smokes and kicks, get on it again and it may smooth out, pulled into the driveway and the motor was still idling funny, I turned it off, restarted it and it still ran funny, turned off and restarted and it ran fine for a second or so. so it seems logical that something is not clearly BROKEN but it may be an apex seal sticking? when my mum cranked the car I did note that the vapor comming out of the motor onto my hand wasn't perfectly clean, it was actually somewhat dirty. as well when it was sputtering a few times it sounded like one entire rotor quit working then other times it sounded like only one side wasn't working.

I have NO clue as to why unless its a motor issue which in all honestly would not suprise me because the motor was beaten pretty good prior to me buying it and the fact that I used only MMO as a premix probably means the sideplates are worn somethin fierce so I'm just gonna aim to start saving for an S4 motor and swap all my current stuff over and probably chop my harness and relocate the MSD while Im at it.
Old 01-11-10 | 08:47 AM
  #32  
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I thought the same thing about my Holley regulator but found that
once you tighten the locknut back down it settles down and limits as
expected. So to adjust it I have to loosen the lock nut back it out,
tighen it down and let it all settle down for a minute or so then
see what the guage reads. Repeat until I got the psi I wanted.

If you can't get below 3 psi you will never be able to tune the carb
reliably. Its designed to work at a max of 2.5 psi. Over that and
you will get a randomly enriched mixture with the symptoms being
sputtering, idle variation, bogging etc. Also only tune the carb when
the car is hot, I mean just off a hard run hot, otherwise it will not
be a consistent.
Old 01-11-10 | 10:28 PM
  #33  
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Have you messed with the pump jets at all? Even if you haven't maybe the previous owner did and that's why the fuel pressure is higher than normal. Since the pump jets are two brass pieces the holes need to line up for proper operation. What happens is the gaskets for the pump jets get squished a little bit each time you tighten them and the alignment of the holes goes more and more out of sync. The bandaid is to up the fuel pressure but then you end up getting to much fuel in the housings which in turn thins the oil lubricating the housings. This leads to poor sealing at idle speeds which causes the running on one rotor symptoms you spoke of because the compression between the two housings are too far apart. It also causes the smoking you're talking about.

I have the same carb on the same motor that did everything you mentioned in your posts and spent countless hours searching the internet and pulling my hair out trying to figure out the problem. Go to this site, http://www.gruntled.com for diagrams and specs on the dellorto carb. hth's.
Old 01-12-10 | 04:37 PM
  #34  
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The Holley regulator also has a lower pressure spring available that definately lowers the fuel pressure.
Old 01-13-10 | 05:51 PM
  #35  
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tg: as soon as I can find employment I will get a new fuel pressure gauge and for sure check to see what the fuel pressure REALLY is as the one I've been using seems to beaten to hell so chances of its accuracy are...well speculative to say the best.

Rotor: Never touched the pump jets only adjust the idle jets as I did not want to get into messing with those before I knew more about the carb itself but I will definately read into that site and check everything out.

Drive: I'll look into taking the FPR out and cleaning it to see if that helps.


Gonna check all the ignition wiring tomorrow including that from the ignitors, to the MSD to the coils. seeing as how the MSD is INSIDE the car I'm thinking I might cut and rewire the MSD box into the engine bay to save me alot of wiring, possible resistance and loose connections.

Is there a way to get that dust cap and the distributor rotor off the distributor without taking it out? the timing was set by the previous owner and I don't want to have to go through the ordeal of static timing the car then adjusting it back to the way it was. I managed to peak under that dust cover if thats what it is and the whole pickup assembly looked to be pretty dirty.

Sorry for the crappy phone vid but its the best I could do and if you listen to when I give it a little rev it kicks and sputters then after Im done revving it, it seems to go calm then shortly after it returned to that rolling idle.

Carbed GSL-SE Idle Issue
Old 01-15-10 | 01:26 AM
  #36  
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Bump for any sort of help, question being is there a way to swap out the ignitors without taking my distributor out? I'm not too confident in being able to re-time the car with the advancment that was put on it by the previous owner. when I drove the car around the block after finally getting it started it was what sounded like missfiring like crazy and if I stepped on it it sounded like a machine gun but not backfiring and all missfires were a bit more violent then usual as well a little bit of smoke was out the back but I could not see the color so I'm assuming it might be an ignition issue not a fuel issue.

I've checked the spark plug wires [MSD 8mms both are 80-100ohms] and checked the coils [both were between 1.2-1.35] so that brings me to the MSD box itself and the distributor but more specifically the pickup and ignitors, could MSD kill the ignitors? or is the fact that they are upstream to the ignitors have no affect on them?

As well could it be the fact that I also run 93 in the car possibly be the issue? I was advised to run 93 [since late august] after talking to a more trusted friend and with the 26° advancement on the ignition it seemed to run alot smoother than the 87 I had been using when I bought the car...I'm still hoping its not a motor issue, I did take the plugs out and have my mum crank the car and all pulses felt the same front and back so I'm pretty much lost at this point.

Spark plugs are also nearly new, didnt even get to run them for 2 weeks before the issue began and i've tried running my other ones and no success. the plugs are the same as the BUR9EQs but the pronged , as well the car runs this way hot and cold.

Sorry for all the questions I'm just trying to eliminate every possibility I can think of and for some reason when It's my own car I'm working on its harder for me to do so, any help would be very much appreciated.

here's the video again, its telling me there is an error in my other post:
Old 01-15-10 | 04:05 AM
  #37  
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Are the plugs fouled? If they got fuel soaked from trying to start it with no start it doesn't matter if the plugs are 5 minutes old. A wet spark plug will not conduct all the spark energy to the tip. At the very least try replacing the plugs on the rotor that's giving you the problems if not all four.
Old 01-15-10 | 04:14 AM
  #38  
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They were a tiny bit damp but not soaked, they are black but not caked on either.

Since the issue now not only happens on idle but under all circumstances I'm not sure its the carb or intake because I know for a fact the idle jets and screws are very clean and the issue still remains. I wish I could rebuild the carb so I could say for certain but not having a job or money is really REALLY making this hard.

Could I theoretically run wires directly from the ignitors to the coils and bypass the MSD to eliminate that as an issue because I've read that if not properly cooled the box can cook itself and well mine sits under the passangers side carpet where the ECU would go and doesnt really see alot of airflow and come to think of it when the temperature around here began to drop I started running with the heater on full blast all the time and I plugged a gromet in my firewall that was blowing air out right above the 6A I dont know if it may have blown all that air down into that footwell and possibly gotten it nice and hot....
Old 01-16-10 | 04:53 PM
  #39  
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A quick bump.

I'm going to go ahead and take off the carb again but this time take out the jets and emulsion tubes as well as the float valve and check it all and blow them all out to see if this is the issue because as I spend the days thinking endlessly about what has changed since the problem began and what the symptoms are the only thing I've noticed or found that the car has done on its own is the fuel pressure spike so I'm going to take out the valve needle seat to make sure there is no blockage in there and the jets/emulsion tubes to make sure they are not blocked or gunked up as well, now are there any tips to taking the jets and tubes out that I should know about other than use quite a bit of caution not to break or bend anything? do the needles simply fit into their respective tubes or must they be properly adjusted to a certain depth etc.
Old 01-19-10 | 07:59 AM
  #40  
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Update: Got the 5 jets out of the carb after a light bulb coming on and me finally realizing how the carb works and where everything is, all the jets appear to be in decent condition but I'll keep checking and seeing whats what and making sure there are no blockages, as well record the numbers for further reference.

Main Jets: 2.2
Main E-Tubes: 7772-8
Idle Jets: .75
Idle E-Tubes: 7850-8
Starter Jet: .95
Starter E-Tube: 7482-4

Anyone care to verify that these should be the right setup to be running? Any help would be great gents. Not sure how to get to the pump jet to check, am I going to need to take the carb off and flip it over?
Old 01-19-10 | 09:38 AM
  #41  
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Originally Posted by DarrenTRS
Update: Got the 5 jets out of the carb after a light bulb coming on and me finally realizing how the carb works and where everything is, all the jets appear to be in decent condition but I'll keep checking and seeing whats what and making sure there are no blockages, as well record the numbers for further reference.

Main Jets: 2.2
Main E-Tubes: 7772-8
Idle Jets: .75
Idle E-Tubes: 7850-8
Starter Jet: .95
Starter E-Tube: 7482-4

Anyone care to verify that these should be the right setup to be running? Any help would be great gents. Not sure how to get to the pump jet to check, am I going to need to take the carb off and flip it over?
Pump Jet is an 80.

The car is still flooding like hell and it seems to be the front barrell is still wanting to just pour fuel into my car so I'm done for now, just gonna let the car sit until I can purchase a rebuild kit and then I will try to take it apart correctly and clean everything because right now it won't even fire and when it does it'll fire twice then nothing or it sounds like one rotor is going, I've taken the spark plugs out and cranked it and all the sides sound identical but I'm a bit over the edge right now.

Thanks to all who helped.
Old 01-19-10 | 10:02 AM
  #42  
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It's my understanding that the Dell and the webers are pretty much the same. That being said, you might find some helpful info on this posting I put up of weber info.
https://www.rx7club.com/forum/showthread.php?t=882842
Old 01-19-10 | 10:12 AM
  #43  
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Originally Posted by installer67
It's my understanding that the Dell and the webers are pretty much the same. That being said, you might find some helpful info on this posting I put up of weber info.
https://www.rx7club.com/forum/showthread.php?t=882842
Appreciate the info and yea it does seem they are very similar my issue seems to lie either with an issue concerning the accelerator pump which is allowing fuel to go into the jets under idle conditions when it should be blocked or yet again my bowls are overflowing, only thing is it only happens to the front barrell, rear seems to be unaffected. So I'll just have to wait till I can get that rebuild kit so I can take it all apart, clean it properly and make sure everything is in check.
Old 01-22-10 | 03:43 PM
  #44  
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Well gentlemen....I have victory! turns out the cap on the bowls was pulling in false air either through the choke or the gasket itself so I'm going to take it apart, clean it up and install a new gasket and it should be good! I also broke the fusable link box installing a new battery cable so I upgraded to the FC fuse box in the process!!! thanks to all who helped, I've learned a great deal about my car and patience!
Old 01-22-10 | 03:53 PM
  #45  
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Glad to see you g/o/t it running
Old 01-22-10 | 04:07 PM
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Originally Posted by Jeezus
Glad to see you g/o/t it running
Haha definately.
Old 01-22-10 | 05:06 PM
  #47  
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So how did you finally determine what the problem was?
Old 01-22-10 | 06:24 PM
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Originally Posted by 88SE_HI
So how did you finally determine what the problem was?
7:30AM rolls around and I head over to O'Riellys to pick up my battery that they were charging for me due to 2 months of basically cranking with a maximum time of maybe 10 minute actually running.

Well the whole day started out with replacing the positive battery cable as the clamp was broken so as I was replacing that and trying to re-wire the accesory line for the fuseblock I broke the insert off going into the fusable link block so after 20 minutes of rage and cursing I managed to find the FC Fuseblock I bought about 6 months ago for this specific reason and proceeded to wire that in.

As I was wiring it in I decided to test everything and I for some reason couldn't get the fuel pump to work so I continued to wire up the injectors and computer [which I dont have] and that solved the issue so I decided to go ahead and give the car a quick crank to see if all the electronics checked out well it kicked right up, I shut it off before it could start and after jumping for joy and screaming I finished cleaning up.

I had also changed out my spark plugs to some BUR7EQs as after a discussion with a friend of mine I should be running a slightly hotter plug in the leading due to running 93 octane in the winter and the MSD so I'm quite sure that helped.

So I proceeded to get the car started and immediately the carb started flooding again, which I believe is due to the floats being too old and bad and apparently my carb sits at an ever so slight angle so it floods only the front barrel and not both at the same time. And as this happened I went ahead and shut the fuel pump off via switch and took off the bowl cap, I have for some time wanted to start the car without the cap on to see what it would do and so I decided to finally do it, of course without the cap on the choke went apeshit sucking in as much air as it could so I plugged it with my thumb and like heavenly angles in course my idle went dead smooth......I nearly cried so I tried it once again taking my finger off slightly to allow it to raise the RPM then covered it again and revved it a few times, sounded great. shut the car off, cleaned up and now I'm here dead tired.

Sorry for the novel but I honestly don't think any one thing did it all, I'd like to think everything helped a little from the fuse block to the plugs to getting the battery recharged etc.


So in a recap of these past 2 months:

Symptoms:
sounding uber ported while idling at normal speed
slight missfire under free-rev
massive missfire under load

Cause:
Vaccum leak by way of choke/bowl cap. thought it seems to have been letting more air into one barrel then the other which is why I think I got the "ported idle" as it was fighting the other rotor for a stable idle.
Old 01-22-10 | 07:04 PM
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Thanks for the Novel explanation I am about ready to take on a dell installation myself.
Old 01-22-10 | 07:24 PM
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Originally Posted by 88SE_HI
Thanks for the Novel explanation I am about ready to take on a dell installation myself.
Very cool and good luck. I assume your using the RB upper intake manifold?

Only advice I can give is just make sure its all clean and everything is good, try not to crack the top open too many times as I'm quite sure thats part of the reason why mine is leaking now, just have faith and have fun.


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