Opel GT Forum banner

1 - 14 of 14 Posts

·
Registered
Joined
·
74 Posts
Discussion Starter · #1 ·
Ok,
I spent the weekend modifying the plenum on my intake manifold and triming the spacers to fit my new(rebuilt) weber 32/36 DGAV with anti-deisel solenoid properly hooked up, I got everything hooked up (exept the charcol cannister-can't figure out where it the two hoses go) I followed the directions ogts sent and set the idle mixture two turns out from bottom and the car will start with the throttle part way open but won't idle at all, I was able to set fast idle by manualy opening the choke with the engine warm and at the slowest speed without dying it would run ok for about 15 seconds then almost die for 2-3 seconds then run ok etc etc. Turning the idle mixture during fast idle did nothing-but shouldn't anyway cause the primary circuit is in play now-right? so basically it will run well at anything other than idle but has the wierd cycling thing going at the slow fast idle setting. I did my best to check for vacum leaks but couldn't find and with either the carb cleaner or the hose in the ear method, but without a stable idle the carb cleaner method is a little hard to use. the main jets (in the bowl) are both 140's and the primary air is a 170 with the secondary being a 160 and I just rebuilt this thing and all the passages were clear. I have the haynes weber book but have so far had a hard time figuring out where to go from here. Please, someone help! this thing was actually running well before I took the old solex off! -the car is a 74 manta automatic
 

·
Senior Contributor
Joined
·
903 Posts
The fuel first flows through the main jets then the idle jets and then through the idle mixture adjustment. The idle mixture adjustment screw will only fine tune the idle mixture. If your main or idle jets are wrong, the screw won't do much of anything. It's been a while since I've run a 32/36 but 140 sounds a bit small and you shouldn't have the same main jets on the primary and secondary of this carb. This is a stock motor, correct?

If you're CERTAIN that you don't have any vacuum leaks and your ignition timing is correct, then I'd start to adjust the jets. Start with the mains. I posted a procedure for this in the last week

http://www.opelgt.com/forums/showthread.php?s=&threadid=1530&

-Travis
 

·
Registered
Joined
·
74 Posts
Discussion Starter · #3 ·
Thanks for the reply!,
It is a stock motor with only 39,000 original miles, the ignition is correct-was running well with newly installed crane xr-700 unit, in Rally Bob's article on the yahoo site he said he usually starts with 140's and sometimes uses a 135 for the primary for economy, I am at sea level as well, so I may need bigger primarys, so I should tune the main jets at the fast idle setting and then worry about base idle settings? -makes good sense, now I just need to find a source of different jet sizes......, is it reasonable to just drill the jets out larger to make them bigger or is that asking for trouble?
 

·
Detritus Maximus
Joined
·
2,787 Posts
The first thing I would do is replace the Idle Cut-off Solenoid with a plug/non-solenoid piece. I dealt with this before on a car (32/36 on a stock Manta motor) and found the solenoids can be erratic. Do not trust it to work even though it seems like it does.
 

·
Registered
Joined
·
74 Posts
Discussion Starter · #5 ·
I was wondering about that, should I just put in a bolt with the right thread? There is also a vacum fiting on the weber right above the throttle that looks like it has threads on the inside, the ogts tech tip has it labeled as a venturi something or other but the haynes book doesn't even mention or label it any where-I tried pluging it and it didn't seem to make a difference but I guess I'm so far off that it may not matter....... Thanks for all the help, this is all new to me
 

·
Detritus Maximus
Joined
·
2,787 Posts
Check with someone local that deals in Webers (maybe a vintage VW, Porsche, Alfa, type shop) or contact Pierce Manifolds in Gilroy, Ca. or Redline Weber for the correct solenoid replacement. It will be a metric thread

As I said, I had exactly the same symptoms. It wouldn't idle on the idle circuit but it would if I used the throttle screw. What was happening was the idle solenoid would not opening consistently thus shutting off fuel flow through the idle circuit.
 

·
Registered
Joined
·
74 Posts
Discussion Starter · #7 ·
So,
here's a pic of the fitting that the ogts tech tip calls a "venturi vacuum fitting" in their diagram it shows what looks like a screw in the end of it how does everyone hook this up? mine has no screw, when I hook a hose to it I can blow air through it so I think I need to do something with it. should it just be plugged?
-thanks again for all the help
 

Attachments

·
Super Moderator
Joined
·
9,742 Posts
Just find a rubber vacuum plug at your local parts store and plug it.
 

·
Registered
Joined
·
74 Posts
Discussion Starter · #9 ·
O.K.,
I have pulled the carb, rechecked everything, and I noticed it was hard to blow air through the primary idle system. Not sure if that's normal or not, so I reinstalled it and it fires right up idles great with the choke engaged, once it warms up it dies again, I just pulled the primary idle jet from behind the solenoid, and it's been crushed by the solenoid, there was no o-ring in there and the little holes in the side of the jet were crushed shut by he over-tightened idle solenoid! I'll be ordering a new one and a idle jet holder from pierce on monday(man I wish they were open on the weekend!) -they will ship small things very cheaply through the mail, I'm thinking about just buying theire jetting kit for fine tunning. I feel like I have a good grip on the proccess of jetting the primaries and idles but how do you go about optimizing the air correctors and emulsion tubes?, also has anyone used the redline "high performance" jet kit? -they make some big claims but it seems hard to believe they can jet my carb via the mail!
Thanks again for all the help! here's a pic of the jet:
 

Attachments

·
Detritus Maximus
Joined
·
2,787 Posts
Do you have the Haynes Weber book (blue cover)? If not, get it. I think it has some tuning stuff on the air correctors and such, but in a general sense. I know I read about it somewhere, just have to remember........
 

·
Registered
Joined
·
74 Posts
Discussion Starter · #11 ·
I have the haynes book and have been pouring over it this last week and don't recall any info on air jet/emulsion tube tuning, If you can remember where you learned it or pass on your method it would be much appreciated,
 

·
Detritus Maximus
Joined
·
2,787 Posts
Look in chapter 5, section 4. It is not a 'how to', but it tells you what they do. I'll do some more checking, I don't think this was what I was thinking of. It might be on the Redline Weber site or Pierce Manifolds.
 

·
Registered
Joined
·
74 Posts
Discussion Starter · #13 ·
Alright!,
I replaced the old mashed jet and switched the solenoid for a jet holder and it runs great, all of the idle adjustment proceedures worked and now I am in the process of jetting the mains, I'm close at 140 but a little lean (plug reading method). Opelbits, I haven't found any direct info on the emulsion tube/air corrector tunning but I did find some datsun 510 and bmw 2002 web sites that describe drastic improvments with emulsion tube upgrades, problem is the weber tubes are not named in a coherrent manner so it's hard to know which ones may change the performance the way you want. Let me know if you ever dig up any info on it, thanks once again!
 

·
Detritus Maximus
Joined
·
2,787 Posts
Hey! Glad it's happy now. Your welcome for whatever help I provided. When I get home tonight I will find the phone number for a guy in San Fransisco that was EXTREMELY helpful with mine. I told him what the problem was (after I messed with it for two weeks) and he diagnosed it in 5 minutes. He has TONS of Weber experience.
 
1 - 14 of 14 Posts
Top