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DCOE Install (Fuel Supply, Linkage and Jetting Questions)


Beach_Bum

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Thanks again for everyone's help. I actually got to drive it tonight! The sound! I'm addicted to that sound! :) As suspected, the carbs weren't syncing properly because of the throttle linkage. Once I figured that out, I was able to get them synced and get a steady idle at about 900 rpm.

I still have work to do though. I need to get my wideband hooked up. It's already routed to the cabin, I just need to figure out the power wiring. The car ran ok. I know there's a LOT more potential once I get the tuning figured out. There's a hesitation at low RPMs and one of the carbs is popping at about 1/4 throttle.

I also think I need to check the timing again. I got a new light with an advance setting and, after reading through the instructions tonight, I'm not sure I used it correctly. What I did was dial in the advance on the light, then time to the ball without getting a baseline setting first. That's what I get for not reading first lol.

 

 

 

Edit: So based on feedback from 73tiiguy and zinz, sounds like I need to adjust my timing. Hopefully I can get at it tonight and report back.

Edited by Beach_Bum
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Got back at it tonight. Re-did the timing by setting my light to 30 degrees advance at 2,000 rpm, timed to the OT line. Drove it, didn't hear any pinging so went back and set it to 33 degrees at 2,000 rpm. Drove it, still sounded good, so left it there. That part went smoothly.

Now the problem...The car stumbles and the left carb pops at 1/4 to about 1/2 throttle. I've tried playing with the mixture screws, but I can't adjust the popping out. I'm also at 4-5 turns out from seated on all four screws which seems to be too much from what I've read. These are brand new 151 DCOE 40s. Both carbs are sucking the same amount of air, and all the linkage seems to be functioning properly.

Sound like a vacuum leak? I'm goin to buy some starting fluid tomorrow and spray it around to check.

Edit: also should add that I've changed out some of the jets based on TEP Steve's suggestions after he asked questions about my engine upgrades. Right now, everything is stock except for the IE full exhaust and shorty headers.

Here are the jets that I changed:

Main jet 120

Air corrector 160

Idle jet 50 F8

Edited by Beach_Bum
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Bummer...Wrong idle jets. Too lean. Gonna need to jump up a size or two...

Do you have the air filters attached? ... That would help, slightly.

At least Weber jets are easy to come by...

Ed

'69 Granada... long, long ago  

'71 Manila..such a great car

'67 Granada 2000CS...way cool

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Bummer...Wrong idle jets. Too lean. Gonna need to jump up a size or two...

Do you have the air filters attached? ... That would help, slightly.

At least Weber jets are easy to come by...

Ed

Hey Ed,

Yeah the air filters are attached. I still have the 45 F9 idle jets that came with the carbs. Maybe I'll give those a try before ordering new ones.

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You could try the 45f9 jets, but they will likely be about the same or make it worse.

Read this http://www.bmw2002faq.com/topic/37704-dcoe-idle-jets/

I'm not sure how much richer you should go but 4 1/2 turns out is too much on the idle mixture.

I'm seeing where others had success with a plain 55 idle jet. No f prefix.

Might drop a line with Steve at TEP since he gave you the jet recipe.

No worries, it should be a simple fix.

Ed

'69 Granada... long, long ago  

'71 Manila..such a great car

'67 Granada 2000CS...way cool

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Update time.

Got my WB02 installed and finally got the new jets in the mail and installed them tonight. They are 55 F9. I also installed 125 mains. Happy to report the car runs much better. No more lean pops, and the screws are only about 3 turns out now (these are new DCOE 151s).

That said, I still think I need to go up at least one more size.

Here are the A/F numbers I'm seeing:

Idle 12-12.5

Steady cruise at > 2,500 rpm 14.5

Steady cruise at < 2,500 rpm 17-18

Full throttle 11

If I lean out the mixture at idle to get to 14.7, the lean popping comes back at steady cruises under 2,500 rpm and my A/F jumps to 18-19.

Should I go to a 60 F8 or maybe 65 F8?

Edited by Beach_Bum
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dang... you are soooo close, but it sounds like you are still too lean.  Those mixture screws should be about 2 turns out.  I bet the 60f8 will be perfecto.

 

Since you already have the 50f9 jets and a set of drill bits...you might try your hand at drilling the old jets to 60 and see how the engine reacts. Now... the f9 hole is bigger, soooo, maybe drill to 58 and see what that gets you.  You can always then re-drill to 60 if 58 isn't big enough.

 

Ed

'69 Granada... long, long ago  

'71 Manila..such a great car

'67 Granada 2000CS...way cool

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Thanks Ed,

 

I PMed this info to you, but am going to post it in here as well, since I've requested a thread title change and hopefully other members can benefit from it.

 

I tried drilling my 50f8 over the weekend with the smallest bit I had, but it didn't work. The idle was great, and I thought everything had went smoothly until I tried to drive it. Wayyy too rich under throttle and the car would barely move.

 

I'm going to order the 60f8 and see how that goes.

 

 

Edit: Thread title has been updated.

Edited by Beach_Bum
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Update:

 

I received and installed 60 F8 idle jets last night and things got a little bit better. I still think I need to go one size bigger because I'm still 3-1/4 turns out on my adjustment screws, but I'm going to keep it like this for the weekend. According to the TEP site, new DCOE 151s should be 2 1/4 - 3 turns out. Partial throttle AFR is much better now. Here's what I'm seeing:

 

Idle 12.5-13

Partial (1/8-1/4) throttle 13.5-14

Partial (1/2-3/4) throttle 12.8-13.2

Full throttle 12.2

 

Current Jetting:

Choke 32

Idle 60 F8

Main 115

Em Tube F11

Air Corr 160 (should probably go bigger here to lean out WOT)

 

I also noticed I wasn't opening the butterflies all the way at full throttle, only getting to about 65%, so I'll have to play around with my linkage at some point. That being said, I feel like I'm getting close. Couple more tweaks with jetting and linkage and I should be good to go.

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Agggghhhh... so frustrating!  I thought we had the idle jet pegged...

 

You are only opening about 65% with your foot on the floor?  Something isn't right in the linkage...  Disconnect the throttle pedal rod and see if you can get full actuation with the linkage pieces on the carb/manifold. Then see if you have some interference with the throttle pedal rod/etc...

 

Dang... was hoping to hear your were tearing up the streets by now. :(

 

Ed Z

'69 Granada... long, long ago  

'71 Manila..such a great car

'67 Granada 2000CS...way cool

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Agggghhhh... so frustrating!  I thought we had the idle jet pegged...

 

Tell me about it! Is it normal to need such a big idle jet? I've seen a few other people running 65s, but not many.

 

As for the linkage...I made sure the pedal/rod isn't hitting anything. The problem lies in getting the arms on the linkage rod to rotate enough to open the butterflies completely. I briefly played with the angles in which they were sitting on the rod last night but ran out of time. I'll try to get some pictures of the linkage tonight to see if you or someone else may have some input. The setup is similar to what Emyers did a page back, in where I've added an extension to reach the OE throttle pedal/rod.

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oh yeah.... the ol' extended throttle arm linkage piece... Guess you need to modify it some more.

 

As for the idle jet... as long as you are seeing results headed in the right direction, keep up with the larger jet. You are right at Sea Level, so you may need to run a bigger jet than other of us who live further inland.  3rd times a charm!

 

Get that linkage worked out before the next jets arrive so you can properly stomp that beast.

 

Ed

'69 Granada... long, long ago  

'71 Manila..such a great car

'67 Granada 2000CS...way cool

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Bum, be sure to check that your gas pedal has a full range of motion.  Sometimes the pinch nut on the lever that transfers downward motion isn't tight and will slip.  Or you can move the lever point closer to the throttle shaft - there should three holes in the throttle rod levers.

 

part number 7 is the lever - the pinch bolt and nut is on the right end of the lever pictured.

http://realoem.com/bmw/showparts.do?model=2552&mospid=47140&btnr=35_0196&hg=35&fg=10

 

Tell me about it! Is it normal to need such a big idle jet? I've seen a few other people running 65s, but not many.

 

As for the linkage...I made sure the pedal/rod isn't hitting anything. The problem lies in getting the arms on the linkage rod to rotate enough to open the butterflies completely. I briefly played with the angles in which they were sitting on the rod last night but ran out of time. I'll try to get some pictures of the linkage tonight to see if you or someone else may have some input. The setup is similar to what Emyers did a page back, in where I've added an extension to reach the OE throttle pedal/rod.

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Thanks again for the advice, guys.

I told myself I wasn't going to mess with it this weekend, so what's the first thing I do when I get off work? Mess with it! I couldn't resist, I hate unfinished projects. Good news is I got the butterflies to open to about 98% by bending the OE throttle rod closer to the linkage arms, which gives it more rotation. What a difference! It still runs rich (12ish AFR) at WOT so I'm going to order a bigger air corrector and a bigger idle jet to get the adjustment screws in more. I have some 200 airs that came with the carbs, so I might try them, but I think they'll be too big because I'm at 160 now. After that, hopefully I'll be set!

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Ok, I need some help.

I tried the 200 (from 160) air corrector to try and lean out my AFR, but I'm still running rich (12-12.5) at 1/2 - WOT. It didn't really seem to do much at all.

Here's my current jetting setup:

Choke 32

Idle 60 F8

Main 115

Em Tube F11

Air Corr 200

For those who don't want to read back, these are for brand new 40s on an internally stock motor with IE full stainless exhaust and shorty header.

Should I go down on the main...isn't a 115 pretty small already?

Could it be float level? I never checked it because they were new carbs (I know, stupid) so I'll check it tomorrow.

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