The 2800 runs totally different then my 3.0!

[execmalibu]

Experts please help! The new 2800 runs totally different then my 3.0!

Drove the new 2800CS to dinner tonight over a windy canyon road... Totally different experience then in my 74 3.0CS auto! the 3.0 is plus and smooth/quiet... The 2800 4 speed is a lot faster, but much noisier, and handled much better etc...

Neither I nor the previous owner has any idea what motor is in my 2800CS... The engine has Webers and the head is date stamped 85... It also has electronic ignition... Thats all I know...

How do I tell what size/year engine it has? )... Were Webers a factory option?


The car runs terrible in the mid range (bucks) but when I give it full throttle it pulls hard to redline... Is the problem caused by Carb adjustment, jetting, linkage or other issues?

 

[x_atlas0]

If the motor was from a vehicle, and not a replacement or crate engine, it should have the original vehicle VIN stamped on the block ring that the starter bolts to. Once you know that, you will know the engine.

 

[61porsche]

Take a picture of the carbs since there are two varieties. But yes, bucking indicates jetting, cleaning, or adjustment.

On the smaller webers, there is a conversion linkage available for progressive secondaries vs. vacumn for those that prefer fun over mpg.

An auto will feel very much different than a manual.

 

[execmalibu]

Here is a photo of the carbs..

The car came with 2 sets of Webers/manifolds ( and a set of Zeniths). I noticed on the car there are electric idle jets and on the extra carbs have standard jets...

Should I use the standard jets? The head has # 1277358 ( 2.8L M30)

 

[61porsche]

carb misdiagnosis

First check your timing thoroughly. For that matter, eliminate everything but the carbs. Just because someone put in a pertronix doesn't mean it's not off because of vacumn advance, weights, reluctor being off, not fully seated, air gap, etc. A retarded distributer will do all sorts of wierd things to running. Especially where you state you have a stumble at mid rpm. No amount of tuning is going to fix a problem unrelated to a carb.

Solenoids- you said the idle is fine. If so, no that's not an issue. Only works at idle.

Webers are webers; meaning the same principles apply to DGVs ( Porsches) as do downdrafts. I don't recall off the top of my head what the baseline screw adjustment is for the mid range but find it and start there after you go through and eliminate everything else.

After that, I'd go through the jet and emulsion tube to make sure they're clean.

Most owners don't realize today's gas is very much different than yesterdays and requires a few adjustments for best running.

 

[execmalibu]

What are the correct jets and emulsion tubes for an M30 2800cc?

Checked timing, distributor works OK...


What are the correct main jets/idle jets and emulsion tubes for a DGAV 32/36 on a stock(?) 2800CC engine?

 

[61porsche]

this should help:

http://www.e9coupe.com/forum/showthread.php?t=7008&highlight=jets

I know someone's posted this info before as I asked them about it.

 

[Stevehose]

rebuild the Zeniths and put them back on that baby

http://www.paltech1.com/

 

[tmason]

So after the purchase what did the Wife think of the bucking on the way to dinner? My would of flip unless I quickly said that's the turbo kicking in HONEY!

 

[OCCoupe]

I had a similar bucking issue. After endless timing and carb adjustments including new jets I took a can of carb cleaner and sprayed it around the carbs/manifolds while the engine was ideling. Turns out I had a vacuum leak at the base of the carbs ie the gaskets were bad. after solving this the bucking went away.

 

[rsporsche]

i had a similar thing on my 73 bavaria - with zeniths ... the bases had warped. we tried everything - we took them off and milled the bases and all was great with the world.

 

[Stevehose]

On mine I trued the flat surfaces of each section - it's a critical part of the rebuild.

i had a similar thing on my 73 bavaria - with zeniths ... the bases had warped. we tried everything - we took them off and milled the bases and all was great with the world.

 

[execmalibu]

THe jets were only 125s The engine needed more fuel! Had some 150s and the car runs

The previous owner was told that these guys(2002AD ..aka CSi ) were the best with E9s and he bought the Webers 5-6 years ago from them.

At the time he also paid them to install the carbs and tune the car... After 3-4 months he got disgusted after being stroked for so long and insisted they finish his CS... Then they charged him 50% more then they quoted when he bought the carbs...

Apparently the car never ran correctly after that time and he let it basically sit for the past 5 years... He was afraid to take it to another mechanic because those guys were supposed to be the best!!

I started checking things and noticed the plugs looked like new... Totally white from running way to lean! I removed the main jets and they were 125s... The car came with extra Webers that had 150 mains so I installed those... The floats were also set very low so I adjusted them also...

The car now runs a 1000% better... I still need to spend a little more time to make it run absolutely perfect but at least now the car is smoooth,fast and fun to drive!! No more bucking/surging!