engine and drivetrain 2002 Cabriolet Project Ignition Problems?

[Jamie Francis]

Hello all,

I’m new to this forum but there seems to be some very knowledgeable people on here, a wealth of info.

I have been working on my first BMW over the past three weeks and thanks in a big part to information on here so far I have completed a decent list of items on my 74 2002 cabriolet

Ireland big brake kit, front and rear bush kits, ball joints, tyre rods, shocks, springs, sparkplugs and leads, distributor cap, starter motor, and a new weber 32/36

The car was my fathers and has been off the road for 14 years It has done very few miles and is very dear to me. I am really keen to get it back on the road to enjoy!

 

All of the suspension and steering went fairly well and I moved onto the engine bay and although I understand the basics and if  I know what is wrong I can normally fix it, as far as diagnosing problems I am hopeless so here I am.

 

The car will very reluctantly start with throttle full on but shakes badly, barely runs and dies straight away when gas is let off.

I can’t get it to idle by itself at all.

 

I started by checking spark and have a strong blue spark on all plugs

I then pulled the valve cover, raised one rear wheel and turned it to get it so the tdc mark on the cam shaft at the sprocket end lined up at the top,

I turned the distributor until the mark on the casing, the rotor and #1 plug cable lined up

put everything back together but I still can’t get it to idle or really even run at all.

 

If i open the gas right up I can see fuel puddles through the carb, I am assuming its fairly heavily flooded my normal fix to this is foot flat to the floor and crank but this gets me nowhere.

 

Are the weber's fairly tuned out of the box? or do I need to adjust it?

 

this is all so frustrating I feel so close but so far away,

 

any help with things for me to check would be really appreciated

 

thanks in advance

James

 

 

 

[adawil2002]

Sounds like the carbs are out of adjustment or the jets need to be cleaned. 

[2002Targa]

Looks like a brand new carb.  Proper jetting kinda depends on where you got the carb from.  Try the general starting point for 32/36 jetting.

 

http://www.bmw2002faq.com/_/technical-articles/engine-and-drivetrain/weber-3236-jetting-prescription-r22

[FunkyLaneO]

If you have manually moved the distributor it could be far enough off to not run, try  moving it a little in each direction while cranking the engine to see if it starts up, then move it and tune by ear to see if you can get it to idle, then bust out your timing light and time it correctly. 

 

Also set the idle screw on your carb to the baseline (like 1 1/2 - 2 turns out) to get it running, after the timing is set you can start to tune your carb, you may need to make some changes to the jets.

 

Also make sure there are no vacuum leaks, your car will never run right with a vacuum leak.

 

Here are some instructions on tuning a weber carb: http://www.carburetion.com/Weber/adjust.htm

[Jamie Francis]

Thanks Fellas!, That gives me a few things to try I will have a play and report back!

and to answer the questions,

Its a brand new carb from Ireland Engineering

and the distributor has been moved alot but im hoping ive got it at TDC as a starting point

cheers

James

[Hans]

Timing. That dizzy notch can be anywhere relative to the crank. Get #1 to fire at TDC to get it started.

[Jamie Francis]

So after another day of trying I still dont have it going,

 

I removed the carb and there was a real puddle of fuel in the intake manifold. so I soaked it up and set the idle and idle mixture screws as per the guide linked by FunkyLane0,

 

tried to start and a no go

there's two other non running 2002's here after checking the dizzys on all three one of the other cars had a MUCH better dizzy the points were new it was super clean and the shaft had next to no play, while it was removed I checked the points gap and it was spot on .016 so I put it in the cabriolet

I pulled the valve cover rotated the engine to TDC and twisted the dizzy so the rotor is pointed at #1 and the points are fully open, checked the gap again - still .016

I figured as suggested in the above post that would have #1 firing at TDC.

I also tested the three cars coils and picked the best one put it all back together

 

still a no go

 

another post mentioned vacume leaks so I removed the larger hose that comes off the intake manifold and heads towards the boosters and plugged the hole

would this take vacume leaks out of play?

 

regardless still a no go.

 

at this stage farly fed up I decided i would sit in the car drink a beer and pretend it was going

 

I guess I can try again tomorrow but Im lost for options, the carb is brand new, the plugs, leads dizzy cap and points, are brand new

I have good spark and its flooding so there is heaps of fuel

 

any ideas?

[FunkyLaneO]

Did you try rotating the dizzy while cranking? if you don't have a remote starter switch then you may need a friends help to turn the key.

 

You could also be 180 degrees out if you are at top dead center on cylinder 1, if you are 180 out it will usually backfire (sometimes through the carb so I hope you have a fire extinguisher handy)  Rotate the engine by hand and make sure the points gap closes during the compression stroke (when both valves are closed)

 

If you have a vacuum leak it will usually start, it just runs like crap so that is not likely the problem just something you may encounter after you get it running.

[Hans]

You need to make sure #1 is at TDC on firing stroke. Both cam lobes for #1 should be facing up (both valves closed). If you have a pointer and marks on front pulley for TDC, those should line up. Otherwise, shine light down hole on bell housing to look for OT stamp. Now, you need to make sure #1 fires close to TDC. Easy way is to turn engine backwards (by hand) about 1/8 turn (easier if you pull a few plugs). Rotor needs to back up, but not back to next post. Put a spare spark plug in #1 wire and ground plug. Turn on ignition, turn engine slowly by hand in normal direction (clockwise viewed from front) and watch for spark. Stop turning and consult TDC marks to see if you are in the ball park. Then make sure dizzy cap goes on with #1 wire over rotor tip. This can also be done with a 12v test light, or by rotating the dizzy while leaving the engine at TDC. Let me know if the plug method doesn't work.

[Hans]

points should not be fully open at TDC for this test - they should just start to open as TDC mark comes by pointer

Edited December 3, 2013 by Hans

[Jamie Francis]

Thanks guys,

It was backfiring out the carb, I will perform the checks today, Really appreciate all this I'm learning heaps!

James

[Stevenc22]

If i remove the dizzy, i just put it back in, try cranking, if nothing, i move it ten degrees and repeat until it starts up. Once you get the motor to fire you can fine tune the timing with your ear and a timing gun.

 

Where ever your dizzy is now, try moving it a few degrees either way and see if the motor responds positively or negatively and keep repeating.

[Hans]

Backfiring thru the carb is one symptom of timing totally out of whack. You can try hit and miss, or take a few minutes to do it right.

[Jamie Francis]

right so I had another crack still no go I thought I would add pics of what I'm doing, incase Im doing something stupid

so

I put it in 4th, lifted one rear wheel and turned the engine over until the TDC line on the flywheel was in the middle of the viewing hole,

 

pulled the valve cover and tried to take pics of where the cam lobes are on cyl #1, I also noted the mark on the timing chain pully that I was going off yesterday was not at the top ( infact i checked and using that mark puts me 180 digree out)

now (according to the flywheel) its at TDC

so I turned the dizzy untill the rotor aimed to #1,

then I put the cap back on and plugged a spare spark plug into #1 lead and earthed it, ignition on and slowly turned dizzy untill sparkplug sparked. (made a short video)

BMW Timing.wmv

I tightened the dizzy and pulled the cap to take a few pics

Alas no go

After this I tried to turn the dizzy a bit either way and still no go

Made short video of trying to start

My Movie.wmv

 

I must be doing something wrong

 

thanks again

james

[Hans]

My error. Cam lobes should point down on #1 - valves should both be closed. You should be able to wiggle the rocker arms very slightly since there is no load on either of them. That's the firing position for #1. Now, I can't see clearly which mark you are looking at on the flywheel. There is a line with OT (TDC in German) as well as a ball pressed into the flywheel at 25 deg as I recall for setting the timing with the motor running. You want the OT line to set the static timing. See if there is a mark on the front pulley - it's easier to see. In any event, you want to set dist. so that plug fires a tad before the TDC line crosses either the pointer on the front (if you have one) or the flat side of the hole in the bell housing (drivers side if memory serves).