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Frustration growing - help with vacuum leaks


Pablo M

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I just want a runner…

1972 2002tii

Has metal replacement TEP brand runners instead of the plastic ones, with silicone couplers. Not elegant but I’ll live with it for now. 

 

Short version: chasing vacuum leaks unsuccessfully. Not sure where else to look. Help! 
 

Long version:

Car is newish to me, having bought it late last year. Previous owner let it sit for 10 years so there’s plenty of dry rot in rubber bits. It ran rough and I’ve been tackling various things, brakes first. Now the engine. 
Tracking down a sticking throttle (fixed!) I discovered the WUR hose not connected at Kfisher end, capped off but also showing signs of massive dry rot. I replaced it and engine ran smooth! So I know the timing and such isnt too far off. 
Here is how it ran after the WUR hose replacement (first video):

 

 

I took it  for a long drive to shake it out some more, about 50 miles up Pacific Coast Highway and into one canyon. Fun! Then on the way back started to run rough again. 
I thought maybe plugs got fouled? Checked them and I think they look good:image.thumb.jpeg.330b5bab5acab99734e46f9862a9bdce.jpeg

The gaps look good, not perfectly consistent but these don’t look bad to me (but correct me if I’m wrong please!). Do these look ok? 

 

Next I shot carb cleaner at the intake couplers and definitely affected the idle positively. So I bought new silicone hose to cut into couplers, especially given the ones on it were too short-they were 2”IDx2”long originally but these were only 1-1/2” long. Replaced tonight thinking problem solved. 
still runs rough, better but feels like it’s misfiring. 

 


My frustration comes from KNOWING it can run smooth, per first video. 
in addition to the WUR I replaced the brake booster hose and check valve (oriented correctly given the smooth running). Replaced valve cover hose to air box, replaced cap at TB where there should be a hose from valve cover hose (but again, it’s already run smooth as is). 
 

I really am at a loss. I don’t know where else to look.  Seems to me there’s a vacuum leak somewhere given that it showed it can run smooth. One option is to replace the runners with the 73-74 metal bolted runners/intake/manifold to eliminate that as a possible cause, but I just lost my job and would prefer not throwing money at the problem right now. 
 

Any advice? Could use a hug…

2003 e39 M5 (daily)

1986 e30 325es (sons car)

1972 2002tii (fun daily alternative)

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The plugs look ok,maybe gapped a bit wide for a traditional points ignition system. Whats the situation with the ignition? Tried replacing the condenser? HT leads in good condition? Rotor arm ok?

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'59 Morris Minor, '67 Triumph TR4A, '68 Silver Shadow, '72 2002tii, '73 Jaguar E-Type,

'73 2002tii w/Alpina mods , '74 2002turbo, '85 Alfa Spider, '03 Lotus Elise

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1 hour ago, dlacey said:

The plugs look ok,maybe gapped a bit wide for a traditional points ignition system. Whats the situation with the ignition? Tried replacing the condenser? HT leads in good condition? Rotor arm ok?

I mean, everything is a possibility given how long its sat. I have pretty good records, back to new, for the car and show there was a tune up (with points/condenser/dist cap/etc replaced) back in 1997. There's a 13 year gap in records between 2000-2013, when the previous owner bought it. There's a 30,000 mile gap in recorded mileage, but in 13 years that could be 130,000 miles. And no records means the car could have been tuned up again and parts replaced, or not.

 

But, The fact the engine ran great before my long drive makes me think the ignition system isnt at fault here. I could be way off base but given the car ran roughly, then ran great means its capable of running well given the ignition and most other bits. That's what's tripping me up...and frustrating me. The HT leads felt sturdy when I pulled them and look in good shape, but dont know how to test them. I'm stumped.

2003 e39 M5 (daily)

1986 e30 325es (sons car)

1972 2002tii (fun daily alternative)

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1 hour ago, Pablo M said:

The fact the engine ran great before my long drive makes me think the ignition system isnt at fault here.

 

Distributors require maintenance or the moving parts inside can get 'sticky' and not always behave consistently.  For example, the center post needs to pivot on the shaft to provide centrifugal advance and then the little tiny springs need to pull it back to the starting point.  If it isn't clean and lubed, it won't necessarily return to the starting point (every time).  Below the points plate the weights and springs can get pretty grimy and there is a friction reducing 'pad' under the weights that gets brittle and breaks apart.  Those bits can interfere with weight travel/return.  (only the early style pre-'75 have the pad)  The amount of advance it'll give tends to increase with wear and it usually comes in sooner as it gets older; so the advance curve might not be ideal.  All that to say, they can behave in weird inconsistent ways.

 

What is the number stamped on the side of your distributor?

 

Have you checked the dwell lately?  If it changes, it'll take the timing along with it.

 

1 hour ago, Pablo M said:

The HT leads felt sturdy when I pulled them and look in good shape, but dont know how to test them

 

One way to look for a misfire is to move your timing light from cylinder to cylinder to watch for gaps between flashes.

 

+1 for making sure the plug gaps are between .024"-.028".  Err on the tight side, so they can erode and still stay in spec.

 

 

 

 

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10 hours ago, Pablo M said:

The HT leads felt sturdy when I pulled them and look in good shape, but dont know how to test them. I'm stumped.

Replace them, they can appear to look fine and deliver proper current at idle but go crappy under load ( ie: higher resistance) Pretty common and after sitting 10 years….

Dont get discouraged, what you are experiencing is unfortunately normal for a long sitting  car.

My car  ( sat 18 years) had leaking intake manifold gaskets

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76 2002 Survivor

71 2002 Franzi

85 318i  Doris

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Don't get discouraged, you've made good progress so far.

 

When restoring any older car your going to have some issues. You run into what I call the weakest link syndrome. Think of your car as piece of chain, when you fix the weakest link it puts more stress on the other links and reveals the next weakest link. To properly fix the chain you have to fix all the links.

 

So you need to go through all of the different systems of the car and repair and replace as needed.

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18 hours ago, Pablo M said:

Any advice? Could use a hug…

Most of us have been where you are at at least once.

Take a break from the car, just walk away for a day or two.

I for one see many bright spots in your situation;

Your car is intact/complete in one piece

It runs

Its a roundie Tii!

None of which can be said for poor little Franzie, my second "parked and forgot" project.

 

🤗

 

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Edited by tech71
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76 2002 Survivor

71 2002 Franzi

85 318i  Doris

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17 hours ago, '76mintgrün'02 said:

 

Distributors require maintenance or the moving parts inside can get 'sticky' and not always behave consistently.  For example, the center post needs to pivot on the shaft to provide centrifugal advance and then the little tiny springs need to pull it back to the starting point.  If it isn't clean and lubed, it won't necessarily return to the starting point (every time).  Below the points plate the weights and springs can get pretty grimy and there is a friction reducing 'pad' under the weights that gets brittle and breaks apart.  Those bits can interfere with weight travel/return.  (only the early style pre-'75 have the pad)  The amount of advance it'll give tends to increase with wear and it usually comes in sooner as it gets older; so the advance curve might not be ideal.  All that to say, they can behave in weird inconsistent ways.

 

What is the number stamped on the side of your distributor?

 

Have you checked the dwell lately?  If it changes, it'll take the timing along with it.

 

 

One way to look for a misfire is to move your timing light from cylinder to cylinder to watch for gaps between flashes.

 

+1 for making sure the plug gaps are between .024"-.028".  Err on the tight side, so they can erode and still stay in spec.

 

I haven’t checked anything yet. Fixing clear deficiencies before tuning it up, and cloven how well it ran the other day didn’t think it needed it as a priority. 
this is distributor numbers. What do they mean? I don’t see other markings  image.thumb.jpeg.1c96ae538aeae7ae4cc78d83a225bcf7.jpeg

 

 

 

7 hours ago, tech71 said:

Replace them, they can appear to look fine and deliver proper current at idle but go crappy under load ( ie: higher resistance) Pretty common and after sitting 10 years….

 

6 hours ago, PhilC said:

^^^ this.

The HT leads on our Golf looked fine but changing them made a huge difference.


But the car ran fine after fixing the WUR hose. That’s what is confusing me. That would suggest the ignition system is working reasonably well. Although that drive may have been longer than it’s ever done in a decade. 
So thinking analytically, the drive seems to have affected something and caused it to fail, at least partially. Trying to think what could have failed on the drive. On the way out the car was running reasonably ok.  I was going through all four gears, downshifting and accelerating to 5k-6k on the tach, etc. Felt good! 
that’s why I don’t think it’s the ignition, and normally I’d throw a bit of money at it and just replace the HT leads but short on cash given my employment status (recently lost my job). Would rather test systems and replace only what’s needed right now. 

 

 

 

 

3 hours ago, 2002iii said:

Don't get discouraged, you've made good progress so far.

 

When restoring any older car your going to have some issues. You run into what I call the weakest link syndrome.

 

3 hours ago, tech71 said:

Most of us have been where you are at at least once.

Take a break from the car, just walk away for a day or two.

I for one see many bright spots in your situation;

 

 

Thanks. I’m familiar with the weakest link concept and totally accept it. The long drive was an attempt to see what might be next. Suspect the rear diff or half shafts or wheel bearings are shot too now based on that drive.  But first engine. 
I’m frustrated mostly because how well the engine was running just the other week, giving me faith in a longer drive lol. 
Ugh. 

2003 e39 M5 (daily)

1986 e30 325es (sons car)

1972 2002tii (fun daily alternative)

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Just now, Pablo M said:

this is distributor numbers. What do they mean? I don’t see other markings  

 

They mean you have a replacement distributor.  Not the original.  This one is the later style, so don't shop for parts to fit a '72 Tii.  That distributor is the early style, with a different cap... and stuff.

 

The good news is, it probably has fewer miles on it than an original one would.  Type those numbers into the search window and you'll find a lot of discussion about that distributor (( within the past five years )).

 

 

 

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A vacuum leak symptom usually will also be slow to return to idle and will hang in higher rpm’s or hunt around at idle.  
With the engine running try pulling each spark plug wire and see what happens. If it gets worse, that cylinder is not the issue. If no change you found a miss fire. Could be fouled plug, bad wire…. 
 

Also I’ve seen distributor caps have tiny cracks which can cause condensation and rough idle…. 
 

just some thoughts

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6 hours ago, larry_in_socal said:

Perhaps you had a vacuum leak before, and when you replaced all the hoses, you sealed it up, so now the car is starving for air?  is this possible ? Sorry just a quick response, I briefly read through the topic...

Weird thing is, it ran great right after I replaced the hoses. Then I took it for a longer drive, about 50 highway miles, to shake it out and on the way back started to run rough again, same as before. That's the frustrating part. It runs good! Something on the drive made it run rough again. At first I thought fouled plugs but I pulled them and they're fine. Maybe the drive set something off in the ignition system, not sure. I'll have to try pulling the plug wires one at a time and see if anything happens.

 

2003 e39 M5 (daily)

1986 e30 325es (sons car)

1972 2002tii (fun daily alternative)

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In the distributor pull off the rotor and add 3 or 4 drops of light machine oil (think 3 in 1 oil) on the felt pad in the center of the shaft, replace the rotor and twist it back and forth several times, this allows the advance to move smothly on the drive shaft.

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If everybody in the room is thinking the same thing, then someone is not thinking.

 

George S Patton 

Planning the Normandy Break out 1944

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