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Date: 7-15-08 03:49
From: rtheriaque 
Subject: Ignition/fuel problem? Definite misfires...  
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Don't fall in love too fast...
I bought a '73 that I've been repairing for the past 6 weeks. I'm already in for hundreds of hours. The interior is just about finished- I have all the parts and was going to install them this weekend.
Since I bought the car it's had an intermittent hesitation- never bad, just a little nag. With a bad center bearing and poorly balanced tires, I never even noticed it while driving. As the car has come along, it has gotten smoother and smoother so other problems have revealed themselves.
One finally came up I don't have the means to resolve.
When I got home from work I figured I'd take a look at the hesitation. The ignition system is almost completely new- Pertronix, rotor, cap, wires, plugs... I started pulling wires. Cyl 1, the car hesitated almost stalled. Same with 2 and 3. Pulled 4. Almost no reaction at all. Uh-oh. I checked for spark with a spare plug. Yup. I've got spark.
I pulled all 4 plugs. Cyl 1, 2, and 3 are a uniform color. Cyl 4 is almost new on on side and far lighter on the other than the rest. Not looking good...
No oil in the coolant, no coolant in the oil. In fact, both still look brand new after about 750 miles since I changed them. I don't have a compression tester, but I figured I could do something simple... The engine was still hot, but I put the car in gear. It was difficult to move, but I could do it. I installed plug 4. I couldn't discern a difference in how it moved. As I recall, when I was doing the valve clearances (engine cold) it moved far easier when in gear. In fact, I could do it by hand. Not so when hot.
Anyway... Even without a real compression test, I know what this means. I have a cracked head, burned valve (probably exhaust if nothing is coming up through the carb?), or piston. I have a '76 parts car, but the motor in that sucked- it had less power than this which has apparently been down on a cylinder all along. I have another motor on a stand in the basement but I have no idea what the condition is. Even if one of these motors ran well, I have no way of installing it (nor the extra cash to do it).
Sorry for the rant... I'm just utterly devastated. I fell for this car too quickly- I've put more time and energy (not to mention cash) into it than I think anything else I've ever done.
Somebody should tell me if I enjoyed the 6 mile drive to and from work before with the car like this, I still will moving forward, especially with the interior finished... It's not like anything has changed. Right?
I'm going to go curl up in the fetal position and suck my thumb...
_________________
~Rob
'73 2002 (runs!)
'76 2002 (parts!)
Last edited by rtheriaque on 7-17-08 06:00; edited 2 times in total
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Date: 7-16-08 03:54
From: rtheriaque
Subject: Re: Whelp... I think I'm screwed...
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| Mr-2002tii wrote: | | Nobody mentioned that it could be a fuel pump problem, they get gunked up, ask me how I know!! |
It's a carbed motor- I assume your symptom was related to fuel delivery on a tii?
I was able to do an unscientific leakdown test by pushing the car again when cold. Good news? I'm generating compression. Bad news? You can actually hear the hiss of escaping air while it leaks down!
I have one thing I'm going to try that seems taboo around here after a search on the off chance this is a deposit hanging a valve open. What I don't understand is the clean spark plug from that cylinder. The implication in my mind is that there's no charge to be burned, like a stuck intake valve. I've watched the rocker press down on the valve, however, so that seems okay. I'd think if it was getting a charge and the exhaust valve was burned, I'd hear it through the exhaust, but the car idles quietly. Something just doesn't add up. _________________ ~Rob
'73 2002 (runs!)
'76 2002 (parts!)
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Date: 7-16-08 04:50
From: mike in Beavercreek, OH 
Subject: Coupla things...
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1. As has been pointed out, do a proper compression or leakdown test...that's the only way you're gonna get a clue as to what the problem is without pulling the head. There are any number of things that can cause low or no compression in the cylinder.
2. Don't spend a lot of time prepping your spare cylinder head. A 121 head won't work on an engine with an E12 head as the pistons are different--valves will kiss pistons with unfortunate results. A good machine shop can either put a head to rights or give it last rites in a couple of days, so short of finding a spare E12 head (and you don't know now if the head's the problem) you'll have to fix whatcha got.
3. Before imagining the worst (bent valve, cracked head etc) remember that a blown head gasket can be blown just enough to mess up compression, allow coolant leakage only into the cylinder (not the oil) and do it slowly enough that you don't lose too much coolant and don't notice any vapor at the tailpipe.
Finally, don't get discouraged--it's not like you ventilated the block with a connecting rod--heads are fixable with minimal trauma and you'll be back enjoying your '02 soon enough.
cheers
mike
_________________
'69 Nevada sunroof--"Wolfgang"--bought new
'73 Sahara sunroof-- "Ludwig"--mine since '78
'87 eta E30 coupe--"Johannes"
+ Fiat Topolini (Benito & Luigi), Renault 4CVs (Anatole, Lucky Pierre, Brigette)...
and Kermit, the Bugeye Sprite
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Date: 7-16-08 02:05
From: Arizona002
Subject: Re: Whelp... I think I'm screwed...
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"Since I bought the car it's had an intermittent hesitation- never bad, just a little nag."
1-Most likely the carb, accel pump weak output or a little clogging of the passages, jets.
2-Timing advance not working properly.
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Date: 7-16-08 02:37
From: rtheriaque
Subject: Re: Whelp... I think I'm screwed...
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| rtheriaque wrote: | I have a rebuild kit, gasket set, and CD prescription on the way, but there's definitely a problem with cyl 4.
You know, something JUST occurred to me...
The vacuum line attached to the brake booster is DEEP on the intake track for cylinder 4 (and cyl 4 only)... That cylinder couldn't be running lean, could it...? |
Well, let me preface this... I've been working in the sun all day AND I just had a good (both in quality and size) glass of scotch.
Please take a look at the attached routing.jpg. See the fabric/braided hose from the brake booster to the cylinder 4 intake track?
I took that off the intake and plugged it with my thumb. When I pull the plug from any one cylinder at that point, they all act the same! Either that line is allowing a huge vacuum leak causing a lean condition (and probably a hot one that has at least partially burned a valve) or my brake booster is dead.
Hooray? I think? Anybody got a brake booster?
I'm going to have the wife drive me down to Autozone after dinner to grab some breather line. What is the fitting in-line there? I can probably rip it off the '76 if it's necessary... _________________ ~Rob
'73 2002 (runs!)
'76 2002 (parts!)
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Date: 7-17-08 05:05
From: rtheriaque
Subject: Re: Don't stop now.....
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Won't work for me, unfortunately. I don't know a Marge.
I drove the car around the block yesterday- I can live with manual brakes for a bit until I can swap boosters.
The hesitation, however...
I hope I haven't used up my quota of help!
I dug around a bit more this morning. The misfire is present in any vacuum configuration (contrary to my previous assertion). So, that's out. We're back to what I'm assuming is an ignition issue.
To recap, I'm running a relatively new Pertronix and a black coil with a ballast resistor. Rechecking everything this morning, I believe the pertronix lead was on the wrong side of the ballast resistor. I think I made a bad assumption when installing that I should just use the free spade on the resistor. Electrically, it was on the same side as the coil. Oops.
So, I wonder if I damaged a component of the ignition system. I have an aftermarket coil I can try. I suppose I could throw the points/condenser back in, too (that would make me a sad panda).
Questions:
Can a Pertronix be partially bad? As a Hall-effect sensor, I wouldn't think so, but the question seems worth asking.
What would your next steps be? The tach is fluctuating far more wildly than the misfire seems to indicate (especially at higher RPM), which has me thinking this is an electrical issue.
Any help is greatly appreciated... I'd be more than happy to gift a spare or a nice BMW t-shirt to whoever hits on the answer!
_________________
~Rob
'73 2002 (runs!)
'76 2002 (parts!)
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Date: 7-17-08 05:15
From: rtheriaque
Subject: Re: Don't stop now.....
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Won't work for me, unfortunately. I don't know a Marge.
I drove the car around the block yesterday- I can live with manual brakes for a bit until I can swap boosters.
The hesitation, however...
I hope I haven't used up my quota of help!
I dug around a bit more this morning. The misfire is present in any vacuum configuration (contrary to my previous assertion). So, that's out. We're back to what I'm assuming is an ignition issue.
To recap, I'm running a relatively new Pertronix and a black coil with a ballast resistor. Rechecking everything this morning, I believe the pertronix lead was on the wrong side of the ballast resistor. I think I made a bad assumption when installing that I should just use the free spade on the resistor. Electrically, it was on the same side as the coil. Oops.
So, I wonder if I damaged a component of the ignition system. I have an aftermarket coil I can try. I suppose I could throw the points/condenser back in, too (that would make me a sad panda).
Questions:
Can a Pertronix be partially bad? As a Hall-effect sensor, I wouldn't think so, but the question seems worth asking.
What would your next steps be? The tach is fluctuating far more wildly than the misfire seems to indicate (especially at higher RPM), which has me thinking this is an electrical issue.
Any help is greatly appreciated... I'd be more than happy to gift a spare or a nice BMW t-shirt to whoever hits on the answer!
_________________
~Rob
'73 2002 (runs!)
'76 2002 (parts!)
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Date: 7-19-08 05:59
From: Pedro
Subject: Re: Don't stop now.....
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I tried to read through your posts and I am confused more by what you have tried than what you have eliminated as a potential cause.
First, you are not clear as to what is going on with compression in each cylinder. You posted some readings, and if they were accurate, you have a snowball's chance in hell of getting the engine to run acceptably. The fact that you MAY have discovered a vacuum leak at the vacuum booster may certainly affect the engine's running even with perfect high compression readings. It will not negate or correct the very low compression reading even in one cylinder.
If you are implying that your compression readings were erroneous and you have 100+ lbs./in2 in each cylinder, then I would consider going back to basics. First, dump the petronix, you can always reinstall it later. Insure that you are getting a spark at each cylinder. If you are not I would not be surprised to learn that you have a problem as simple as a bad rotor or even a bad rotor and cap. Do not take these mundane items for granted. If they are not the right part or carbon tracked, they can be the difference between a good running engine and one that doesn't.
Make sure your cam timing is correct too. Set engine to TDC and make sure the mark on the cam points in the correct direction. If this is foreign to you obtain a Haynes manual and READ.
If the carb has problems, be they floats or jets or disconnected idle solenoid, as you originally suspected, you can still get the engine to start (not well) with starting fluid or even a few teaspoons of petrol down the carb's mouth.
But, if you do not have compression, give up now and figure out how to get some.
Post an update either here or in a new post so we can follow your progress. You are not alone. There are plenty of yahoos that have been in the same situation probably more than once. And there are plenty of experienced/knowledgeable folks who would like to help you.
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