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Old Car Performance/Efficiency Suggestions
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RoboDisko
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Feb 8, 2014, 5:49 PM
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Old Car Performance/Efficiency Suggestions
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Hey, I've got an old car. 84 Volkswagen Jetta (1.8L engine) with 237,000 on it. I got it fairly recently from a friend, and I was wondering what some of the things I should do to it to increase performance and efficiency are.
So far I have taken my injectors off and cleaned them, and lightly cleaned the throttle body. I think I messed up one of the injectors in the process, and it seems to run rougher, and the injector seals are hard as rocks, so I was planning on pulling some newer style but compatible injectors, with new O rings, from a jetta at the junk yard, after ultrasonically cleaning them. I am also planning on pulling the cat off, because a 30 year old cat with no maintenance probably isn't helping anyone. I am also considering changing the manual transmission oil, because the current stuff might be stock.
I also think i messed up the fuel to air ratio. When I got it, the exhaust smelled like fuel, so I adjusted the fuel to air ratio until the exhaust no longer smelled like fuel. I think the reason it smelled like fuel is because, as I recently noticed, it does have an oxy sensor, but it wasn't plugged in, so I think it was making the mixture as rich as the system was able to automatically adjust for. Keep in mind this has a mechanical fuel injection system. (K-Jetronic I'm pretty sure, google it)
Some other thoughts on it. It doesn't idle very smoothly. Sometimes it idles smoother than other times, but in general I think it should be smoother. Also, I've noticed that the difference between half-throttle and full-throttle is miniscule. Not sure what would cause that. I also know the alignment isn't right, because my front left tire is almost bald while the other tires are in good condition.
My friend that I got the car from said he was getting 30+ mpg from it. So far, on my first fill up I got about 18 mpg, (I had some major timing issues that I think had a big impact on that) and 24 mpg on my second fill up. Its going up :), but I hope to be able to touch the 40's with this car :/. Also, when he had this car, he usually drove 80 miles at a time, and when I use it, I rarely go more than a mile, so the engine is still cold when I get there most of the time.
Ok, I know this car has problems, but what are my priorities in fixing it? Anything I haven't mentioned that I need to look at? Anything else?
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Discretesignals
Ultimate Carjunky
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Feb 8, 2014, 8:48 PM
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First thing you should do is run a compression check on it. Make sure the battery is fully charged, the ignition and fuel systems are disabled, and the throttle is wide open when you perform your compression test. Write down the numbers for all cylinders. Post them in here, so we can see what your dealing with.
If the engine is tired, messing around with the other things is a waste of time.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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RoboDisko
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Feb 10, 2014, 4:21 PM
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I think I know someone that has a compression checker, I will see if I can borrow it and check.
Also, a piece of metal is a piece of metal, in my opinion. I don't think that just because an engine has provided enough energy to travel 237k miles means that it is a baby. However if the cylinder walls are oval, then yea... Let's stick with the compression check and then go from there.
Also, I have a friend that own a junkyard with a few more of the same engine. If this engine goes boom, I've got another one :) although that doesn't sound like fun :(
I should mention that I am more interested in efficiency than performance.
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Hammer Time
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Feb 10, 2014, 4:29 PM
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All the bearings in that engine have 237K on them and there can't be much left. The oil pump has done more work than it's designed to and you can say that engine is on borrowed time from here on.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Tom Greenleaf
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Feb 11, 2014, 3:12 AM
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Whole car is 30 years old - every last moving anything. Plastics and rubber things all over go brittle, springs, seating hinges latches even wiring insulation and connections and so on. Point is it's not just a brick of metal, T
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RoboDisko
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Feb 11, 2014, 3:47 PM
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Fair enough. And now that you mention it, my friend did give me this car for free because it had broke down, the problem being that the ground for the ignition module had come off of the battery. But I can repair and replace wires as they go. Reliability isn't a big deal anyways, since I rarely go more than 5 miles from my house, and I'm not afraid to try to fix it on the side of the road.
Still trying to get access to a compression checker...
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Tom Greenleaf
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Feb 12, 2014, 1:45 AM
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Compression tester:
In stock item almost anywhere! Probably rentable but only about $25 bucks.
Totally not adverse to older vehicles. Just know to go thru check and fix certain things pro-actively or declare one not practical any more for the time it would take or raw expense of parts to make one legally useful for public roads,
T
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RoboDisko
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Mar 10, 2014, 8:55 PM
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FINALLY GOT A COMPRESSION TESTER!
Like a month later I know :)
Someone I know owns a mechanic shop and he loaned me his. He warned me that it was damaged but usable. Without anything connected it 0'd at 25 psi. So I think the readings are at least 25 psi higher than real. It also didn't hold the pressure, so I had someone crank it while I recorded the peak value. The values I recorded are:
1. 177 psi +-3
2. 177 psi +-3
3. 177 psi +-3
4. 177 psi +-3
They were all darn close so I just rounded to the same number. They were all between 175 and 180 though.
Because the meter 0'd at 25 psi and because it is well used, I think subtracting 30 psi from each would get us a more accurate number.
I interpret the data as all cylinders with 147 psi +-8.
From what I have read that is a good psi and so I shouldn't have any compression-related issues, although I am open to other opinions. So, what can I do that is relatively easy and relatively cheap that would help the engine run better. I am already working on the fuel system. I know it is running lean, and I have ordered a new oxygen sensor/injector O rings/fuel filter and I will set the combustion ratio when they come. What else?
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Tom Greenleaf
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Mar 10, 2014, 9:47 PM
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You really are looking for them all to be close to each other, 4th bounce up while cranking and it locks that pressure as cylinder would leak down. Then small squirt of oil to see the difference that makes especially if one is off from another and so on.
Accuracy of the actual PSI# I wouldn't be way too worried about. A real nice gauge would have a screw to set to zero.
You can also get a good clue from a vacuum gauge on crude mechanical engine wear - all this to know what you are dealing with.
You mentioned you seek "efficiency" and it's prior long run at a time use is naturally going to do better than short runs not even warmed up.
Think: World's largest cruise ship and most fuel efficient moped are both getting ZERO MPGs sitting still and it goes from there. Just make it to run as well as possible and you are there and there are no magic tricks short of pushing it or towing it to alter efficiency much.
It's sarcastic but just make all your trips downhill with a tailwind roundtrip helps
T
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RoboDisko
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Mar 12, 2014, 7:56 PM
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All of the PSI values I measured were very close. Also, the gauge I was using leakes and you have to be watching it while you crank.
Anyways, after I measured all of the PSI values on Monday, I put the spark plugs back on and parked it. The next day I noticed that something was wrong. When I rev the engine it sounded like 1 or 2 of the cylinders wasn't firing right or at all. And when you give it some fuel to accelerate, there seemed to be a 1-2 second delay before I got most of the acceleration force. For example, I shift into 3rd and give it some fuel. It slowly accelerates for 2 seconds, and then I can feel a small jerk as it starts to accelerate much more quickly. Let go of the fuel and shift to 4th, and this happens again. In addition, I have killed the engine several times lately because it doesn't have the power it used to have.
On Tuesday I thought, "No big deal. I probably forgot to plug a spark plug wire in or messed up the gap." Well today I pulled my plugs, cleaned them, checked the gap, and re-tested the compression. The #2 plug was very black like it was running very rich. I didn't pay much attention to the plugs on Monday, but I don't think it was that black. As for the compression:
1. 150 PSI!!!!!!!!! This was 180 on Monday, what happened?!
2. 180 PSI
3. 180 PSI
4. 176 PSI
#1 cylinder with a cap of oil in it: 160 PSI
FYI firing order is 1-3-4-2
Ok, my car was running well on Monday, and now it sounds and runs like a trash can. What could have messed the #1 cylinder up so much? What should I check? What should I do?
The guy that loaned my the compression tester gave 2 suggestions. He said he thought it was running rich (I'm still planning on tuning the f/a ratio, but I thought it was running lean), and the valve springs. I believe he owns a mechanic shop, but I didn't give him as much description as I have given you.
Video of the issues my car is having:
http://youtu.be/PPNANeybdGc
(This post was edited by RoboDisko on Mar 12, 2014, 8:07 PM)
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Tom Greenleaf
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Mar 12, 2014, 9:44 PM
Post #12 of 33
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OK - Vid only showed that it sounds like crap as you sad.
Your tester is in question so that ends most of that. I did show what looks like a single putt out tail pipe as if one cylinder is not firing properly. If that cylinder is cold, fuel washed compression would be off or something alarming.
Just in handling plugs and wires could have harmed them?
I'll try to paste a basic idea of how to take compression or if it doesn't show right remove it. Engine somewhat warm. Plugs out, marked for correct location with wires. Spark and fuel disabled.
Crank and watch pulse increase compression #. By 4th rev it should be about what it can do.
KEY IS EVEN MORE THE TEST THAN THE exact # you get. Oil test will seal lower end things more like rings, cylinder wall wear mostly if dramatically changed by that more inspection to find out. You didn't have dramatic so forget that. Wet test will not change valve issues.
In your case engine is running so lousy in that vid that I think test results are inconclusive. Might behave if it was stone cold and move on to other reasons if compression is within 10% or so.
That black plug is telling of problem there. Wire, plug itself, over fueled etc. Heat clean and swap it for another or replace with new plugs OE for an engine. Leave tricks for the last run to the salvage yard.
It's open book on this. IMO a fussy and old car with plenty of miles. Right now compression is in question and something else my be the cause as said fuel or ignition. IDK why two test showed so differently except for the known leaky tester? Guess you could move on to a leak-down test on that cylinder?
---------------------------------------
I just said most of this but just some fool thing I found out there on compression test. I don't agree with it totally but the idea there....................
Difficulty: EasyTime Required: 30 MinutesHere's How:- Let the car run for about 5 minutes, you always want to compression test a warm engine for best results.
- Disable the ignition system so the engine does not fire up during testing.
- Label the spark plug wire with the same number as you label the spark plug hole, 1 through 6 for example, before removing all the spark plugs.
- Insert the compression tester into the cylinder spark plug hole labeled #1 and tighten by hand only.
- Have your helper crank the car’s engine 7 to 10 times continuously to obtain the most accurate reading on the compression gauge.
- Record the reading for the cylinder labeled #1 and remove the tester from the spark plug hole.
- Make sure that the pressure gauge returns to zero before continuing testing and recording the rest of the cylinders while the engine is still warm.
- Clean and replace the spark plugs with the correct spark plug wire.
Tips:- The compression test is not so much about the absolute level of compression; it is the difference in the compression between each of the cylinders. If all cylinder readings are within 10 percent of each other, your engine compression is considered optimal. However, if any of the cylinders compression vary 10% or more from each other, a problem may exist and further inspection of the engine should be completed.
+++++++++++++++++++++++++++++++++
T
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RoboDisko
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Mar 12, 2014, 10:01 PM
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Those steps you posted are almost exactly what I did. I feel fairly confident that the PSI values I got both times are fairly accurate. I had double checked #1 cylinder on Monday, and I triple checked it today, with consistent results. Right now I'm not so concerned about cylinder #2 because I am about to redo f/a ratio anyways. But what should I do about cylinder #1?
(This post was edited by RoboDisko on Mar 12, 2014, 10:02 PM)
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Tom Greenleaf
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Mar 12, 2014, 10:45 PM
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I plain don't know what you mean by adjusting air to fuel ratio on this or if so if you can target ONE cylinder.
If #1 is really off it will effect the overall show. At TDC on that one apply pressure and see where it leaks. Let's rule out plain wear on this thing.
If you can see if wires will fit another and the problem follows checking misfiring at a cylinder or cancel them one at a time to focus in better. RPM if just one will stay the same if one is dead and canceling that one doesn't change anything. A good one on a 4 cylinder with one bad cylinder would stall out no doubt.
* If cancelling a cylinder by taking off plug wire ground it as if just left hanging that spark might seek other routes confusing that test. This is crude basic testing. Any wires and plugs don't like being fussed with, dropped, pulled wrong or even good stuff will be harmed messing up diagnosing.
Keep trying and keep the investment low IMO. Rent, borrow and swap known good things within that car to a known bad and follow is cheaper than tossing all for a maybe on things.
For finding random or one cylinder not behaving without wild tools you can feel the pulse at tail pipe and usually tell just don't burn yourself please, use a rag if you do that.
I don't think converter is the issue on this for just this right now.
For whenever or soon if still not nailing it, a vacuum gauge test can be informative also. Takes stuff/tools even for the most basic things,
T
#1 compression funky and #2 with fuel fouling apparently
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RoboDisko
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Mar 13, 2014, 5:36 PM
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Interestingly enough, the k-jetronic lambada fuel system that my car is equipped with allows you to adjust the fuel going to each cylinder. However, some further tests seem to eliminate that cylinder #2 is getting excessive fuel in comparison to the other cylinders. Here is what I did.
I pulled the spark plug wires one at a time, and then two at a time, and then three at a time, and then four at a time. (I'm just kidding about the four at a time) Anyways, with only 1 cylinder firing, I could keep the engine running on each of the cylinders except #2. For the most part, cylinder #2 didn't fire at all. Occasionally, it fired a few times sequentially, and then stopped firing again. Cylinders #3 and #4 seem to be running absolutely fine.
I KNOW that cylinder 1 leaks, because I put one of the compression checker tubes on that didn't have a 1-way valve, blew into it, and I could feel the air go into the cylinder. I turned the engine several times to make sure it wasn't just on the intake or exhaust stroke. I did this on the other 3, and when they weren't on intake or exhaust, they felt air-tight.
I am planning on hooking a compressor to the #1 cylinder using the compression gauge adapter without a 1-way valve, and then listening and feeling for the leak location. I am also planning on taking the #2 spark plug out and seeing if it fires when not in the cylinder.
I would rather deal with the compression issues on cylinder #1 before tackling the combustion issues on cylinder #2. Or maybe one of the gaskets between the cylinders developed a leak recently? Anyways, I am open for any suggestions at this point.
I think it is worth mentioning that I used a flash light on a spark plug hole to see inside the cylinder, and it looked really dirty. Like, there were spots that one could see the metal, but most of the surface area was covered by black stuff, presumably carbon. It was like this in both cylinder #1 and #2, I didn't look into #3 or #4. Is that normal? Does that affect performance? How would one go about cleaning carbon in the combustion chambers?
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RoboDisko
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Mar 13, 2014, 6:56 PM
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Someone please reply to this and say "random" because I got into my car to pick up the compression gauge again, and it was running great again! All I did was take the #2 fuel injector out and put it back in... Anyways, on further inspection, it seems than #2 is firing normally again. I was hoping that #1 also was up to 180 PSI, but it was not, still at 150 PSI. After that, I hooked up the 1-way valve-less adapter to the cylinder, and my compressor to the adapter. After establishing that anything over 40 PSI was enough to turn the engine until it hit an intake or exhaust stroke even when in 5th gear, I discovered that it seemed that the air was leaking into the cam-case. (I don't know if that is the technical term) When I took off the oil lid thing, which is directly above the cam and above #1, I can hear a rather strong hiss, and I think I can feel some air come out.
I could be wrong, but I think there is a leak on the top of the #1 combustion chamber. There are 2 reasons I think this: the above mentioned compressor test, and the fact that putting oil in the cylinder did not have a significant affect on the compression PSI. I also don't think it is the valves because I couldn't hear or feel air comping out of the intake or exhaust. What part of the engine would allow pressure to leak out of the top of the combustion chamber? What other things should I try?
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RoboDisko
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Mar 13, 2014, 7:52 PM
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Ok, I feel like I am on a wild goose chase. Checked the compression again:
1. 176
2. 177
3. 175
4. 178
Also, I put the compressor to all 4 of the cylinders, and they all made the same mild hissing sound coming out of the oil pour hole. So maybe the head gasket is a bit worn? I'm just guessing here, you guys are the pros. I have a spring break coming up and I wouldn't mind getting in over my head in an engine repair like a head gasket. But would it help? Or am I just crazy?
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Tom Greenleaf
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Mar 14, 2014, 1:29 AM
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OK: Oil test remains unproven. Guess to be verified is that #1 needs better leak-down test but might be intermittent which is troublesome by itself but a gasket could allow it's compression into no useful place in cylinder #2 throwing off proper firing and complicating even that one getting correct useable spark, fouled plug from fuel or if metal shaving ground out plug that ends that. Consider cylinder wash and more.
High miles for this engine let alone age. May need to pull head to get a good look to see it this engine is even worth your time!
T
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RoboDisko
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Mar 14, 2014, 3:16 PM
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Ok what I am thinking is I can pull off the head and do a partial overhaul. Clean the cylinders, replace head gasket and header gaskets, valve gasket, replace the valve springs if then need it, clean up valves and camshaft, ultrasonic clean anything that fits in my little ultrasonic cleaner, and put it all back together. Would that be worth my time? Is that way over my skill level? Can I get a time estimate, cost estimate, steps and some advice?
As a side note, I decided it was time to patch some exhaust leaks, and it quickly escalated to my exhaust getting cut right behind the cat. I'm planning on bypassing the cat, cleaning the exhaust pipe, and patching the holes, but it sure is fun to drive without a muffler. I knew it was going to be loud, but it is louder than I expected. There is a kid at my school that probably has $50K into his truck, probably several thousand just in his exhaust, loves blowing black smoke clouds. Anyways, I was passing him opposite direction and I pushed the clutch in and revved it, and his jaw dropped. It was awesome. Especially the fact that I have put less than $150 into my car, $110 of that was the stereo, and the car itself was free.
I know I am going to have to put the muffler back on if i don't want to get tickets, but it is sure fun to drive without it.
Anyways I would like several opinions on if the partial overhaul I proposed would be practical.
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RoboDisko
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Mar 14, 2014, 5:11 PM
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I meant remove the cat. Yea I know it's illegal, but my dad has been running his car without the cat for over 10 years. In addition, vehicles over 25 years are exempt from emission testing, and where I live doesn't do emission testing anyways. In more addition, this cat is over 30 years old, has been through rich and lean. Do you think there is anything left?
I would be surprised if the cat is still functional at all. Just in the time I have had it, I had 1 cylinder that wasn't firing, sending a ton of unburned fuel to the cat. If it is not doing anything, and if I am not going to get caught for it, then I see no reason to leave it on. Do you?
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Hammer Time
Ultimate Carjunky
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Mar 14, 2014, 5:41 PM
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None of that changes the fact that it is illegal to remove it without replacing it with a new one. I doubt you will find a shop willing to do that.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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RoboDisko
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Mar 14, 2014, 10:46 PM
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:) you don't know me. Half of my friends are in automated manufacturing. Plasma lasers, lasers, welders, grinders, metal benders, cnc machines, all manned by a bunch of teenagers. I know a shop that will do it for me. How do you think I took my muffler off anyways?
Also, I would really appreciate if we can get away from the morality of removing my cat and get back onto how feasible it is for me to pull the head off. Thanks.
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nickwarner
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Mar 15, 2014, 3:07 AM
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I think you pulling off the head is feasible. I think you having a running engine when you are done is not.
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Discretesignals
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Mar 15, 2014, 8:03 AM
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You shouldn't be pulling anything apart until you have absolutely isolated your problem, unless your into that sort of thing. Compression numbers look fine. You can also do a dynamic compression test on that cylinder you believe it having an issue to see if you have an engine breathing problem. A static compression test won't tell you if the exhaust valve isn't opening.
Haven't played around with any K jet fuel systems that one has, but it does have an O2 sensor. You could scew a back pressure gauge in place of the O2 sensor and measure that amount of back pressure in the exhaust before the cat to see if you have an excessive amount of restriction going on. That would save you the time and expense of removing the exhaust system.
Is this vehicle going to be your daily driver or are you wanting to turn it into a race car?
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
(This post was edited by Discretesignals on Mar 15, 2014, 8:18 AM)
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