Dropped Cylinder...

ac604605 · 05-12-2008, 11:35 PM

Follow up from my earlier issue where the engine wouldn't run past 6,000RPM. Thought it might be the cat, so we took it off and ran without it but still had the same problem. Only this time at around 6,000 the engine made an odd sound that according to my father sounds like a dropped cylinder. We tried a few things to try and improve is; first was to slightly pinch off the fuel return line which only made the problem happen at 5,000 instead of six. Second we pulled open the MAF black box and loosed the gear two clicks to make the engine run more lean. This made a world of difference. The problem is still there, however now the car will actually accelerate past six grand. Still has that little bump when you can tell its lost some umph but much better than before. So my question is, if it really is a dropped cylinder whats the most likely place for the problem to happen? Distributer?

Mista 2 · 05-13-2008, 07:54 AM

have you checked you plugs, leads, dizzy cap, rotor and injectors?

ac604605 · 05-13-2008, 06:53 PM

Checked the distributer, bearings in the rotor were grinding... I had an extra one laying around so I replaced it, no difference. Cap looks fine, tried different wires, same. I've checked the plugs several times and they all look good, also I don't suspect the injectors, mainly because I don't want to pull them out, haha; but the engine was rebuilt such a short time ago I really don't think something would have gone wrong with them. This may sound stupid, but I don't know where the engine was rebuilt or by whom. The car was given to my father as a gift from his MR2 obsessed buddy, along with the engine. When he gave it to him he said he had the engine rebuilt at a shop in Santa Fe NM. The old engine never had this problem, when it spun a bearing and we replaced it is when it started acting up. Is it possible this engine has something different about it that keeps it from reaching the same redline?

ac604605 · 05-15-2008, 07:06 PM

Holy TVIS Batman.....

I took apart some more things today... Pulled injectors to find that although one of them had a ripped o-ring that needs replacing, they look fine. I also took apart the throttle body because the butterfly valve looked dirty, when I removed that I discovered the throttle body was the least of my worries; the entire TVIS was caked with sludge!! The metal tube running from the EGR valve was actually clogged with god knows what,and I could scrape piles of thick black texas tea off the inside of everything. I have included pictures for your enjoyment, before and after, as well as my theory.... Last time we worked on the car, we tried to make the car run both rich and lean to see if it made a difference, and when the car runs lean the problem is less noticeable, however still present. Could the TVIS be so caked with exhaust crap that the engine is being starved of air, therefore making the problem less aparent when running lean?

ac604605 · 05-15-2008, 07:10 PM

MySpace

MySpace

mr2tim · 05-15-2008, 10:41 PM

Scrape 1/4' of insulation off the side of each injector wire, touch your ohm-meter to each injector wire,other side to ground? Are all 4 readings similar?

TVIS requires the "butterflies" to be full open, if your gunck constricts this action then...
The 'Butterflies" work thru that blue VsV under the intake, (it's mechanical action is weak, being vacuum oriented) make sure action is smooth offering little resistance.

Keep us posted, we all get your messages..

ac604605 · 05-16-2008, 08:54 AM

Thanks! I actually have a spare set of butterfly valves that are all gunked up that I was using as a reference point. I won't be able to take off the tvis till this weekend but thanks for the help.

feral4mr2 · 05-18-2008, 09:08 PM

have you done a simple compression test yet?

ac604605 · 06-05-2008, 03:18 PM

No, considering the engine was just rebuilt I didn't think that would be an issue. However I did just move to New York from Texas and the long drive brought up another problem. The muffler was severely clogged, with chunks of material from the cat. I cleaned it out as best I could and the problem is a lot better now. Sometimes the engine drops out at six grand, and sometimes it keeps on going right up to seven; still it never reaches red line but it is much less noticeable.

lsgheero · 06-11-2008, 01:00 PM

I wouldn't continually try to push the engine past 6k if it is having issues. And if you muffler or cat is coming apart I would get that fixed because a malfunctioning cat can catch fire. I've seen it its not pretty lol.

ac604605 · 06-12-2008, 01:39 PM

Well the muffler and cat are clean now. The only other thing I can think of is to take the tvis off the motor and see if there is any residue built up from the cat being clogged. However I don't have the right tools to do this, so I probably won't get around to it for a few weeks.

mr2tim · 06-20-2008, 05:56 PM

Earlier you mentioned in a post that you moved the (AFM) maf sensor 2 clicks?

If you cleaned up the TVIS why not go back and undu the Air flow Meter and see what happens?

It will give you a more even idle without "idle search'.

Lean engines blow easy...(actually melt)

ac604605 · 06-24-2008, 08:10 PM

Thanks Tim, I had almost forgotten about that. I'll adjust it tonight and see if it makes a difference in the idle.

ac604605 · 06-28-2008, 10:00 AM

Adjusted the afm spring and the car does idle better. I have another question though. If the timing belt or one of the camshafts were off when installed, would it cause this issue of dropping out at high rpm?

mr2tim · 06-30-2008, 09:47 PM

It's relatively easy to confirm the cams are matched by poping the upper cover. The marks are atop and easily seen.

When you confirm they are ok, mark the crank pulley in a location easily seen for later reference.

I had a loose belt tensioner and got similar? rev up problems.

The timing mark for the crank timing gear is buried under the lower timing cover and requires outer crank pulley removal.
Save this as a last ditch effort?

Tvis is all ok?

MR2TRD1 · 06-30-2008, 10:08 PM

You keep saying "it was just rebuilt." Doing a compression test is the easiest thing you can do after all the random things you have tried so far. At least that will confirm your belief in the engine's integrity. In my experience I always say similar things and my issues land up being exactly where I thought it wasn't.

ac604605 · 07-01-2008, 11:48 AM

Going to get a compression tester today. Crank gears matched up perfectly, but the marks on the crank pulley were off. T-VIS is clean, but still pulling in what looks like oil. If the compression is off, should I pull the crank pulley and check the gear underneath?

ac604605 · 07-01-2008, 03:27 PM

Well now I feel like a jackass..... I tested the number four cylinder and its running 95lbs... Number two was about 190lbs, the other two were in range. I'm certain this will be one of those important lessons I remember the rest of my life. I don't know too much about engine compression, but if the timing was off, would it create low compression in only one cylinder? It would create low compression in two cylinders.... Right?

lsgheero · 07-01-2008, 05:14 PM

im not a certified mechanic lol so by all means let others chime in but heres my

:

The timing being off should effect the compression levels just the point @ which the spark happens. The reason for this is all your cylinders are connected to the con rod and they cant be out of sync unless of course you really fubared the engine.

Now one thing you can do to further test your compression is squirt a tiny bit of 30w oil into the spark plug hole onto the cylinder if your compression doesnt change then you most likely have a bad valve. If it does the rings are bad. (the reason the compression would go up with the oil being placed on the cylinder is due to it temporarily sealing the rings.)

I hope that helps and I am not too incorrect in my statements lol But thats the way I have done it and the way it was explained to me.

ac604605 · 07-01-2008, 06:09 PM

Thanks for the input, I actually haven't tried the oil test yet, but I will tomorrow when I have more time. One more question. All of my mechanical knowledge stems from the big green book. I read over the section on checking valve clearance and such. When I try and fix this problem myself, will I actually need any of the special tools listed in the book? I'm also curious about the best way to get the bolts off the bottom of the intake, particulary the ones near the T-VIS vacuum tank. Any suggestions would be great. I can follow directions to a T, however there are just so many tight spaces in the engine bay...

05-12-2008, 11:35 PM	#1 (permalink)
ac604605 No Skills Join Date: May 2008 Posts: 32 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Dropped Cylinder... Follow up from my earlier issue where the engine wouldn't run past 6,000RPM. Thought it might be the cat, so we took it off and ran without it but still had the same problem. Only this time at around 6,000 the engine made an odd sound that according to my father sounds like a dropped cylinder. We tried a few things to try and improve is; first was to slightly pinch off the fuel return line which only made the problem happen at 5,000 instead of six. Second we pulled open the MAF black box and loosed the gear two clicks to make the engine run more lean. This made a world of difference. The problem is still there, however now the car will actually accelerate past six grand. Still has that little bump when you can tell its lost some umph but much better than before. So my question is, if it really is a dropped cylinder whats the most likely place for the problem to happen? Distributer?

05-15-2008, 10:41 PM	#6 (permalink)
mr2tim SUPERcharZed ToyZ RacZer Join Date: Mar 2008 Location: South Florida Posts: 1,789 Thanks: 8 Thanked 118 Times in 111 Posts My Google Map iTrader Rating: (6/100% )	Scrape 1/4' of insulation off the side of each injector wire, touch your ohm-meter to each injector wire,other side to ground? Are all 4 readings similar? TVIS requires the "butterflies" to be full open, if your gunck constricts this action then... The 'Butterflies" work thru that blue VsV under the intake, (it's mechanical action is weak, being vacuum oriented) make sure action is smooth offering little resistance. Keep us posted, we all get your messages.. Last edited by mr2tim; 10-27-2008 at 02:22 PM..

06-20-2008, 05:56 PM	#12 (permalink)
mr2tim SUPERcharZed ToyZ RacZer Join Date: Mar 2008 Location: South Florida Posts: 1,789 Thanks: 8 Thanked 118 Times in 111 Posts My Google Map iTrader Rating: (6/100% )	You mentioned.. Earlier you mentioned in a post that you moved the (AFM) maf sensor 2 clicks? If you cleaned up the TVIS why not go back and undu the Air flow Meter and see what happens? It will give you a more even idle without "idle search'. Lean engines blow easy...(actually melt)

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05-13-2008, 07:54 AM	#2 (permalink)
Mista 2 Cage Fighter Join Date: Nov 2006 Location: Adelaide, Australia Posts: 463 Thanks: 16 Thanked 21 Times in 21 Posts My Google Map iTrader Rating: (0/0% )	have you checked you plugs, leads, dizzy cap, rotor and injectors?

05-13-2008, 06:53 PM	#3 (permalink)
ac604605 No Skills Join Date: May 2008 Posts: 32 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Checked the distributer, bearings in the rotor were grinding... I had an extra one laying around so I replaced it, no difference. Cap looks fine, tried different wires, same. I've checked the plugs several times and they all look good, also I don't suspect the injectors, mainly because I don't want to pull them out, haha; but the engine was rebuilt such a short time ago I really don't think something would have gone wrong with them. This may sound stupid, but I don't know where the engine was rebuilt or by whom. The car was given to my father as a gift from his MR2 obsessed buddy, along with the engine. When he gave it to him he said he had the engine rebuilt at a shop in Santa Fe NM. The old engine never had this problem, when it spun a bearing and we replaced it is when it started acting up. Is it possible this engine has something different about it that keeps it from reaching the same redline?

05-15-2008, 07:06 PM	#4 (permalink)
ac604605 No Skills Join Date: May 2008 Posts: 32 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Holy TVIS Batman..... I took apart some more things today... Pulled injectors to find that although one of them had a ripped o-ring that needs replacing, they look fine. I also took apart the throttle body because the butterfly valve looked dirty, when I removed that I discovered the throttle body was the least of my worries; the entire TVIS was caked with sludge!! The metal tube running from the EGR valve was actually clogged with god knows what,and I could scrape piles of thick black texas tea off the inside of everything. I have included pictures for your enjoyment, before and after, as well as my theory.... Last time we worked on the car, we tried to make the car run both rich and lean to see if it made a difference, and when the car runs lean the problem is less noticeable, however still present. Could the TVIS be so caked with exhaust crap that the engine is being starved of air, therefore making the problem less aparent when running lean?

05-15-2008, 07:10 PM	#5 (permalink)
ac604605 No Skills Join Date: May 2008 Posts: 32 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	MySpace MySpace

05-16-2008, 08:54 AM	#7 (permalink)
ac604605 No Skills Join Date: May 2008 Posts: 32 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Thanks! I actually have a spare set of butterfly valves that are all gunked up that I was using as a reference point. I won't be able to take off the tvis till this weekend but thanks for the help.

05-18-2008, 09:08 PM	#8 (permalink)
feral4mr2 ghetto modder Join Date: Sep 2006 Location: Western Australia Posts: 130 Thanks: 0 Thanked 11 Times in 10 Posts iTrader Rating: (1/100% )	have you done a simple compression test yet?

06-05-2008, 03:18 PM	#9 (permalink)
ac604605 No Skills Join Date: May 2008 Posts: 32 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	No, considering the engine was just rebuilt I didn't think that would be an issue. However I did just move to New York from Texas and the long drive brought up another problem. The muffler was severely clogged, with chunks of material from the cat. I cleaned it out as best I could and the problem is a lot better now. Sometimes the engine drops out at six grand, and sometimes it keeps on going right up to seven; still it never reaches red line but it is much less noticeable.

06-11-2008, 01:00 PM	#10 (permalink)
lsgheero RAR! Join Date: Feb 2007 Location: Arizona Posts: 747 Thanks: 9 Thanked 31 Times in 31 Posts My Google Map iTrader Rating: (1/100% )	I wouldn't continually try to push the engine past 6k if it is having issues. And if you muffler or cat is coming apart I would get that fixed because a malfunctioning cat can catch fire. I've seen it its not pretty lol.

06-12-2008, 01:39 PM	#11 (permalink)
ac604605 No Skills Join Date: May 2008 Posts: 32 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Well the muffler and cat are clean now. The only other thing I can think of is to take the tvis off the motor and see if there is any residue built up from the cat being clogged. However I don't have the right tools to do this, so I probably won't get around to it for a few weeks.

06-24-2008, 08:10 PM	#13 (permalink)
ac604605 No Skills Join Date: May 2008 Posts: 32 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Thanks Tim, I had almost forgotten about that. I'll adjust it tonight and see if it makes a difference in the idle.

06-28-2008, 10:00 AM	#14 (permalink)
ac604605 No Skills Join Date: May 2008 Posts: 32 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Adjusted the afm spring and the car does idle better. I have another question though. If the timing belt or one of the camshafts were off when installed, would it cause this issue of dropping out at high rpm?

06-30-2008, 09:47 PM	#15 (permalink)
mr2tim SUPERcharZed ToyZ RacZer Join Date: Mar 2008 Location: South Florida Posts: 1,789 Thanks: 8 Thanked 118 Times in 111 Posts My Google Map iTrader Rating: (6/100% )	It's relatively easy to confirm the cams are matched by poping the upper cover. The marks are atop and easily seen. When you confirm they are ok, mark the crank pulley in a location easily seen for later reference. I had a loose belt tensioner and got similar? rev up problems. The timing mark for the crank timing gear is buried under the lower timing cover and requires outer crank pulley removal. Save this as a last ditch effort? Tvis is all ok?

06-30-2008, 10:08 PM	#16 (permalink)
MR2TRD1 pimpin' valet ;-) Join Date: Feb 2005 Location: Atlanta Posts: 2,180 Thanks: 1 Thanked 37 Times in 34 Posts iTrader Rating: (19/100% )	You keep saying "it was just rebuilt." Doing a compression test is the easiest thing you can do after all the random things you have tried so far. At least that will confirm your belief in the engine's integrity. In my experience I always say similar things and my issues land up being exactly where I thought it wasn't.

07-01-2008, 11:48 AM	#17 (permalink)
ac604605 No Skills Join Date: May 2008 Posts: 32 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Going to get a compression tester today. Crank gears matched up perfectly, but the marks on the crank pulley were off. T-VIS is clean, but still pulling in what looks like oil. If the compression is off, should I pull the crank pulley and check the gear underneath?

07-01-2008, 03:27 PM	#18 (permalink)
ac604605 No Skills Join Date: May 2008 Posts: 32 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Well now I feel like a jackass..... I tested the number four cylinder and its running 95lbs... Number two was about 190lbs, the other two were in range. I'm certain this will be one of those important lessons I remember the rest of my life. I don't know too much about engine compression, but if the timing was off, would it create low compression in only one cylinder? It would create low compression in two cylinders.... Right?

07-01-2008, 05:14 PM	#19 (permalink)
lsgheero RAR! Join Date: Feb 2007 Location: Arizona Posts: 747 Thanks: 9 Thanked 31 Times in 31 Posts My Google Map iTrader Rating: (1/100% )	im not a certified mechanic lol so by all means let others chime in but heres my : The timing being off should effect the compression levels just the point @ which the spark happens. The reason for this is all your cylinders are connected to the con rod and they cant be out of sync unless of course you really fubared the engine. Now one thing you can do to further test your compression is squirt a tiny bit of 30w oil into the spark plug hole onto the cylinder if your compression doesnt change then you most likely have a bad valve. If it does the rings are bad. (the reason the compression would go up with the oil being placed on the cylinder is due to it temporarily sealing the rings.) I hope that helps and I am not too incorrect in my statements lol But thats the way I have done it and the way it was explained to me.

07-01-2008, 06:09 PM	#20 (permalink)
ac604605 No Skills Join Date: May 2008 Posts: 32 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Thanks for the input, I actually haven't tried the oil test yet, but I will tomorrow when I have more time. One more question. All of my mechanical knowledge stems from the big green book. I read over the section on checking valve clearance and such. When I try and fix this problem myself, will I actually need any of the special tools listed in the book? I'm also curious about the best way to get the bolts off the bottom of the intake, particulary the ones near the T-VIS vacuum tank. Any suggestions would be great. I can follow directions to a T, however there are just so many tight spaces in the engine bay...