2.5 Jetta Won't Start--Any Suggestions?

The new engine arrived today. This is what it looks like. It was not cleaned before leaving the salvage yard. I truely believe it has only 850 miles on it. It is spotless!



$1500 and $150 shipping. Sweet! It came from a 2011 that was toatled with 850 miles on it. Yes, 850! and its a CBUA (a BGP is in it now). There are some minor differences in the add-ons and a few of the sensors have different part numbers (or letters), but I can swap over the different stuff from the old motor. One oddity is it has two single-wire oil pressure switches on the block, whereas the BGP has oneswitch, with two wires, but on the filter housing. To be safe I will use the old pressure switch and move the filter housing over and just leave the new pressure switches installed to plug the holes. There is also some sort of sensor near the oil pan and the Bentley manual does not cover it. My manual goes up 2009, so that must be a newer add-on. All the drillings and the block and head castings seems to be the same though. At this point, if something major won't bolt up, I will just have a fit.

--Nate

Sweet! Keep us posted on your progress. I'd be curious to see if the newer engine will work. For $1650 to your door, you really got a deal if all goes well.

Good luck. That is a sweet deal on the new engine.

Yea, I can't believe it. I will keep you all posted.

One oddity I noticed is that it has standard spark plugs installed, with the round steel center electrode. Not platinum plugs. I thought they were specified and the old BGP had platnums in it, with the VW logo on them (they were NGKs) (maybe VW is now cheaping out). The plugs in the new motor have prominent VW logos on them (made by Bosch) and are completly unworn with only slight coloring, so I don't think the salvage yard switched them on me.

I have no idea what I'll do if I reach an insurmountable roadblock, like something won't bolt up that is critical, but this engine was used in the A5 Jetta from 2007 - 2010.

--Nate

Subscribed !! Best wishes !!

Thanks. I'll take pictures along the way. I am swapping the manifolds because the fuel injectors are different. Here are two pictures of the intake ports after removing the intake. There again, you could eat off of these parts:





And here is the funky oil solinoid valve I thought was a sensor. I got it out of the block this evening:



Zeb at 1stvwparts.com said it was used begining in 2011. Its listed simply as "oil control valve". I'll have to leave it unplugged and hope I always have oil pressure. I would like a desciption of what this does, though.

--Nate

You might want to fit an oil pressure gauge to keep an eye on things.

J

Could that oil control valve divert oil to something critical... like timing chain components or cam timing device?? Can you figure out where passages lead??

Where was the oil control valve in the block? Vaccuum fitting? Electrical fitting?

The oil control valve appears to be a (electrical) solinoid. It is pressed into a hole in the block near the flywheel end, about the level of the center of the crankshaft. An "O" ring seals it and a screw retains it. As pictured, nothing is externally moveable, i.e., its not a pistion valve. There are two big grooves (channels) machined into the valve (pictured). That part of the valve is stationary and I assume there are two oil passages perpendicular to the valve and the grooves allow oil to pass by all the time.

There are two small holes in each groove (I think they are drilled through the valve, put something is inside to open and close those little holes). You can see two of them in the picture. At the small end of the valve (you can't see it in the picture) that is inside the engine, there is a supperfine screen about 3 mm accros. So I assume the valve opens and closes to divert a small amount of oil flow from the main galleys, through the valve, to another oil passage, or to a bleed off back to the sump.

My guess is the extra oil pressure switch acts as a trigger to the control unit to cause this valve to open and close. The valving must be internal, because the silver portion you see, with the two chanels in it, does not move.

It looks as if only a very small quantity of oil can flow through the valve, due to the tiny size of the holes drilled in it.

It is definetly installed in a main oil passage, because when I worked it out of the block, a bit of oil flowed out of its mounting hole.

--Nate

These guys make it. Maybe you can call them and find out what its purpose is?

http://www.bontaz-centre.com/en/nosProduits.php

It sounds like that valve is drop dropping oil pressure to something. Is that lifters, or cam phaser? I don't know, I'm just throwing things out. Maybe a cold oil bypass of some sort?

Does this engine have VVT, by any chance? If it does, you are going to be in trouble. Probably would be worth popping the valve cover and make dang sure it does not.

Yes, the intake camshaft has variable valve timing (the BGP motor had it too, the one that was in the 2005.5 Jetta), but I do not think this solinoid changes oil flow to the camshaft timing mechanism (I think the variable cam adjuster uses oil flow, though). My reasoning is because the CBUA engine was used in the A5 Jetta from 2007 - 2010 and beginning in either 2010 or 2011, this oil solinoid appeared on the CBUA engine, so the variable intake camshaft timing worked without it before. Perhaps this solinoid is to trim the timing more accurately. I just don't know. Looks like I'll have to leave it unhooked. I would imagine th eVW engineers would have designed the system, whatever it is, where if the solinoid (or its wiring) fails, the engine won't be damaged.

--Nate

Was the old motor the 150 hp version? The new one is probably rated at 170 hp. Will the ECU know what to do with the new motor? It probably will. There must have been a software tune to get more power because as far as I know, the motor and transmission gearing are the same between the 150 and 170 hp versions of the car.

Yes, 150 is the BGP and 170 hp is the CBUA, but I am swapping all of the BGP stuff over, including the ECU, so I would imagine the output will be more like the 150 HP. I don't know if the compression ratio is different.

I would imagine if I somehow inactivated the VVT, the engine would not be damaged. Performance would be suboptimal, though. The pistons rotate in the same manner, no matter what the VVT mechanism does. It must move the valve timing only within a certain degree range to prevent piston/valve contact. Too advanced or too retarded, pistons will smack the valves.

Here is what Wikipedia says about VW's variable valve timing (but I don't think that the the CBUA and BGP are electrically controlled, and only the intake camshaft on each engine has the VVT, and the VVT mechanism is on the end of the camshaft, under the chain cover):

Volkswagen system
Volkswagen use a variator system with two variators, one for each camshaft. Like the Alfa Romeo system, these are electrically-controlled hydraulic units, mounted in the camshaft's timing belt pulley.[3] These systems are fitted to the Volkswagen VR5 and VR6 engines, and also to the W8 and W12 engines. The multiple-bank W engines have four variators in total, one for each camshaft.
The Volkswagen variator is referred to as a 'fluted variator', owing to the shape of the hydraulic components. Unlike the Alfa Romeo system with its helical splines and indirect actuation,[note 3] the Volkswagen system has a direct rotational action. The internal components of the variator resemble a paddle wheel inside a loose casing, so that it is free to move a few degrees from side to side. By applying hydraulic pressure one one side of these paddles, a phase shift is achieved.[3] The hydraulic fluid is engine oil, controlled by a solenoid valve mounted on the cylinder head and controlled by the ECU. A Hall effect sensor also monitors the camshaft position.

--Nate

About a Third of the Way There

Got the old motor out with the trasnsaxle today. My neighbor let me borrow his engine hoist. Now I have to remove the tranny from the engine and clean ithe tranny up a bit and check the clutch.



--Nate

PDJetta said:

I pulled the valve cover and oddly, both camshafts rotate when cranking the engine. This engine has roller lifters (or rockers), so I can not tell if there is valve damage. Oddly, if I rotate the engine in the reverse direction (using the clutched alternater pulley and my serrated bit for the TDI), the intake camshaft rotates some, stops, jumps forward and makes a clicking noise when it jumps. The exhaust camshaft seems to rotate normally when I keep turning the engine backwards. Perhaps this engine was not meant to be rotated backwards.Nate

Click to expand...

I pullled the timing cover off of the old motor all appears well inside. The timing chains are nice and tight and seem to rotate both camshafts in the direction of engine rotation. BUT if I rotate the engine backwards, the chain tensioner immediatly collapses, releasing tension on the upper timing chain and the chain ratchets over the intake camshaft cog, and the intake camshaft remains stationary when this happens! Of course whatever this happens, the the intake valves move out of time. This is what happened to the motor when my son ran it backwards, rolling backwards and using second gear to attempt to roll-start the car.

If I let the chain jump enough over the intake cog, and then when I rotate the engine forward, I hear a pistion hitting a valve and I can't rotate the engine any more.

I'd like to pull the head and take a close look, but I need a special VW serrated tool for the camshaft cog securing bolts and another special VW driver for the head bolts, per the Bentley manual. Neither are allen, torx, tripple square, or hex.

--Nate

Polydrive.

How's the engine install coming along?

I got everything switched over to the new engine and got the single-mass flywheell clutch kit installed. Other than the engine slipping off a 4X4 and pinching my finger, all went well (my finger is still numb).

My son and I got the engine and transmission installed this weekend, but had one heck of a time getting it to line up with its mounts. It kept pitching forward. It was awkward, even with an engine lift. Best I could figure out is the block and transaxle drive flanges were hitting the inner CV joints. After we finally got the drivetrain in and mounts bolted in (with all new bolts for the mounts), we went to lift up the drive axles to attach them to the transaxle. Both were firmly wedged under the drive axle flanges (they appeared about half an inch too long to clear) and we pried and pried and could not get them unstuck. I think I may have busted the transaxle mount in the process and now have one on order. I think I should have tied the drive axles up before installing the drivetrain, but I've never had any issue with letting them lay flat on the diesels. It was easy to fix, though. After I calmed down, on each side, I removed the three ball joint-control arm nuts, released the control arm and moved the strut out an inch or so at the bottom and this freed the inner CV joints and I was able to lift them to their flanges on the transaxle.

Hopefully this won't progress beyond the next two weeks. I'm getting too old for this and the expense is a good bit greater than I anticipated, with spending about $2500 so far!

--Nate

You know those axles should come out pretty easy. You do not even need to mess with the suspension on the A5, since they have bolts on the outside, like the B5s.

One Other Thing I Did Was Thread Repair on the Tranny Mount

I used a TimeSert thread repair kit on the aluminum transmission mount threads that were begininig to strip out after one use. The TimeSert is one SLICK professional repair that won't fail. I did a write up (with pictures) on how to do it here (glad I did, because I now have to remove those bolts again to replace the body mount to transmission due to slop in the rubber):

http://forums.tdiclub.com/showthread.php?t=350365&highlight=TimeSert

--Nate

The New Engine Does Have a Variable Pressure Oil System

Through the following link I verified that the new CBUA engine does, in fact, have a variable pressure oil system. I finally found the level of technical information I need for VW's self-regulating oil pump. The info is contained beginning on page 16 of VW Self-Study Program 922903 (even though this is a different engine, the oil system is probably similar. The control piston I removed looks identical, as does the description of the two oil pressure switches):

http://152.66.93.29/audi/download/au...%20w%20AVS.pdf

Please check my thinking on one item: If oil pressure regulation valve N428 is never activated, i.e., left unplugged (it is normally closed when no power applied--I verified by removing it and connecting to a 12-volt power source and the ports opened and then closed when disconnected), will the oil pump pump at its maximum rate? This is what I have concluded from reading the technical information, but I would like some confirmation of this, since I am swapping in a motor with a self-regulating oil pump into a Jetta that does not support this feature, so I'll have to leave the N428 unplugged.

--Nate

I read through the link, and agree with your conclusion. With n248 de-energized, system should revert to high pressure. Confidence level on the conclusion is not 100%, though!!

When you start it up, do check oil pressure under various conditions to see what the system is doing.

Why would you want to reduce oil pressure in the first place?

turbocharged798 said:

Why would you want to reduce oil pressure in the first place?

Click to expand...

Less hp to drive pump, thus less drag on crank and better mpg (probably pretty slight).

99% of the time, the oil pump is moving more oil than needed to keep engine safely lubed. The system has to be designed for that worst case 1%. So it makes sense to have some sort of volume control system to put pressure right where it is needed, and no more. Dumping pressure out a pressure regulating valve is a waste of energy (old style system). We will probably see more of these types of systems.

^^^ exactly why I am stocking up on old cars to last me till I die. The point of diminishing returns costs major $$$$$$$$$$$$$$$$$$. Buying an 02 Beetle later this week.

Got the Engine Installed--It Runs Flawlesly!

Finished up this Staurday. Only issue I thought I had was when I connected the battery, I got some really big sparks. Seemed like a direct short. Was not the alternator or starter. I could not narrow the issue down (I disconnected all wires with the fusible links at the under hood fuse box and still got sparks), and I noticed that all the electricals worked regardless, so I used a jumper cable on the negative post to the chassis to prevent sparking at the battery. Bled the fuel system, cranked, and it fired right up and ran. When trying to figure out the electrical sparking, I had the alarm activated and disconnected tha battery again and the alarm kept going off. Odd, no battery, but the alarm is shrieking. Also after leaving the battery connected for a few minutes, it no longer sparked when connecting and disconnecting. The original sparking must have been from a normal current draw to charge a BIG capacitor of somthing similar for the alarm. I have never seen this on a car before.

No CEL, runs smooth and has ample power, BUT my chipped TDI has better acceleration in the lower gears, hands down. Both my '04 PD and this '05 2.5 now have the same clutch, the Sachs for the VR-6, (with solid steel flywheel) and the one in my TDI slips and the 2.5's does not. So my TDI must produce more torque. The gear rattle (from the solid flywheel) on the 2.5 is almost non existent. Its pretty noticeable on the TDI.

Here are a few pictures:


Getting ready to mate the transaxle to the new engine.


New solid flywheel clutch kit installed.



Flushing the brake fluid when the front clip is off. Very Easy!


A/C blows 38 degrees F now after a new receiver-drier, evacuation and weighing in 18 ounces of R-134a.


All put back together. What a job!

One thing I noticed was no oil light with the ignition on and engine not started. I figured it was in the tachometer or speedometer cluster. I was positive I connected the oil pressure switch wiring connector. Obviously it has oil pressure, because I drove the car a bit. The owner's manual seems to indicate it is in the multi-function display (and a text message would appear and an alarm would sound if low), but I could not even find the icon for it with the ignition on and the engine not started. Anyone know about that?

The A5 is a nice car. Has a lot of features my A4 does not.

--Nate

I don't think the oil light comes on in my 99.5 or my 2012 before starting.

-J