92 TSI Slow acceleration after rebuild

[Bchiles]

I have just recently put my 92 6 bolt back together and I am getting very little acceleration, to the point that in first gear it almost stalls when I release the clutch. I replaced the head gasket, removed vacuum lines, replaced almost every component in the cooling system, as well as the timing belt and accompanying components. I timed the engine to make sure it was at 5 BTDC, ran a boost leak test, checked cylinder compression. Everything seemed to come check out. I did install a manual boost control and a mechanical boost gauge, however I have that boost control up quite a few turns and it is only getting to about 5 pounds of boost. I felt no play in the compressor of the turbo, there is no discolored smoke coming from the exhaust. The coil packs are giving me a good reading on my multimeter, plugs and wires are new within 1,000 miles. I did have to replace the stock turbo manifold with a new one I went tubular stainless. I am still getting no power even after messing with the MBC. The vacuum on my boost gauge reads between 15-20 sometimes between shifts it seems to get all the way to about maybe 22. I am not sure what other information I can provide that would help. Does anyone have any ideas?

 

[BeeRacer930]

Have you tried a boost leak test yet?

 

[daplatano91]

I timed the engine to make sure it was at 5 BTDC, ran a boost leak test, checked cylinder compression. Everything seemed to come check out.

Think he already said that


Have you tried disconnecting the manual boost controller and just running a vacuum line from the turbo to the wastegate?

 

[BeeRacer930]

Woops must have missed that. My bad.

 

[Bchiles]

I have not tried removing closing that loop yet. What results would should I see by looping the wast gate to the turbo(I'm assuming you mean the J pipe).

Also On a side note I do have the MBC going from wast gate to J pipe, I did not "T" into the BOV line.

 

[daplatano91]

I'm just giving some ideas to check why the car isn't accelerating the ways you expect it to. What turbo are you running what are you wideband reading?. How are you tuning for the extra boost?

 

[Infamous33]

How is the idle? Smooth or rough, wondering on firing order...
You said you rechecked the timing to 5 before, but did you recheck the cam timing marks....
What were the compression test numbers? Even numbers across, but all lower? (see above comment)
You say it makes only about 5 psi boost, how long does it take to build that? Just thinking maybe the waste gate rod is off...
Did you recheck all the vac lines?
Just trying some basic options to start with.

 

[Bchiles]

I am running the stock turbo, I dont have a wideband so I have no numbers for that, and I am still new to DSM's so I dont know how to tune for the new boost control. My goal was to just bring it up to stock boost to start with, the engine has higher miles so I was not trying to push it hard.

Idle is a little high about 900 after warm up but its smooth, before I had a pretty bad idle surge that seems to be gone it will surge for a couple of seconds but calms right down. Yes I did go back over firing order when I checked the coil pack.

I have not rechecked the cam timing marks.

The compression numbers were in the 150's for the two cylinders closer to the cam gears, and 140's for the two further away cylinders. I cant remember the exact numbers. I was wondering about the differences in compression numbers if that would have an affect on acceleration.

The turbo takes a good amount of time to spool up longer then I would expect. Is there a way that I can manual check the waste gate rod?

I have gone back over the vacuum lines as well as checked the throttle body bolts because I had loosened them when I adjust the CAS. Everything on that end seems to be holding tight still.

The MBC is just a cheap NXS that I got online. Since I was not planning on cranking the Boost way up I was not trying to get an outrageously priced one. I have also checked to ensure that it is properly fitted and not leaking air as well.

 

[daplatano91]

Well let me be the first to tell you if you continue to run the car on 16+psi with nothing to monitor you A/F ratios and tune with your going to be looking for a new motor. In order to run those high levels of boost you need an upgrade fuel system and something to tune the car with along with a wideband gauge. Do yourself a favor and hook the j pipe to the wastegate and run the car like that for now until you have the proper supporting mods to raise boost. Heres a link to the proper upgrade paths to get you started in the right direction.

 

[Infamous33]

Well let me be the first to tell you if you continue to run the car on 16+psi with nothing to monitor you A/F ratios and tune with your going to be looking for a new motor.

He was referring to vacuum readings, not boost pressure. It only makes about 5 psi of boost.
To check the wastegate linkage, look for a 'lever' sticking out on the turbo, there should be a rod connected to it, or at least near it, coming from the wastegate. If the rod is not on the lever, hook it back up and put a thin washer and cotter pin to secure it.
I would pull the upper timing cover and make sure of your marks on the cams, if the exhaust cam is off by a tooth or two, then all of these problems would make sense. Ignition and injector timing runs off the intake cam. Compression test numbers are ok (min. 133, standard 178 @ 400 rpm)
If all is well, take the MBC out and recheck it.
Any other info you can give us? Noises, leaks, CEL?

 

[daplatano91]

He was referring to vacuum readings, not boost pressure. It only makes about 5 psi of boost.

My apologies not sure how I missed that.

Like infamous said check your timing marks on the cam gears and crank then check to make sure you cam sensor is adjusted right with a timing light. Heres the link to check ignition timing from vfaq.

 

[Bchiles]

The timing marks are all correct, I have rechecked all of them I even went as far as to pull off the lover timing cover(giant pain in the ass) to make sure that every timing mark was correct. As well as rechecking the ignition timing with a timing light they are all match up.

The rod for the waste gate is connected appropriately. I pulled the MBC and looped the waste gate to the J pipe and still got zero boost even less than five. Which leads me to believe it could possibly be a bad turbo, or that I need to again do another boost leak. I did use the fuel pressure regulator line to hook in for the boost control just so you guys know where that is tied in at. Could I still get that much vacuum and have a boost leak in the system?

As far as other information is concerned, the idle sounds good I don't even get a lifter knock which there was a little before I put the new head gasket on.

The car does take a few cranks to get it started, which then there is a faint smell of gas from the exhaust after start up which dissipates after a few seconds.

There is a CEL that comes on but it has been there since I have owned the car.

Side note I am trying to follow the guide for upgrades, the aftermarket air can was on there when I purchased the car, and the only reason I went stainless was because I found a good deal when I needed it so timing was the reason for that.

 

[92AWDHX40]

Well a cel is a cel, find out what that is of course, so you know what the malfunction is something the re isnt right.

 

[Infamous33]

Well a cel is a cel, find out what that is of course, so you know what the malfunction is something the re isnt right.

There is no way to be sure what the light is on for. I am fairly certain you would have disconnected the battery when doing all these repairs, so the CEL came BACK on. One cannot assume that everything was reconnected after doing all that work. Even after 18 years working on cars.... I still do it occasionally. Starting to seem like a possible MAF issue here.
What was the reason for the HG replacement? Wondering about the exhaust being plugged.
Last question, it ran pretty good before all these parts were swapped out?

 

[92AWDHX40]

I have over 15 years myself, i know sometimes things work one day and another something doesnt ive seen and experienced just about everything with these cars.

 

[Bchiles]

I will be checking the codes, but is there a way to do it with a factory radio installed, or just the test light counting light pulses way?

The headgasket got swapped because of an over heating problem. That is also why I did the other water pump just to be safe, and since I was down that far.

It ran pretty good it would drop boost sometimes, always after about 2500 RPM. When it didn't do that it drove very well. the throttle was very responsive.

I will check my manual and attempt a check of the MAF as well.

What did you mean by plugged exhaust like a valve stuck closed or actual Blockage of material in the manifold.

Hope these Ideas will help

 

[92AWDHX40]

What? pulses get a logger, or link to tell you what those codes are.

 

[Infamous33]

Do you still have the cat. converter installed? Really wondering, now that you say you would lose boost pressure over 2500..... If it is plugged, you would have an issue along these lines.



The engine codes can be tested with an analog volt meter. See attachment:
Connect the volt meter as indicated, THEN turn the key to run. Count the pulses of the meter, Long pulses are 10's and short pulses are 1's.
Report back with the codes and we will see where we need to go from here

 

[Bchiles]

OK thanks again everyone for the help. I did what was suggested ran the codes and, and figured out most of the problems.

The was still an issue with the timing and the firing order once that was fixed the car accelerated and idled well the way that it should. for the most part I am still dropping boost around 3,000 rpm and it still seems to be mostly in second gear, but I can not pin point the exact circumstances. Any advice?

The engine codes were because of the timing and the firing order, and also I need to replace my IAC.

The oil return line is leaking but I know the engines are notorious for doing this any suggestions? I am gonna try to replace the gaskets first because It looks like its leaking from the actual connections not the line its self.

Other then that the car is running good idles fine once it is warmed up and there is no cooling issues.

 

[bryanwheat]

The oil return gasket isn't leaking, you are missing the crush washers that to on the bolts that hold it on. They should be replaced every time.

 

[Bchiles]

I never removed any part of the oil return line, there could be washers missing I have not even had a chance to pull the line down yet.

 

[Bchiles]

Thanks everyone for all of the help after continuously running the engine codes, I have solved the acceleration issues. It was replacing a series of sensors and fixing a few electrical connections that were just not getting the contact that they should. Thanks everyone for all of the help. The car is running better then when I bought it. I am a firm believer that you can still have a quick car that has over 200,000 miles and is reliable as long as you are prepared to take care of it and do the work necessary to maintain a vehicle.