New B4 Passat Wagon TDI

In the past week I have purchased this Storm Gray B4 Passat Wagon TDI. Paid $3k for the car. Last owner was the second owner and owned it for 15 years, from 40k to 260k. The car has been maintained very well from what I can tell. 260k on engine and many maintenance repairs have been done through out its life. I noticed it did the limp mode thing......except at all times. I has low power all the time. Hills it can barely make it up and you can barely get up to speed. It like limp mode but all the time. Needing some advise. Im in the process of changing the N75 valve once it arrives, also gonna check on the hose inside the ECU. I had the same issue on my 98 Jetta TDI.

Intake could need cleaning.

-Todd

Hi Tim,

Welcome to the B4V world! Your next purchase should be a VagCom/VCDS. It is very much worth the money to have for issues just like the one you are having.

Check the for sale section, you can usually find one with some patience on your part.

Well John I have the cable.....but I run Apple products and no way am I running Windows on my Mac. Ill just borrow a laptop....haha

As far as what I have done to run the problem down. So....checked the vacuum hose in the ECU....was good. Replaced that and the vacuum hose from ECU to the turbo intake. Didn’t resolve. Removed Intake manifold....was not clogged at all. Cleaned it up a bit reinstalled and deleted the EGR with my Delete kit on my 98 Jetta TDI. Limp still exists. have the N75 valve on the way. After that I will mess with the leaky vacuum pump....possibly there. Is there any way the Turbo could be acting up.....like waste gate malfunction?

thoughts

I have replaced the N75 valve and not change. Does it which bottom valve is connected to what. Also would the Waste gate cause me to have low power at all times if its malfunctioning. or if the actuator is stuck.....what does it do. 260K Im gonna replace in several months. I am wanting to upgrade the turbo for slightly more power/efficiency. Also 502 Bosio Injector Tips. Any Suggestions

Assuming the hoses are good.. did you check the one inside the ecu? Another thing to try since you already did the egr delete you might want to test the maf sensor by doing the mod. I had one go on my 96 about a year ago and replaced it. Recently my wifes 97 went, it had low power, did not pull up hills at all. It did the trick for me, but it was not like it was in limp mode all the time, was just more of low power and intermittent surging issues.

Putting a diode (1N4148) between pins 1 and 6 of the maf wire connector, fools the ECU to think that there's max airflow to turbo... I found info somewhere here on it.

Yep

Yeah I check the Hose inside the ECU...was fine but I replaced it anyways. I cleaned the MAF, how can I check if its bad. I just have low power all the time. Up hills kills it. I can hear the turbo spooling up, thought I am thinking the Wastegate is stuck or something like that! I will look into the MAF

Unplug your MAF and do a quick test drive. Let us know if it drives any differently. It would be best to log a run in 2nd gear actual/requested using vagcom but you'd have to borrow a laptop as you said.

I will be getting VAG COM setup soon, with a new laptop. Does VAG read if the Turbo is malfunctioning? like the waste gate or not enough boost. Does it check timing and such? is there a detailed site on how to run VAG COM
my vacuum pump is leaking oil around the top, may be an issue.

Using the logging of VCDS you can tell how the turbo is functioning, though only through physical inspection can you tell if late spool is from a stuck actuator, failing N75, or worn turbo. As for vacuum, that has no effect on this turbo as it is pressure actuated, not vacuum, but getting a replacement oring isn't that hard. I used a standard off the shelf part.

Oh, and VCDS is REQUIRED for doing a timing belt properly.

Is that to make sure timing is correct as run it......I did a timing belt on my 98 Jetta and timing is off just a hair need to adjust the injector pump location a bit.

What upgrade did you do on the turbo on your 97? and how extensive what the work. Also, do you think Bosio 502 are a safe upgrade for the 1Z engine. I have the Bosio 502's on my AHU and it give a ton more power without any other upgrades.

TDITim83 said:

Is that to make sure timing is correct as run it......I did a timing belt on my 98 Jetta and timing is off just a hair need to adjust the injector pump location a bit.

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TDITim83 said:

What upgrade did you do on the turbo on your 97? and how extensive what the work. Also, do you think Bosio 502 are a safe upgrade for the 1Z engine. I have the Bosio 502's on my AHU and it give a ton more power without any other upgrades.

Click to expand...

You cannot adjust the pump properly with the ECU's output, which is via VCDS. If it sounds a bit off, then it's a significant margin off usually. Not anything that would be engine damage worthy, but the amount of movement needed to adjust the injection quantity is less than +/- 0.5mm. Adjusting the injection timing by rotating the pump isn't much more than that.

I sold my stock turbo a couple years ago to a member in need. I currently have a GTB1756VK, converted to vacuum so really just a GTB1756 if memory serves. Due to x2 or more power and torque than stock, I rebuilt the engine. THis turbo is vacuum controlled/actuated and I just finished redoing the vacuum system to make it respond as fast and the electronic actuators, and also since the vacuum plumbing from the stock B4 is *not*setup for a VNT turbo.

You can go with the 502's, though I and other would suggest a tune to have the fueling setup properly for them. Don't lean on it all of the way too much with the stock turbo because your EGTs will climb quite a bit. There are a few different ways to adjust your IQ after installing the nozzles, speaking of which you need VCDS, and adjusting the QA (quantity adjuster) housing on the IP (injection pump) in tandem to adjusting the adaption in the ECU will help quite a bit before the tune is purchased and installed.

I have PP764's on a stock tune. Just be careful with the skinny pedal if you use it for any length of time. But I had the flow reduced by DBW, so it has a little less flow now, coupled with a much lower IQ.

Im not understanding the terms you guys are using.....such as IQ, EGT, Skinny Pedal, still learning a lot here. I understand the basics, after owning my 98 Jetta for 8 years and love the AHU engine. Also is there a weakness in this engine if I upgrade stuff? I've heard the Rods are weak or something like that.

IQ is injection quantity. EGT is exhaust gas temperature and is telling you if you're quite literally cooking your turbo. Look at your three pedals and tell us which one coresponds to the accelerator

Upgrades should only be considered after you decide where you're going to stop modding the car.

Haha, I totally get it....sorry for the delay. My personal turbo wasn't kicking in....lol

Alright Guys, I now have VAG COM up a running. I am gonna start running it. I did check each cylinder and only three showed up.....so.....any thoughts

Yeah, if you are referring to group 13 cylinder balance, then yes you will only see 3 - it uses Cylinder 3 as reference, and the 3 you see are cylinders 1,2 and 4. This is the case on AHU and 1Z engines.

Are you sure the two lines going to the turbo are connected to where they belong ?

Cylinder readings

Cylinder 1 ........ 0.87 mg/str
Cylinder 2 ........ 0.54 mg/str
Cylinder 3 ........ -0.12 mg/str
Cylinder 4 ........ blank

Which setting or diagnostics do I run to see whats going on with the cylinders
Also Can I see if the injectors are getting fuel or not?

A quick way to see if fuel is getting to the injectors is to get a wrench and loosen up the injection pump lines at the top of the injectors. Crank it over for a second, if fuel squirts out, you can tighten it down and move to the next one. If no fuel sprays out, errr, drink a cold one (or 2...maybe even 3) and start troubleshooting!

Also, I believe the safe number is +- 2.0 mg between the highest and lowest value from Group 13, so you look to be good in that regard.

Also the car had low power issues a couple years back so they installed a Rebuilt Injector Pump......the problem didn't go away!!!!! Idles great

Also wondering why Cylinder 4 says blank........why is it not showing up. I see the values go down each cylinder.....any input on that

Injector 3 is your baseline. Consider it to be 0. The other values are injectors 1,2 and 4.

IIRC, the deviation should be no more tha 1.0 among the 3. Don't get too hung up on it, if it's out of range. DBw told me this is the injector balance at idle, not at higher flow rates when driving.

-Todd

Next Two Questions
It has the original transmission and the fluid has never been changed. 262k miles What are the odds of it shifting better instead of having a hard time going into gear. And will the fluid change possibly start at bad leak in the trans?
Second Question on a turbo how can you check and see if the waste gate is operating properly?

Question 1: Odds are good it'll shift a lot better with new fluid. The manual specifies GL4 fluid only but some on here will reference GL5 that is supposedly backwards compatible. I don't risk it and use a combination of Amzoil MTG and syncromesh, both of which are GL4.

Question 2: you can check to see when it opens and when it stops opening with a bicycle pump. It should crack (start) opening at 8-12 psi and be fully open by 20. Attach this to the turbo wastegate control line.

Abacus said:

Question 1: Odds are good it'll shift a lot better with new fluid. The manual specifies GL4 fluid only but some on here will reference GL5 that is supposedly backwards compatible. I don't risk it and use a combination of Amzoil MTG and syncromesh, both of which are GL4.

Question 2: you can check to see when it opens and when it stops opening with a bicycle pump. It should crack (start) opening at 8-12 psi and be fully open by 20. Attach this to the turbo wastegate control line.

Click to expand...

I will check on the waste gate soon. What about new fluid in trans causing slips or leaks????

I think slipping is more associated with autos.

I've replaced the fluid in plenty of manuals without issue. Personally, I use Pennzoil Syncromech.

-Todd