Engine Misfire / Studder at Cruising Speeds

[rackaracka]

The vehicle data: 1998 NB TDI, 5 SPD, 11MM, Sprint 442 Nozzles. 11,500 miles on rebuilt motor. (Frank06 head and block rebuild, assembled by a hack - but he did have the correct tools including VCDS) I re-did complete timing belt job when purchased. New 11MM pump installed 10k ago, purchased from BoraParts when the 11MM that came with the car (prothe) grenaded.

How does it run? Engine starts and idles beautifully (Occassional SDS that requires a blip of the pedal when stopped), Pulls hard, No power issues, boosts to 17 when pushed and holds 13.5. Stock ECU for now.

What's the problem? During cruising in 4th or 5th gear, when trying to hold constant speed and RPM between 1800 and 2200 - engine starts to hesistate or studder - like a miss. Tach stays steady, boost gauge (Tied to MAP sensor) flutters from 3PSI or so to 0 - bouncing around in synch with the power loss. Pushing the go pedal makes everything fine - boost climbs smoothly and power is excellent. 11,000 Miles on fuel filter - current setup has no thermo-t. Solid fuel lines so I can't look for bubbles. Problem exists using the pedal as well as when using cruise control. Timing and IQ are perfect. Car has no fault codes. I have VCDS. Any thoughts or recommendations on this problem?

Figured it might be a MAF Sensor starting to degrade so I swapped it with a new one - same issue still exists. Now concerned about any long distance / highway trips.

 

[Sevenjays]

Interesting, my 2004 BEW Jetta has a very similar issue right around 2000 rpm when I'm just cruising on the straight and level. To me it almost feels like the clutch is jerking, but is quite similar to a miss. Could the clutch disc springs be worn out and cause it to do this? I don't have a boost gauge or any diagnostic tools so I haven't been able to troubleshoot further, just going by what I feel in the car.

 

[rackaracka]

Sorry for this duplicate post. Also posted in TDI 101.

Adapted my IQ a bit higher (4.8) and changed the fuel filter. Have to take it for a ride on a highway to see if the issue is resolved. Not sure if this could be a symptom of a clutch problem, but I don't think so. I'm going to check my motor mounts carefully as well - because something is telling me that if a motor mount is broken you won't feel the engine wobbling when accellerating or decellarating, but things could get wobbly when your trying to just maintain constant speed.

 

[SmithRP]

Having the exact same issue on my 02 Mk4 Jetta_ auto tran.

Changed the MAF sensor=fail, Fuel filter(seemed to clear problem for an hour or so, but returned - tried duplicating the experience=fail)... Gotta get VAGCOM so I can check/swap tranny fluid and check fuel delivery values.

***Can't understand why it would be tranny - cause if I step on it anywhere through the power curve, it hooks up and goes without hesitation - only happens when at a steady speed or light acceleration(1500-2200RPM).

Pls keep me posted - as I'll do the same.

 

[SoaceMunky]

06 golf with PD experiencing the same here... or i may be halucinating it, because it occurs rarely and is very slight.
something similar happened to me on the way from florida, where there is no speed limit on 95, under heavy acceleration - i thought it was a slipping clutch at the time but have not been able to repeat it for a while now. currently i can sometimes feel it around 1900-2000rpm in 5th, but only when the pavement is really smooth.
i have no tools, but i would be interested in the outcome of this thread.
its been over 20K on the same fuel filter. new in-tank pump. i have a popped off intake hose thats held on with some wire for now, and a leaky vacuum system attributing to poor brake performance.

edit: could be a misfire. pretty rought idle.

 

[rackaracka]

Still have the problem. Took a 50 mile trip to a client. Car was pretty good heading out in the AM, and ok in stop and go traffic for the 1.5 hour trip there. Heading home at 7:30PM - 70MPH cruise and it was bad. Lots of hesitation / misfire / studder. I checked the motor mounts this weekend. All vacuum lines are new. Turbo boosts great when you push the go pedal. Not sure what to do next. I might swap my injectors and put the calibrated (drivbiwire) PP520s back in - to eliminate a failing injector. I am afraid it might be the relatively new 11MM Injection Pump that I bought from BoraParts.

 

[oilhammer]

Does this car have a functional EGR system? If so, disconnect the EGR valve vacuum hose and test drive, see if it acts any different.

 

[rackaracka]

Does this car have a functional EGR system? If so, disconnect the EGR valve vacuum hose and test drive, see if it acts any different.

Yes the car has a functional EGR system. I'll pull and plug the line and go for a ride.

Update - I did this test. No different. The only good news is, since I posted this last month, it's getting worse - so at least I'll find the culprit soon. It happens when the motor is up to operating temp (around 180 water temp) - at cruising constant RPMS between 1800 and 2300 in 3rd, 4th or 5th.

 

[PnutButrJelytime]

I'm in the same boat. 02 jetta auto tranny. its quite annoying when this happens.
i find myself now down shifting to get into the higher RPM's until i can speed up past 2k or over 55mph. i hope someone can come up with a solution or things to check.

 

[rackaracka]

PnutButerJelytime - sounds to me like you have a bad maf or a bad turbo actuator solenoid valve. My car is experiencing a bad miss / shudder at cruising speed while trying to stay at a constant speed. As soon as I press the pedal a bit down boost kicks up from 3 - 5 psi to 15 psi levels and smooth power is ready and waiting. I left the Herbie at home today and took the Buick to NYC I'm going to put the pp520's in tomorrow morning and then head into my office. I find it hard to believe that the new injectors with sprint 442's I bought have a problem, but I don't know what else to do. I hate to pull the IP and send it off for testing. I've e-mailed BoraParts about the warranty on the 11MM pump I bought from them.

 

[rackaracka]

So - I put the PP520's in the car and took it for a ride. Power has increased as expected, boost is excellent - but after driven for a while and normal temps are achieved - cruising at a constant speed results in shuddering. I notice if I flog it hard in second then its easier to reproduce the studder in 3rd gear. I spoke with Aaron from Boraparts that said if it is the IP, He'll take care of it. What a stand up guy! I notice I used 1/2 quart of delvac1 5w40 in the past 600 miles. Is it possible that the turbo seal is blowing by oil when I am not calling for boost, and the studder is small slogs of oil being injested? There are no leaks, there is no visible smoke. I imagine the turbo is original (130k miles) but I can't be sure. The actuator isn't rusty, but that's not very telling.

Looking for help / advice before I order a StreetToys hybrid turbo or pull the IP and send it to Aaron. Is there anything I should / could log with VCDS to find the culprit?

 

[rackaracka]

I just had a very interseting call with Franko6. I had been wondering if my studdering, and my slow down shudder, might be being caused by a engine mechanical timing issue. If the crankshaft bolt was re-used by the "hack" mechanic that assembled the rebuilt engine, could that be allowing the crank pulley to wander between Acceleration and Deceleration - retarding engine timing and causing the issue. I have a new crankshaft bolt and crank yank on the way from Frank - before I dig any deeper.

 

[bgroicahn]

VERY similar to my current issue. Studder at cruise, okay power, but some black smoke out tailpipe under medium load.
Found bad fuel pump (04 BEW engine)
Then with the hood open I run it up to 3000-3500 for a several seconds (building boost) and exhaust seemed to be leaking from somewhere. Found a bad egr tube (cracked in folds) that goes from exhaust manifold to EGR cooler.
Hope this fixes my studder and P0101 code.

 

[rackaracka]

Installed new crank bolt and pulley last night. Going to be a bit before I can re-fire the engine because I took this opportunity to install a new accessory bracket. The IP, powersteering pump, alternator and AC Compressor are off the car and the accessory bracket was taken off last night (it had a couple of stripped bolt holes so I bought one from RetroMike here on the club). The new one has been painted (crazy right?) and will be installed hopefully this evening. I'll post an update when I get the car back on the road and see if the crank bolt was indeed my issue.
bgroicahn - I never had smoke, black smoke is overfueling which might indicate an air leak in your turbo plumbing or perhaps sticky turbo VNT vanes resulting is lower boost than fueled for.

 

[rackaracka]

Update - For those viewing - and Thank You!
Took the car for a good ride tonight and it seems like (fingers crossed) things are better. Really have to go for a highway ride to see if things are right. IP timing is set to "dead on" with an occassional blip into the "slightly advanced" area. Car has tons of power, smooth boost and didn't studder which cruising. Still have slow down shudder. If all is well with my next couple of highway trips to clients, I'll take a trip (3 hours each way) to Red Lion, PA to see RocketChip Jeff and see if an ECU tune will deliver a punch and eliminate my slow down shudder.

I'll update this thread if I find I get the cruising studder / misfire symptom back, but for tonight, I think it was the re-used crankshaft bolt.

 

[rackaracka]

The shudder remains. Turns out that as I've been doing my tests and thinking that I've found the issue, its just waiting around the corner. Intermittant problems are the hardest ones to solve. I removed the injection pump and have shipped it to DFIS, care of BoraParts. We'll see what they find.

UPDATE *** - Sort of good news, sort of bad news... Spoke with Mark at DFIS. My pump ran on their test stand for an hour and perfromed flawlessly. The only thing they noted was that the fuel that was removed from the pump was "odd". I agree, and I had suspected bad fuel early on - as the sample I drew when bleeding the IP after swapping the injectors was very light in color - almost like Gasoline... But it smells similar to diesel, and it burned like diesel. I tested it by igniting a bottlecap full of it and compared ignition reaction as well as burn time. (Not as scientific as it could have been, but all I could do at home) I compared it to a sample of diesel from another provider.

The pump is on its way back to NJ. When I install it I will be emptying the tank and refilling it with some diesel from another station. Not sure what else to do...

 

[canast]

I have been having same intermittent problem, always after car is up to temp. Wife was following me last night and asked if I had problem at a certain point on way home. When I indicated yes she said she could smell Diesel fuel real bad. Would a leaking or sticking injector cause this??

 

[rackaracka]

A leaking injector could definately cause extra fuel to be dropped in a cylinder at the wrong time which would result in unburned, unatomized fuel - which I suppose you'd smell and should also provide smoke or haze from the exhaust. They are most usually identified by a smokey startup as they leak down into the cylinder while the car is off and sitting.

I reassembled the engine with the returned IP (which DFIS had calibrated). I adapted IQ as high as I could, which could only get me to 1.8 and the car had a bad shudder and smoked like a freight train. I reset the IQ to the default value and hammer modded the IP to 7.0. I took it for a short ride last night and there is no smoke and I couldn't get any slow down shudder to happen. I'm going to take it to work today and see if this is better. I also siphoned out the fuel and got a full tank from a different station. We'll see if its better.

 

[rackaracka]

160 miles later and the car performs flawlessly. It really sucks that I pulled the IP and sent it to DFIS unnecessarily. I'm going to stop by the fuel station where I was always buying my fuel and see if he's had any complaints about the diesel, but I am pretty sure that was the problem. I used to religously buy fuel at Hess. I'd go way out of my way to make sure I got fuel there. I got lazy over the past few years and just bought diesel anyplace that was convenient. A local no-name gas station sells diesel. I suppose he buys from any supplier, and I think he got a tank of fuel that is contaminated with gasoline or something other than D2.

 

[rackaracka]

Update.... Intermittant problems really suck.

Anyway - I broke down with about 800 miles on the re-installation of the pump. I was driving to a client out in Chambersburg, PA (About a 3.5 hour drive) and the engine shut down as if the key was shut off. I pushed the clutch in and turned the key off and coasted to a safe spot on the shoulder.

After the tow home, I pulled the timing belt cover and everything was intact - so I tried to start the car with the key. It immediately started and ran perfectly... I was really getting dumbfounded - but then, after about 5 minutes of idling it started to stumble, shudder and then stalled. I got a flashing glow plug light and check engine light. I scanned it for codes and finally got codes from the IP.

00765 - Modulating Piston Movement Sensor (G149)
35-10 - - - Intermittent
01268 - Quantity Adjuster (N146)
18-10 - Upper Limit - Intermittent
01268 - Quantity Adjuster (N146)
19-10 - Lower Limit - Intermittent​

I made sure my connections were good and re-tested the electrical lines, made sure there was no air in the fuel system, and even tried to run the car directly on a jug of fuel. I got it to run a few times, but barely idled and couldn't clear the MIL. So - now I was at a loss. I decided to pull the IP and send it back to DFIS, as know the IP was at least throwing codes. I figured it was either the IP or maybe the ECU at this point, as everything else has been eliminated.

DFIS has the pump now. I spoke with them yesterday and sure enough, they found a bad solder connection inside of the IP. I guess this is very rare, but it was this way when delivered to me from VW as a bosch rebuild. Hopefully I'll have it back on Monday and Tuesday so Herbie can ride again.

 

[rackaracka]

Update - The pump showed up on Saturday and I got the pump installed yesterday. Got the timing set to slightly advanced and had to adapt IQ via Vagcom to get it close to 3.0. This value is a bit low still so it's billowing black clouds but it runs smoothly. I had an hour long battle with one of the hard lines to get it to stop dripping (of course its the one that's difficult to reach) but I'm pretty confident that it's good to go. I'll update the thread after some signifincant mileage is put on.

 

[BobnOH]

take this with a grain of salt if you like- but I'd recommend running the IQ at the factory setting for a tank or two. I know mine ran quite good at 2.4, till the pump died.
I'm waiting for UPS to deliver my rebuilt pump from DFIS as I type.

 

[4ringking]

I guess it is Fixed?

After having the IP repaired, the vehicle has been running good?

 

[rackaracka]

Herbie rides again

4ringking, thanks for asking! Car is running great. I still have an intermittant slow down shudder and am probably going to adjust the IQ up to 6.5(currently at 6.0). I've gone about 3000 miles since I put the car back together and its not given me one hiccup. a few trips from NJ to CT, on trip to Worcester, MA, and lots of NJ stop and go traffic.

 

[BobnOH]

R - If I can just get you to verify this, your pump was sent to DFIS three times before the problem was fixed?
I've had like symptoms, intermediate, for over a year. Last summer DFIS did a complete rebuild ($800). I'm still getting pump codes. I drive the car only occasionally. I've been pulling apart wiring harnesses, checking various sensors, etc. w/VCDS to no avail.
Maybe I need to face the fact that my pump is bad.

 

[rackaracka]

My pump was sent to DFIS twice. First time they found no issues, and it failed shortly after.

The shudder I was experiencing was a failing dual mass flywheel.

 

[BobnOH]

That could be my problem, seems odd that it remains intermittent.
Wish I could find away to diagnose the DMF without pulling the transmission...

 

[BobnOH]

Rack- Sorry to keep at this, but I'm way beyond wits end with mine.
Did the failing DMF cause the codes you listed?
00765 - Modulating Piston Movement Sensor (G149)
35-10 - - - Intermittent
01268 - Quantity Adjuster (N146)
18-10 - Upper Limit - Intermittent
01268 - Quantity Adjuster (N146)
19-10 - Lower Limit - Intermittent
I can't get it it thru my head that a failing DMF would be so intermittent and the pump codes.
thanks again

 

[rackaracka]

The Injection pump codes were not caused by the flywheel issue... They were caused by a bad electrical connection in the injection pump.

My failing DMF was really intermittant. The stumbling idle could ususally be cleaned up by a blip of the accellerator pedal. Sometimes it would stumble and shudder at idle and on VCDS you would see the idle and IQ jumping around, instead of sticking rock solid at 903 RPM with slight variation on the ip timing log screen... A blip of the go pedal and it would be better - sometimes...

 

[jchan]

When you sent your IP back to DFIS did they charge you?

I had the same Quantity Adjuster (N146) problem.
I read and scoured the forums and then saw this posting.

I had sent my IP to DFIS last July and they swapped out my core<11mm> with a 10mm core, since the<11mm> had a problem.

After the swap and error went away, but the problem resurfaced 2 weeks later, I checked and replace alot of stuff, except the IP.

Once I read this thread, I finally decided to buy a new/remanufactured IP.
After the swap the (N146) issue is gone.

I would like to get my bad IP fixed, but I don't want to be charged another $800 for a fix that was never fixed.

It's been 15 months, so my warranty for the repair has elapsed.
If they didn't fix it went I sent it to them, can they fix it now, for a nominal cost$?