2003 a4 jetta blip throttle results in rough idle

[burpod]

the automatic does have different maps... like if you run the automatic maps on a 5spd car, at least with the 4-wire glow plug ecus, you'll get some bad rev-hang between shifts. i thought about that. it could be a bug/issue that is exaggerated by the automatic maps with just the right hardware glitch...

 

[ninedee_golf_tdi]

Original complaint was only when cold, but now seems to do it more frequently even when hot. When i ran the engine off a bottle of fuel, results were the same. I do have the immo deleted fd installed instead of the original gn.

I'm now noticing the unplugged maf specified jumps around too when it spazzes. Right now Temps are fuel 23, air 23 and coolant 91.

 

[csstevej]

Another wag……. Have you tried another ECU? Maybe the one has some corrupted programming.

 

[burpod]

i wouldn't think MAF would have any affect... but.. the MAF sucks. i maf-delete everything eliminates lots of potential for weird issues and when you delete the egr, the maf becomes useless...

 

[ninedee_golf_tdi]

I reinstalled the stock gn ecu and started it. Raced the engine a bit and let it idle, ran fine. Did it again immediately afterwards, spazzed. Injectors are probably from a 5 speed set I had on the shelf. The customer had a different used set installed trying to troubleshoot, I removed them and installed a set I have.

 

[burpod]

Make sure the spare ECU is set to automatic coding and cycle key. Those manual nozzles will flow about 25% more fuel, so... More potential for problems but depends... Compounding errors etc

 

[burpod]

That's probably why IQ changed when you installed it the spare ECU, if it was set to manyla coding the IQ at idle would change because it's using difference pump maps

 

[burpod]

i guess i also wouldn't rule out n75 acting up either.. maf + egr. blipping that throttle if one of those is acting up, could create some sort of choking affect which would cause IQ to bounce trying to compensate to maintain idle....

 

[ninedee_golf_tdi]

Sooooo... I have another a4 with an 01m in my yard. It runs great with zero issues. My plan is once I get back from a business trip to SC that I'm going to swap parts one at a time from the problem child to the guinea pig with a test run after each installation. I think the order will be install the rebuilt pump first, then the injectors, then maybe n75 and the ecu last. Or should I alter that list ? Your guess can't be worse than my guess, so guess away. Thanks.

 

[Mozambiquer]

One of the other things to check would be the lifters. If they are pumping up it can slightly open the valves especially when cool..I had an alh do that.

 

[ninedee_golf_tdi]

So you are saying it might be an low oil pressure / worn lifter issue ? Induce the issue, shut it off while it's acting goofy and check for weak lifters ? I just resealed the valve cover on this yesterday and inspected the cam lobes, nothing found.

 

[burpod]

i would try a real maf/egr delete before going that far. only takes a couple minutes and a few key strokes to change that

 

[Mozambiquer]

So you are saying it might be an low oil pressure / worn lifter issue ? Induce the issue, shut it off while it's acting goofy and check for weak lifters ? I just resealed the valve cover on this yesterday and inspected the cam lobes, nothing found.

Actually it's a lifters not releasing issue... I have seen it a couple of times, and often when it gets worse when you rev it cold itll die out or start to misfire and then when you restart it itll act like low compression in some of the cylinders. Not saying it is what your issue is, but its one possibility I thought of that I have seen before.

 

[jmodge]

Do you run 15w40 in it by chance?

 

[BobnOH]

Still guessing.......
Contaminant in vacuum tubes?
Bad N18 or EGR?

 

[ninedee_golf_tdi]

All righty, back to this problem child. I have the luxury of having a fine running parts car in the yard, so if someone has mentioned this or that, I tried it with the exception of the n75, which I'll do tomorrow. After 3 different pumps, 3 sets of injectors, a maf/egr delete tune and some trickery by Burpod in his attempts to tune this problem away, it still persists. Oil has been confirmed as Rotella 5w-40. I'm still looking for my sae/metric adaptor to connect my oil pressure gage and monitor that. Mozambiquer mentioned the possibility of lifters staying pumped up, which I guess is from too high of oil pressure or plugged oil passages. Where is the oil pressure relief valve on an alh ? I'm guessing it is in the oil filter housing somewhere which I might just swap out tomorrow. If the swapped oil filter housing doesn't fix the problem, I'll put a new set of lifters in it. And if that doesn't work, any more ideas ?

 

[ninedee_golf_tdi]

Back to the problem child. I put a new set of lifters and a cam in it although to be honest I saw nothing "wrong" with either the old lifters or cam. Same problem. Oil pressure cold when rev'd maxes about 75 then goes down a few like the relief valve is controlling the pressure. Cold at idle is 45psi give or take. I'm obviously overlooking something, but I haven't a clue what that "something" is. Any more guesses ? Thanks.

 

[JDSwan87]

Have you double checked vacuum lines?
Throttle pedal flakey?

 

[burpod]

how cold is cold? that oil pressure sounds like it could be a bit on the low side, at least based on pressures i've seen in my cars with an oil pressure gauge

 

[ninedee_golf_tdi]

Ambient temp was about 40'ish. This is on a slightly warmed up engine having run only 2 minutes or so to pump up the new lifters, then shut down for an hour while I configured the oil pressure gage. Per Bentley, at 176f (coolant temp?) there is no minimum specification, at 2,000 rpm minimum is 29 psi and maximum is 103 psi.

I just ran a can of sea foam in the crank case for 30 minutes and am letting it drain now. I'll put in Rotella 5w-40 which is what the car supposedly had in it.

The throttle was graphed and looked linear, but I'll check it again when it's spazzing. I did replace a few sketchy vacuum lines but the condition pre-existed that.

 

[braddies]

Getting plenty of vacuum out(in) the vac pump?

 

[ninedee_golf_tdi]

Sunday update time. Vacuum pump is putting out (sucking in ?) 29inches, blah blah. I logged 007, 001 and 004 which shows that once the coolant reaches around 45c depending on what log you view, the spazzing ceases. Any more guesses ? Thanks. (edit: phew, what a mess that looks like, but it's the best I can do right now).


Sunday 18 December 2022 10:06:54:12705-VCID:57B7E02DB53CC53593-4ACE VCDS Version: Release 22.10.0 (x64) Data version: 20221026 DS344.0
038 906 012 FD 1.9l R4 EDC G000AG 4102

Group A: '007 Group B: '001 Group C: '004
Fuel Temp. (G81) N/A Intake Air Temp. Coolant Engine Speed Injection Quantity Mod. Piston Coolant Engine Speed Start of injection Start of injection Cold Start Injector
TIME (G72) Temperature (G62) TIME (G28) Disp. (G149) Temperature (G62) TIME (G28) Specified Actual Duty cycle
Marker STAMP °C °C °C STAMP /min mg/str V °C STAMP /min °BTDC °BTDC %
0.63 15.3 6.3 36.0 0.95 903 7.4 1.800 36.0 0.29 903 3.3 3.3 45.8
1.59 15.3 6.3 36.0 1.91 840 11.2 1.780 36.0 1.27 945 3.3 3.1 44.6
2.57 15.3 6.3 36.0 2.89 966 5.6 1.700 36.0 2.23 945 3.3 3.3 45.8
3.55 15.3 6.3 36.0 3.87 819 14.0 1.840 36.0 3.21 819 4.0 3.5 43.4
4.51 15.3 7.2 36.0 4.83 903 8.0 1.860 36.0 4.19 945 3.3 4.0 41.0
5.49 15.3 7.2 36.0 5.81 945 6.0 1.740 36.0 5.15 945 3.3 4.2 41.0
6.45 15.3 7.2 36.0 6.79 819 13.4 1.900 36.0 6.13 840 3.7 4.0 43.4
7.43 15.3 6.3 36.0 7.77 945 6.2 1.540 36.0 7.11 924 3.3 4.0 46.6
8.41 15.3 7.2 36.0 8.73 945 6.0 1.740 36.0 8.09 924 3.3 3.1 47.0
9.37 15.3 7.2 36.0 9.69 903 7.4 1.840 36.0 9.05 840 4.8 3.5 44.2
10.33 15.3 7.2 36.0 10.65 819 13.6 1.840 36.0 10.01 945 3.3 3.7 43.8
11.31 15.3 7.2 36.0 11.63 945 5.8 1.720 36.0 10.99 945 3.3 4.0 47.8
12.29 15.3 7.2 36.0 12.63 819 13.2 1.920 36.0 11.95 819 3.3 4.0 42.2
13.29 15.3 7.2 36.0 13.63 945 5.8 1.740 36.0 12.95 945 3.3 4.0 43.4
14.29 15.3 7.2 36.0 14.61 798 15.4 1.980 36.0 13.95 819 4.6 3.7 41.4
15.27 15.3 7.2 36.0 15.59 945 6.2 1.520 36.0 14.93 945 3.3 3.7 43.4
16.27 15.3 7.2 36.0 16.59 903 7.8 1.840 36.0 15.93 903 3.3 4.0 42.2
17.23 15.3 7.2 36.0 17.57 903 7.8 1.560 36.0 16.91 945 3.3 4.2 41.8
18.21 15.3 7.2 36.0 18.53 966 5.4 1.740 36.0 17.89 945 3.3 4.0 49.0
19.17 15.3 7.2 36.0 19.51 882 8.6 1.940 36.0 18.85 903 3.3 4.2 41.0
20.15 15.3 7.2 36.0 20.49 903 8.2 1.640 36.0 19.83 903 3.3 3.7 53.0
21.13 15.3 7.2 36.0 21.45 945 5.8 1.780 36.0 20.81 945 3.3 3.7 39.8
22.11 15.3 7.2 36.0 22.43 882 8.0 1.940 36.9 21.79 798 5.7 3.7 43.4
23.09 15.3 7.2 36.9 23.43 945 6.2 1.500 36.9 22.76 966 3.3 4.0 61.4
24.07 15.3 7.2 36.9 24.38 966 5.4 1.720 36.0 23.75 903 3.3 4.4 39.0
25.05 15.3 7.2 36.9 25.36 798 15.8 2.020 36.9 24.73 819 4.6 3.5 94.4
26.03 15.3 7.2 36.9 26.35 945 6.0 1.500 36.9 25.71 945 3.3 4.0 36.3
27.00 15.3 7.2 36.9 27.33 945 6.2 1.740 36.9 26.67 945 3.3 4.4 37.9
27.99 15.3 7.2 36.9 28.30 819 13.8 1.840 36.9 27.65 819 4.4 3.3 28.3
28.95 15.3 7.2 36.9 29.28 966 5.6 1.780 36.9 28.62 966 3.3 4.0 40.6
29.93 15.3 7.2 36.9 30.24 924 6.0 1.740 36.9 29.61 903 3.3 3.7 42.6
30.88 15.3 7.2 36.9 31.22 819 13.8 1.920 36.9 30.56 819 4.2 3.7 29.9
31.89 15.3 7.2 36.9 32.22 966 5.4 1.720 36.9 31.56 945 3.3 3.7 42.6
32.87 15.3 7.2 36.9 33.20 798 16.0 2.000 36.9 32.54 819 5.1 3.7 42.6
33.85 16.2 7.2 36.9 34.17 903 8.0 1.840 36.9 33.52 945 3.3 4.0 40.6
34.82 15.3 8.1 36.9 35.15 966 5.4 1.720 36.9 34.50 945 3.3 3.5 71.7
35.80 15.3 8.1 37.8 36.12 819 14.4 1.840 37.8 35.46 798 5.7 3.7 41.8
36.78 15.3 8.1 37.8 37.10 945 6.0 1.480 37.8 36.44 945 3.3 3.7 50.6
37.74 16.2 8.1 37.8 38.06 966 5.4 1.720 37.8 37.43 945 3.3 3.7 42.6
38.72 16.2 8.1 37.8 39.04 798 16.0 1.840 37.8 38.38 819 5.1 3.3 41.4
39.68 16.2 8.1 37.8 40.02 945 6.2 1.600 37.8 39.36 945 3.3 3.7 41.8
40.66 15.3 8.1 37.8 41.00 945 5.4 1.700 37.8 40.34 945 3.3 3.5 41.8
41.64 16.2 8.1 37.8 41.96 903 7.8 1.840 37.8 41.32 819 4.2 3.5 70.5
42.64 16.2 8.1 37.8 42.96 966 5.6 1.540 37.8 42.30 966 3.3 3.7 40.6
43.64 16.2 8.1 37.8 43.96 819 14.0 1.880 37.8 43.30 819 4.8 3.5 41.0
44.60 16.2 8.1 37.8 44.94 945 5.8 1.460 37.8 44.28 945 3.3 3.3 42.2
45.60 16.2 8.1 37.8 45.94 924 5.2 1.520 37.8 45.28 882 3.3 3.5 43.0
46.60 16.2 8.1 37.8 46.92 861 5.2 1.660 38.7 46.28 903 3.3 2.9 46.2
47.58 16.2 8.1 38.7 47.90 882 6.0 1.640 38.7 47.24 861 3.1 3.3 42.2
48.54 16.2 8.1 38.7 48.86 924 3.6 1.460 38.7 48.22 924 3.3 2.6 48.2
49.52 16.2 8.1 38.7 49.84 903 5.4 1.720 38.7 49.18 882 3.1 2.6 43.8
50.50 16.2 8.1 38.7 50.82 903 5.4 1.540 38.7 50.16 882 3.1 2.6 49.0
51.46 16.2 8.1 38.7 51.80 903 4.8 1.560 38.7 51.14 924 3.3 2.6 46.6
52.44 16.2 8.1 38.7 52.76 903 5.2 1.720 38.7 52.12 882 3.1 2.9 47.4
53.40 16.2 8.1 38.7 53.74 903 5.2 1.640 38.7 53.08 882 3.1 2.6 48.2
54.38 16.2 9.0 38.7 54.72 903 4.8 1.600 38.7 54.06 903 3.3 2.9 44.6
55.36 16.2 9.0 38.7 55.68 882 5.8 1.660 38.7 55.04 903 3.1 3.1 45.8
56.34 16.2 9.0 38.7 56.66 882 5.8 1.620 39.6 56.02 903 3.3 3.5 43.8
57.32 16.2 9.0 39.6 57.64 903 5.2 1.600 39.6 57.00 903 3.1 3.3 41.8

 

[ninedee_golf_tdi]

More putzing reveals that yes, the spazzing does cease when it reaches a certain coolant temperature, but after more logging, graphing and experimenting the temperature seems coincidental and not causative. Even when from cold, touch the throttle, spazz, let it idle until it normals up, then you press the go pedal to about 15% and you start the spazz sequence all over. I'm not sure if the 15% throttle is a clue or coincidental, but it's done that now four times, such that when the engine normals up, raise the throttle to 15% and the spazz sequence starts again regardless of temperature not fully hot. I graphed the throttle and it certainly looks linear up and down. I just finished driving it around the block a few times. Until fully hot, hit the go pedal too hard and it spazzes / stumbles a few seconds, then corrects itself. When fully hot, it is now driving fine.

 

[ninedee_golf_tdi]

This is a log file that shows once you bring the go pedal to about 15%, the pump spazzes. Now, is the spazzing from the pump being stupid, or is something telling the pump to act stupid ? (Speaking of stupid, I struggle sometimes with learning things like gmail and permissions, and....

LOG-01-001-004-007.CSV

drive.google.com

 

[Nuje]

You need to set SHARE permissions on that file. Set it to "anyone with link can view" and make sure it's just "view" access (as opposed to "edit").

 

[ninedee_golf_tdi]

Update time. It's 22f here, maybe 35 in the garage where this car sat overnight. It started perfectly, and I drove it out of the garage at idle only to a parking spot. It ran perfectly at idle, but once I touched the throttle a bit after parking it, it spazzed. Can the throttle pedal be part of this mystery even if it shows linear on vcds graphs ?

 

[Nuje]

If you have a spare pedal (or one on a different car?), doesn't take too much / too long to swap them and see what happens; I'd give that a try.

 

[ninedee_golf_tdi]

Update time: I found my spare go pedal and swapped it, no change. Idles fine, but give it a bit of motivation with the pedal and it spazzes. One thing I noticed is that once the spazzing starts, if the engine is turned off for about 10 minutes, it starts and idles fine.

Pump was swapped x 3
Injectors were swapped
ECU was swapped
Harness cut open to check for defects
Go pedal swapped
ASV was disconnected
EGR is relatively new, but disconnected
Vacuum lines checked
Turbo is brand new
Fuel tank / filter was bypassed with a separate source of treated fuel
Can of sea foam dumped in the oil before draining it
Cam/lifters were replaced
Oil / filter changed Rotella t6 5w-40 put in
Oil pressure measured, cold was 75 at around 2000rpm

What can I be overlooking ? Thanks for any suggestions.

 

[braddies]

That's quite the list, maybe the symptoms change when adjusting IQ?
Thread on checking and adjusting IQ in vcds

 

[JDSwan87]

Update time: I found my spare go pedal and swapped it, no change. Idles fine, but give it a bit of motivation with the pedal and it spazzes. One thing I noticed is that once the spazzing starts, if the engine is turned off for about 10 minutes, it starts and idles fine.

Pump was swapped x 3
Injectors were swapped
ECU was swapped
Harness cut open to check for defects
Go pedal swapped
ASV was disconnected
EGR is relatively new, but disconnected
Vacuum lines checked
Turbo is brand new
Fuel tank / filter was bypassed with a separate source of treated fuel
Can of sea foam dumped in the oil before draining it
Cam/lifters were replaced
Oil / filter changed Rotella t6 5w-40 put in
Oil pressure measured, cold was 75 at around 2000rpm

What can I be overlooking ? Thanks for any suggestions.

Time for a for sale sign!