Uneven and Jerky running at certain rpm

Uneven and Jerky running at certain rpm

Author
Discussion

VikingCerb

Original Poster:

18 posts

209 months

Tuesday 26th May 2015
quotequote all
Hi,

I have a 2004 4.5 Red Rose with short induction mapped by Joolz. The car feels very jerky around 2.200-2.300 rpm using constant throttle. Above and below this range the car is very smooth. TPs are equal , as are adaptives which fluctuate +/- 3 from 0.

My problem is that with the speed limits here in Norway most of my driving is in the "problematic" rev range.

To see if there is a problem, I used the logging function in the RS.AJP app and have taken out some data both at idle, in the problem range and at higher revs/speed. Before i did the logging i reset all fault codes, TPs and adaptive. This is what I get:

TIMEMS RPM TP1 TP2 ADAPTIVE_1 ADAPTIVE_2 LAMBDA_1 LAMBDA_2
1,43267E+12 2330.0 21.2 18.7 7.5 10.6 0.06 0.04
1,43267E+12 2309.0 22.6 20.1 9.8 18.4 0.05 0.04
1,43267E+12 2288.0 24.0 20.5 9.8 20.0 0.05 0.04
1,43267E+12 2279.0 23.3 21.9 10.6 19.2 0.05 0.04
1,43267E+12 2287.0 29.7 22.6 9.8 20.0 0.05 0.04
1,43267E+12 2296.0 28.3 26.2 12.2 15.3 0.06 0.04
1,43267E+12 2289.0 29.7 26.9 8.2 14.5 0.05 0.04
1,43267E+12 2246.0 28.3 27.2 11.4 11.4 0.73 0.04
1,43267E+12 2309.0 24.0 22.6 14.5 19.2 1.28 1.26
1,43267E+12 2313.0 26.9 22.6 16.2 20.8 1.29 1.26
1,43267E+12 2325.0 26.2 22.6 13.7 20.0 1.29 1.24
1,43267E+12 2306.0 23.3 22.6 16.8 22.4 1.29 0.15
1,43267E+12 2251.0 26.9 23.3 12.2 23.9 1.27 0.1

1,43267E+12 868.0 14.8 14.8 1.2 1.2 0.01 0.03

1,43267E+12 3125.0 38.2 38.6 -0.4 -0.4 0.09 0.29

I have tried reading up on posts as well as the manual for the original software to connect to the ECU. However I cannot figure out what to read from the above data. It only being in a certain isolated and small rev-range keeps me puzzled.

Do any of you have any input or experienced the same. And have any input as to what to look for?

Thanks in advance.

anonymous-user

53 months

Wednesday 27th May 2015
quotequote all
No idea what any of the numbers mean, bar RPM, but may help others to read and decipher.

TIME MS RPM TP1 TP2 ADAPTIVE 1 ADAPTIVE 2 LAMBA 1 LAMBDA 2
1,43267 2330.0 21.2 18.7 7.5 10.6 0.06 0.04
1,43267 2309.0 22.6 20.1 9.8 18.4 0.05 0.04
1,43267 2288.0 24.0 20.5 9.8 20.0 0.05 0.04
1,43267 2279.0 23.3 21.9 10.6 19.2 0.05 0.04
1,43267 2287.0 29.7 22.6 9.8 20.0 0.05 0.04
1,43267 2296.0 28.3 26.2 12.2 15.3 0.06 0.04
1,43267 2289.0 29.7 26.9 8.2 14.5 0.05 0.04
1,43267 2246.0 28.3 27.2 11.4 11.4 0.73 0.04
1,43267 2309.0 24.0 22.6 14.5 19.2 1.28 1.26
1,43267 2313.0 26.9 22.6 16.2 20.8 1.29 1.26
1,43267 2325.0 26.2 22.6 13.7 20.0 1.29 1.24
1,43267 2306.0 23.3 22.6 16.8 22.4 1.29 0.15
1,43267 2251.0 26.9 23.3 12.2 23.9 1.27 0.1
1,43267 868.0 14.8 14.8 1.2 1.2 0.01 0.03
1,43267 3125.0 38.2 38.6 -0.4 -0.4 0.09 0.29

VikingCerb

Original Poster:

18 posts

209 months

Wednesday 27th May 2015
quotequote all
thanks for the assistance in formatting djstevec

Steve_T

6,356 posts

271 months

Wednesday 27th May 2015
quotequote all
You need to keep the throttle pot readings within 3 of each other from what I understand. Your car is pretty close over most of the table, but is sometimes slightly over this. You could either try slightly adjusting one of the throttle pot positions assuming the airflow is balanced between the banks and see if things improve, or go through the full throttle body balancing sequence with a synchrometer. I would also check for any slop in the linkage between the two banks and that the throttle pots produce sensible readings as you open the throttle, i.e. the value goes up and down as you open the throttle in small steps and does not jump between readings.

Byker28i

58,831 posts

216 months

Wednesday 27th May 2015
quotequote all
ECU can run the engine on one throttle pot, so if you suspect one is spiking then you could disconnect one at a time to see if it's any difference?

spitfire4v8

3,990 posts

180 months

Wednesday 27th May 2015
quotequote all
The throttles aren't really in sync, but even allowing for that the adaptives are almost always positive, and massively so in places .. suggesting things such as throttle sensor position relative the throttle shaft has been reduced, fuel delivery pressure low, global air leak (restrictor removed from purge line, split vacuum hose to servo etc etc.)
After all that though you'll probably still have a running issue at around 2000rpm, it's well known and can be reduced but rarely eliminated.
But check for faults first.

TVR8BLACK

1,405 posts

128 months

Wednesday 27th May 2015
quotequote all
spitfire4v8 said:
The throttles aren't really in sync, but even allowing for that the adaptives are almost always positive, and massively so in places .. suggesting things such as throttle sensor position relative the throttle shaft has been reduced, fuel delivery pressure low, global air leak (restrictor removed from purge line, split vacuum hose to servo etc etc.)
After all that though you'll probably still have a running issue at around 2000rpm, it's well known and can be reduced but rarely eliminated.
But check for faults first.
Mines the same 4.5 idles spot on but around 2000 rpm it's dreadful and feels like it's getting
Worse and now missing around 3000rpm
Cars driving me mad at moment. Love this little car and rearly hate her sometimes

ukkid35

6,138 posts

172 months

Thursday 28th May 2015
quotequote all
spitfire4v8 said:
The throttles aren't really in sync, but even allowing for that the adaptives are almost always positive, and massively so in places .. suggesting things such as throttle sensor position relative the throttle shaft has been reduced, fuel delivery pressure low, global air leak (restrictor removed from purge line, split vacuum hose to servo etc etc.)
What is the maximum that the adaptives should read? My car seems to be pinking again under 2k, much worse than after your remap. Could this be a fuel pressure issue? I've never replaced the fuel filter because it needs an extra pair of hands, I think I should do so now though. What else should I look at?

spitfire4v8

3,990 posts

180 months

Thursday 28th May 2015
quotequote all
The ecu can trim + / - 37 % . The way the ecu is set up means it learns values quickly, but not always sensible values.. I think they do this on the basis that getting somewhere closer quickly is better than not learning anything at all.
Have you put a pressure gauge on the fuel line to actually see what's happening? But yeh change the filter anyway just in case, they're cheap enough.

Demondad

474 posts

214 months

Thursday 28th May 2015
quotequote all
Seems a few of us having this problem right now. I get a very spikey rpm with the ignition on and the engine not running, so cleaned the crank case sensor, lambda connectors, injector connects, TP connects and the ecu connectors, no change. After changing nearly everything my faults are coming out as AFR, so I balanced throttles. During that I discover one of my cats glowing cherry red. Got to get it off and see if its blocked. Next I will change my fuel filter and then I'm stumped.

VikingCerb

Original Poster:

18 posts

209 months

Thursday 28th May 2015
quotequote all
thanks for the pointers. My car also has very noticeable pinking below 2k.

Jhonno

5,762 posts

140 months

Thursday 28th May 2015
quotequote all
ukkid35 said:
spitfire4v8 said:
The throttles aren't really in sync, but even allowing for that the adaptives are almost always positive, and massively so in places .. suggesting things such as throttle sensor position relative the throttle shaft has been reduced, fuel delivery pressure low, global air leak (restrictor removed from purge line, split vacuum hose to servo etc etc.)
What is the maximum that the adaptives should read? My car seems to be pinking again under 2k, much worse than after your remap. Could this be a fuel pressure issue? I've never replaced the fuel filter because it needs an extra pair of hands, I think I should do so now though. What else should I look at?
Extra pair of hands?!

Steve_T

6,356 posts

271 months

Thursday 28th May 2015
quotequote all
Demondad said:
Seems a few of us having this problem right now. I get a very spikey rpm with the ignition on and the engine not running, so cleaned the crank case sensor, lambda connectors, injector connects, TP connects and the ecu connectors, no change. After changing nearly everything my faults are coming out as AFR, so I balanced throttles. During that I discover one of my cats glowing cherry red. Got to get it off and see if its blocked. Next I will change my fuel filter and then I'm stumped.
That could happen if you had an ignition problem with one of the cylinders, i.e. fuel is injected but not burnt in the cylinder and hence is ignited by the exhaust of another cylinder and the mixture is still alight as it reached the cat. Have you checked to see if the exhaust from any of the cylinders is cold to pinpoint the offender?

ukkid35

6,138 posts

172 months

Thursday 28th May 2015
quotequote all
Jhonno said:
Extra pair of hands?!
Perhaps he could do it without help






Demondad

474 posts

214 months

Thursday 28th May 2015
quotequote all
Steve_T said:
That could happen if you had an ignition problem with one of the cylinders, i.e. fuel is injected but not burnt in the cylinder and hence is ignited by the exhaust of another cylinder and the mixture is still alight as it reached the cat. Have you checked to see if the exhaust from any of the cylinders is cold to pinpoint the offender?
Steve, maybe the damage has been caused like that and since then I've replaced the coils, ht leads and plugs. The banks were running at a huge heat difference after a journey to Brands Hatch and back. I think I've been chasing symptoms caused by not using the car for a few months, and the time when non serviced things are needing replacing, she's done 45k.

Jhonno

5,762 posts

140 months

Thursday 28th May 2015
quotequote all
ukkid35 said:
Jhonno said:
Extra pair of hands?!
Perhaps he could do it without help





Erm... That isn't how I did it last weekend on my Tod! Just reached in through the wheel arch/from underneath!