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(Post Link) post #1 of 17 Old 19-02-18 Thread Starter
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156 1.6 TS

156 TS live data analysis

Ciao Alfistis!

Anyone here willing to take a peek at my recorded data i made today? I experience misfiring above 4000 on high loads. I just broke in a rebuilt 1.6 TS CF3.
4 new pistons, big end shells, 3 original new lambdas, new spark plugs, new coil packs with wires. Have decent compression, cold starts like a baby, goes well, pulls at low speeds. I wouldn't even notice a thing in the city, but as soon as i go faster than 100Km/h the power seems to be gone..
Anyways, here's the chart i made, hope it's usable : https://public.tableau.com/profile/i..._180219/Sheet1
I also attached the data in xls
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File Type: xls 19.02.2018_04.55.20.344_ME731EOBD.xls (106.5 KB, 7 views)
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I had a look and things seem ok possibly apart from I thing...
The airflow should be up to just over 400 (grams per second?). I did calculation from KG/HR and I only got about 50 not 400.
Either my arithmetic is rubbish or there is an issue.

Look at all inlet hoses and air filter. Are you sure you didn't stick a rag somewhere to block a pipe during rebuild? Anyway, check that again.

The only other thing which springs to mind is fuel pressure. I don't mean static or idling but when driving. A blockage, restriction/weak pump/water in tank unit would cause low flow and pressure loss at high glow rate.

You could check spark plug wells for liquid and ECU earth point on cylinder head also.
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(Post Link) post #3 of 17 Old 21-02-18 Thread Starter
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Originally Posted by Fruity View Post
I had a look and things seem ok possibly apart from I thing...
The airflow should be up to just over 400 (grams per second?). I did calculation from KG/HR and I only got about 50 not 400.
Either my arithmetic is rubbish or there is an issue.

Look at all inlet hoses and air filter. Are you sure you didn't stick a rag somewhere to block a pipe during rebuild? Anyway, check that again.

The only other thing which springs to mind is fuel pressure. I don't mean static or idling but when driving. A blockage, restriction/weak pump/water in tank unit would cause low flow and pressure loss at high glow rate.

You could check spark plug wells for liquid and ECU earth point on cylinder head also.
Thank you for the answer! Unfortunately i didn't rebuild the engine, my "mechanic" was.. if i knew how he woud do it, i wouldn't let him.. first time he only replaced two of the cylinders (pic included), and assembled the engine. After a brief 3000Km, he had to pull it apart again, and replace the remaining two (i lost 4l oil in 300km). I don't know how the cylinder walls survived, but after 13000Km, i have 12bar compression on all 4. He also removed the pipe from the air filter (the horn thingy i don't know the name) and put a metal ball in the pcv pipe, before the valve. Luckily i noticed these and fixed them.. I still loose some oil, but the spark plugs look okay, and i don't see smoke, so it's more of a small leak somewhere.
So i have all the parts in the inlet pipe, the filter is a moth old. I also tried to unplug the MAF, only resulting in a MIL , and no change in the misfire..
Looks like i'll have to pull the whole intake assembly to check for leaks. Or/and check for a new fuel sender...
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Misfire?
I thought it was only poor performance.

If just poor performance, I'd try disconnecting the inlet hose leading to the MAF and testing it without the air filter box (just to rule it out).
I take it that it is a standard air box?
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(Post Link) post #5 of 17 Old 23-02-18 Thread Starter
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Yes, i said, that its misfiring in the first post. The mil doesnt stay on, but stores misfire codes. I'll check the intake pipe, thanks! Yes its a std airbox with all the components.
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It may point to a defective MAF. Fuelling may be so weak at maximum demand that it causes the misfire.

I'll try to hook up one of the 156s to diagnostic for a comparison over the weekend.
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(Post Link) post #7 of 17 Old 25-02-18 Thread Starter
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Originally Posted by Fruity View Post
It may point to a defective MAF. Fuelling may be so weak at maximum demand that it causes the misfire.

I'll try to hook up one of the 156s to diagnostic for a comparison over the weekend.
Thank you! I'll look for a f00c2g2030, that was the one i got it with (10years ago) The current one is a f00c2g2063. I bought it about 5 years ago..
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Argh. Sorry, I forgot to hook up my JTS today but I was busy.
I'll get round to it as soon as I can though. I'll try after work tomorrow and use MES to ensure we compare apples with apples.
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(Post Link) post #9 of 17 Old 26-02-18 Thread Starter
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No problem, whenever you have time. You helped a lot already!
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Ok, definitive comparison.

At idle, my JTS uses 15 KG/HR of air.

Full throttle at 2000rpm it is 175 KG/HR.

Maximum reading obtained from a single acceleration test was 460.5 KG/HR.

It's definitely your MAF.
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From memory, even a 1.6 should flow at least 380KG/HR.

I'd be interested for a figure from your new MAF and your thoughts on engine performance.
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Assuming Lambda 3 is post cat - it is all over the place. It should be rock steady at about 0.46v. Something going badly wrong with the mixture - also points to the MAF.
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Ideally, yes. Varying throttle and wide open throttle when the system goes open loop does have an effect on the return voltage for the rear sensor.

If it was a steady throttle condition. I'd give more consideration to the rear sensor.
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(Post Link) post #14 of 17 Old 27-02-18 Thread Starter
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I'll sort the MAF out, since it's relatively old.
Also, maybe my cat is on the way out? Hence the 3rd lambda signals..
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Quote:
Originally Posted by Fruity View Post
Ideally, yes. Varying throttle and wide open throttle when the system goes open loop does have an effect on the return voltage for the rear sensor.

If it was a steady throttle condition. I'd give more consideration to the rear sensor.
Not sure if it is the same system as the V6 - that goes open loop above 4K rpm. All the time below that is closed loop and it should be steady and .46 or so. Replace the MAF first, if that is giving bad data, then everything else will be wrong.
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(Post Link) post #16 of 17 Old 06-03-18 Thread Starter
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Okay, MAF sorted, problem remains.. Time to get one lambda out and see the cat, and rattle the rear one.. I was getting some vibration around 2800RPM, but didnt take it too seriously .............
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Argh! I was sure it was MAF.
Obviously a partial blockage could reduce airflow. It just needs the source identified. Do the rattle test first as that may point to a collapsing cat monolith.
Disconnect exhaust to see if it revs up better (you noise won't annoy anyone).

Sometime is responsible for MAF low airflow.

Last edited by Fruity; 07-03-18 at 20:09.
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