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Technical Strange stalls but no power loss

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Technical Strange stalls but no power loss

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Picaxxxu

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Hi guys!
I have a very strange problem with my mk2 1.9 jtd. I have searched the forum and found nothing like this:
Sometimes my punto stalls, it just dies on me when I try to make rapid accelerations. When I put the gas pedal all the way down at about 2000rpm, I have full acceleration power, car speeds up fine, but sometimes if I keep pushing it too much, it dies. I have to pull over, turn off the key, wait for 10 seconds, and it starts again just fine. :confused:
There is no error or warning lights, it just goes down, and then it starts normally.

Let me give you some info: The original 80HP motor was damaged, and I recently bought a new (used) motor. Seller told me it is a 115HP one. (y) No repro was made to the ECU, so it still is factory default. Car is running fine, I have made many km with it now with no problems. It speeds fine, even at high revs and with no power loss even uphill.
Only problem is just when I try to speed it too fast, when I push gas down fast, I feel some vibration when the turbo kicks in, car speed just shoots like hell, sometimes front wheels drift on the road even in 3rd gear :D, and if I keep pushing it, it stalls and I have to stop. :mad:

Any ideas? I'm thinking it has something to do with de turbo pressure, because everything else is fine if I dont push it.

Any help would be appreciated.

Thanks!
 
Forgot to mention two things:
- On the new engine I have closed EGR. Don't think this could be an issue, I've seen many people on the forum closing EGR's.
- The new engine came without turbo, turbo is from the old one.

Maybe the 115HP should use a different turbo?
 
Hello twotoncarman.
Thanks for your reply.

I don't think it's fuel related. I can get the engine to high speed and high revs with no problem.
When I'm stopped in neutral, I can push down the gas pedal and get the engine to 5000 or 6000 rpm without a problem, no stalls there.

It only stalls in movement, when I try to get fast boost.

I'm almost sure it is boost related, just don't know where to start, it could be some damaged sensor, or some sensor may need to be modified to work properly on the 115hp engine block.

I've installed AlfaOBD on my android cell, and went for a ride to get some readings:
The most significant ones were:
- the overboost pressure - car starts vibrating whem pressure gets close do 2000mbar, and stalls before it gets to 2300mbar (highest reading I could get was 2249). Don't now if boost is supposed to get that much pressure.
- the overboost valve opening max reading was 40%. It wont open more than that. Maybe I have a faulty wastegate? and it is not releasing boost overpressure?
- Got diesel pressure measured up to over 900 bar. Don't know if this ok.

Any thoughts on this?
 
Hi,

You say that when the engine stalls you wait 10 seconds and then restart it. If you don't wait 10 seconds and try and re start what happens?

If it won't re start and just spins over I would say you almost certainly have a failing crank sensor.

Alan
 
You are exactly describing a fuel supply problem !.
The rpm has nothing to do with it. Off load the engine does not consume the amount of fuel it does on load.
 
a1ant said:
Hi,

You say that when the engine stalls you wait 10 seconds and then restart it. If you don't wait 10 seconds and try and re start what happens?

If it won't re start and just spins over I would say you almost certainly have a failing crank sensor.

Alan
Click to expand...
Unlikely Alan as the issue would not occur only in high fuel demand. It would be far more random.
 
Twotoncarman said:
Sounds like a fuel feed problem. Pump filter, in line filter etc.
Click to expand...

How would that explain so little fuel that the car has to be pulled over and restarted? I would have thought that releasing or easing back on the pedal would be sufficient to enable sufficient fuel to flow to keep the engine operating while being driven without the earlier high fuel demand.

If the car actually stalls and has to be stopped then it cannot be fuel starvation at max power unless there is something peculiar about a diesel that becomes temporarly starved of fuel - just for a few seconds. Does the ecu shut down a fuel starved diesel?
 
Last edited:
Twotoncarman said:
Unlikely Alan as the issue would not occur only in high fuel demand. It would be far more random.
Click to expand...


Ill stick by my original speculative diagnosis for now, until the OP comes back with its re-starting behavior.

With these JTD's the crank sensors seem to fail in the same way each time (ie repeatable time frame/ freeze frame data)

With low fuel pressure I would expect a FRPS code to be flagged as they are fairly picky with fuel pressures.

To the OP your boost and fuel pressures sound ok, although obviously it would be useful to see them alongside rpm etc to get a full picture of real time fuel pressure and boost pressure.

Which bits exactly did you swap over from the donor engine to the new engine? As there are some slight differences assuming that your 115hp motor came from a stilo or similar.

Alan
 
Last edited:
The fault codes would be a good start.:)
Ah, noted the bit about boost, the wastegate doesnt seem to be opening properly !, that is way too high.
Probably self protecting.
 
Last edited:
Hi guys!
I really appreciate your ideas! Sorry to take so long to answer, I've been working overhours, and all my free time has been spent messing around with my jtd. :)

When I try to restart it before 10sec, it just spins over. If I wait around 10sec, then it starts fine. If it was fuel related, it should start immediatly, right? As judderbar said, I should even be able to start it in movement, just by releasing the clutch, I think.

Abou ECU readings, they seem to be a little random: U1602, P0191, P0110, P0101, P0235, P0404.
Some where caused by me while making experiences, meanwhile I restored EGR to its factory default and error codes disapeared. I sprayed a little of WD40 lubricant on the wastegate actuator arm (externaly), and overboost valve now opens up to 60%. Also discovered a damaged pressure hose that was causing the turbo overboost. Max boost pressure now is 1900mbar, I cant reach 2000 anymore. Car boost seems now normal, that excessive super boost disapeared.
However, before repairing this hose, I managed to drive boost pressure up to close 2500mbar, and car wouldn't stall. So now I don't think boost pressure was the issue.


Stalls are now less frequent, I've been driving the car all weekend pushing it to high revs, and to its max boost pressure (now less than 2000mbar), and it only stalled once.
When it did, I got a diesel pressure error (cant remember code) and a P1320, wich is the only one that makes sense since all this saga started, wich indicates a fault between camshaft and crank sensors. However it was the first time it appeared, and it hasn't stalled again since then, not sure why stalls are now less frequent.
I'll just change both if it stalls again.

U1602 error it's permanent on my ECU. I can't clean it, so indicating some CAN line error, any ideas on this?


Once again, Thank you for all your thoughts! :)
 
p1320 is a crank sensor error
The ecu is seeing a different number of signals per revolution vs the cam sensor

This could be the crank sensor starting to break down?

U1602 - IIRC U code are pending codes, but it relates to immboliser i believe
But i've googled and found some say its Canbus related

Ziggy
 
Picaxxxu said:
Hi guys!
I really appreciate your ideas! Sorry to take so long to answer, I've been working overhours, and all my free time has been spent messing around with my jtd. :)

When I try to restart it before 10sec, it just spins over. If I wait around 10sec, then it starts fine. If it was fuel related, it should start immediatly, right? As judderbar said, I should even be able to start it in movement, just by releasing the clutch, I think.

Abou ECU readings, they seem to be a little random: U1602, P0191, P0110, P0101, P0235, P0404.
Some where caused by me while making experiences, meanwhile I restored EGR to its factory default and error codes disapeared. I sprayed a little of WD40 lubricant on the wastegate actuator arm (externaly), and overboost valve now opens up to 60%. Also discovered a damaged pressure hose that was causing the turbo overboost. Max boost pressure now is 1900mbar, I cant reach 2000 anymore. Car boost seems now normal, that excessive super boost disapeared.
However, before repairing this hose, I managed to drive boost pressure up to close 2500mbar, and car wouldn't stall. So now I don't think boost pressure was the issue.


Stalls are now less frequent, I've been driving the car all weekend pushing it to high revs, and to its max boost pressure (now less than 2000mbar), and it only stalled once.
When it did, I got a diesel pressure error (cant remember code) and a P1320, wich is the only one that makes sense since all this saga started, wich indicates a fault between camshaft and crank sensors. However it was the first time it appeared, and it hasn't stalled again since then, not sure why stalls are now less frequent.
I'll just change both if it stalls again.

U1602 error it's permanent on my ECU. I can't clean it, so indicating some CAN line error, any ideas on this?


Once again, Thank you for all your thoughts! :)
Click to expand...
Diesel pressure error:idea:
Fuel starvation;)
 
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