Elusive 1.9 JTDM 16v issues incl hesitation - Alfa Romeo Forum
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(Post Link) post #1 of 5 Old 11-08-13 Thread Starter
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Elusive 1.9 JTDM 16v issues incl hesitation

Hi All,

First post, been lurking for a while.

Hoping for some tips / ideas with regard to the following issues on a 1.9 JTDM 16v (159SW):
- Irregular idle RPM, worse if fans/AC turn on. Not misfiring irregular, just hunting up and down between ~750-900rpm. Occasionally at traffic signals it almost feels ready to stall on take off.
- Hesitation between 1750 and 2200rpm
- Occasional wastegate / blow off valve like noise around 2200rpm if shifting
- Power feels down / restricted

In April, mainly for preventative measures, I replaced the EGR, installed a "blanking" plate (genuine gasket, 4 holes on the intake side) and cleaned the MAP and MAF. Car was running really well after that. Also ran a bottle of Redex Gold through the tank.

Had an issue in May, where the car stalled at a set of traffic lights, then ended up needing towing. Would stall as soon as put into gear. Was taken to a local Alfa specialist, plugged into examiner, loads of EGR faults. They said the reconditioned EGR that I'd installed was faulty, replaced it, cleaned the throttle body and it ran again.

Since then, it's just not felt right. Symptoms described above. So far I've tried:
  • Checking for error codes using FiatECUScan (no faults)
  • Recleaning MAP
  • Verifying EGR and swirl flap operation using FiatECUScan (can hear swirl flaps. EGR makes a faint noise?)
  • Replacing air filter
  • Checking for split turbo hoses and vacuum hoses (I can't see/feel any splits)

On the last point, I did note that there was some oily residue on the outside of the hose from the turbo to the intercooler, and that the intake hose to the turbo isn't exactly tight, I can shift it by hand quite easily.

Took the car for a good run today, as DPF was 85% blocked. Regenerated fine, now at 18%, 75km after last regeneration. Didn't make any noticeable difference to drivability.

Noticed the injector correction values are a bit over the place. At idle, injector 1 is at +5mm3/inj, though goes down to +2mm3/inj if held at 2000rpm for ~ 30sec. Injector 3 is at -3mm3/inj, though goes down to -1mm/3inj if held at 2000rpm. Injector 2/4 both read between 0 and -0.5mm3/inj.

I'm presuming those injector values are not healthy?

At the moment my plan of attack is:
  1. Take vehicle to a bosch injector specialist, have them test the injectors properly and recondition if required
  2. Replace diesel filter
  3. Try running car without MAF connected, to see if it improves (and if so, replace MAF)
  4. Clean my spare EGR, and fit it to see if it improves (and if it does, take it back to the Alfa specialist to replace the EGR under warranty)
  5. Tighten the turbo intake hose with a jubilee clip

If none of that works,
  1. Clean MAP again or replace MAP?
  2. Replace vacuum hoses?
  3. Replace boost control solenoid?

Does this seem reasonable?

Any other suggestions / ideas to try?
kook is offline  
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I had the exact same problem with my alfa.I did a remap+egr off, changed the air and diesel filter and nothing fixed the problem.
When I changed the intake with a brand new one, everything went back to normal..I can say that it is a brand new car.
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(Post Link) post #3 of 5 Old 20-08-13 Thread Starter
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When you replaced the intake, do you mean the manifold/swirl valves? It's a step I'm avoiding, looks like a massive job.

Removing MAF plug made no difference. Injectors will be done tomorrow along with the diesel filter.

Cleaned up the old EGR ready to test on the weekend.

Slowly but surely!
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Just fully blank off the EGR with a bit of metal on the underside, a lot of the cleaned or even 'refurbed' ones still have issues ( as you found).
I'd clean the MAP anyway, such an easy job whilst you are there, if it has gummed up already ( as you cleaned it before) might give an indication if the EGR is going again.
I'd then look at injectors as far more expensive!

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(Post Link) post #5 of 5 Old 13-04-14 Thread Starter
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Still not fixed this, it's been smoking more too. Keeps clogging the DPF within 400km due to the excess smoke.

Already had Cyl 1 injector, EGR and MAP replaced.

Think I've found the problem. Finally took the manifold off to clean/inspect.

Swirl valve for cyl #1 is MIA. Soot on the spindle too. So presumably been missing for some time.

Think it's time for an expensive trip on the back of a flat bed.
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16v , elusive , hesitation , incl , issues , jtdm

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