2002 1.9 JTD 8v misfire after rebuild - Alfa Romeo Forum
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(Post Link) post #1 of 10 Old 19-07-11 Thread Starter
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Help 2002 1.9 JTD 8v misfire after rebuild

hi all, i've posted this in the Fiat Doblo owners forum, but thought that some of you Alfa guys may have some idea too 'cause of the JTD connection

i'm hoping to gain wisdom and insight with a challenge i've got!
so, briefly, we have a 2002 doblo 1.9 jtd ELX car, owned for 5 years.
had 54,000 miles when bought, now got 108,000 miles on the clock (although the ECU says 125,000 ! )

car details (if it would be helpful)
engine type - 182B9000
bodywork code - 223AXE1A02
chassis code - ZFA 223.000
ECU is a Bosch EDC15C7 CF3/EOBD
BTW, i have Fiat ECU Scan + interface and it does not show any errors.
(the ECU thinks everythings fine - it lives in La La land )
Injectors are Type 2 - 28209

now, the problems -
1) over the past 18 months it has been smoking more and more (blue smoke - engine oil level creeping down), and power has been reducing.
2) as it got worse, it was using around 2 litres of engine oil every 600 to 800 miles
3) as it got colder, it was harder to start.

so, i decided to 'do'something about it -
1) i had the four injectors checked, one was out of tolerance, the other three were 'OK'. - nochange.
2) battery eventually died - replaced with new.
3) checked glow plugs, only 2 working well - replaced all 4 and kept the 2 old as 'spares'
4) compression test - cylinder pressures varied from 280 to 320 psi - not very good.
put some oil down the cylinders and retest compression - a small improvement, up to about 330-350psi.

so, first conclusions drawn were - possible wear on valve stems / valve guides, and worn piston rings / bores.

action - wait for 'summer' then commence major surgery....

so 'summer' is here (aparently ),
creamup,
on with the latex gloves,
eyes down for a full house...

after dissembling (?) the head and removing pistons - i found the valve seats needed re-grinding, the valve seals needed replacing, the piston rings were 'WORN' down past the chrome layer etc.

so the work was carried out -
1) hone the barrels
2) replaced 4 sets piston rings
3) replaced valve seals
4) re-ground valves
5) re-assembled with clean oil, new gaskets etc
6) set valve timing
7) refil all vital fluids
8) turn key...

and it started to run with a 'misfire'.
it is not smoking like it used to though
so, one by one i removed the injector connectors, and tried to start the engine.
i found that number 4 connection removed made no difference to the running of the engine, but no's 1 to 3 connectors would prevent it running.

so i thought it was an injector problem.
removed no 4 and no3 injectors, swapped round and reconnected everything.

the problem stayed on no 4 cylinder.
so now i believe that the problem is with the wiring/electrics for no 4 injector plug.

i've got a multitester and understand some of the auto electrics, but most of my experience has been on petrol motorcycles, this is my first diesel.
i've looked through both google, this forum, the alfa owners website (same engine in some) etc and not yet come across much info on this specific issue.

has anyone got any idea if i can test the plug and wiring some how?
what voltage or readings should i get?
so, i'll attempt to trace the wiring back to the ECU to check for a break
and i'm going to check the compression on no 4 cyl, just in case.

any other ideas?
help and advice please?

thank you!

austin

ps
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(Post Link) post #2 of 10 Old 19-07-11 Thread Starter
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Help Re: 2002 Doblo 1.9 JTD 8v misfire after rebuild

so, i've traced the wires from the injector connectors for no's 3 and 4 - all the way to the ECU.
no breaks, continuity is good for all the wires, no earth leakage.

next job is to find my compression tester to check cylinder no 4.

the other thing i'll check is the no. 4 fuel delivery pipe from the manifold (just in case some how it is blocked) and to check the leak back from the injector.

i'll keep updating as i try things

austin

Last edited by dobloz; 20-07-11 at 21:21. Reason: bad spelling corrected!
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(Post Link) post #3 of 10 Old 20-07-11 Thread Starter
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Boring 2002 1.9 JTD 8v misfire after rebuild

so, to any who are still reading...

compression test reveals 400 psi in 3 cylinders, but the no. 4 cyl is 0 psi

i'm not sure what i could have done in the rebuild for this to be the case?

but the lack of compression is a bit of a problem for combustion to take place...

so, i'll start the stripdown in the morning.
not looking forward to all that again so soon after doing it ... ah well

by the grace of God my heart still works,
so onward...

austin
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(Post Link) post #4 of 10 Old 21-07-11 Thread Starter
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Idea 2002 1.9 JTD 8v misfire after rebuild - pictures offer!

hi again,

as i have to strip the JTD down again, i thought i'd offer to take and send any pictures of the engine that any of you might like?

so if you would like to see pics of drive belts, turbo etc, let me know.
time limited offer !
when it is back together it may be too late...

austin

ps, just in case it might help, home bargains is selling 20 pairs of vinyl gloves for 79p, used with barrier cream they save my skin from cracking and make cleanup much easier.
saves buying 100 pairs if not needed

Last edited by dobloz; 21-07-11 at 09:48. Reason: extra value!
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(Post Link) post #5 of 10 Old 22-07-11 Thread Starter
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Wave 2002 1.9 JTD 8v misfire after rebuild -solved !

aha !

by the grace of God i found it !

sorry, calm down,

first, thank you Grahame, your help and advice is appreciated.
thanks for taking the time to reply

but there is another, more sneaky and trixy thing that can cause no compression...
yes, yes, my precious, we are talking .... shim buckets
(if that is what you call them ?)

picture the scene, and sing
(to the tune of 'ten green bottles')

8 little shim buckets all in a line,
put one in the head,
and then there were 9, erm, 7,
7 little shim buckets all in a line,
put one in the head,
and then there were....

you get the idea !

yes, i somehow swapped the exhaust shim bucket on cylinder no. 3 and the inlet shim bucket on no. 4 ...
-
resulting in a +1mm gap for no.3 exhaust valve,
and a -0.5mm gap (ie no gap, a constantly open valve) on inlet
which = no compression in no 4 cylinder !





the clue to this was in the wear on the low or 'back' part of the cam lobe.
as i checked for the valves operating correctly, i noticed that only one lobe had wear marks on the 'low' part of the cam (opposite the high lobe).

so, i did not have to strip down the whole engine,
i didn't need to send off the ECU just in case it was faulty,
etc etc...

horay !

i'll let you know if it runs when i get it all sorted...

Last edited by dobloz; 27-07-11 at 14:03. Reason: removing html, cause i don't know how to enable it!
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Great read! Good luck with finishing it.

Keith
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(Post Link) post #7 of 10 Old 23-07-11 Thread Starter
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Cheese pilgrims progress - little by little...

so, i removed the cam cover etc,
swapped the buckets and shims,
rebuilt again,
and...
ta da !
10 psi compression... really, 10 psi !

ah, what can this be ....? hmmmm..

ok, check clearances again...
ah, no clearance on inlet cyl no. 4.

but all the other 7 valve gaps are ok.
double checked.

so why the lack of a gap?

quick review of what i've done...

ah !

i lapped the valves in, and one of them was worse than the others, this one!
so, lapping the valves in reduced the clearance, and the 4.05 mm shim is now too thick.
simple.

should have thought of it earlier, but i haven't rebuilt an engine for about 15 years,
so i'll cut myself some slack, just a bit

and hey, it makes it more interesting for you guys reading, sniggering along with me

so, just been and bought a 3.50 mm shim to enable me to gauge the gap and calculate the correct size i need.
made a shim bucket tool out of an old allen key so that the cam can stay installed, saves time - well probably takes the same time as making the tool, but hey, it's more fun making stuff...

i'm working over the weekend 'til tuesday, so i'll get stuck in then, and update here when i've progressed.

austin
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(Post Link) post #8 of 10 Old 25-07-11 Thread Starter
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Well Happy done !

yes !

more info in the morning

austin
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(Post Link) post #9 of 10 Old 27-07-11 Thread Starter
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Thumbs Up finished rebuild !

hi there,
all those of you who have been reading this mini epic (for me at least!)

a 3.60mm shim finally sorted out the problem.
the engine now runs smoothly, has lots more power and smokes much less.
i hope that the economy will be improved now too, because i found the valve timing to be out by one tooth.
very pleased.

any questions (not that i'm an expert now ) just ask

thanks again for reading,
austin
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Well done! Do you know why it showed such early engine wear? Or was the car 'clocked'. Its rare for diesels wear so soon.

Keith
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