Cold misfire cyl #1 [with compression readings]

jasantos40

Well-known member
Joined
Aug 11, 2018
Location
EU
TDI
g4 tdi
Greets

I've been having some trouble with my tdi pd150.
On cold starts I get misfires for the first 5 seconds, with white smoke, and injector #1 reading starting at 2.99, and slowly droping, 10 secs after the engine is fine, the other injectors are ok, just negative compensating the first injector,

When warm I get all the injectores between -0.12 and 0.12, due to new camshaft and lifters. While warm is perfect. Pulls ok, mpg is ok.

Oil level doesnt move. Although I have some oil in the intake, already installed a oil catch for that and a new turbo is ready to install.

Have clear lines at the fuel filter, no oil on fuel.

I have a video with inj values but I can't share it. I'll give you the numbers since the engine is turned on, after sitting for +8 hours at 17°C, the values appear every second since startup, from 1 to 4 cyl has vcds shows:
2.99 -1.41 -1.15 -0.59
2.99 -1.29 -1.29 -0.52
2.99 -1.27 -1.36 -0.47
2.96 -1.18 -1.41 -0.40
2.80 -1.08 -1.46 -0.21
2.61 -1.04 -1.48 -0.07
2.40 -0.94 -1.44 0.00
2.16 -0.87 -1.36 0.02
1.93 -0.80 -1.29 0.09


And after some minutes:
-0.02 -0.12 0.00 0.12



On a compression test, cold readings, I get:

#1 28.5bar
#2 33bar
#3 30bar
#4 32bar
#1 27bar

Hot:

#1 29bar
#2 33bar
#3 31bar
#4 32bar
#1 30bar

Is it the gap between #1 and the rest thats causing my problem? Or it's not enough to cause my problem?

Could be an injector problem or seal?

Do I take the trouble to swap injector #1 and #2, also have a spare loom I could swap, or do I just take the head off?
 
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jasantos40

Well-known member
Joined
Aug 11, 2018
Location
EU
TDI
g4 tdi
Any expert? Just need to know if the compression readings justify pulling the head off.
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
I'm no expert but even though 1 and 2 are kinda far apart I wouldn't pull the head for that without other symptoms of a bad gasket.

Have you tried chemical warfare yet?
 

jasantos40

Well-known member
Joined
Aug 11, 2018
Location
EU
TDI
g4 tdi
I'm no expert but even though 1 and 2 are kinda far apart I wouldn't pull the head for that without other symptoms of a bad gasket.

Have you tried chemical warfare yet?
Chemical Warfare? You mean injector cleaner?
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
I would not pull the head unless you have serious air in the coolant issues, milky oil or coolant, soot build up in the coolant, or you fail a leak down test on any cylinder. Compression check is great for checking initial issues but does nothing other than tell you if its good or bad, a leak down test will let you know if any part of the head or rings are bad and will tell you how its bad and what is bad. don't go ordering parts or pulling them off with out more testing.
To me, this sounds like an injection issue. I would start by swapping injectors. If problem continues, pull the cam off and inspect your lifters. Other than that im clueless and btw im not an expert but that where i would start. Cleaner is an easy and cheep fix, if it works. i never rely on a chemical to fix a mechanical issue. But ive been known to blow money on some magic beans now and again.
 

jasantos40

Well-known member
Joined
Aug 11, 2018
Location
EU
TDI
g4 tdi
I would not pull the head unless you have serious air in the coolant issues, milky oil or coolant, soot build up in the coolant, or you fail a leak down test on any cylinder. Compression check is great for checking initial issues but does nothing other than tell you if its good or bad, a leak down test will let you know if any part of the head or rings are bad and will tell you how its bad and what is bad. don't go ordering parts or pulling them off with out more testing.
To me, this sounds like an injection issue. I would start by swapping injectors. If problem continues, pull the cam off and inspect your lifters. Other than that im clueless and btw im not an expert but that where i would start. Cleaner is an easy and cheep fix, if it works. i never rely on a chemical to fix a mechanical issue. But ive been known to blow money on some magic beans now and again.
Thanks for the input.

Lifters and cam are new, ina black lifters, although I never truly believe a new part is 100%, I rotated the engine by hand and started after, lifters did not discharge, also inspected the new cam and lifters, they seem ok.

Even after installing the oil catch can and a 200kms journey, I still find a lot of oil on the intake and I'm suspecting the injectores #2 and #3 are cutting off fuel because they are burning oil.

Next friday I'll be swapping the turbo. Haven't done yet because I was undecided about pulling the head off.

Like you said, I don't throw parts to find the problem. I'll try to swap the injectors if the turbo swap and intake clean doesn't solve the problem.
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
Connect an Air hose from a compressor to the compression fitting to the glow plug. WHEN COLD and HOT try this. Put 20 PSI into it, listen for hissing or other noises coming from the radiator/ coolant cap, intake air filter box, exhaust pipe, oil dip stick, and spray soapy water around the seating of the injectors and glow plugs. If nothing then try it at 50, then 100, then as high as the compressor will go. If it hisses out of the dipstick when colt at 50psi, that’s not uncommon and why you do this when hot as well, should not hiss at all when hot at 50psi but if it does, it’s not necessarily the rings. Now when the engine is warmed up, put like 4 to 5 drops of Trans oil like 80W and crank it over a few times, like 3 or 5 rotations. If the compression jumps up when hot, your rings are suspect and if hissing is present at 100PSI you have a fouled/ bad set of rings but the thing is your compression is within a good area and does not mean the engine needs a rebuild by any means. The reason you want to do staged increments is that things like your rings when cold should have a bit of hissing in the dip stick at 150PSI! But the valves should not leak at all. and a head gasket won’t show symptoms if it’s not high enough if in like some cases, like mine, the higher boost levels are lifting the head but never has issues at normal operation other than WOT RACE KILL ME NOW BOOST LEVELS.
 

jasantos40

Well-known member
Joined
Aug 11, 2018
Location
EU
TDI
g4 tdi
Turbo Swapped. I'm getting less oil in the intake, still a bit, didn't had time yet to clean the intake and IC.

While I was swapping the turbo, I took off the intake manifold and I notice a lot more oil going to cyl1 than the rest. That could explain the injector deviation on cyl1.

Today started the car, after siting for 12 hours.

Injector deviation started:
1.72 -0.87 -0.19 -0.66

Much better, probably the first time cyl1 didn't started at 2.99.

Temp 24.3, readings at 8.1° BTDC

Last reading 2 weeks ago, I was getting 2.99 at 7.8° BTDC.

Going to wait for more colder days to check it.
 

jasantos40

Well-known member
Joined
Aug 11, 2018
Location
EU
TDI
g4 tdi
Colder days are back, mornings starting at 20°C and I still get injector deviations on cyl #1. So even after turbo swap, oil on the intake is now clear, which means I can floor it, but still have the startup to solve. I conclude that is not oil dripping on the intake that's causing the problem.

Got some readings the other day, 24°C:

1.72 -0.87 -0.19 -0.66
1.81 -0.94 -0.26 -0.59
1.67 -0.80 -0.68 -0.21
1.55 -0.71 -0.78 -0.05
1.46 -0.64 -0.87 0.02
1.39 -0.59 -0.92 0.09
1.18 -0.35 -1.04 0.19
0.94 -0.12 -1.13 0.28

Yesterday I swap Injector #1 and #2 to check if the inj deviation moves, also swapped the wiring loom.

Today, 20°C, I start the day with these values:

2.61 -1.20 -1.01 -0.38
2.64 -1.18 -1.13 -0.35
2.49 -1.06 -1.18 -0.24
2.38 -0.99 -1.25 -0.16
2.31 -0.85 -1.29 -0.12
2.14 -0.78 -1.34 -0.05
1.95 -0.66 -1.32 0.00
1.72 -0.59 -1.27 0.14
1.58 -0.52 -1.27 0.16

Same values. At least it's not and injector dripping.

Any more ideas for diagnostics before pulling the head? Or should I do the leak down test before?

Camshaft and lifters also new, had a broken lifter a #4, that's solved. Glow plugs swapped also.

Could it be valve stem seals? Is there a way to diagnose that?
 
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