running n 3 cylinders when cold

where to start, just replaced turbo, timing belt, and all 4 glow plugs. three of the GP's were open, and the remaining one was still ok.
when starting it seems like it runs fine for 10 seconds then starts losing power and running on 3 cylinders for 1/4 mile. at that point what ever is going on it clears up and runs fine.
other observations: bluish white smoke when cold. vag-com basic #2 box 14. noticed before repairs poor idle and smoke.

I’ve got a neuspeed pchip

You probably still have a glow plug issue, or a glow plug wiring harness issue. This model ('96 Passat according to your profile) doesn't have the "glow plug monitoring" trouble code implemented.

I suppose. But it sounds more like fuel starvation to me.

just tried to start it. seems more like air starvation but i know better.

error on vag-com something like: 0058 intake manifold pressure differential.

weedeater

do these car have a pre-filter in the fuel tank like the rabbits???

went out this morning with voltmeter and lifted the harness at each GP. 12v at each GP.

Could an injector with a poor (bad) spray pattern do this?
This is a 96 passat with 130K miles.

Originally posted by go_tdi:
other observations: bluish white smoke when cold. vag-com basic #2 box 14. noticed before repairs poor idle and smoke.

Click to expand...

<font size="2" face="Verdana, Helvetica, sans-serif">When you say "vag-com basic #2 box 14" are you referring to the injection pump base timing? If you are, then "14" is way too low. Retarded injection timing will definitely cause poor cold start and smoking.

If that's not what you mean, then never mind...

Patrick

Your injection timing is late (14 in box 2 is off the bottom of the scale) which explains the rough starting - I didn't catch that tidbit in your first post (me bad), and you probably have impending trouble with either the N75 valve or (more likely) the hose from intake manifold to ECU, which is why you are getting the intake manifold pressure code.

It is possible that the intake manifold pressure code is related to the late timing, but I doubt it.

The timing is causing the engine to fire on only one of three cyls?

1. there is not a 'pre-filter'. but you should search for 'fuel sender' and see some the threads here lately discussing this thing. It has a check valve in it that can clog in cold weather causing starvation. Also, it has a flapper valve thingy for proper fueling when on an incline. One member's flapper float broke causing starvation.

2. if the timing is that retarded the car will be hard to start and run like sh!t and smoke like an old coal stove.

.

[ February 14, 2003, 15:54: Message edited by: red golf tdi ]

OK timing has been reset to 42 box #2 when cold. It starts and idles for 5 - 10 seconds then it shuts down with an ECU fault for the 0058 intake manifold pressure differential.
So much for timing
When turbo went, I lost 2 Quarts of oil into intake. I will check all of the n75 hoses for oil.
IF I disconnect the hose from the pressure side of manifold do you think I will still get the error?
Oh I'm aware that with it disconnected there is no boost control so idle is all it will see.

Is your intake clogged? Have you changed your filter lately? Have you ever cleaned your snow screen?

96 Psat. Isn't this one of those with the pressure transducer in the ECU? If so, have you checked the 'vacuum' line?

You're not getting any glow plug system errors? Perhaps your coolant temp. sensor is failing (not totally dead). You can read that with vag-com to see if it's reasonable.

You know you're not supposed to adjust the timing when cold. The engine has to be warm (Bentley mentions the numbers.)

MITBeta
When I replaced turbo I removed a mouse and his home that was packed tight with junk. Air filter was changed 4 months ago.

Weedeater
Checked line from manifold to ECU and it is in good condition. Tested pressure sensor in ECU vag-com shows that it is accurate.

VelvetFoot
Temperature sensor is close, but not quite liner. It’s off by 4 deg. F on the low side at 32 deg. F and 1 deg. F at 200 deg. F high.
Yes the engine was up to operating temperature when timing was reset.

How about a clogged intake?

Could fuel delivery problem with injection pump or bad injector. If air is getting to the engine to run on 3/4 cylinders, I don't see it as an intake problem, and the glow plugs shouldn't make that much difference.

If you can duplicate it, you may want to run the engine and loosen the metal lines at the injectors to see if one injector behaves differently from the rest. If you do, swap that injector with one from another cylinder and see if the problem moves or stayes. That would indicate if its an injector or pump problem.

-brian

It has warmed up to 35 deg f today and it started fine. The idle is ruff with some smoke for a couple of minutes then smoothes out some what. Still smokes a little once warm.

Is there an O2 sensor or something that monitors un-burnt fuel?

No sensors in diesel exhaust.

With 3/4 cylinders firing, sounds mechanical: pump, injector, or cylinder problem. Did you have the car since new, use syn oil the entire time? Possible low compression from stuck ring? Very rare pump problem? At 130Kmi you may have some injector issues, too.

[ February 21, 2003, 05:16: Message edited by: brian ]

I'm not the expert on these cars, but didn't they have some sort of supplemental fuel injector in the exhaust? Could that cause some problems with smoke?

If you disconnect the electrical connection to the coolant sender the brain will assume some low temp and glow the plugs for the max. Maybe you could see how that works. You will get a code (dtc) and maybe a light. This might show that it's the coolant temp sensor that's to blame, although it's looking pretty good according to vag-com, I guess, but what have you got to lose?

GoFaster says the there aren't any glow plug monitoring features. It does sound like glow plug system.

How about this: What effect could all that oil from the turbo blow have? There does seem to be some sort of at least intermittant turbo control issue based on that code you have. But would that cause a starting problem like you have? I doubt it and you're not complaining about lack of power so that's probably not it. Again, you're not complaining about lack of power, so it's probably not things like a sticky egr control valve or clogged catalytic converter.

Does your car have the clear fuel hose? Maybe you could look under the hood when it idles bad to make sure you have good fuel flow.

Is that chip any good? Maybe you could replace it with the stock chip and see how it works.

(Excuse the rambling, just thinking out loud)

Yes I have had synthetic oil since new. I disconnected temp sensor still had very ruff idle. Checked all of the GP's they were ok.
I’m leaning towards a bad injector. Good excuse to get a set of 205’s

NEW INFO:

This morning it was hard to keep running. i has able to get vag-com readings from #13 smooth idle -2.9 -2.9 +2.7 this changed to 0.1 0.1 0.0 after holding @ 2500 RPM for 40 seconds.

Your injectors are fine. You have a pair of cylinders that are not firing due to inactive or weak glow plugs when cold. I betcha it's cylinders 3 and 4.

What are the measured resistances of all four glow plugs? What voltage do you measure at each of the four harness plugs within 15 seconds of switching on the ignition key with the coolant temp sensor unplugged?

It should also be noted that glow plugs for cylinders 1 and 2 are on one electrical circuit and cylinders 3 and 4 are on another electrical circuit. If you've got a dodgy connection inside that harness, it could be giving a voltage reading when you probe the connector with a multimeter but not actually connecting properly to the glow plug.

OK GOFASTER I'll Check.

thinking about what you said, is there two wires or one that run back to the fuse block for the GPs.

if there are two wires i can use my ohm meter to test the pairs seporately. (easier thats all)

is there any way of testing the the connection itself?
Need to solve this before i go to Ontario, Canada in March

Why would the car start fine and then start running on 3/4 cylinders if its a glow plug problem??? GoFaster, please explain.

I have a suspicion that there is a dodgy loose connection somewhere, involving the glow plug harness. If that's the case, vibration could make the connection go intermittent as soon as the engine starts. It is also possible that some of the glow plugs have higher resistance (therefore less current, therefore less heat) than the others.

I don't think the original poster said he has replaced the harness.

The injectors are fine. The injector balance once the engine warms up shows that.

all 4 GP's are new.

Any suggestions on testing intermittent connections?
As far as resistance i didn't check that becauce my ohm meter is an old digital that the lowest range is 2K ohm, time to buy a new one.