Author Topic: Miss during cold starting (Read 4438 times)

dieseldunebuggy · « **on:** March 11, 2008, 03:46:00 pm »

First off I have a 1981 VW Rabbit with the 1.6N/A and it's the old one with the 11mm headbolts.
I just got done getting my car back together from making a dual exhaust header, a huge custom intake, getting the head redone, porting the head, ARP headstuds, and a GILES PUMP!!!
When the engine is cold and I try to start it, it'll miss on one cylinder for about 30sec and it won't idle on its own. It has been right around freezing point around here. All the glow plugs checked good and about 5000 miles ago I had the injectors checked, and they said they still had many miles left on them. I also have clear fuel lines on the car and there aren't any air bubbles before or after starting.
Could this be happening because it's getting too much cold air in from the intake causing it to not burn the diesel right, or could it be a injector bleeding off? Any help would be nice.

jtanguay · « **Reply #1 on:** March 11, 2008, 04:53:52 pm »

checked compression??? a worn out engine will behave like you describe. sometimes it is glow plugs though.

mine is getting tired... it misses in at least 1 cyl @ -15c but starts right up with 4 good glowplugs.

dieseldunebuggy · « **Reply #2 on:** March 11, 2008, 05:25:00 pm »

When I checked it around 5000miles ago, the compressionin each cylinder were between 400-450. I'll probably check it again this weekend since the head has been redone.

jtanguay · « **Reply #3 on:** March 11, 2008, 05:42:01 pm »

with that much compression it shouldn't be missing at 0C. mine does not miss at all with cold start pulled @ 0C. -10C and below she will idle on her own but will start to miss worse and worse as the temps get lower.

dieseldunebuggy · « **Reply #4 on:** March 11, 2008, 06:11:13 pm »

Do you think it would be worth a try to put an intake heater on it like the ones on the cummins. Has anyone had a intake this big on a 1.6N/A. Would you think it's reasonable that it could be getting to much cold air causing it not to fire right?

jimfoo · « **Reply #5 on:** March 11, 2008, 06:33:48 pm »

The thing is with good compression, it should start with the glowplugs. It could be that some burned out in those 5k miles. If your relay sticks on, the glowplugs won't last long at all.

MaxHedrm · « **Reply #6 on:** March 11, 2008, 06:42:46 pm »

Kind of a hijack, but sweet intake. Very nice work.

dieseldunebuggy · « **Reply #7 on:** March 11, 2008, 06:44:32 pm »

I checked the glowplugs 2 days ago and they got good and red hot.

jimfoo · « **Reply #8 on:** March 11, 2008, 07:48:33 pm »

All you're left with is compression, timing and fuel then.

Vincent Waldon · « **Reply #9 on:** March 11, 2008, 08:35:02 pm »

Quote from: "jimfoo"

All you're left with is compression, timing and fuel then.

2X.... what do you have the timing set at ? What color is the smoke as it's missing ? Might be worth checking the compression when the engine is stone cold ?? Should be lower, but should still be pretty even from cylinder to cylinder.... might pinpoint a bad cylinder that gets better when it warms up. BTDT.

dieseldunebuggy · « **Reply #10 on:** March 12, 2008, 01:17:28 pm »

The timing is set at .90mm, just as Giles told me to set it at. I actually haven't look at the smoke when it's missing, but I will tmmorow morning. I believe there the original injectors and when I had them tested they told me they had many miles left on them. I'll check the compression cold this weekend.
Today it was 70F and the car didn't have near as bad of a miss but it still had one.

jtanguay · « **Reply #11 on:** March 12, 2008, 03:00:41 pm »

you can always crack each injector nut one at a time to see if the engine rpm changes. if not, then that injector isn't firing right.

any wet spots around the injectors? return lines are notorious for leaks

zukgod1 · « **Reply #12 on:** March 12, 2008, 03:08:02 pm »

Ok sweet intake

And where did you get that fuel line?

dieseldunebuggy · « **Reply #13 on:** March 12, 2008, 03:26:19 pm »

Quote

And where did you get that fuel line?

I got the fuel line at my local lawnmower shop.

Quote

any wet spots around the injectors? return lines are notorious for leaks

No, there aren't any wet spots around the injectors. All the fuel lines in the engine bay have been replaced.
This weekend I'll also try to crack each injector while running.

diffdude · « **Reply #14 on:** March 12, 2008, 04:06:34 pm »

Check the valve adjustment mine was doing the same thing. There too tite untill the head gets a little heat in it.