pump timing + MPG's

[Corlebra]

hey guys,

My car will not start in the cold midwest weather unless i plug the block heater in. I've been told if you advance the IP timing it makes cold starts alot easier.

well, I don't have a dial indicator so i have no idea what i'm running for timing. I tried to use the dial from the start of my rebuild but had no luck and decided it was easier to tune by ear.

Last night i went ahead and bumped the pump advance just tiny tiny tiny bit and it seems to have made starting alot easier. But it seems like it's chugging fuel now. The motor sounds the same as before, it feels like it may have lost a little power as well.

Is this normal when you advance the IP too far?

[TylerDurden]

First thing: scratch two registration marks into the pump and its mounting-plate that you can see, to show how much you move the pump during tweeking. Putting the scratches by the bolt near the inlet is common... easy to see them there.

If you advance the timing too far, you'll get constant pinging/nailing/clatter. Usually, you want just a bit of clatter as you floor the throttle.

Constant clatter means the motor is not running most efficiently, so reduced power and increased fuel consumption results.

[Corlebra]

Well, I've got loads of rattling, especially when your trying to accelerate at a constant slower speed. I played with it a little tonight, pulling it back far enough so the motor would start to lower it's idle. The noise didn't really change much as I moved it though.

I feel like the car performed much better before i messed with it. The turbo used to spool immediately, but now there's much more lag to it. The car also doesn't seem to start any easier now than it did before. probably a little down on compression and the battery is definately too big for this car.

So, rattling generally means too much advance, correct?

[steevz]

Shouldn't be rattling.. are you describing a noise or the car is physically rattling?

You'll hear the engine clacking or clattering. It's a sound distinctively different the regular diesel sounds.

[Fatmobile]

Grab your crank pully and see if it's loose.

[Corlebra]

It's definately a diesel knock rattle that i'm hearing, crank pulley is nice and snug. I advanced the pump too far apparently, now it makes NO noise, it's like driving a gasser... it sucks lol. It's also spooling rather slow and doesn't have the power it used to. It actually started at 40* today though after cycling the glow plugs 4 times.

I retarded the pump enough today so that it would smoke white at idle, then I advanced it just a little bit before it'd start to smoke. It sounds close to what it did before, but it still doesn't feel nearly as 'fast' as it did before i screwed it all up.

Should I be tuning the pump while the engine is cold or normal operating temp?

[bbob203]

I tune it warm. you just have to mess with it until you get it right. also make sure there are no bubbles in lines took me awhile to figure out how much this affected how my engine started and ran/idled and my gas mileage.

[82vdub]

Just wondering, what direction are you rotating the IP to advance the timing and what direction are you rotating it to retard the timing? From your descriptions, I think you've got them backwards. Are you rotating the IP towards or away from the head to advance the timing?

[Fatmobile]

Do you start it with the cold start lever in, then pull it as the car starts?

[TylerDurden]

Small alterations make big differences, when moving the pump. I gauge my marks by the IP bolt in 0.1" increments.

The top of the IP moving toward the head is advance.

My '89 NA lights-off first crank now (down to 10F), CS lever out.

My turbo '86 has bad rings. I keep the CS lever in when I crank just until the engine fires, then I quickly pull the CS lever out. Seems that the CS advance will bog down the cranking until compression gets high enough for combustion.

[Corlebra]

I knew which way to rotate the IP to advance it. When i first got the motor running i kept screwing it up though lol. Unless the engine has been ran within an hour or two, I'll use the CS lever and leave it pulled out until the engine is about half way warm.

Today I started it and it smoked white pretty bad for about 6 minutes until it warmed up. So, i advanced the pump a little more today and it seems to have made the boost come on quicker along with easier cold starts.

I'm pretty sure I got bad fuel along with poorly timed IP.

[Fatmobile]

Are you making a scratch mark by the bolt near the fuel inlet?
So you know how much you are moving it.
As Hagar used to say, "just a pencil lead width" meaning the thickness of a pencil line,
can change smileage and power.