Cold timing advance problem

[Nero]

I think I might have a cold timing advance issue, wanted to see if anyone else has experienced something similar.

Cold starts are fine. Smokes a little, I think I have an injector bleeding down at night. Something to ask about later.

Once running, drives just fine. As soon as coolant temp warms up for fast idle and timing advance to shut off, say I'm cruising at speed, engine at 2000rpm, when the timing advance clicks off, engine surges like crazy shaking the whole truck through the driveline. If I push the clutch in and let engine return to idle, then resume driving, it completely goes away.

It only does this once per drive, only when cold advance is needed.

To help kind of confirm this, ive disconnected my cold timing advance solenoid, and I'll drive it into work tomorrow.

So far its done this three times.

 

[hacked89]

That doesn’t sound right but I don’t run cold advance so I can’t say 100%. Cold advance is like 3 degrees. That won’t cause those symptoms unless you think there’s something downstream funny happening in the pump?

Do you know it’s clicking off or guessing it’s clicking off right when it happens?

 

[Nero]

I'm guessing its clicking off right when it happens, because when I let it return to idle, it goes to low idle, not the raised warmup idle, and coolant temp is about 130 ish

 

[The_Josh_Bear]

That should NOT be happening. What a very strange thing... my guess is IP, but you never want that to be the case with a brand new one.

I know you know this, but the cold advance solenoid is separate from the high idle solenoid, so there are two different things happening at the same time. But whether losing 3* of timing or 200 rpm or both, it should never cause the engine to buck or surge.

I would disconnect one one day, see how it does, then repeat with the other the following day. But either way, something is problematic with the IP. I've had 4 IP's on my engine and the high-idle step-down is always very, very smooth and many people wouldn't even notice it.

 

[Nero]

@The_Josh_Bear so far, due to limited time since getting it running, it has only done it the last 3 cold starts.

I did just fill up, I wonder if I need to replace my filters, they are old... I have the one at thr IP head, and a frame mounted one.

I guess I'll order those today as a start.

For safe measure, I checked fuel pressure at my IP again, still about 6psi at all engine speeds.

 

[Nero]

Now that I think about it, these filters were probably 4-6 years old. I don't drive my truck much so they probably only had 4-6k miles on them.

Oh well. New filters on. I use a Napa 3120 as a prefilter just after the tank selector valve, plus the one above the alternator. I switched from the style that has the removable bowl to the unitized filter.

Checked my fuel pressure after replacing, still 5-6psi. Course pressure doesn't equal volume. I'll report back after the drive to work tomorrow.

I did prefill both filters with power service, ran it for a bit, then shut er down.

 

[rreegg]

As soon as coolant temp warms up for fast idle and timing advance to shut off, say I'm cruising at speed, engine at 2000rpm, when the timing advance clicks off, engine surges like crazy shaking the whole truck through the driveline.

to make sure I understand: this happens at ~2k rpms while the engine is still warming up - 130-140*f coolant temp range around when the timing advance turns off.

Have been geting similar shakiness around these conditions for maybe 10seconds. would not say it “surges like crazy” but some surging back and forth on the cusp of when the timing advance turns off.

Probably about 8k miles with new fuel filter and it’s been a todo to drain the separator

willl usually let the engine warm to above 140* before driving much in the colder months but don’t wait as long during warmer months

Hadn’t considered this to be a fuel delivery/injector thing as much as just being on the cusp of temp range

 

[Lumberjackchuck]

Cold starts are fine. Smokes a little, I think I have an injector bleeding down at night. Something to ask about later.

How long does it smoke for? I had the same issue with the stage 1 injectors. On cold starts the truck would smoke a little, up until it was pretty much warmed up. Once it was warmed up the smoke was gone, I think they were leaking down over night or leaking until warmed up.

With my new set from Russ I only get a quick puff of smoke when cranking, after that it’s completely clear.

Also, I no longer use the cold timing advance anyway. Truck runs just fine without it when cold.

 

[Nero]

@rreegg you nailed it precisely. So far ive only let it occur for at max two seconds before pressing the clutch in and letting it return to idle. Don't need to snap a u joint. As soon as it returns to idle I give it maybe a second then rev match to get it back in gear and keep going. Doesn't do it again.

@Lumberjackchuck if I let it idle, there's an obvious misfire, engine mildly shaking, ect. If I rev it up to about 1500, it clears out pretty fast. Usually within a few seconds as it, as I presume, burns off the leaked down fuel out of the cylinder. Its 100% fine the rest of the day.

Since putting new filters on it I'll follow up tomorrow on how she does.

 

[Nero]

So small update.

I forgot to unplug the cold advance solenoid this morning before I left.

Still did the shudder, but it was significantly smoother this morning. Just a little light bump a few times, then cleared itself out I didnt even have to move the throttle at all.

Got off the phone with Justin a bit ago, he said I could run it without the cold advance solenoid, but as I was explaining what all my readings were, he said everything sounded good, so advised keep adding fuel cleaner and keep sending it see if it clears out. If it doesnt, take them off and ship them back again.

One thing he pointed out, with the 90cc pump, I should be seeing high teens for boost. On a good day I barely see 12. Guess me wiring the wastegate shut wasn't enough. Good thing I have a wastegate delete kit coming in the mail. Will also help lower my egts too!

 

[Lumberjackchuck]

he said everything sounded good, so advised keep adding fuel cleaner and keep sending it see if it clears out. If it doesnt, take them off and ship them back again.

I tried that when I was having that problem and sending it actually made it get really stuck open and knocking bad.

Sounds like you’re in the same place I was with those injectors. Though I didn’t send them back a second time. If you want, I’ll send you mine so you have extra. I had 7 good ones.

 

[Nero]

I might take you up on that offer, then I might hit up Russ if they don't get any better.

 

[Lumberjackchuck]

I might take you up on that offer, then I might hit up Russ if they don't get any better.

ok, send me a PM with your address and I’ll send them over.

good luck diagnosing which one(s) may be leaking.