Cold timing advance problem

[hacked89]

I know we spoke about the technical details in my thread Nero. It’s simple to replace the check valve. We could also probably run no check valve and adjust accordingly like the big pumps. I don’t think it’s many degrees that the housing pressure drop results in.

 

[hacked89]

I haven't run my cold advance system for 15 years now. Never understood what it did and saw no difference in making it work. I am sure it does something, I am suspicious it has something to do with emissions/smoke when the engine is cold.

I caveat that I only post what I know from hands on experience and I’ve never disassembled a pump yet. That said, below is the theory that was explained to me.

Fuel goes in the cone, enters the vane style transfer pump which bumps total hydraulic pressure based on speed (and bleed, but that's tunable). From the transfer pump, it goes 3 directions: 1) pumping plungers, 2) timing advance mechanism (high pressure), 3) residual to the housing (which contributes to housing pressure, this is important).

Obviously the volume into the plungers goes out to the injectors. The high (transfer) pressure end of the advance ends up as housing volume as well after it completes it's function. Both 2 and 3 end up as housing pressure. Housing pressure is the other side of transfer pressure at the advance piston. The little timing actuator on the side of the pump determines how much pressure differential goes on in that mechanism... Beyond that, too much housing pressure will keep the plungers from filling.

The regulator fitting on top of the pump has a little check valve in it. In natural form, it regulates housing pressure to 10-12psi... The solenoid for the cold advance opens the check valve, and drops all housing pressure. Dropping all housing pressure makes transfer pressure advance the timing.

 

[Nero]

Having it plugged in this morning on my way to work, it definitely drove like the symptoms I had.
On my way home I finally disconnected it, and it was smooth sailing the whole yime. Mind you it was 77F out so it warmed up fast.
I did finally start sucking air on my front tank after about 202 mules, started getting the sucking air acceleration. Switched tanks and it smoothed out.
My shower cones fell off years ago, I put regular tubes on the bottom to get to the bottom of the tanks.

 

[Nero]

First day doing a true overnight cold start since disconnecting the timing advance.

Definitely a significant more amount of smoke. Didnt clear up until about 130f coolant temp. It wasn't consistent smoke either, it would be smoke for a bit, clear up, fart a few puffs, clear, then smoke some more, then clear up again for a bit.

Dang this is irritating.
Maybe I have some junk in my pump relief valve?
I can't send the injectors out for rebuild again, especially so close to my summer trips. But on the other hand... I have a mobile mosquito killer....

 

[IDIBRONCO]

. I have a mobile mosquito killer....

Well one of those sure is handy to have around this time of year.

 

[hacked89]

First day doing a true overnight cold start since disconnecting the timing advance.

Definitely a significant more amount of smoke. Didnt clear up until about 130f coolant temp. It wasn't consistent smoke either, it would be smoke for a bit, clear up, fart a few puffs, clear, then smoke some more, then clear up again for a bit.

Dang this is irritating.
Maybe I have some junk in my pump relief valve?
I can't send the injectors out for rebuild again, especially so close to my summer trips. But on the other hand... I have a mobile mosquito killer....

Did you talk to Justin after this post?

 

[Nero]

Did you talk to Justin after this post?

No not yet. I'm going to park it for a few days, I feel its good enough to haul my camper round trip 300 miles now, so I'm probably not going to take the injectors back out or anything until after that trip, which is in a few weeks.

On another note, on my way home ambient temps were about 86F and giving it all the beans going up that steep grade, my egts never got above 900 at 70mph in 5th, coolant temp did creep up to 210 by time time I got to the top of the hill, but cooled back down by the time I got off the freeway.

Seems like only cold starts are my issues now. Oh and weeping valve covers.

 

[hacked89]

No not yet. I'm going to park it for a few days, I feel its good enough to haul my camper round trip 300 miles now, so I'm probably not going to take the injectors back out or anything until after that trip, which is in a few weeks.

On another note, on my way home ambient temps were about 86F and giving it all the beans going up that steep grade, my egts never got above 900 at 70mph in 5th, coolant temp did creep up to 210 by time time I got to the top of the hill, but cooled back down by the time I got off the freeway.

Seems like only cold starts are my issues now. Oh and weeping valve covers.

Do you use rubber or cork valve cover gaskets?

 

[Nero]

Rubber ones.

I used rubber on both of my old mans trucks, plus on mine before redoing the heads.
I think because I over torqued them I may have warped them a little. Its just low priority for me at the moment. Right now its make sure she's ready for going long distance with a load. I think she's ready, given the issues going on.

 

[hacked89]

Rubber ones.

I used rubber on both of my old mans trucks, plus on mine before redoing the heads.
I think because I over torqued them I may have warped them a little. Its just low priority for me at the moment. Right now its make sure she's ready for going long distance with a load. I think she's ready, given the issues going on.

I use rubber too, no leaks torqued to spec. I just happen to have cork ones I tried and threw them away. Did not like them. That’s why I asked.

 

[Rdnck84_03]

@Nero is it possible your getting some air intrusion from somewhere. A little air getting in the system could cause the intermittent smoke on start-up.

Air in the system could also cause the symptoms you were describing with the surging, and the cold advance could have made it more noticeable.

Just some thoughts.

James

 

[Nero]

@Lumberjackchuck when you swapped out your R&D injectors to the Russ built ones, was it an immediate difference with the cold start smoke? Did you make any IP timing adjustments?

I drove my truck into work today, so it had been sitting since last week.
Firing her up it smoked out my whole street for a good minute or two and was stumbling a little. As soon as it warmed up a little, it completely went away.

I hit up Russ about having some injectors built, I can't have my truck down anymore waiting on parts return. I think I'll toss Russ injectors in, get these stage 1's fixed and then probably post them to classifieds.

Just so crazy, it runs so well when its warmed up a little....

 

[Lumberjackchuck]

@Lumberjackchuck when you swapped out your R&D injectors to the Russ built ones, was it an immediate difference with the cold start smoke? Did you make any IP timing adjustments?

I drove my truck into work today, so it had been sitting since last week.
Firing her up it smoked out my whole street for a good minute or two and was stumbling a little. As soon as it warmed up a little, it completely went away.

I hit up Russ about having some injectors built, I can't have my truck down anymore waiting on parts return. I think I'll toss Russ injectors in, get these stage 1's fixed and then probably post them to classifieds.

Just so crazy, it runs so well when its warmed up a little....

You have the same exact issue as I did.

Once I swapped the Russ set in there was no smoke on start ups at all. Still none and just fired it up after 2 weeks of sitting while I was on vacation.

 

[Nero]

You have the same exact issue as I did.

Once I swapped the Russ set in there was no smoke on start ups at all. Still none and just fired it up after 2 weeks of sitting while I was on vacation.

Perfect thats what I was hoping for.

My injectors should be ready for pickup tomorrow. I'll follow up with how it runs afterwards, thanks for getting back to me.

 

[Nero]

Update, got my Russ injectors installed, first start there was a slight puff at initial firing off, then immediately clear. I also plugged my timing advance back in while it was running. Definitely an audiable change in the engine running.
Drove it around cold, so far no surging anymore as the fast idle was turning off. But its also the first day. I'll daily it a bit and see how it goes.

I did start pop testing the injectors I pulled out, before testing there was evidence that two of them were leaking down, had moist tips when the rest were dry.

Pop testing them the two suspect ones were indeed bleeding down and had a poor spray pattern. Rest looked okay.

Gonna send them back to be repaired again, then I don't know what I'm going to do with them.