Blowby buildup in cdr valve cause mild runaway?

[ASPHALTVICTORY]

I have ditched the thought of the tps causing a sudden acceleration condition.

My theory is that the cdr isn't working properly and is acting like an oil catch. Uphon taking a left turn it dumps this blowby oil down the intake causing a mild runaway condition.

Does this sound plausable?

[bowtiebutler]

I have ditched the thought of the tps causing a sudden acceleration condition.

My theory is that the cdr isn't working properly and is acting like an oil catch. Uphon taking a left turn it dumps this blowby oil down the intake causing a mild runaway condition.

Does this sound plausable?

If its dumping enough oil into the intake, it could happen. Unhook the hose going from the CDR to the intake, and take it for a drive. You might want to run a hose from the CDR to somewhere under the truck to avoid making a mess under the hood of your truck for this test.

Matt

[turbovanman]

No.....

[ASPHALTVICTORY]

It's not the cdr. Plugged the tps back in and it did it again.

[arveetek]

Air in the fuel system can cause surges. Could be a fuel line pulling apart when turning left?

Casey

[DmaxMaverick]

....Or a partially filled fuel filter. A failed/failing fuel lift pump can cause this, as well as a fuel line leak upstream of the lift pump.

[DmaxMaverick]

And to answer your initial question, no. It does not sound plausible. If the CDR is accumulating excess oil, the problem isn't with the CDR. Under normal operation, the CDR is open, and only closes if excess crankcase vacuum increases, normally at higher engine RPM's. If a condition of oil catch/dump at the CDR exists, the problem is why there's that much oil reaching the CDR, not the CDR itself. If you had that much blow-by, you'd have many other significant issues. An overfill may cause issues, but you'd need about double a fill, and that would cause other, more serious issues.

[Robyn]

I'm on board with Maverick regarding the CDR/oil issue

The air in the fuel thing is a possibility.

To check this, connect a length of clear tubing to the return fitting on top of the IP then loop it up by the wipers (Don't pinch it with the hood)

Run the rig and watch the flow of return fuel through the clear line.

If after you get the "surge" you see a bunch of bubbles go through, you have your gremlin.

Then trace the fuel supply line back to the tank to source the air leak.

Does the issue happen with the tank full, half, quarter or does it matter ???


Some fuel pickup tubes have a safety valve above the sock that contains a little spring loaded valve, that can leak, and when the fuel level is low enough air can enter under certain conditions.

Make sure the fuel filters are all good.

Far too many gremlins have been chased around and around, only to find the fuel filter was the culprit :eek:


Check that air issue with the clear hose and keep us in the loop.

Can you post some details on the rig Year, etc.

Missy

[ASPHALTVICTORY]

I replaced so far:

Fuel tank & pickup
Hoses and hard lines from the tank to the injection pump
The lift pump
The stanadyne model 80 with a marine style racor filter setup

I took the return fitting off the ip to inspect the check ball placed a clear line on the return side and got it down to a ball pen roller ball size bubble over 24 hours.

I took apart the cdr system and cleaned it there was no oil present ( a film to be expected) actually the only thing that worried me was the crap inside the cdr pipes.

I am now looking at a sudden trigger of the cold advance solenoid i understand its only triggered by a temp switch on the passenger side but that seems like the likely culprit to explain the "run away"

[DmaxMaverick]

Simply disconnect the HPCA, and give it a test. If that cures the problem, the HPCA may be getting power, externally, by some means related to the turns. While it could be the temp switch, it seems very unlikely, as the G-force encountered by a simple turn is much less slight of an affect, compared the typical engine vibrations. The temp switch is relatively cheap, so no harm in just replacing it. In any case, disconnecting the HPCA, if it has no affect on the issue, eliminates the switch as a suspect.

If no change, power the HPCA, bypassing the temp switch (so it stays on, regardless of temp), and test. If the HPCA works (advances timing), and the problem persists with the HPCA engaged, the problem is not the HPCA. If the engine speed increase stops with the HPCA forced on, then the likely suspect is the HPCA circuit, either internal electrical, or mechanical. If disconnecting the connector stops the speed increase, and forcing it on also stops the speed increase, then the problem is likely external of the IP. If disconnecting it doesn't stop the speed increase, but forcing it on does, then the problem is likely internal to the pump (time for a new IP).

[ASPHALTVICTORY]

I disconected power to the cold advance and so far it has not "run away" on me.

If i stay on the accelerator when this happens it GOES if i let off the fuel completly it stalls BUT will start right back up. At this point the engine is at running temp after a stall during a start the glow plugs will come on and go through a full cycle as if the engine was cold.

Your saying keep the cold advance ON and seeing if it happens? Intresting i simply never thought of that. I imagine just unpluging the conector at the temp switch and bridgeing it would do?

[DmaxMaverick]

The reason for testing both, disabled by removing the HPCA power connector, and forcing it on by supplying constant power, is to determine if the failure is internal to the pump, or external. If disconnecting the power (temp switch connector) stops the condition, the problem is very likely external to the pump. It may be as simple as a failed temp switch. Cheap. That's a good thing, meaning the pump isn't toast, and you only need to figure out the electrical problem. Not necessarily easier, but a whole bunch less $$. At this point, with the problem stopped by removing the temp switch connector, I'd just replace the switch, verify the wiring, and give it a go from there. That may be all there is to that.

[ASPHALTVICTORY]

Dam for a temp switch it sure is expensive $80:eek: