No Boostage--What Gives?
#1
No Boostage--What Gives?
1997 Dodge Cummins 12V, OE turbo (HX35) and P7100, 215hp/440lbs.ft.; a 4-inch turbo-back pipe the only mod (if you don't count the boost gauge and pyrometer) (and the fact that it ain't in a Dodge no mo').
I noticed the boost gauge wasn't moving; duh. Gotta be the boost gauge feed hose. Nope--no joy. No compressed air leak sneakin' out at other ducting joints twix compressor outlet through intake manifold top, neither.
Then I went for a ride, city streets and highway and just had to mash the stoopid pedal. Repeatedly. Nothing...well, a strong naturally-aspirated diesel, but no turbocharger surprise for obnoxious rice-rocket fart boxes. No fast-building EGTs nor black smoke, either.
Then I filled up...and the thing is getting way better gas mileage. OK, no boost, no fuel enrichment, I sorta gets it.
I pulled the air filter hose off, and fired 'er up. The turbine sucked air hard (I still have to explain my to my neighbor 'bout his missin' cat...).
Obviously, the fuel's pump's not seeing any reference boost along with the engine not seeing any manifold pressure.
Could it be the wastegate is stuck open? Underneath, the wastegate and its connecting rod moved easily by, er, finger.
What is going on?
Eddie
I noticed the boost gauge wasn't moving; duh. Gotta be the boost gauge feed hose. Nope--no joy. No compressed air leak sneakin' out at other ducting joints twix compressor outlet through intake manifold top, neither.
Then I went for a ride, city streets and highway and just had to mash the stoopid pedal. Repeatedly. Nothing...well, a strong naturally-aspirated diesel, but no turbocharger surprise for obnoxious rice-rocket fart boxes. No fast-building EGTs nor black smoke, either.
Then I filled up...and the thing is getting way better gas mileage. OK, no boost, no fuel enrichment, I sorta gets it.
I pulled the air filter hose off, and fired 'er up. The turbine sucked air hard (I still have to explain my to my neighbor 'bout his missin' cat...).
Obviously, the fuel's pump's not seeing any reference boost along with the engine not seeing any manifold pressure.
Could it be the wastegate is stuck open? Underneath, the wastegate and its connecting rod moved easily by, er, finger.
What is going on?
Eddie
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#8
YAY! I Likes It When Somebody Gets It...
Super-nice day outside today, so I had no excuse, er, "reason" for not flopping a chunk of cardboard* down on the driveway and sliding on it underneath El Troca Blanca and trying to move the diaphragm-to-wastegate connecting rod; "trying" being the operative word here.
And Herself had the only working flashlight in the house (the bit@#h) so I couldn't use that excuse, err, "reason"; something about "Hurricane Preparedness" (I always thot "Hurricane Preparedness" meant filling the bathtubs fulla I ice and 108 cases of cheap beer). Nobody wanted to hear about the swarming mosquitoes, lying on vicious pecans on concrete, nor my gettin' eat up by the Ebola, neither.
1. Wastegate wouldn't move, both with (a) direct connecting rod hand pressure/hand torque on the wastegate valve axis' throw (the connecting rod that connects the wastegate's valve's axle via (b) the connecting rod itself.
Keep the connecting rod /crankshaft analogy in mind; we're talking about a con-rod/crankshaft small-end relationship here. Sooooo...the connecting rod could be seized OR the spring could be too stiff for the slight amount amount of pressure I could put on it; a really convoluted reach to that connecting rod--one of those arm-reaches where you really need four or five extra elbow joints (available via alien abduction, I hear, "probes" included. Handy, but forgettaboutit). I seem to almost remember my being able to move that rod before, though (scary thot, that).
2. The wastegate's "small-end" crank throw was positioned across the centerline of the turbine downtube, i.e., across the exhaust flow. In normal mechanical terms, the valve should be closed.
Didn't try checking compressor output directly; maybe tomorrow. Maybe not. Keep in mind that there is a small fine-thread metric nut (a 5/16 hex bit almost works here) that I gotsta unscrew. My battery-operated drill battery was dead, which means I hadda recharge it. Never mind the 5/16 bit wasn't screwed in. I woulda hadda get out my 125VAC drill motor and an extension cord AND that would have been work. (sniff)
Eddie
*Cheap-*** chinese cardboard IS superior for sliding across 'cause it's so slick (from all the lead that puts in it).
Last edited by The Eddie; 10-14-2014 at 08:18 PM. Reason: crappy punctuation
#9