02-07-2018, 04:33 AM
the test is easy, to find cause. (mostly) in your case.
use the test resistor. if the 51 ends.?
that means the sensor is bad or there is no proper exhaust flow across the sensor. (gee it dont take much flow,imo)
code 51 is not smart like 1996+ here.
it's a very crude and fast test.(obd1)
you said it has new EGR valve, so was that with or with out the EGRT inside? new.
if the resistor test passes, (if fails means wiring bad to ECU)
if it passes 10k test.?
and the EGRT passed the water test boiled then we know the exhaust flow is weak past it.
only why remains....
what can make the flow weak, well losts really (but not EGR main, its open you prove it)
the flow can be weak for 4 reasons, my guess.
1: the gasket on those header put on wrong causing the EGR port there to be blocked, and no flow there, but this error would make the stall test fail.
2: the head tunnel packed or was necked down fooling us. 10mm is size clean, here 1/2" bore. what if was 1/8" and packed.? oops.....
3: all quadra port egr injectors packed but 1 good?, fooling us that stall test passes.?
4: The cat is too big, causing the back pressure wrong and the EGR mod to be weak and the flow now weak. not dead but weak. yes this is a silly way to do EGR but is here. sadly.
i sure you know the status of the path that its Ok or now, so will go farther, if not...
id go the 10k ohm resistor of any kind, just some jumper clips there, attach it and see.
I understand you clearly " hate not knowing", me too,, i always think its something going to get worse. (or something I left loose)
we can find it, but the 10k ohm test is important.
as is the boiling tests. my guess is you reused the old EGRT..
most EGRT in most old EGR mains, are packed solid in carbon. and must be removed and cleaned.
to be re Used the sensor , must be clean. just a naked probe in the flow of exhaust gasses.
also I worry that code 51 might cause the ECU to do other odd things, a punishment of sorts (like retarding spark when it fails to prevent Ping detonations) Like modern cars do with Knock sensors.
we do know the most old sidekicks did not do punishments, 89-91. for EGR. (well if not stuck open)
most EGRTs do not fail, ever. just pack up. it's just a thermister and vary robust. (a passive device too)
use the test resistor. if the 51 ends.?
that means the sensor is bad or there is no proper exhaust flow across the sensor. (gee it dont take much flow,imo)
code 51 is not smart like 1996+ here.
it's a very crude and fast test.(obd1)
you said it has new EGR valve, so was that with or with out the EGRT inside? new.
if the resistor test passes, (if fails means wiring bad to ECU)
if it passes 10k test.?
and the EGRT passed the water test boiled then we know the exhaust flow is weak past it.
only why remains....
what can make the flow weak, well losts really (but not EGR main, its open you prove it)
the flow can be weak for 4 reasons, my guess.
1: the gasket on those header put on wrong causing the EGR port there to be blocked, and no flow there, but this error would make the stall test fail.
2: the head tunnel packed or was necked down fooling us. 10mm is size clean, here 1/2" bore. what if was 1/8" and packed.? oops.....
3: all quadra port egr injectors packed but 1 good?, fooling us that stall test passes.?
4: The cat is too big, causing the back pressure wrong and the EGR mod to be weak and the flow now weak. not dead but weak. yes this is a silly way to do EGR but is here. sadly.
i sure you know the status of the path that its Ok or now, so will go farther, if not...
id go the 10k ohm resistor of any kind, just some jumper clips there, attach it and see.
I understand you clearly " hate not knowing", me too,, i always think its something going to get worse. (or something I left loose)
we can find it, but the 10k ohm test is important.
as is the boiling tests. my guess is you reused the old EGRT..
most EGRT in most old EGR mains, are packed solid in carbon. and must be removed and cleaned.
to be re Used the sensor , must be clean. just a naked probe in the flow of exhaust gasses.
also I worry that code 51 might cause the ECU to do other odd things, a punishment of sorts (like retarding spark when it fails to prevent Ping detonations) Like modern cars do with Knock sensors.
we do know the most old sidekicks did not do punishments, 89-91. for EGR. (well if not stuck open)
most EGRTs do not fail, ever. just pack up. it's just a thermister and vary robust. (a passive device too)
http://www.fixkick.com