Yes, you do need to sync the fuse box. Turn the key on and let it sit for 30 mins to sync.

Is the running different with the mafia disconnected?

 

Synching now. No difference in behavior whether MAF is connected or disconnected.

 

Hey Best 4x4, are you sure it was the wrench-a-part in Belton that had some fat D2 carcasses that hadn't been too picked over?

Could it have been a different self-service yard you went to?

I checked online and according to their online inventory, the only place wrench-a-part has some D2s is San Antonio and Lubbock.

Think I am going to need a new compressor clutch as the one I pulled off after going for who-knows-how-long without a securing bolt seems to not have any friction material left on it, just metal.

 

Never mind Best 4x4, they have them listed as a Range Rover(2x) and a D1. There are three three, and they are fresh, meat left on those carcasses.

 

Fuse box sync'ed.

Pulled the SAI solenoid just to test it, and I either broke one of the vacuum lines (from the vac reservoir to the solenoid) or it was already broken.

Repaired the broken plastic vacuum line, tested it for leaks and got the beast running again.

Put about 21 miles on it driving it 7 times around a 3 mile loop in the 'hood.

Best it has run so far in the nearly 8 weeks since it went south, though that's a bit like saying it is now the "queen of the pigs" as it is still sickly.

It'll accelerate slowly/smoothly to about 2,500rpm (50mph), then it starts to stumble/lose power.

When I try to kick down the transmission by putting the accelerator to the floor, it falters badly, backfires and almost dies until I back off.

But NO codes. Some weird things going on here.

Going up to the Wrench-a-Part in Belton to see what I might be able to find (another IACV, maybe a SAI vacuum harness, compressor clutch, etc.).

Also, after cleaning all the dielectric out of the MAF connector with brake cleaner and cleaning it off the sensor itself with a Q-tip, it didn't throw any codes over the 20-some miles -- longest it has gone so far without throwing the P0102/P1884 combination. So wondering if my MAF problem was caused by too much dielectric gunk as the MAF (like the knock sensors) are very sensitive and produce a very low signal.

 

You might have a short somewhere in the MAF wiring. Hopped in my latest project to take it to the muffler shop to have new cats put on, stumbled going up the street like you said and died. Hopped out, unplugged the MAF and she happily went the rest of the way to the shop with no running issues other than CEL.

Are the 02's cycling correctly? If not, unplug them and it will go in to full speed density mode using only the TPS and CPS to control fueling.

Hard to overstate the benefit of having known good parts to swap. You might want to do a thorough problem analysis. IS/IS NOT - Systemic list of known good vs questionable based on testing. Create hypothesis to be tested and eliminated. Process of elimination, deductive reasoning. We read a handful of threads every day, day after day, and as you progress through your troubleshooting we don't typically go back and re-read through everything. Create a bullet summary of everything hear to help us leverage experience across your situation. Maybe checkboxes that we can x out as we go through it.

You mentioned RPM, you might be at the point to consider a plugged CAT - pretty rare but it has happened.

 

Sorry, been offline for a few days.

Went to the yard suggested by Best 4x4, stripped an '03 D2 clean of a bunch of SAI, emission and related stuff (including the entire vacuum piping harness for the SAI). Good call, Best 4x4.

As I mentioned in my prior post, I drove it about 21 miles around a 3 mile circuit in my 'hood after having cleaned all the dielectric out of the MAF connector. The P0102/P1884 codes would usually pop up after driving a few hundred yards but they didn't after 20ish miles, so hoping the MAF issue was related to my liberal use of dielectric and not to a short somewhere.

No O2 sensor codes. I thought someone said to cycle them but not sure how to do that. And what would disconnecting the O2 sensors (all 4 or just the front?) demonstrate?

I want to test to see if the cats are clogged, someone suggested disconnecting the Y-pipe at the exhaust manifolds and then put a wet-dry vac on the tailpipe in blower mode and see what kind of air volume I get at the other end.

However, it's a lot easier to remove the SAI valves (esp since I did this on the donor I just cannibalized) and was wondering if I could do the same airflow test but measure the flow at the SAI plumbing instead of disconnecting the y-pipe.

Thoughts?

 

The instruction on the 02 sensors was to check and see if they are cycling, you need the torque app or something similar to do that, we want to see them cycling. If they are not, they could be causing the improper running. Disconnecting them completely takes the closed loop control out of the equation, the ECU then uses the MAF only for fueling.

To get conclusive results you need to disconnect the y pipe, the shop vac is high volume flow, low pressure. Sai tubes are really small and won't test the full flow ability.

 

So explain what cycling is exactly on the O2 sensors?

I have both a ODBII reader and a Torque capable wifi ODBII plug-in module that will let me watch the voltages of the O2 sensors in real-time.

Which O2 sensors should I watch -- front or rear or both? and what should I be looking for graph-wise? I can't recall the voltage range they move thru, but I have watched their behavior before for yuks.

And figured I was going to have to take the Y-pipe out -- or at least unbolt it at the manifolds. It unbolted pretty easily at the flanges to the manifolds when we disconnected it to pull the engine 6-7 years ago, but I have never really looked at the condition at the other end of the Y-pipe where it goes into the muffler plumbing flange, so not sure how rusted that is going to be.

 

They cycle between 0 and 1 volt on a very rhythmic frequency, I would guess about 3 seconds peak to trough. The ECU does it on purpose, increasing fuel flow until it reaches 1 v and then decreasing until it reaches close to zero. If they do not cycle like that, then it is because either the sensors are bad or the engine is actually rich (1 v) or lean (0 v). For either cause the ECU tries to compensate by adjusting fuel. Typically sensors fail open (0v) and the engine compensates by overfueling. A leaking injector, plugged injector, dead injector, or vacuum leak will also cause it to be rich or lean.