maxvp01

So I retested the entire EFI page in my FSM. everything tested out good except the AFM tests.

At the ECU Vs-E2 at idle measured 2.08V (Spec 2.3V-2.8V)

Vs-E2 at 3000 RPM measured 1.2V (Spec 0.3-1.0V)

I also did these tests backprobed on the AFM connector, I got about 2.10V at the idle measurement, but same measurement at 3,000 RPM

This tells me the wiring is good between the two because there is no significant voltage drops.

My AFM is in spec besides a couple areas in the sweep it goes out of spec.

Today the local NAPA actually had a AFM in stock, so I bought it and put it on, still running rich as all get out, still could not force a lean condition by taking off brake booster hose.

Next I measured the Vs-E2 backprobed at the AFM connector:

Reman AFM:
Vs-E2 at idle: 1.8V-1.9V
Vs-E2 at 3000RPM: 1.08V

The next step on flow chart says if it’s not the AFM, it’s the ECU. Would a bad ECU be able cause the voltage to do this?

dbittle

I just went back and re-read through the thread from the start. It sounds like you have changed a lot of parts already, eliminating large parts of the fault tree. When I mentioned spark plug wire routing originally, I really meant to verify that the firing order is correct. Swapping a couple of plug wires was what tripped me up one time. You've double checked that by this time though, I'm sure. You mentioned the truck never has run correctly. To me, that is a key point. Have you checked that the harmonic balancer hasn't started to shift position? That would mess up the spark timing settings and make the engine run poorly (its just another thing to cross off the list). You have pretty well beaten the emission control system fault tree to death it sounds like. Maybe, since you changed the injectors, you can adjust the VAFM a few clicks leaner to put the engine closer to where it needs to be?

maxvp01

What do you mean by making sure the harmonic balancer hasn’t started to change position? If you meant like the rubber separating from it, that part is in tact, I made sure to check that in the rebuild.

Then engine was bored .020 over, this would make me think it was run a little more lean than anything, because of the extra displacement. But even when trying to force a lean condition by pulling off the brake booster hose, the O2 sensor still stays pegged at 0.9V. Adjusting the VAFM sounds like putting a band aid over the problem but I could be wrong. I have 3 VAFMs currently with me so I will adjust one of them to see what will happen.


ALSO I found the page in the FSM where I can test the ECU with the ohmmeter. Probably 1/2 of the tests I conducted were out of spec, not by much but they were still out of the range provided in the FSM. I also opened up the ECU to look for any obvious signs of failure, did not see any corrosion or burn spots.

And the last 3 tests for the ECU test are suppose to be infinity, all 3 of those read about 2.2 kOhms, at no point did they reach infinity. I triple checked.
STJ-E1
FPU-E1
HT-E1

dbittle

Good on you for checking the harmonic balancer; that can be crossed off the list. My thinking is that if the new upgraded injectors flow more than the stock ones, you are outside the range where the ECU can correct the mixture. I think these things are super limited and crude and can be easily flummoxed. Just for fun, crack open the VAFM, mark a dab of paint where it is set now, and see if you can crank it lean until you get the darn thing to at least respond to you.

Co_94_PU

iTrader: (-1)

The rubber letting loose of the pulley is a red herring, yeah it's good to check the #1 cylinder is at or near tdc when the crank indicates 0° buts it's more about power lose than open and closed loop.

The cylinder was bored but what was done with the deck height.. This is tangential to you primary issues..

...
You can't force a lean condition by pulling the brake booster line persay, the TCCS/EFI ECU will compensate for this. It's literally it's job to keep the AFR in range.

You really need a good calibrated meter or oscilloscope to read the OX sensor and VF signal, f you're meter is smoothing this ten samples per second switching your not going to see it swing like it's supposed to.

Adjusting the vafm spring isn't a band aid, your experiencing spring fatigue (out of bounds due to the spring tension has worn out) as well as a worn or dirty circuit board.. The vafm has a redundant resistive ladder which is supposed to prevent dropouts of the VS signal, this is apparent when you look at images of the circuit board or images of it but you can still wind up with a bad connection due to wear.. Pull the cover lift the wiper with a pick and shoot the board with electronic contact cleaner and wipe it with a qtip then run the sweep tests again..

Once it's clean and still out of spec or has no or little dropouts go ahead and ratchet the spring a notch, this should put it in spec and move the wear band to a new spot..

...
You're resistance checks at the ECU maybe confusing you. These checks are done with the ECU unplugged from the engine harness and are done on the harness and not the ECU. They verify engine sensors and the engine to body harness aren't out of spec. All of these are relying on the primary TCCS/EFI ground battery ground don't have loses, if everything or most things are out of spec expect a bad ground.

..
VC/VCC are your 5v reference circuit, you're looking for 4.5-5.5 and ideally 5v +/- 0.05 on these at the tps and vafm
...

Your THW doesn't seem very out of spec, the THW (water temp) should never hit zero volts since it's the sample point of a voltage divider circuit compared to say the ground side of a load circuit like the blower fan or fuel pump (where if you see a voltage potential other than zero indicates a voltage lose it shows a bad ground. )

maxvp01

So I got my old AFM, and was messing around with it all morning. Nothing really changed, I started with 3 clicks clean, no change, so I went to about 7 clicks. At 7 clicks the O2 voltage was jumping to about 1.08V

So thinking I may have gone rich instead of lean, I went the other way. 2 clicks Rich had it over 1V aswell for the O2 signal.

I put my new AFM on (non adjusted) and measured the signal from that, sure enough that’s .998-1.0V aswell.

..
As for the ECM resistance readings, I will redo those as I did not know I was suppose to measure the connectors and not the ECM.

..
As for the rest of the machining, the block deck was left as it, and the heads were both milled down. I am not sure how much he milled them down but I don’t think it was much, the rebuild was not due to a head gasket. I basically just had him mill them down to be safe than sorry.

..
As for what I am using to measure my specs, I am using a fluke 87 multimeter

..
Since the new AFM yesterday truck has only been driven like 7 miles. Do I need to drive it more for the ECM to get a better A/F ratio?

dbittle

Wow. The system is still pegged rich, per the O2 sensor, at 7 clicks lean on the AFM. If you go to that setting, warm it up and drive it around, what are the symptoms you are seeing other than the voltage readings? I'm thinking of things like smoke, excessive smell, poor throttle response, that sort of thing. The one thing you have in your setup that is different from mine is the CS performance fuel injector. Other than that, we have mostly the same setup. My O2 sensor, when I pulled it out during the rebuild, was as black as yours also.

maxvp01

Ill put that afm with it clicked lean in and test drive it more.

Some more symptoms I am having:
When the engine is cold, 2,000 rpms feels and sounds like a redline in 1st and second gear, pretty jerky when cruising down the road too. The loping idle and roughness at idle is still here too.

I also reset all the spark plugs back to FSM Soecs at 0.031”. As expected- all dark black


EDIT:
Test drive it with it 3 clicks lean, I feel more power, and it’s a little more responsive.

Test drive it with 5 clicks lean, a lot harder to drive than the baseline 0 clicks, need to use a lot more gas to get it going

When doing these tests do I need to adjust the ignition timing too?

dbittle

None of these adjustments should affect timing, so it should be ok. Does the idle lope seem like a miss on the same cylinder everytime, or is it different than that? That engine should idle with silky smoothness, cold or hot. When its idling, does it blow clouds of smoke or anything like that? I'm going to re-read your thread again. You've done a lot of work and posted a lot of information already..

maxvp01

It puffs out black smoke from the tailpipe but that’s about it. It idles good when cold, and idles good right up until it’s at operating temp.
Once it hits operating temp is when it will start to idle roughly.

I will make a new list of the new parts I have:
Fuel:
Fuel tank
fuel pump
injectors (cs performance)
fuel supply line
fuel pressure regulator
fuel vent line (hard)
fuel filler neck and vent hose
Injector pigtails
Fuel filter
Last time checked fuel pressure it was up to spec

Ignition:
Plugs
Wires
Rotor
Cap
Ignition coil/igniter from junkyard

Sensors/EFI:
TPS (new beck arnly and used oem toyota)
VAFM (NAPA brand)
ECT (standard or WVM)
IACV cleaned
Denso O2 sensor


Engine:
Timing belt, water pump, tensioner
Accessory belts
EGR and PAIR valve delete
Air filter
No Air in cooling system
Engine bored .020 over
Heads milled slightly
Machine shop adjusted valves
Less than 400 miles on engine

Exhaust:
Hollowed out cat (temporarily)
Muffler is blown out
Afterfire still occurs
Approximately 20+ holes in exhaust pipe


If I remember more parts I will add

EDIT:
Got to thinking, maybe I had gotten the fuel return and fuel vent line switched at the tank, or one has a blockage. I got an air compressor and blew through them. Return line feels free flowing, and vent line feels restricted but I believe that is because of the check valve in the rubber vent line at the tank. I figured when I replace the line I better put the check valve back in that hose because toyota put it in there for a reason. Will crawl under the truck tomorrow and see if the lines are switched at the tank.

I have not checked fuel pressure since before I replaced my injectors about 3 months ago. At the time it was within spec.

Going to also test if the truck is running rich at higher RPMs or just idle. I wired in a 4runner cluster with a tach. Going to hold at 2500 RPM and see what the O2 signal voltage reads.

dbittle

Ok, that is more good information. Does it take about 5 minutes for the engine to warm up enough to start cutting out? And when it does, is it a miss on one cylinder or is it different than that? Have you done a compression check, and how many inches of vacuum is it pulling at idle?

maxvp01

Ok so today i did the 2500RPM O2 signal test. The truck continues to run rich no matter the RPM.

The truck is running at 20 in/hg at idle. (I think the general spec for vehicles is about 17-21)

I went to get a fuel pressure reading but the darn banjo fitting from the kit snapped in half. I’ll have to find somewhere to get a replacement.

For the truck to warm up to operating temp it takes about 7-10 minutes usually. I’m not sure if it’s missing or not when some of these symptoms happens. I will take a video one of these mornings of it.

I have not done a compression check, i’ll have to source a kit from somewhere to do so.

I also hooked up the VAFM directly to the rubber boot that connects to throttle body to bypass that rubber boot that looks like a “y”. The truck continues to run rich and runs about the same.

I also messed with the distributor a little bit, advanced it and retarded it all the way, runs rougher when retarded, so I advanced it more than what it was originally. (was at 12 BTDC).
I do not have access to a timing light at the moment but the engine seems to like the advanced timing and I will leave it like that for a week to see how it performs. No spark knock either.

When looking inside the distributor cap, it looks like there is some fancy stuff going on inside there, a reluctor wheel maybe? Is there technically a Camshaft Position Sensor on this truck but it’s just integrated in the distributor?

Going to fill up the truck in the next couple days, so I will report the fuel mileage when that happens.

dbittle

The 20 inches of vacuum is spot on, so that's a good sign. If you can advance the timing like you did and not get spark knock, the knock sensor assembly is most probably ok as well, which is also good. What I'm after with the vacuum and compression information is to double check there isn't something funky going on with one of the cams or the valve timing (like maybe one of the cams is off a tooth). There was a thread some months ago about someone that had an issue there that caused no end of aggravation until he got it diagnosed. One other thing to do is to start the truck and go to the end of the tailpipe and put your hand lightly over it so the exhaust stream goes into your palm. If there is a miss, you will feel the missing pulse If one of the cams is off a tooth, you should get some more complex pattern of stronger and weaker pulses. What you want is every pulse to be the same, both in timing and strength.

maxvp01

I’ll see if i’m able to borrow a compression tester from one of my buddies, one of them might have a banjo fitting for fuel pressure aswell. I didn’t think of the compression test to check timing, that’s a good idea.

For the checking exhaust with my hand... My exhaust pipe has 20+ holes in it and the muffler is still slightly clamshelled open. I’ll give this a shot and see if it will work with the holes in it.

dbittle

Ought to. The holes will muddy the signal up a bit. If you do the same thing on a car that is running properly, you will see the difference. It really just a way to do a quick check of whether every cylinder is firing evenly. The big thing we're after right now is to verify that the valvetrain is in synch the way it should be and that all of the valves are sealing properly. If it is firing evenly on all six when it is cold and then starts breaking up when it gets warm, it might throw the spotlight back on the emission control system or ECM.

maxvp01

I took a video when I checked my timing belt a few months ago, here is some pictures of the timing marks:






Not ruling this out yet because it’s still possibly it could have jumped since then.

dbittle

That first picture worries me a little, on the left hand cam. The paint mark looks lined up but it’s half a tooth away from the intention in the pulley. Let’s just note it for now. I would say compression test next.

Co_94_PU

iTrader: (-1)

Camera angles are deceptive, the cam pulley mark is on the tooth not the valley which is where the paint mark is..

maxvp01

Today I ohmed out the ECU connectors. Red are the results out of spec, blue are the results in spec. OL=infinity/out of limits.

Sorry for bad lighting.. winter nights are awful to work in..

Possible bad ground somewhere? Since B+ E1 is infinity, does that mean there is a broken wire?

IDL-E2 Throttle valve open: Out of limits
IDL-E2 Throttle valve closed: 0.052
VTA-E2 Throttle valve fully open: 1.52
VTA-E2 Throttle valve fully closed: 0.671
VC-E2 :0.269
THA-E2: 3.663
THW-E2: 0.666
+B-E1: out of limits
Vc-E2: 0.269
Vs-E2 plate closed: 0.249
Vs-E2 plate fully open: 0.087
Ne-E1: out of limits
STJ-E1: 0.003
FPU-E1: out of limits
Ht-E1: out of limits

I was able to borrow a compression tester and a fuel pressure bit. I will be able to get those measurements when I get enough free time to do so.

Co_94_PU

iTrader: (-1)

Looking at the diagrams here, with the harness unplugged, the only thing between B+ +B1 and E2 is the vafm circuit which clearly had two resistors and are never OL.