Gevo

I love my $13 analog meter!

RSR

Thanks Gevo -- more work than we expected but super awesome. Everyone's healthy, so we're blessed. Pretty much one or the other of us is sleeping, working, or tending to the baby so a little hard for 2 person tasks right now... Baby's grandma is visiting from out of town this weekend so an extra set of hands will be helpful.
The recent Sequoia addition in signature was specifically for a baby hauler, and we looked at landcruisers as well, but a LC or Lexus LX w/ similar mileage, safety features, but a less comfortable ride and more compact cabin were about 2x the price here locally... And the mrs preferred the sequoia and she'll be primarily driving it -- sure beats a GM vehicle. Pleasantly surprised w/ it all things considered.

To my pickup:
5 seconds at most guesstimate on running w/ VAFM. Probably at least 3 seconds of a run. Didn't have a timer out or really counting.

Yes, engine off VAFM check only just at the connector and didn't disassemble airbox to test when moving the flap, basically just the part in the first photo RP posted. Didn't do the running VAFM check; though did printout the FSM afm diagnostic pages w/ that info on it.

The FP connector in particular I read as related to fuel. Based on smelling fuel at the tailpipe when not starting, I am getting fuel w/o jumping the connector as well as when, but will still check. While it's possible, it's a FI issue or pressure issue, it doesn't seem to be the case. I bought a can of starting fluid to try as well but didn't have a need yesterday evening as it started before working through to that. Nevertheless will re-confirm FP connector w/ test light.

To confirm, VAFM issue can cause both spark and gas issues, or could cause just one or the other?

Any concern w/ the coil primary resistance being nearly double FSM spec?

Hadn't made any changes and everything was running good before the no start. No indication of compression issues, oil in water or water in oil, etc.

RSR

*Preceding was a draft that had saved earlier today....

This evening my progress was as follows:
-Tried to start by turning key. No start after a few tries.

-Popped the hood and connected test light to FP terminal in diagnostic connector -- it lights up when I turn the ignition key to crank the engine. Engine still wasn't starting.

-Next tested the moving flap portion of the VAFM test, page EG2-234 of the 1993 FSM many others reference here...
--E1-FC measured at 1 (infinity) when plate is full closed; spec is infinity
--E1-FC measured at 0.05 ohms (200 ohm setting on mm) when plate was other than closed position; spec is zero.
--E2-VS measured at 298 and 305 ohms in two tests (2,000 ohm setting on mm) when plate was fully closed; spec is 200-600
--E2-VS measured at 49.8 (200 ohm setting on mm) when plate was fully open; spec is 20-1,200 ohms
--Below this last measurement E2-VS, the FSM reads "HINT: Resistance between terminals E2 and VS will change in a wave pattern as the measuring plate slowly opens. If not within spec, replace the VAFM." Testing the wave function, I got readings from 50-600 ohms (2,000 ohm setting on mm) with probably 4 or so wave peaks (didn't think to count those at the time) when moving the plate. I'm uncertain if not seeing any #s close to 1,200 is to be of concern.

-I then decided to check starting w/ same process I did last night. After putting the VAFM box and intake back together, I tried starting w/ the VAFM sensor disconnected. No start. Tried again. Again no start.
-I tried plugging the VAFM sensor back in and trying to start again no start.

-I then thought I'd try starting fluid to see if that did anything, so undid the intake at the throttle. Opening the intake tube there, I found some fuel in the throttle/intake body there (where parked leaned slightly to drivers side) so presumably the cold start injector is working. My intake has a little bronzing worth of crud but still very clean after the Amsoil intake treatment detailed in another thread. The gasoline made cleaning the oil, carbon, gum, etc, crud off the throttle plate easy, so I went ahead w/ wiping that down while open.

-In light of my pointless "shortcut" the other day, I figured what the heck and tried to start w/ the intake tube off the throttle. Low and behold, the truck started. Tried again, it started. But both times it promptly died. A second or two to chocking and another second or two until engine came to a stop. I put the intake tube back on and tried restarting again. This time the truck started. While running I worked on tightening the intake tube clamp at the throttle. Not sure if related, but it almost once died while I was doing this.

-Again tested turning off and restarting once truck was brought to operating temp. Started right up. Waited about 30 minutes and went out and started it again.
-Took it on a gas run since down to about 1/8 tank. Filled up and a little slow starting after getting gas but only one turn of the key. Drove it for 30 minutes or so including idling through a fast food drive-through, and no issues w/ truck running while hot, power, acceleration, etc.

I'm thoroughly stumped at this point. The issue only seems to be a "Cold Start Startup" issue at this point. Importantly, the truck is not firing in the sense of combustion when I try to start it when cold -- so I don't think it's possible that it could be a belt, etc, issue. I replaced the starter solenoid including contacts in late 2015, battery was replaced a week or two before the starter, and everything sounds good when running. I get a slight squeak from somewhere (think probably PS pump pulley), but if anything was seized in that regard, I shouldn't be able to start at all...
I'm still leaning the spark route, but need a 2nd set of hands to turn the key to better examine that.

If anyone has more thoughts, they'd be greatly appreciated.

Gevo

Don't I know it man. My son is now 9 months old. My wife and I been doing it ourselves, both of us work. Sleep has been difficult to get



Yes a faulty VAFM can disable the fuel pump and I am pretty sure the spark as well.

I can't say about the coil, but it isn't causing a no fuel condition. I'm 90% sure about that too. It's been a while sinc ei had to worry about these things!

RSR

Well, big congrats to you all as well! Sad to hear that sleep remains hard to come by, haha. 3 weeks old as of today is definitely much easier than 1 or 2... Our son is finally sleeping without being held.

Back to the issue at hand -- 4crawler has a great VAFM writeup here: http://www.4crawler.com/4x4/CheapTricks/AFM/index.shtml

Best as I can tell, the VAFM only affects fuel, which makes sense from a fuel-air mix perspective.

Importantly on startup, it should be open loop and not looking at O2 sensor... So can probably rule that out, maybe unless it's not in open loop for some reason I suppose. But on WOT would be open loop too, but no issues once warm there either. O2 sensor was replaced in 2011 or 2012, whenever I did the amsoil intake cleaning and probably has 20k miles on it, so that might be worth looking at..

rustypigeon

That was one of tests that you needed to do. The other one is to check FC-E1 continuity when the engine is cranking or you open the flap with your finger. I didn't read your post thoroughly because I am off to work and don't have much time to respond so if you did this, I missed it. The only test you need to do right now with the VAF is the FC-E1 continuity with engine cranking. I posted the VAF tests so you could identify the pins, you don't have to keep checking those other VAF pin resistance specs.

RSR

Yes, tested the E1-FC continuity. Didn't get a straight zero, but pretty close at 0.05 @ 200 ohm mm setting -- not certain if that's an issue or not...

rustypigeon

If I am reading this correctly, it starts when you add starting fluid to the intake. This would confirm a fuel delivery issue.

Try using the starting fluid again. Squirt the fluid into the intake through the brake booster vacuum port on the intake plenum or into the throttle body itself. Just make sure to reconnect the hose before you try to start. If the engine starts again using this method, I would check the Cold Start Injector Time Switch and the Cold Start Injector.

Cold Start Injector Time Switch diagnostic...
http://htftp.offroadsz.com/marinhake...-E/97colds.pdf

Cold Start Injector diagnostic...
http://htftp.offroadsz.com/marinhake...88coldstar.pdf

RSR

Running through my truck over the weekend and today, I found that the fuel pulsation dampener is leaking. I noticed a bit of fuel smell after one of my recent bringing to operating temp runs (near charcoal canister so thought that might be leaking and didn't think much of it at the time)
To find the dampener leak, go to the rear bypass hose at back of engine, and put hand between engine and bypass hose from passenger side. The far side of that hose is where the V ends between the two engine banks and there should be fuel there if leaking... Touch and sniff was my methodology after letting the truck run for 15 minutes or so. Be careful w/ hot coolant piping and exhaust crossover in the vicinity however.

So good news here is that I found the most likely culprit. The bad news is I really shouldn't drive my truck before fixing. Further bad news is that the Toyota Dampener is expensive and I'm going to go ahead replace the Regulator too while I'm in there since both have rubber components that don't like modern ethanol gas... But the good news is I now have an excuse to spend the time to fix leaking valve cover gaskets and install flamethrower injectors -- but bad news on the injectors is that w/ the leak my most recent mpg #s won't be too reliable for comparison...

One question though for the resident braintrust -- when removing spark plug wires when running to check for possible dead cylinder (found none), the wire 1 at the distributor cap shocked me despite wearing nitrile gloves before even detaching the wire. Ground was damp from recent rain, but still was literally and figuratively a shock. No other wire did so... I tested with a wire lead attached to a ground for spark and #1 repeated that behavior as well (without shocking me this time), while none of the other plugs caused the issue. I pulled the distributor cap and saw nothing weird...
So is this common, should this occur, etc? I want to say I replaced spark plug wires in summer of 2014 w/ blue NGKs that have less than 30 miles on them. Distributor and cap is maybe a year older w/ no more than 10k mile difference between the two... I suppose now thinking I could or should test resistance in the # wire vs FSM specs to see if that might be the reason for the jump.

Linkback to the yota thread that pointed me in the right direction: https://www.yotatech.com/forums/f116...mpener-188341/

speeddream

My 1990 3vz 4Runner would have similar symptoms. It was annoying as hell!! It would fire up on cold but once it got to normal operating temp and I would drive it it wouldn't stall. But if if I shut it off to go into a store or whatever it would crank but wouldn't turn on sometimes. I ended up changing a green Temperature sensor behind the manifold and that issue completely went away. If all checks out ok with yours, look into that area.

scope103

"Damper." It doesn't dampen anything (at least it isn't supposed to). https://www.yotatech.com/forums/f116...octite-266710/

About $112 at the dealer, about $85 aftermarket at RockAuto.

Replacing the Fuel Pressure Regulator at the same time isn't strictly necessary, but it is probably a very good idea. You DO need to remove the plenum to get it off, but you'll have that off anyway to get to the Fuel Pulsation Damper.

Co_94_PU

iTrader: (-1)

Panties bunching up on ya? let me help you with those Does this make them "more damp, or damper?"


I giggle every time I see that some one says it knowing what's coming. Much love from the Rockies..

RSR

Picked it up for $108 from amazon (third party fulfilled by amazon so no tax).
Also picked up the FPR for $111 plus tax from amazon as well: Kyosan is a DENSO company, so I'm guessing it'll be marked like factory. If not, I'll return it and pay $140 for the part from Toyota...

Question -- does the entire fuel rail need disassembled per FSM to install injectors or does it come off on one piece w/ just the inlet union bolt needing removed? Trying to figure out what all I need in the way of gaskets, etc.

I need to inspect the #1 wire and distributor more closely in the daylight still... Don't need another quite literally shocking experience.

Gevo

If you are replacing the injectors, you will have to take out both fuel rails. The FSM will probably say you need some new crush washers to put the fuel rails back on.. but I flip them 180 degrees and reuse them and have yet to have a problem. At some point I was doing an injector job on my car once a month, once you get used to it it is pretty quick. Unless you need to for other items, you don't have to completely remove the plenum. You can unbolt everything from the top, unhook everything from the drivers side and just use something to prop it up while it hinges on all of the hoses on the passenger side. And, you wont screw up which hose goes where.

scope103

The crush washers are only available from the dealer (so far as I know), but they are cheaper than dirt. Some report "I reused them and have had no trouble so far," but once you HAVE trouble, you have an uncontrollable fuel-fed fire. I recommend getting two more of each size you need; otherwise, one of them will get the idea of jumping out of your hand into the grass. (Plus you'll have one chance to do one wrong, then replace it.)

The studs that hold the rails are angled in slightly, and so are the injectors themselves, so I'm pretty sure there is no way to lift the rails out without disconnecting from the lines.

Prepare to evaluate the electrical connectors to the injectors; for most of us, time (and heat) has made the plastic very brittle. Often, the clip that locks the connector together breaks off. I got by for many years with zip-ties holding the connectors together, but I eventually replaced each connector. (You can get the connector with pigtails, but I disassembled the connectors from the bodies, clipped off the metal, and re-crimped new pins for the new bodies.)

Gevo has success with the "flip over the plenum" method, but I don't. If you have the ~20mm hose to the PAIR, I don't see how you could bend that enough to lift the plenum. Once you disconnect that hose, you're 90% done anyway, so just remove the plenum and park it someplace safe. Of course, you need to take some notes about what hose goes where, but you should do that even with the flip method --- what if something comes loose?

Gevo

Saves a bit of time. Works just fine. Doesn't hurt anything (pic is my car)

RSR

Received the fuel pressure regulator today. The markings on the Kyosan FPR is DENSO and the balance of the part numbers match the FPR on my truck exactly. Saved ~$30 (before accounting for sales tax) over cheapest online dealer price I could find, and about $90 vs my local dealer. Small victories!

Will follow up on balance of responses later this evening. Thanks all.

RSR

Pretty sure mine was free or at least sub $5 w/ harbor freight coupons...

RSR

Re: fuel rail washers -- yes, I am replacing. I found someone that removed the studs to lift out, but it looked to me like there could be a point or two where disassembly would allow it to be removed in one piece -- but now knowing that angled it makes sense why you can't do that... Regardless, can disassemble and reassemble per FSM.
Scope -- thanks for the recommendation on spares. I am taking you up on that for sure. I always seem to lose small parts; worst case it saves the time to pick up dropped items at the end of project rather than in the middle... And yes, I will be taping up intake holes to ensure nothing drops in there!

Gevo -- I remember your injector woes, but don't recall specifics. I'm have a set of the flamethrower orange or yellow (forget exact color) that are supposed to flow w/in a percentage or two more than originals, so hopefully I'll avoid the repeat challenges you had -- IIRC some dead injectors and issues w/ the flow of the 10-15% more flow ones...
I am planning to uninstall the big stuff on the plenum and then flip w/ all the small hoses onto the passenger side fender. There's a writeup on here somewhere for that I recall seeing once. Worst case I can tape and number each hose/connector ensure it all goes back together properly...

Scope -- re connectors, found your writeup here: https://www.yotatech.com/forums/f116...ectors-290886/
And another good one here: https://www.yotatech.com/forums/f128...s-3vze-218912/
I thought I had a question or two but can't recall at the moment...

RSR

So I had some more time to tinker on the truck this weekend. Jumped the B+ and FP connector for about 30 minutes to see if that would allow it to start right up like it did time before this one. No dice. Tried starter fluid. Again no start or firing, just cranking. Oil pressure went up so sure the engine is cranking strong as well...

I hooked a lead wire onto the coil to distributor wire and ran to ground that I could reach while cranking engine. Definitely no spark. (Same wire I used for testing jolts at distributor wire plugs earlier in the thread so know it works for task at hand...).

Which makes some sense in that leaking pressure damper shouldn't alone cause a no start issue...

I also looked at distributor and confirmed rotor is moving when cranking. Tested resistance on a couple spark plug wires and those are all well within spec. So b/c coil primary resistance was about double spec, I went ahead and ordered a $15 richporter coil (spectra premium branded nowadays; went w/ richporter distributor replacement awhile back and it works well vs folks issues w/ OE remans and sensors not testing to spec) to test and see if that solves... I will probably upgrade to Toyota eventually. If that doesn't work then igniter, ECM, and wiring are next I suppose...