qdude79

Oh boy...

Went to do the time honored Toyota tradition of replacing my front lower valence today...

Ran it while tightening the screws to warm it up to check the kick in temp of my new electric fan, after having replaced the bearing on my idle tensioner.

Guess what? The draw down from the fan is what's causing the stumble. It was added just before sending it to the muffler shop. It was set too low and after just a few seconds at a stop it would kick on. I adjusted it up so it wouldn't kick on so soon (with plenty of temp gauge left before half way) = stumble gone.

Questions:

1) Should a single 16" fan cause enough draw down from idle to sometimes kill the engine? I see no light dimming, though I did upgrade the Big Three.

2) Should I still be looking at the AFM to maximize the mods I've added? Still feels "anemic."

myyota

Its possible, electric fans can draw alot of power when there on, you might consider upgrading to a larger alternator.

abecedarian

and now it's known:
an electric fan gives you more power ... when it's not running ... and puts more of a load on the engine when it is running...
... than the mechanical fan does at any time.
in the end... 0 + 3 = 1 + 2.

abecedarian

considered replacing the elec fan with the stock fan / clutch / shrowd and comparing?

qdude79

Nope. Sticking with electric. Freeway and winter driving will be "drag free." Consider that the 16"er I put on pulls enough to move the aux fan in front of the radiator at a stand still.

TOYOTA 1

hmm, in my rig its blatantly obvious when the manual fan engages."i can feel power loss" but Ive never noticed a power loss when my stereo and headlights are on. until that massive fan kicks on of coarse.

qdude79

Back to the question.

Went with the Street RV/268 setup with upgraded exhaust (see above). Throwing out the stumble aforementioned, SHOULD I MESS WITH THE AFM???

abecedarian

kinda funny. my rad fan on clutch only lets itself known when I'm running warm by the howl it makes.

abecedarian

4Crawler and myself gave you some things to consider.

you can't just throw out a stumble at idle. the entire air/fuel induction system is interrelated.

qdude79

Why can't I throw it out? I'm satisfied that it's the draw down from the fan, not air/fuel system related. Aside from the now resolved/solved stumble problem, would richening the AFM help optimize the mods added?

TOYOTA 1

well lucky you.. mine feels like i just turned my ac on lol. it makes a good howl to.

muddpigg

iTrader: (1)

I would and have, still need to reseal my AFM. Mark the it before you adjust anything, so if you don't like it you can set it back. Don't use something that will rub off, I notched it with a knife. All your doing is tricking the computer into thinking more air has entered thus riching the mixture. With a carb you'd adjust the mixture with a screw. Don't forget to pull the EFI fuse to reset computer so it collects a new set of value for ratios. You'll tell a difference.

As for the step down/stumble d/t electric fan you could have a clogged VSV, but mine stepped down when the fan came on, though wouldn't call it a stumble. You may want to think about putting in a manual always on switch and an off switch so if and when the thermo switch fails you have a back up, and also when wheeling or at slow speeds your power steering will thank you. Also you can try setting you Idle up some too these little 60amp alt. take a hit from the start up load of an electric fan. My electric fan grenaded but that's another story.

qdude79

Will regular old silicone be sufficient to seal up the AFM?

saitotiktmdog

I did a similar rebuild on the first rebuild in my truck. 22re, I believe the same cam you have, new head with oversized valves. Northwest Offraod tri y header and venom injectors. Adjusted AFM. I noticed the same stumble at low rpms. Mine however was fairly consistant. Every 20 seconds or so it would kind of stumble. I never really put much effort into tracking it down because the truck always ran great. If I had to guess I would say it has something to do with the cam maybe. I adjusted the idle up because otherwise it would sort of lope. Anyways thats just my experience anyways.

qdude79

Was there any noticeable difference, good or bad, with your AFM adjustment?

saitotiktmdog

with regards to the stumble no. ran better though. Gas mileage went down some too though.

qdude79

Minor epiphany: "Hey, why don't I ask Engnbldr, since they're HIS parts??"

So I did.

His reply:
Hi!
The system should be able to easily compensate for the added airflow, the
best we can seem to get to is about 85% of the injector capability. Very
rarely is any adjustment needed except for cases when almost constant full
throttle operation is desired like offroad racing, things like that. A few
have tried but we normally find they are looking for a cure to problems like
the EGR opening early, etc.
Thanks again,
Ted

abecedarian

If you decide to do the mod, I would only use a sensor safe sealant, one that does not use an acetic cure (smells kinda like vinegar as it cures) process.

qdude79

More discoveries. The guy that wired in my electric fan ran it all the way back to the fuse panel inside. It occurred to me that this is a lot of wire, and a lot to draw from the fuse block. aka: lots of wasted draw down.

To test my theory, I temporarily routed the power line straight to the battery.

Problem solved!

Now when the fan kicks on, it's BARELY noticeable. Like the stock one on my Accord. You feel a slight drop in rpms, that's it! It must've been KILLIN' the accessory fuse block...

Moral of the story: direct is better for the higher powered electric accessories. Errrrr... I take that back. Most all of us would know that. True moral: check the work of others that may not realize this.

abecedarian

true moral- do the research and ascertain the best way to do the work, then do the work yourself