chevota87

ok it was the A/C VSV so i by passed it just to see if it effects anything.i also checked my fule regulator and vapor canster and they both seemed fine.

ChefYota4x4

iTrader: (5)

The VSV on the rear is connected to your Fuel Pressure Regulator. You CAN bipass that, for now, and it will effect, literally, almost nothing. It's SUPPOSEDLY a "Hot Soak Condition Valve" that switches vacuum off or on according to Hot Soak Starts. Just plug that FPR directly into your plenum for now and plug off the other ones. Think about it before you do it, ..you'll see how to do it. The AC VSV is on the front of the v-cover. It's black, usually, with two ports on the side, facing the pass. fender. If you reverse the hoses on it, backwards, it will make the WEIRDEST sound! hahaha.

There are tests in the FSM for the FPR, ...maybe check the haynes, too. Did you test that one? The Fuel press. reg.? It takes a vacuum 'PUMP'. Same with the EGR and the BVSV.

That idle air screw being out? Yeah, that's strange. But I just thought of something. Take that screw all the way out and look in there with a light, k? Air HAS TO be able to work through lil ports in there. Clean it out well and the screw as well. Also, you might want to consider removing the throttle body and cleaning it up. It's a couple hour job, most. Just wanna get it really clean and clean out all the TINY ports that go to the EGR, etc., from the top(you can see these tiny lil ports right up next to the flap, inside. Open your flap, as well, and see if it's completely covered in carbon?

Report back, see ya soon! lol.

Mark

Doyle

I just recently purchased my four runner. Thought it ran OK slow but OK. Until the other day. I lost the second cylinder. Throttle had NO response and it backfired. Turns out when I bought it it was running smoothe on 3 cylinders. Lose the second and it ran like CRAP. After new exhaust manifold, O2 sensor and checks of a million things totaling $100 I played with the injectors. The retainer clips are gone and my #2 and #4 cylinder were not getting fuel. Pulling spark plugs to these cylinders made NO idle change. Upon pushing electrical plugs back snug and twisting #4 injector back up straight my truck throws me into the back of the seat and is quick as hell. I gotta find clips to hold them down. Havent had any more problems with it but carry a long skinny screw driver with me just in case. (untill I find the $$$ to fix clips). Like you I know all about carbs (15 years ago I owed an '85 Toyota 4X4 pick-up for 10years)
GOOD LUCK TO YOU.

chevota87

ok ima pull my intake this coming week to check injectors and clean carbon we have had nasty weather this weekend.but..i have noticed it seems to run cold? the heater vent are blowin some what luke warm air and the temp gauge is just a hair above cold at all times.im wondering if it is staying in warm up mode all the time?burning more fule?this weekend i did put a 195 thermostat in it hoping the old one may be bad but it is still the same thing?what yall think?

ChefYota4x4

iTrader: (5)

Hey Chev...

The heater vents blowing 'warm', well, that COULD be because your coolant is not coming up to temp. You need to get a thermometer in there to know exactly what the temp is, yeah? I had a very WEIRD temp gauge, so I swapped out that and the Oil press. gauge in my SR5 cluster, ...it fixed it FOR THE MOST PART, ..but since I took it from another "OLD TRUCK", it's got it's own issues. Needless to say, it's "CLOSER" to accurate than my orig.

I used to rap on the plastic cover, and the needle would jump up. Anyway, your most accurate way is to put a thermometer in there.(Honestly, I lived in Spokane, WA, VERY COLD, lots of snow, and still my truck would warm up fully within minutes. So yeah, something is not right, IMO)

Far as staying in 'open loop', the initial pre-set conditions... I thought it started going into closed loop at around 96*F? I'll have to refresh on that, as well. I know the Coolant Temp Sensor, TPS, AFM and 02 can all have lots of effect on performance/mileage. Injectors being clogged really can as well, ...but just FYI, not that it's related directly, just sharing, lol>>>; I'm getting 15.5MPG in the city, ....and my injectors were all serviced by RC Engineering, one of the best around, and all given an "Excellent Flow Pattern" rating, with no leaks, etc. They look and work like NEW, Chev, ....yet still the bad mileage.

chevota87

well i have ohmed out my TPS AMF and put in a new o2..ima try that intake this coming week and hope 4 the best .thanks alot for all the help i will deff keep you posted.

chevota87

ok latest update.i pulled the intake and injectors and sent the injectors to my buddys work to be tested and they were shot.i have new ones on the way.hoping for the best.if this dont work i got a carb set up that im going to put on it lol

ChefYota4x4

iTrader: (5)

Wow, as strange as it is to say, "THAT'S GREAT NEWS they were shot!" ....You know what I mean, right? lol.... It beats chasing your tail for another month, eh? I know, time and application will tell...but you'll be surprised what a difference having injectors that ACTUALLY WORK will make, eh? haha.

Right on, can't wait to see your results, man!

Mark

chevota87

finally ran the first tank through. im avg 19 mpg.im happy with that.the prefomance is still the same but im just happy the mpg is better.just wondering .if i put a vacume gauge to it at idle whats a standard reading?

ChefYota4x4

iTrader: (5)

I think it's 14-16"...but I'd have to look again to refresh on that one.

chevota87

thank you very much for the help chef!my vacume is a 20 at idle when i checked it but i reved it real hard one time cause the truck was already warm and noticed the fan flexing out?whats weird about this is it free spins when its not running?i checked my 2wd 88 pickup and it kicked out like it was supposed to when it was cold?too weird but im thinkin new fan? maby electric?would make since to power loss but is very strange that it free spins when not running?im also going to install a permanent vacume gauge because with the EFI it wouldnt hurt to know what u got.

ChefYota4x4

iTrader: (5)

Well, vacuum varies. It can go from 14" at idle to 22" at ALMOST WOThrottle and then when you are fully open, it will drop off the map, as the adequate combustion takes over(sorry, brain is on overload, I might have misquoted how that works, lol)... But I DO KNOW that it varies as to where you're at on the throttle/idle/wide open, etc.

Fan thing? Wow, .....hmmm, a clutch fan is just running on and on with if off(KEY OUT AND ON THE DESK OFF?) It does stop eventually, right? I guess that would most likely be the clutch in there. There are many threads on rebuilding those/repairing them.

Not sure on the Electric fan part... I've look into that a lil but not made up my mind just yet. One thing at a time and I still have a few kinks to work out, ya know? I think Taurus and Mercury Minivan fans are used a lot. Pretty sure 4Crawler, Wabfab and marlincrawler explain all that in tutorials.. should be good to go from those guys if you go that route. Plus, all that's on this site, ya know?

chevota87

put a new clutch in the fan today after work and mann what a diff! it seems to be running great and has more power.cant wait to find out the mileage now.hopin 4 the best.but the new injectors did give me another 5mpg bringin me to 19 from 14 .hoping maby this thread can help ppl just a heads up if you use a steathascope to test your injectors it is not acurate and mine were not leaking .

Toadyota

I really enjoyed reading this write-up, I've had these same issues with mine and of course having 409,000 means that many of my sensors and valves probably need to be changed but it was good to read through this and see that it could also be my injectors which I have suspected along with the AFM and the engine taking a long time to warm up. Currently the motor is blown but when I get the new/rebuilt one put in I'll refer back to this to check out problems.
Thanks!

chevota87

the ol 86 is getting 21 mpg now and she gets atleast 100 miles put on it everyday

ChefYota4x4

iTrader: (5)

Great news man, Congratz!

Nuckinfut

Just got done reading this entire thread and enjoyed it. I am getting not so great fuel mileage myself and now I have some great places to start ( I think my injectors are shot as well )

ehlertbp

This forum talked about rebuilding the fuel injectors. I sent mine in for a rebuild hoping they would come back in better condition, but it turns out they were performing just fine before I sent them in. I guess I now know they're in prefect condition after the rebuild. I went through Witchhunter, and their service was great.

http://www.witchhunter.com/