car idle problems

[Krimzen]

Now I am just trying to fix the bugs. I just rebuilt a 4agze motor with some mods: (HKS 264-8.1 cams, hks valve springs, underdrive pulley kit, aluminum flywheel, venom 10% more fuel pump and injectors, adjustable fuel pressure regulator). I am pushing about 45 psi fuel pressure.

The car starts up without a problem but I cant get it to stop idling rough. It fast idles at 2000, then jumps repeatedly from 2000 to 2500. It sounds like I could have an air bubble in my coolant system but b4 I jump to that I was wondering if anything else could cause that.

My ECU is throwing the "51" diagnostic code which points to the AC system (I removed mine), idle switch, and the Throttle position sensor. My other mod is an RX7 throttle body (bigger), I had to do some mods to get the piping right. It has the adjuster screw on the AFM. Maybe my problem lies there.

Thank you.

Jerry.

[ToyotaTechGeek]

hmmmm, there are a plethora of 'possible' problems with some of the mods you've listed. i think that perhaps air metering might be a problem, but i also think there may be some conflicts with re-adjustment and checking the coolant bleed that would beg for attention before going any further. does that make any sense? i'm tired from sitting up and arguing on the 'other' board only to get censored after owning a moderator.

[Enthalpy]

i'm tired from sitting up and arguing on the 'other' board only to get censored after owning a moderator.

One of the reasons I love this board is they don't let certain notorious flamers from the *other board* go free with their comments on here. It doesn't matter if you are a corporate sponsor, they call certain members on their flaming.

Anyway, this issue could be so many things! Your TPS might not be compatible from the new TB. Your coolant might need burping (remember, it's a different procedure from most cars!). Your throttle stop might not be adjusted correctly. You are running large cams with the stock ECU, which rarely works perfectly. You have the wrong injectors and no additional fuel control.

I'm not exactly sure why you posted here, you already have a laundry list of things to fix. Go fix them and report back if you are truly stumped.

[ToyotaTechGeek]

Originally Posted by Krimzen

<venom 10% more fuel pump and injectors> <I am pushing about 45 psi fuel pressure.>
<Throttle position sensor> <RX7 throttle body (bigger)>,

those are the specific things i would check. idle fuel pressure is like 30-38psi at idle if memory serves me right.

[ToyotaTechGeek]

Originally Posted by Enthalpy

One of the reasons I love this board is they don't let certain notorious flamers from the *other board* go free with their comments on here. It doesn't matter if you are a corporate sponsor, they call certain members on their flaming.

it's just interesting to see the 'agenda' work in-favor of the 'party' versus the proletariat and bugeoise.

[Enthalpy]

Certain loud mouths that irritate the vast majority of folks I talk to are allowed to continue unfettered by both their employer and the admins. It defies logic.

Sorry for the tangent.

[ToyotaTechGeek]

interesting. sorry to thread jack!

[Krimzen]

Cool, I definately want to make it all work. Running 40 to 45 psi shouldnt be a problem. I also dont see why running 10 % boost injectors and pump sold specifically for the car will be a problem as well. Ive heard from many other people that the stock ecu should not have a problem with the set up I am running. I am gonna go for the TPS adjustment. I was just hoping that someone else had experience down the road that I am taking.

I appreciate it.

Jerry

[ToyotaTechGeek]

most people i know who had anything to do with anything venom ended-up taking any/all venom products out of the car.

[Krimzen]

Hey tech man. Perhaps you have been down the same road as I. Why is it that they took these Venom parts off? I understand I am not modifiying my block enough to really need those parts but i just wanted a little more fuel for the extra boost and cams, is that so wrong? Bottom line, I would love to have as much power as I can squeeze out of the 4agze without spending too much cash (standalone), and without modifying the engine to much (stroking). Everything I have on it are somewhat bolt-ons but I figure that all the little bit helps. I still think that my TPS is conflicting with the RX7 AFM mod that I put on. Bigger throat, way bigger. Have you ever heard of anyone doing that on an mk1?

I appreciate the help guys.

Jerry.

[ToyotaTechGeek]

i read this. i will be back after i get my haircut!

[Krimzen]

Also, I wonder since I removed the AC, do I have to plug the connector to fool the ECU?

[ToyotaTechGeek]

ok, first:
the venom thing, module, whatever...
there is no manipulation of their little black box. it's either on or off, so the fuel map or curve or whatever they 'do' is generic. it isn't specific to whatever supporting mods you have. the injectors are also probably overkill for the car because the car already tends to be rich until you start doing 'major' things like going to the HUGE pulleys, etc. even with the huge pulley, you still have to get the afr's right or you'll end-up with melted parts and such. again the venom is useless. sheesh, i think that going to an S-AFC is better than the venom thing.
i have heard of using the afm from an RX, but mostly drag racers in puerto rico and such. yes, they make them work, but creature comforts like good idle is lost along with the usual Toyota reliability with many of those guys. no offense to them, 'cause they can make some cars RUN!

what kind of motorsports do you participate in? or, what kind of build-up are we talking about here?

[Krimzen]

Hey man, I appreciate the help. Well, I am basically your average grease monkey that has a dream. I know cars very well but struggle in all the details of the EFI and electronic systems. My father, who taoght me auto mech. was more of an old school mechanic. Unfortunately I bought a boat load of parts with a heavy wallet from a tax return. I would like to race the car, but I am not sure if my dreams of at least 180 to the wheels will be fullfilled. That is why I started buying up all the parts I could find without doing sufficient research (cyberspace automotive) . I would love to make it all work if I can, but hey, If i have to put the old AFM and FPR back on then so be it. I will have to start with the TPS, then the AC ciruit, and of couse the air bubbles in the coolant. If all that does not work then I guess Ill put my tail inbetween my legs and start bolting back on some of the stock components, however, if I get it right, I still have hope that the mister two will scream more than it ever has.

Hey, I did not check your profile yet, are you in the ATL?

Thank for all the help.
Jerry.

[ToyotaTechGeek]

nope (atl) but have a really good froend who lives in cartersville.

your pops is ok, i'm sure. it takes old school know-how to pair-up with the modern stuff to make things right in my opinion. i am old school Toyota through-and-through, but love the more 'modern' stuff as well. no offense, but you sound like most young guys who are into motorsports who find some money in their pockets (which is proverbially burning holes in said pocket) and has 'dreams' of owning a 'fast' car. you're young, you will learn.

if i were you, the coolant is where i would start (as mentioned above) because you could be looking at headgasket failure if you merely have a coolant bleed problem and persist in running the car without addressing that problem first. you have to know that 180 to the wheels with what you have listed is probably NOT going to be possible, right? it's going to take much more than a few hokus-pokus pop-bang gadgets than those you have listed! you stayed away from real engine management, yet opted for bigger fuel pump/injectors/fpr. that is surprising. you have NO way to make any of that stuff work for you. i mean, yes, you can richen the he77 out of everything, but no way to really adjust the fuel curve. the other thing is that i wonder what consisted of your engine rebuild? the head could have been 'massaged' a little bit before re-assembly for a little bit of gain. did you balance your rotating assembly? how about balancing with your lighter flywheel? that's where i would have spent money rather than the venom stuff. sorry! what have you done exhaust-wise? freeing up your exhaust will help. not too much, though. so, don't spend boatloads of money on that. money well-spent would go towards things like good couplers and intercooling. go with some good NGK bcpr7es-11 (or stocking #1095) for spark plugs. get good wires. clean everything. get good trans lube. back to coolant: you DID use Toyota RED coolant, right??? you should. also use distilled water and feel free to add RedLine WaterWetter. a good K&N drop-in filter replacement should be adequate.

anyway~
what type of racing are you considering? you KNOW drifting an AW11 is more than difficult (sustaining a drift in a short wheelbase MR is NOT easy) and dragracing isn't the MkI's forte either! both can be done, but sometimes you'll find that cost vs. result is a crazy thing.
good luck!

[Krimzen]

None taken, I know I have alot of learning to do. Mainly I know more now than I did when I purchased the parts. Luckily I do have experience in the rebuilding dept. The Engine was press. checked, and bored out. The rings and bearing are OEM along with a new set of OEM piston heads. The Crank and all of the attachments (rods, allum. flywheel and centerforce clutch and press. plate., allum crank pully) were checked and balanced. The tranny was completely rebuilt and filled with Mobile one, the Supercharger has some nice expensive oil in it, The head has been milled, lapped, re-valved with hks valve springs and hks cams, all checked at the shop as well (oil clearances are perfect), My compression is 119 all the way accross the board, and the car is not overheating in the slightest. The oil pump is brand new along with the starter, alternator, waterpump, slave cyllinder, master etc....... New NGK plugs, Magnecor wires, ACCELL super coil, new ignitor.

Basically, I have crossed my T's and dotted my I's in that dept. Its been about 2 years so far since I took the engine out to rebuilt. Not to mention about 4000 dollars of money spent total on parts and shop work.

Everything is like brand new, checked, and verified. Now I just have to get some of the bugs out. I know its nothing big, just some bugs.

Ps, I think my turbo Mk2 will be faster with not even half of that money. ..lol...

I know I am trying the bolt on performance, but Everyone goes down that road perhaps. Ive rebuilt MR2's before, This one is my fifth one, but this is the first time that I have gone aftermarket with attempts at HP gain. Ive never had these issues b4...lol... I know that I have some learning to do but believe me, I am not one of those punk teenagers with a pocket full of daddys cash, I have worked hard on my own, with my own money and blood and sweat for years to get this car where it is at right now. You know the story....

Either way, I appreciate all the help. Im sure I will many more questions down the road and I could use the help of someone with your expertise. Please, though, dont compare me with one of those punk kids bc it seems I get that vibe when I post on this site. Ive been driving these cars for seven years now and will continue to probably for the rest of my life. Luckily I live right next to MR. Nocturnal mr2expert here in GA.

Thank you for your time.

True to the Two
Jerry.

[Krimzen]

Oh yeah, I would love to own the GTS for the drifting. I will most likely just take my cars to the track for fun, I dont have enough experience yet in race driving to get down and dirty with it, nor do I have the cars yet (working on it). Down the road maybe.

If you aint too far, you should do a NC Dragons run with the club.

[ToyotaTechGeek]

cool! i don't compare, just taking a stab. it's good that you have your focus. i didn't think you had daddy's money. if you have questions, just ask! good luck!

[Krimzen]

Its cool. I appreciate all the help.

Ill talk to you later

Jerry.

[ToyotaTechGeek]

good to help a fellow enthusiast!