Zealot

So I have a 92 Yota pickup with a modified 22re and the Idle is acting up.

Modifications:

block shaved alot, pistons slightly above block.

head ported and polished, oversized valves.

dual pattern lobe 260 duration 420 lift camshaft

lc adj. cam gear

pacesetter 4 into 1 header

MAF enriched 4 clicks.


So it idles around 1500 rpms, with the idle screw all the way down. When I put my foot on the brake it lopes from normal back to 1500. Heres a kicker, when I put it in 4wd it does not lope at all, it stays at the constant high idle.
I have been trying to figure it out for 3 months now and nobody has a clue.

Robrt32

If you figure out why your idle is so high and get it down to where it should be, I bet the loping when you mash the brake will stop.. Atleast it did on mine..

notanymore

i dont know alot about this but with your maf enriched 4 clicks could that affect your idle? someone correct me if im wrong because im not really sure

stormin94

Vacuum Leak. Thats what I have to say about the High Idle, or throttle positioning sensor is bad, or has a bad connection.

Zealot

TPS is fine and no vacuum leaks, and no adjusting the maf has no affect.

Zealot

Problem Solved!!! By clicking my MAF sensor around 20 clicks, my idle stabilized.
I guess my engine sucks alot of air.

DaveInDenver

Seriously? Seems like 20 click is a real boat load. Could that indicate anything else, like the AFM spring is getting weak or the wiper that the flapper moves is hitting an oxidized spot?

bastos21211

how do you adjust your MAF sensor?

dj86515

I have the exact same issue on my 93 22RE 4WD. I adjusted the idle to where I can't go any lower. Sometimes it idles ok, but other times its high and/or high and low simulataneously when I press the brake pedal. I get 21 mpg, but I think it could be better. What do you mean by clicking the MAF? Thanks. DJ

Zealot

No joke, thats what I thought, but my engine has been so modified thats what had to be done. My MAF is fine nothing wrong with it.

DaveInDenver

Well, that's just odd. My engine is idling bad and it's got some new, some old. The long block is mostly new, in fact it's all new. But my sensors and intake are old. My AFM is not adjusted yet and I have Engnbldr's RV head with O/S valve, his 261 cam, a LCE header, clean injectors and all that. So I'm wondering if my ECU needs the AFM to be adjusted, too. Guess I'll try doing that afterall. All my sensors check out OK by the book, so I don't think I have a failed part anywhere, but I'm wondering if the AFM gets weak over time. That click wheel is adjusting the preload on a spring that holds the flapper closed, right? Maybe that spring gets old and with the higher air flow the flapper isn't moving smoothly, like it's fluttering or something, which confuses the ECU. I'm just grasping at stars trying to explain it.

Zealot

Here is what I think is going on. I now have an engine that can pull air in better than a stock one (ported head, over sized valves, BIG cam, header) At idle, the mass air sensor is seeing more air being pulled through than it normally would. The ECM doesn't expect that much air flow at idle and tries to compensate.

All I did was tighten the spring on the MAF about 15 clicks, or just enough to make the idle even out. I checked all of my sensors and looked for vacuum leaks. Everything checked out. With it adjusted, I now have more low end torque than before. Just make sure you don't lean it out too much. If you smell the exhaust and you eyes start burning and it smells really sharp, then its too lean.

Doing this will only help if there is nothing else wrong with your engine. But if you want to do it anyway, just mark the stock setting in the MAF and you can play all you want to. (Learned the hard way on my Corolla)

DaveInDenver

Yeah, Zealot, your situation sounds a heck of lot like mine. Haven't been able to find a vacuum leak (still replacing hose, but nothing bad so far). Sensors are all testing OK, no ECU codes, etc. I have a RV head with O/S valves and larger combustion chambers, LCE header, good exhaust, 261 cam. What makes me think that my problem is a confused ECU, too, is that when I turn the A/C on, the idle smooths out even if I adjust the idle-up valve not to actually increase the RPM. So the engine is idling rough at 1000 RPM and I kick the A/C on, the idle doesn't jump above 1000 but it smooths out. Maybe the increased load on the engine makes the ECU give it more gas. I do think I'm running lean, too. It sure smells to my very uncalibrated nose like I'm lean at least (but it's been 7 years since I drove a truck with a carb, so I could be triggering faulty memories).

kmat123

My truck has been doing this same thing lately. Where exactly is the MAF? I want to try adjusting it a little to see if this fixes my problem.

Matt16

The MAF (mass air flow) is located on top of your air box (where you air filter is). Looks like a quarter circle from above. There a wire going into it.

Bako88

I'm looking for info. I have been fighting a similar idle issue and have a bad smelling exhaust. I thought it was running rich, didn't know a lean condition caused bad smell.

Also, I tested the temp sensor located at the front of the intake (truck won't run when unplugged) and want to see if anyone in this forum knows if my results are normal. I took only 2 readings. Cold = 3.4 K ohm & Normal oper temp = 0.2 K Ohm. I read some where that cold should be 1.4 and warm should be 0.2.

abecedarian

Sounds like warm, you're okay. Cold resitance will, however, depend on what temp "cold" is. The temp sensor will read different at 80F than it will at 30F. Get my meaning?

Bako88

Not to be redundant (I posted my fix on another thread), but just in case my fix helps someone else. Everyone says look for vacuum leaks, and I found one. All problems went away when fixed. Hose was barely attached and letting a lot of unmetered air through.