jennygirl

Hi guys! So I am trying to narrow down this problem I have been having forever. I did an intake battery swap a while back, and now my AFM is much closer to the TB.



I have been having hard warm start issues, with low idle until I get the car moving or rev it a whole bunch. Not sure if it is rich or lean, but I do get lean O2 CEL on highway if I hold the throttle steady for a while. Blipping the throttle changes this.

I am also suspecting fuel is contributing to my hard starts. But dang, I think this just may be it!!

Has anyone ever relocated the IAT outside of the engine bay? Would there be any ramifications of this? I could even put my whole AFM in the fender if necessary. I think getting it (IAT) farther away from the TB might work! What do you think?

rworegon

If I was you, I'd do the planned fuel system work and see what happens. My science background only likes changing one variable at-a-time.

Cannot recall seeing any discussions around here about moving the IAT like that.

What O2 sensor do you have in there now? The new Denso one?

jennygirl

YOU GUYS

That is it!!! I just confirmed it!

rworegon

Confirmed what???? How? Don't leave us hanging.

jennygirl

Just drove it around hard, got the engine really nice and hot.

• Parked it at home and immediately threw the voltmeter into ECU's THA terminal = 2.148V.
• Start car, starts up with slightly under ideal idle (700rpm).
• Grab my electronic spray cleaner and pop the engine bay
• Check voltage, it's already dropped to about 2.11V
• Blast the AFM with a good deal of cleaner, carefully away from intake as not to get it in the intake itself. IDLE RAISES to normal and stays!
• Close engine bay, turn car off. Wait.
• Voltage reading 1.74V and dropping.
• Start car, probably been off 5 minutes now.
• Idle is CRAP, 400rpm
• Pop engine bay, blast that friggin AFM with cold spray
• Engine idle returns to a perfect 850 with just ever so slight of a stumble! THA voltage stabilizes at 2.074V. Outside air temp = 60 degrees F

rworegon

Nice detective work.

jennygirl

This has seriously been plaguing me since I did the intake battery swap, 2 months ago.

Definitely going to have to move the AFM farther away from the TB and probably insulate it. Just so flipping happy to know what the issue is.

I still have a fuel issue (fuel is depressurizing quickly after shutoff), so the fuel upgrades will still be worthwhile. If it's not the pump, it's an injector. And I have both on the way

jennygirl

My next step with this is to find out if this is the cause of my CEL on the highway, rather than the O2 sensor.

This also means I've been running lean for a while :/

rworegon

The injector in one of your posts, is it out of your rig? The really dirty black yucky one?

jennygirl

I think you must mean the cold start injector. I'm going to properly clean that bad boy myself. When I cleaned it before, I just kinda got the stuff on the outside.

I actually used the CSI from the later model intake manifold I just installed. The connector is different so I just left it unplugged.

Pretty sure I'll never need a CSI anyway!

rworegon

Yup, just looked back at it and realized CSI. If the fuel injectors look like that....yikes!
Any chance heat is conducting up the 90 deg elbow? You probably mentioned what it's made out of but my old brain can't remember.

Poking around I found a case or two where it appeared similar symptoms as yours ended up being a wonky coolant temp sensor. I'm guessing you've already looked at it?

jennygirl

Yeah it's made of el cheapo plastic. That elbow is from autozone "Spectre" brand.

I think it absolutely is.

I was able to replicate the solution using ice water alone, so I know it was not the electrical cleaner getting into the intake.

Instead of relocating the whole AFM, what I might do is just relocate the IAT sensor. Seems to be a common mod, although there is a lot of controversy over it. In my case, something definitely needs to be done.

rworegon

Isn't the IAT sensor inside the AFM?

I just noticed in the 22re FSM (granted the '93 version) Engine Mechanical Trouble Shooting section Difficult to Start Hot Engine and Poor Idling Low Engine Idle Speed both have as the #1 option Engine Coolant Temp Sensor Circuit. The IAT circuit hit #5 on the Difficult to Start and not ranked on the Poor Idling.

jennygirl

I would imagine the coolant temp gets heat soaked as well, but didn't toyota release a fix for that- the two stage thermostat which starts flowing coolant instantaneously? I have that 2 stage installed btw

jennygirl

It's just crazy how many people have this problem. I hope this solves it for a large part of them.

I just got called in on a weekender gig. I am hopping on a plane early tomorrow morning and won't be back until Monday or Wednesday, so it will have to wait a few days before I can develop a solution further.

I'm just so happy to have found it!! I literally can't stop smiling

rworegon

There was a 22re TSB for a couple of sensors too related to poor starting and idle. Think it came out like October 1989 or so.

Have fun at the gig. I'll be laying about from Weds afternoon thru the weekend. ;-) I'll be checking in from time-to-time.

jennygirl

Oh yeah! That's right. Wishing you a fast recovery

I think the tsb was for the temp switch and cs time switch. I haven't seen anything for IAT

rworegon

You are right. It was for those.

muddpigg

iTrader: (1)

Not trying to be an ass but several ppl have done this swap. I can't imagine the heat on the intake side is more than the OEM location, exhaust side. If the problem started right after the relocation of AFM. Then is it possible that something in the swap caused problem? ie a poor electrical contact? I have completely removed the IAT from my '86 really only difficult to start on cold mornings, takes and extra crank or two to fire up. But otherwise runs fine. Not having a CSI would make cold starts even more difficult.

Have you gone through and double checked all the electrical connections you spliced?

jennygirl

I assume by remove IAT you mean removed CSI, the IAT is part of the AFM and the engine wouldn't run well at all without it. I as well have disabled the CSI and CSI time switch.

You raise a good pt about the electrical connections. I honestly don't know why I haven't looked at that yet and it's a great idea. Imma do that and I'll let you know if anything changes.

It did seem weird to me too that I was having this issue right after the swap and so many people do it- though in my searches I have noticed that quite a few ppl having startup issues are people who have done the swap which made me think about a correlation.

Anyway I'll rewire it and test for continuity and let you know if I find any errors in my work. I'm also going to be installing flamethrowers and a new fuel pump. I'll try to stagger the installs so I can do things one at a time to know exactly what fixes it if anything...