Help! My 1J vvti is running crapy. trouble shoot to end all trouble shoots.

[swapinthedark]

Please oh please help me guys! I am about to go back outside and try to get the ECU into diagnostic mode with the check light wire hooked up to a random bulb, but in the meantime, could yall put your heads together on this PLEASE?


Background= I swapped a 1999 chaser 1JZ into my R32 a few months back and have been enjoying it ever since...until last week.

A few days ago, I drove off from the house after the car sat for a couple of days and all was normal. Idle started off at the usual low 400ish RPMs and was creeping up to 550ish as the car warmed up. I pulled out of the neighborhood and onto the main road and as I got to 5th (about 2000rpms in 5th) and settled in to a normal speed, I felt the car kindof "hump" a lil as I drove at steady speed. I pushed in the clutch and let the car come to an idle an it sputtered then died. I pop started it and continued on. I came to a light, and had to keep the RPMs at around 2k to keep it running and boy was it ROUGH... like brah...ba..ba..brahhhh. buh buh. (sorry best way to say it). Now here is the thing, if I am accelerating or decelerating, it runs smooth as glass and pretty normal. When I try to hold a steady RPM, it jumps around and sounds all retarded. If I let it come to idle, it will catch near normal idle for a sec than die out slowly. The car is also a smidge weak when you let it rev on out under load, but just noticeable...once again, smooth though, no skipping/missing.

engine is on stock ECU, stock boost, FMIC, traction shit unhooked,3" exhaust after the elbow, walbro pump...oh, the "fuel damper" is bypassed. WTF was that thing for anyway?

This car has the idle air contral wired, but I disconnected it DURING THE SWAP because the stepping motor it'self was bad and I canot find one in the US. The car has run this whole time with the big hose blocked off via a peice of plastic lodged in it and the plug unhooked. The car idles at 400 cold and 550 warm with NO issues normally so that is not the prob.

I did not get the check light working with the swap but will try my best to have that working and read the codes here in a few mins.

Things I have checked.

MAF was swapped with a known good one.

TPS was checked/reset.

Coil packs/plugs checked to be safe. (plugs are 2 weeks old).

I checked over everything for vac leaks.

I vac tested the FP regulator.



Please help folks. Is there anything I am missing in the usual checklist so far?



oh, btw, I have good fuel pressure.

[cambelt]

Thats prob your answer , the computer will hold the iscv open a certain amount at idle. If you have plugged it you will have rich running conditions and prob hunting . If you reajusted the throttle to make it idle the tps will be sending accerating signals to the ecu and richining it up also.
Get another ISCV and see how you go .
Dave

[swapinthedark]

Huh? I don't think that is my problem. The car ran and idled PERFECT for the past 5 months of me driving it without the idle air stuff hooked up. This problem developed LONNNNG after the fact.

The idle has never hunted before so why would it start out of the blue? Besides, this is not an idle issue only, it runs crappy almost EVERYWHERE. The only exception is at 5k rpms it is smooth and under load it is smoothish.


I am starting to think it can only be the Crank angle sensor or the ECU is dieing.



What are yall's experiences with the way a car with a dying crank sensr runs????

[wilbo666]

Check the ECU for error codes as you say...

From the sounds of it I suspect it has a sub par wiring job? Perhaps that is why the IACV doesn't work (wiring...)

Cheers
Wilbo

[swapinthedark]

Hey! I did this mess... I mean wiring job. I am pretty darn sure it is fine but hey it COULD be a possibility.

I thought I made it clear that the IAC stuff was working (giving power in steps) but that the IAC was toast and not opening when the power was given and that they are not a common item here so I bypassed it.

Scratch that one off.

Come on yall.

Ah, forget it I guess. I figure it HAS to be the ECU or the Crank angle sensor.




I forgot to mentin that IF it is the ECU, I may have helped it along by doing an event in the rain the other week... They make us leave the windows open no matter how hard it is raining for saftey reasons. My ECU was SOAKED on the outside but the car ran fine all day THAT day... maybe it is an after affect? LOL.

[wilbo666]

I thought I made it clear that the IAC stuff was working (giving power in steps) but that the IAC was toast and not opening when the power was given and that they are not a common item here so I bypassed it.

To dwell on this, what you are saying is taht the IAC works, if you give it power in steps, (Like the MA70 TSRM indicates)... yet it doesn't work under ECU power....?

That really, really sound a lot like it could be related to a wiring problem myself

I.e. you don't have the +B supply that is meant to be switched via the master relay going to the IACV for example?


And really, pull the codes, they are helpful at times

Cheers
Wilbo

[cambelt]

Hell water and ecu,s dont mix what do you expect .
Take the cover off and if theres any water droplets WD40 it and then electrical contact cleaner all the inards of the ecu .
Dave

[swapinthedark]

I'm trying to make it clear that if I check the PLUG to the idle air control, I have power and the signal is being sent aka it powers one then the other then rotates back to the other etc... the IAC ITSELF does not move. It does not move when hooked to my engine, and it does not move when TESTED on a bench. The IAC MOTOR (magnetic piston thingamajig) is bad bu the ECU was giving it signals.

See what I was saying?

IT WAS MECHANICAL, not electrical.... well it was... now there is a seperate problem.















As for the water situation, I knew I was doing lots of harm when I was out there, but a good time got the best of me. I should have atleast moved the ECU to somewhere I could put a bag around it that day, but runs kept coming up and I kept driving "like an idiot".

I took the covers off and it looked clean in there (darnit) with no water stains or anything. I am thinking about giving it a spray down with contact cleaner, letting it sit 12 hours or so and trying just to see.



Side question. (I'm searching now but a quickie answer would be wonderful). Is the crank sensor the same as a regular 1j, a 2j, any other toyota? I wanna try that and then I'm off to find an ECU to "rent".

[swapinthedark]

...was searchin around and found my own old post.

I fixxed the problem many months ago. It urned out that the VVT-i solenoid/actuator had stuck, I did not have a way to get another, but ironically, pulling it out and rapping it against the bench did the trick,wtf. That fixxed it straight away and it has been wonderful since.

If anyone has similar symptoms to what I posted, try the vvt-i actuator!