jammer6

Hey Guys,

I have been having this problem for some time now on my 4Runner. It's a '95 and I have had the engine completely rebuilt and it runs great. The problem is that when it is cold and I first start it up it will not go up on the high idle like it should and as you drive it each time you let of the gas the tach drops all the way down to 500 rpm and the check engine light flashes. Once something under the hood warms up it starts running fine except that it surges 200-300 rpm when it's not under load.

I have had the Coolant Temp Sensor replaced but it didn't help. The shop that rebuilt the engine ran their diagnostics and said all they could determine is that the CE light indicated the "No Ignition Reference Signal" error. I now suspect the TPS or the MAF not sending back the correct signal. There is a vacuum damper right by the TPS that would keep the engine from dropping rpm quickly but it never engages.

Any help here would really be appreciated.

Thanks
Jake

Flash319

What engine are we talking about?

Flash319

If it is the 22re then it sounds like it is your cold start plunger thingy under the throttle body. Coolent runs through it. There is a spring pushing on a plunger that lets air bypass the throttle plate. The plunger is open when cold, thus causing a high idle, and as the coolent temp rises it pushes the plunger closed causing the idle to go down. The plunger may be stuck.

If its the 3slow that you got nevermind what I said.............

jammer6

It's a 3.0

dcg9381

I'm not 100% sure, but I think it's telling you that there is a problem at the ignitor... If the ECU doesn't get a good signal from the ignitor, VAST goes into "limp home" mode, which minimizes your timing... IF you clear that code, does it come up again immediately?

miket223

The no IG Ref trouble code is a load of bull. If everyone with a 3VZ-E checked their vehicles for codes that would probably show up in 25% of them. That trouble code means absolutely nothing and you should ignore it. The idle system on the 3VZ-Es is all mechanical and the computer has no control over it. I would first suspect that you have a plugged idle-up bypass. This bypass is controlled by the coolant temperature and is located on the throttle body.

dcg9381

The ECU controls timing at idle.. :-)

jammer6

Mike,

Thanks man, I really appreciate the input. I was heading in the wrong direction troubleshooting this problem because of the IG Ref. Now, my question is how can I go about checking and cleaning the idle-up bypass?

Thanks again for your help.
Jake

miket223

I would start by trying to clean the idle-up bypass while it's still on the vehicle. There's a hole in the throttle body outside the throttle plate, that is the intake for the idle-up bypass. I would give it some throttle plate cleaner or some break cleaner. Fill that whole thing up with that stuff and let it soak for 15 minutes and then give that hole a shot of compressed air or just reassemble everything and try to start the vehicle.

If that doesn't work then you're going to have to remove the throttle body for a supreme cleaning. Before you go through all the trouble of that, first rehash over some basic stuff. Make sure your idle after the engine is warm is at the proper RPM, check your ignition timing warm, check for any air leaks between the VAF sensor and the throttle body (This is a common one because the boot closest to the throttle body likes to split), and make sure the VAF sensor plate moves freely.

jammer6

Thanks Mike,

I have already changed the bellows going to the throttle body and I saw the hole you are talking about. I will try cleaning it this weekend and let you know how things turn out.

Jake