Engine uncontrollably revved to 5500 rpm's on startup???

[Red Fox Ranch]

I just picked up a 1993 FZJ80 a couple days before Christmas from Northern CA, drove it back from Reno to Utah, drove it to Idaho, everything's been great.

Today I drove it, pulled a light trailer back, took the O/D off, pulled it into my garage when done, left for a couple of hours in another vehicle. When I started it to pull it out, instantly upon startup the RPM's shot all the way to 5500 rpms, it happened so fast my eyes just about bugged out of my head! I just turned the ignition off immediately, waited 30 seconds and started it again, this time started just fine as usual.

What the hell? has anyone ever experienced anything like this? This is the second 80 I've owned, the other was a 96 and I never have seen anything like this.

Any help would be greatly appreciated.

 

[emr88]

I saw this happen once to a 4Runner my father-in-law owned, the throttle cable was out of adjustment.

 

[Red Fox Ranch]

I saw this happen once to a 4Runner my father-in-law owned, the throttle cable was out of adjustment.

I checked the throttle cable from the inside of the cab all the way through and it looks to be in perfect working order.

 

[Montana Cruiser]

I had mine do this once, although it only went to about 4000 rpms and then dropped to 1000 rpm, then surged back to 4000, it did this a few times before settling down to it's normal idle and has never done it since?? The ONLY thing I can think of was that I had recently disconnected the battery to work on something and had not started it yet.

 

[dfmorse]

Wonder what the build date is? Some of the older 93's had a recall on the ECU.

...

 

[Red Fox Ranch]

Wonder what the build date is? Some of the older 93's had a recall on the ECU.

...

Yeah the build date is 11/92 so it is a very early truck that had the 1FZ.

 

[speedracer]

(1) Check the throttle adjustment and check the cable - (dirty)
(2) Check for vacuum lines - crack, or not connected properly

 

[stlcruiser]

Greetings:

Did you use the cruise control on your trip back? Mine did this once after a long trip with the cruise on. The brake did not disengage the system. Scary indeed.

Steve
94'

 

[AppleTech]

Mine did this right after I disconnected the battery. It settled down after a couple starting cycles. The ECU is reprogramming after you disconnected the battery (if you did). For me it took a couple hours of driving before idle and everything were completely back to normal.

 

[e9999]

darn, I would have had a heart attack....

good I have a quick disconnect on the battery too...

 

[Red Fox Ranch]

Mine did this right after I disconnected the battery. It settled down after a couple starting cycles. The ECU is reprogramming after you disconnected the battery (if you did). For me it took a couple hours of driving before idle and everything were completely back to normal.

That's the thing, the battery never got disconnected, it's been there for a while and in perfect working order. It happened so fast I was in panic mode, I just looked at the needle at 5500 and was dumbfounded, I finally told myself... shut off the ignition!!! It's one of those things where you try to remember what was going on, I keep telling myself you must have had your foot on the gas accidentally, but then I say there's no way, I would never do that!

Anyway my buddy said don't worry about it unless it happens again, so I guess I'll just play it by ear, literally!

 

[Red Fox Ranch]

Greetings:

Did you use the cruise control on your trip back? Mine did this once after a long trip with the cruise on. The brake did not disengage the system. Scary indeed.

Steve
94'

Never did use cruise on the way back, I did look at that since the CC has it's own cable right next to the throttle cable and is electronically controlled.

 

[MoGas]

Since you have a pre 5/93 1993 model, check the part number of the ECU...

89661-60170 =
89661-60221 =

The early ECUs had issues that the post 5/93 and 94 model year 80's ECUs didn't.

Dave

 

[Red Fox Ranch]

Since you have a pre 5/93 1993 model, check the part number of the ECU...

89661-60170 =
89661-60221 =

The early ECUs had issues that the post 5/93 and 94 model year 80's ECUs didn't.

Dave

I knew someone would know the goods!

Is the ECU located on the pass side kick or ???

 

[MoGas]

Remove the glove box and look up. I think you might be able to see the sticker with a mirror if you don't want to spend the 1.5 minutes removing the glove box. Yours should be easy as you just got it and the glove box isn't full of junk yet.

 

[cruiserman]

Mine did this right after I disconnected the battery. It settled down after a couple starting cycles. The ECU is reprogramming after you disconnected the battery (if you did). For me it took a couple hours of driving before idle and everything were completely back to normal.

Not at 5000RPMs it isn't. The typical relearn sequence is drop to very low RPMs for several restarts.

 

[Red Fox Ranch]

Remove the glove box and look up. I think you might be able to see the sticker with a mirror if you don't want to spend the 1.5 minutes removing the glove box. Yours should be easy as you just got it and the glove box isn't full of junk yet.

How about part #89661-60220, that's what it is...

 

[MoGas]

How about part #89661-60220, that's what it is...

That is the "good" ECU.

Did you get any lights while this was happening? It was probably too quick for you to notice. Does the check engine light come on when you start it? (indicating a self check)

 

[Red Fox Ranch]

That is the "good" ECU.

Did you get any lights while this was happening? It was probably too quick for you to notice. Does the check engine light come on when you start it? (indicating a self check)

No lights that I noticed, I guess I'll just wait to see if it ever happens again??? No check engine light either at all anytime.

 

[MoGas]

No lights that I noticed, I guess I'll just wait to see if it ever happens again??? No check engine light either at all anytime.

So you never see the engine light, even at startup? Not good.