3.0 VZE Issues .. please read !
 

So here is the skinny. I have a 93 with a rebuilt 3.0 VZE. The motor has probably 2200 miles on it. It has the LCE headers and Y-Pipe, Flamethrower Injectors, New distributor Cap and rotor, plugs and wires, belts, oil and water pump, etc.

Long story short, the motor ran fine for about a month and one day i started the truck in the parking lot of work and all of a sudden it started running really bad, almost like a spark plug wire was pulled for about 15 seconds and after that it cleared up and started running fine. I drove the truck about 40 miles home with no issues. The next day, half way to work, it did the same thing... started sputtering and running rough for about 10 second and then cleared up, no issues the rest of the day. After this happened, i started to hear a valve tap in the motor and it has a slight miss every 5-10 minutes or so. The motor runs great and has good power , well much better than before the rebuild anyways.

Here is the other issue. I don't know if it is because of the EGR delete and all of that with the LCE headers, but i cant get the timing correct with a timing light. Closest i cant get is about 18*. The other day i pulled off the timing covers and checked all the marks and everything was good with the belt. I jumped the terminals, started the struck and adjusted it and it adjusted to 10* like it should be, so i moved it to 12*. within a couple minutes, the timing all of a sudden went to around 20* and i couldn't adjust the distributor enough to bring it back without the truck running like crap.

The truck has good throttle response and runs smooth besides the miss here and there and the episodes of running rough here and there, so im thinking the timing is ok, even though the timing light shows different. Im starting to wonder if one of those flamethrower injectors are acting up.


Any feedback or ideas would be great .. thanks in advance guys/gals !

I have the same 3.0 VZE in my 89' runner. I rebuilt it a few years ago and had a few issues, including this one, within the first 1,000 to 2,000 miles. I need to go back in my notes to remember which one this was but off the top of my memory I think it was the knock sensor.

It was a pain to find the issue and a pain to fix it. I read many of the blogs about the knock sensor. My issue ended up just being the wire harness. There was a bad wire or connection which made it intermittent.

If I remember it was something different with mine I will let you know.

Thanks !! ill be looking forward to it !

BTW, I also have the flamethrower injectors. Along the way I thought a couple of my issues were due to them to the point that I put my old ones back in temporarily. Long story short...it was not the injectors. I have been running them for three years and very happy. Can't speak for yours though...

Idle speed must be in spec(not too high), for the ECU to go to base timing.

TPS must also tell the ECU that throttle is closed before it goes to base timing.

Satisfy that these parameters are met, and then try to time again.

^^^^
He is dead on. Both the above can cause issues with setting the "base" timing. I don't know if the knock sensor would cause a timing change with the Pins jumped and the ECU in diagnoses mode.

Im guessing i can find spec idle in the repair manual ?? I have it set at the moment to idle at about 1600 rpm due to the low idle when the AC kicks on. Sometimes when i would push in the clutch to come to a stop, the truck would start idleing low and die, so i idled it up.

Usually if it is the knock sensor it will throw an engine light and a code 52...

I agree with the last two comments. Here is a helpful link for adjusting/troubleshooting your TPS. http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml

Thanks alot guys, i will try the above things, in the meanwhile, any other ideas are greatly appreciated !

And as an FYI, i have no check engine lights or anything like that on at the moment.

You cannot successfully set the base timing with the engine running at that kind of speed.

It needs to be lowered to around 800-850 RPM.

The factory idle speed spec may be found on the emissions sticker on the bottom side of the hood, or in the FSM, as you say.

Ok, so once base timing is set at that RPM, i can raise it a bit if needed im assuming ?

After the base timing is correctly set, you should be able to increase the idle some, but if the engine and its systems are operating correctly, you should'nt need to.

Don't neglect the TPS tests and adjustments, as well, before retiming.

Update. Check the TPS , looked good, idled the engine down to around 800-850, set the timing to 12*, drove it 20 miles, ran great. About half way home, I stopped at a stop sign and then the engine knocking and rough idle started, lasted about 20 seconds, it stalled at the stop sign when it did it. Started the truck back up and it knocked and. Ran rough for about another 10 seconds and then it cleared back and ran fines for the remaindered of the 10 miles back home. So I'm still unsure of what the cause is

Sure sounds like an intermittant electric gremlin.

Injector wire/connector??

thats what im afraid of ... electrical issues could take forever to figure out .. i think i may just end up bringing it to an import shop .. im tired of dealing with it.

I was experiencing same issue with my 92 3.0 4runner. Sometimes ran great, I
Most of the time ran bad. No power, got got etc.

Ended up being the keyway on crank was warned out, key broken off so that when you thought timing marks on pulley were lined up, they really weren't.


Shop welded and retapped crank and she runs fine.