Startup RPM gone

M

misterjack

New member
The patient is an 89' 30VZ with auto tranny. Engine ran great until just recently. When the engine ran as it should considering its age at start up the RPM would go to about 1300 and then settle back to around 900 after warm up.
In an earlier thread (my newbie introduction thread) there were thoughts that the timing was out of whack. I have verified the TDC location of the crankshaft, both cam marks and the distributor rotor location. All perfectly in order.

My 4-R is not a daily driver, it is my hobby 4WD and a backup for heavy snow. In other words I don't mind going through a trial and error procedure one component at a time but I just don't know where to go next?

These items have been recently replaced with new. Plugs, plug wires, rotor, distributor cap and fuel pump. The recent change in engine performance came on suddenly, not associated with any exchanges in parts.

Where to next my friends?

I like this smilie, must add for the heck of it.:girl:
 
Register to hide this ad
So you checked the timing using the jumper as specified and an actual timing light? Typically you have a shot of gas coming from the cold start injector that is dependent on temperature that takes your idle up a bit. Check the connector on the passenger side of the intake plenum and maybe pull the injector and clean it. The other possibility is your TPS needs adjusting.
So if you are from FL, where do you have the snow?
 
I used an actual timing light and jumpered properly according to Haynes manual.
I am in Florida and so is the 4R, for now. When November comes it will be in North Texas. Snow comes to North Texas in blizzard format, not the pretty snow globe type. In North Texas 4WD is not a luxury, it is life support.
Cold start injector has been removed, evaluated and replaced. I forgot to mention that originally.

What is TPS?
 
I believe the 3.0 has a high idle built into the throttle body. You can remove the throttle body and there is a small access plate to remove. Clean up the passages and put back together.
 
Not Dalhart but close. Amarillo! It ain't the TPS either. I replaced the TPS yesterday to no avail.
There are only 3 things inside a combustion chamber, fuel-air-spark. I removed the fuel filter last night and was not impressed with the contents. Getting it off took 3 beers, 1 neighbor and a 16" pepperoni pizza.
Keep those ideas coming, will return with results of replacement fuel filter later.
 
I hate to say it but possibly a bad Ecm :( since you have replaced nearly every part of the fuel and wearable parts of the ignition syatem
 
What happens when you run it with the AFM plug undone?
What happens when you run it with the TPS plug undone?
What condition is the boot between the AFM and Throttle body?
I got stopped driving a rental truck in Amarillo once.
They wanted to know if I was hauling illegal immigrants.
I told them "No" I just had court room furniture for a project in Albuquerque.
They let me go.
They make good cheese in Dalhart I hear.
 
misterjack said:
Not Dalhart but close. Amarillo! It ain't the TPS either. I replaced the TPS yesterday to no avail.
There are only 3 things inside a combustion chamber, fuel-air-spark. I removed the fuel filter last night and was not impressed with the contents. Getting it off took 3 beers, 1 neighbor and a 16" pepperoni pizza.
Keep those ideas coming, will return with results of replacement fuel filter later.
Click to expand...

There is something on the throttle body that allows more air when cold to UP the rpms. It's just been a while seen I messed with one. Got the clean & simple 22re now.
 
misterjack said:
The patient is an 89' 30VZ with auto tranny. Engine ran great until just recently. When the engine ran as it should considering its age at start up the RPM would go to about 1300 and then settle back to around 900 after warm up.
In an earlier thread (my newbie introduction thread) there were thoughts that the timing was out of whack. I have verified the TDC location of the crankshaft, both cam marks and the distributor rotor location. All perfectly in order.

My 4-R is not a daily driver, it is my hobby 4WD and a backup for heavy snow. In other words I don't mind going through a trial and error procedure one component at a time but I just don't know where to go next?

These items have been recently replaced with new. Plugs, plug wires, rotor, distributor cap and fuel pump. The recent change in engine performance came on suddenly, not associated with any exchanges in parts.

Where to next my friends?

I like this smilie, must add for the heck of it.:girl:
Click to expand...
does the 3.0 use an IAC? if so, I would suspect its clogged/dirty or bad.
 
Yeah, the IAC. It is built into the throttle body. It is located below the TPS. I believe it's like a triangular plate with small phillips screws. Valve is probably either stuck shut and/or passage is clogged.
 
I remember seeing the IAC while replacing the TPS. If it is something that can get clogged then it probably has. Wish I had opened it up and cleaned it while I had the throttle body off. No biggie, can do easily.

I pulled the ECM to get the number off of it. No visible signs of foul play. Only a replacement will verify.

This I do know for sure. The TPS, IAC and ECM are PIA's that are participants in a WTF process.:hunter:
 
Mission accomplished. When I removed the fuel filter it was incredibly dirty. I replaced the ECM with another and absolutely no change. I decided that there would be no more speculating on the fuel delivery to the combustion chamber.
Air plenum and fuel rails removed and each fuel injector thoroughly cleaned. The injectors were so bad that the small screen on the top side of the injectors were packed solid like a blackhead growing on some awkward body location.

Thoroughly cleaned and replaced. All systems go!!!!:washing:
 
Had the same issue on a '88 4runner with the injector screens being packed with "mud". Replaced the filter & celaned the injectors and problem went away for 2 weeks. After that, same thing. Injectors packed full again. I ended up cutting the fuel line in the engine bay and installing a 2nd filter, one of the see through type. Had to change that filter every 2 - 3 weeks for a couple months to remove all the crap that the regular filter was not catching.
 
You must log in or register to reply here.

Members online

Total: 191 (members: 1, guests: 190)

Forum statistics

Threads
278,309
Messages
3,554,071
Members
248,016
Latest member
Advally Service

Share this page

Trending content

Back
Top