Help! Batmobile Refuses to Idle

[tchort]

Hi everyone,

Things have been going swimmingly for the past couple of months since we figured out the cooling fan relay/switch problems.

Day before yesterday, the Batmobile decided it no longer wanted to idle. It starts up - a hard start - then dies. If I catch it in time and raise the RPMs, it runs. If I let off the throttle, it will either die, or idle low - at around 600. If I start driving it, it does fine.

There are no fault codes from the ECM. There is nothing obstructing the airflow. It does not backfire, or sound like it's misfiring.

BTW, it's a 1988 with a 4+3 manual, with around 169,000 miles on the odometer.

Any thoughts? Any help is greatly appreciated.

--Gary D.

 

[air1jpg]

Could it be the mass air-flow sensor bad?

 

[Hrtbeat1]

Sounds like a clogged EGR valve.

 

[jmccloud]

Poor idle

Yep, crud in the EGR and it's leaking, causing lean mix. Often the EGR simply sticks or there is carbon in the valve. Or the control system may have expired. Test the valve itself by applying/releasing vacuum and observing full movement. Usually poor control causes the EGR to stick closed but if the movement is full, check to assure the EGR is closed during idle. It normally opens only at cruise.
Good luck

 

[tchort]

I don't think it's the MAF since there are no codes being set.

I'll check the EGR valve like you guys recommend. Wish me luck. I'll let you all know the results.

 

[tchort]

Let the flaming begin...

Well, as sometimes happens, the most obvious turns out to be the problem. It was out of gas. I know, I know, I'm a dumba**. :bash

 

[kenmack]

Gas

I have found that when my gas tank is empty,the idle is very poor.:confused
The solution for me has been to put gas in the tank to bring the gas needle above the E mark.When the gas needle shows above the E mark the idle is much better.
P.S. The gas needle and the E and F marks are in the little window behind the steering wheel.
Sorry I couldn't help myself !!!!!!!!!
Toooooo Funny

 

[tchort]

I have found that when my gas tank is empty,the idle is very poor.:confused
The solution for me has been to put gas in the tank to bring the gas needle above the E mark.When the gas needle shows above the E mark the idle is much better.
P.S. The gas needle and the E and F marks are in the little window behind the steering wheel.
Sorry I couldn't help myself !!!!!!!!!
Toooooo Funny

Hey, funny guy! You have the down-graded analog gauges with things like "needles"... We don't have no stinkin' needles in our 84-89 dash!!! :crazy Here, it's all digital, all the time (except for when it breaks, of course)..

 

[ecss]

Remove the throttle body and clean out the air bypass circuit on the bottom of it. It gets blocked with carbon. Also remove the IAC (idle air control) which screws into the side of the throttle body and clean its tip and the bore in the throttle body of any carbon.

The IAC via the ECM controls idle speed by bypassing air around the throttle plate.

One way you can tell if the IAC is working is when you turn on the AC, the engine idle speed will increase to compensate for the load the compressor places on the engine when the clutch engages.

 

[Red Vette]

All joking aside about the tank being empty causing the poor idle, you should read previous threads on the fuel pump heating. It seems that the fuel in the tank cools the pump and extends its life. Many of us keep our tanks full and refuel when the gauge drops to 1/4 tank. And, an added benefit is that your batmobile will idle just fine.
Barrett

 

[tchort]

All joking aside about the tank being empty causing the poor idle, you should read previous threads on the fuel pump heating. It seems that the fuel in the tank cools the pump and extends its life. Many of us keep our tanks full and refuel when the gauge drops to 1/4 tank. And, an added benefit is that your batmobile will idle just fine.
Barrett

Yeah, I usually refuel at 1/4 tank as well. What threw me is that the gauge wasn't reading much lower than that. Thinking back though, I realized that we were sitting at an incline with the nose up. That tells me the gas pick-up must not be at the center of the tank.

Recently, my refueling has been timed to gas price fluctuations on the futures market. We're seeing $4.05+ for premium here in the Bay Area. Pretty soon, a gallon of gas is gonna go for a pound of flesh.

I wonder though, what's the connection between keeping the tank above 1/4 full and smooth idle? Is that a sign of a failing fuel pump?