1989 300 TE starting problem
 

A friend is visting and drives a 300TE and it suddenly quit starting (been starting fine until tonight, but has idled a little rough at times he says). If we take the breather cover off and manually push down the "choke" (not sure what the piston is called) it will start. It will run with some extra RPMs on it, but sputters at idle and will stop when that piston closes. We can push the piston down and it will start again.

So, if it isn't premature to ask, what sensor is controlling the air flow into the engine that we override by manually allowing air in?

Or is it some other source?

I searched through, but didn't see any posts with such a specific problem with the starting that could be manually overridden.

Need help quick - he has to get on the road tomorrow. Thanks in advance.

Probably a blown ovp fuse or bad ovp relay.

I think what you are referring to, that you are pushing on, is just the plate for the airflow sensor.

Gilly

How long since the fuel filter was replaced? Could simply be fuel line obstruction or a dying fuel pump relay. After that, the possibilities become $$$: weak fuel pumps, EHA, fuel distributor, CIS control unit.

Thanks for the reply. Where is the OVP fuse? Is it in the fuse box? Or is it in the OVP Relay?

Also, my hunch is that it isn't the fuel filter since it runs so smoothly when it has RPMs. I know it would still smooth out with a partially clogged filter, but it seems to have the fast rev ability and its power.

I am hoping it is a fuse.

I had a similar experience with my 91 300TE. It turned out to be the ignition coil wire was carbonizing at the coil end.

Needed a cut and a re-scrimp and the hesitation went away.

Hi,

I still haven't found the OVP relay with the fuse. Does it still look like this in 1989?

http://www.peachparts.com/shopforum/showpost.php?p=2464286&postcount=10

Also, since it will run when we allow air into the manifold by pressing the plate, and it will run with RPMs on the engine, I am wondering if it is a vacuum problem somewhere. In other words, unless there's enough RPMs, there's not enough vacuum to operate the little plate (I am assuming it is vacuum controlled based on the feel of it when it is pressed down).

Are there any common vacuum culprits for this car? Again, no one had been in the engine compartment recently before this trouble began - so I don't think it is a matter of someone putting their hand on a line and breaking it. But maybe there's a place that commonly fatigues and lets vacuum escape?

Thanks.

That is what the OVP looks like. But, it should be behind your battery on the passenger side (in my '91 there is a plastic cover that has to be lifted out to expose it behind the battery. It (OVP) faces to the middle of the car and sits with the red cap towards the top of the car. When it isn't working, the car runs very rough and you usually get the ABS light coming on from what I understand. One of the other hundred things you can check is the Idle Air Control Valve. It's under the front side of the air filter housing. Has a black air hose that runs from one side to the fuel assembly and the other to the manifold. I found that my hose on the fuel assembly side was cracked (and so have many others) and caused a "hunting" idle issue and tough starting problem. You can also take it off and clean it out. Some say theirs were really dirty inside (mine was very clean). Other things that can cause the issue that I've come across...O2 Sensor burned out giving erroneous signals, Water Temp Sensor ($30.00), Air Intake Temp Sensor (you would think this thing lasts forever but they don't...located on the air intake bridge to the air cleaner assembly $25.00), cheap 1.99 Copper Plugs from Autozone (get some and put in), coil ($70.00) and rotor ($35). Did anyone ever mess with the air mixture that's accessed from atop the air cleaner assembly? If richened or leaned too much, will cause that problem.