89 300TE Sudden stalling repair

[turner]

I have an 89 300TE with a new used engine and 130K miles on it.

My Blower fan went out a few months ago so I did a blower and regulator replacement on it. After I finished I put the kids car seats back in and did a test drive thinking that this was a good idea as it had been sitting for 2 weeks. After the car warmed up it started idling like crap, as if it was misfiring. Even when you gave it gas it would bog down and then finally it would rev up again. Then in the driveway it stalled and wouldn't restart. So I had it towed to my mechanic, M&J's Foreign Auto in Rowley MA.

He diagnosed it as a cracked rotor and moisture problems. I picked it up and went on my way, only to find that as soon as it warmed up it stalled when I came to a stop.

I took it back and he replaced the fuel filter and checked the OVP and the fuel pump. I took it back and it did it agian. So I took it back to him again. This time he swapped out the idle air valve from a junker and told me to try it again.

I have been driving it for 2 weeks and it has consistently been dying, after the car warms up just over 80C, whenever I come to a stop or slow down under 10 MPH. It doesn't sputter it just dies, though I can catch it and put my other foot on the break and rev it up past 1000 rpm to keep it from stalling.

It happens at a gradual stop, not when turning or specifically on a hard stop. It restarts usually just fine right after. It can do it and then work fine right after at a stop, but it only happens when hot.

The other day when it was really hot 96F and had been sitting in a parking lot all day it really wanted to die the whole ride home.

I just dropped it back off today to see what else can be done.

I have seen this post SSS (Sudden Stalling) Factsheet

So anyone have more advice? Is there any way to diagnose this other than swapping out parts? This seems like it should be something stupidly simple but yet it makes the car unsafe to drive.

I have given all of these details in case anyone out there can point me in the right direction. Was it the blower replacement? Did I crack the wiring harness in front of the blower? Is there a way to electronically check the OVP that I should be asking for?

Any help is appreciated.

Thanks

John

[david s poole]

based on your description,i suggest that you check the pins in the socket that the ovp plugs into.the small pin is terminal #15[which is ignition switch power]that powers the relay.the relay in turn powers the f.i.computer which operates the idle valve.if computer loses power you lose idle valve.

[turner]

I'll check that.

Any idea as to why this might only affect the engine at idle speeds and hot? If the FI computer lost power at speed wouldn't the engine shut off or stutter?

[david s poole]

if the elec conns are marginal when hot everthing expands and you could lose idle and also drop into limp mode.

[ps2cho]

my 88 300TE stalled at random times too. Almost certainly the OVP. Your problems sound just like mine. Dies at low speeds/come to a stop. Once I replaced the OVP it cured it right away.

[turner]

The OVP was swapped out with a known good unit.

That was one of the first things he tried.

[sbourg]

Having been in problem diagnosis and resolution all my career, I'll give this tip - the chance that the problem having occurred after your blower / regulator replacement being related to that action is about 90%. I would minutely inspect everything that was disconnected, moved, jostled, etc during the repair. Don't forget to think of secondary effects. If the 'sitting' for two weeks was also an unusual occurance, then consider that a highly possibly related event also.

Steve

[psfred]

Did you replace the fuel pump relay?

Peter