[bdevereux]

Hi everyone Im new here and in desperate need of some help.
The car Im trying to fix is a 93 mercury sable with a 3.8 and automatic transmission.
It all started about a month ago. while driving the car at normal speed it would surge and act like it was going to stall. As time went by the problem got worse.
I started by changing the fuel filter and checking for trouble codes. The only code returned was one that said the car wasnt in park?
Needless to say this didnt fix it. Next the car died while driving and wouldnt restart. I had the car towed to my house and here is where im at=
when the key is turned on there is a realy loud buzzing coming from the (BCC I think its called its located in the front on top of radiator). The car cranks over fine but wont start.
I figured the BCC was bad because the loud buzzing was never ther before so I replaced it.
No luck with the new BCC it still has the loud buzz and wont start, but if I disconect the fuel pump at the inertia switch in the trunk the buzzing goes away.
So I replaced the fuel pump thinking it must be shorting the BCC again no luck, buzzing still there car wont start.
So I have pressure at the fuel rail and I have spark at the plugs but the BCC wont stop buzzing and the car wont start.
So why is the BCC buzzing and could it be the injectors arent firing?
Thanks in advance and I realy appreciate any help you guys can give me.

 

[carfixer68]

Do you remember what the code was? Did it involve an MLP sensor (manual lever position)?

 

[bdevereux]

Do you remember what the code was? Did it involve an MLP sensor (manual lever position)?
[/b]

Sorry I dont remember the code but it wasnt MLP but something more like "not engaged in park or neutral"
Its just odd that it gets fuel at the injector rail and gets spark at the plugs wont start.
Thanks

 

[gohim]

The error regarding park or neutral is probably due to a defective or misadjusted TRS (transmission range sensor). When you first turn the ignition key, the PCM (computer) does a POST (power on self-test) similar to the way a PC starts up. One of the things that is checked is the transmission gear selection. The error that you are looking at says that the PCM is not getting a signal that the transmission is in "Park".

While I am fairly sure that this is not causing your engine surge problem, it only takes a minute to try to adjust or replace the TRS, and the cost should be less than $30. It is located on the top of the transmission and is easily reach by going in over the left front fender.

I am not sure about your Gen.II car, but on my Gen.I 87 Wagon, there was an alignment hole in the TRS, and all you have to do is loosen the linkage, drop a nail in the alignment hole, and tighten the linkage. On my Gen.III 96 Wagon there isn't any alignment hole, so the alignment is done by loosening the TRS linkage, then setting the transmission gear shift lever on the steering column to Neutral, setting the TRS to the Neutral position, and tightening the linkage.

The fuel injectors are electrically fired. Just because you have fuel at the rail does not mean that the injectors are being fired and that fuel is being dunked into the cylinders. You need a "noid" light (a test light plugged inbetween a fuel injector and the wiring harness) to determine if the fuel injector are actually being fired.

And just because a spark plug will arc to a ground, does not mean that you have enough spark at the right time to fire the engine.

I would use a timing light to verify that the spark plugs are firing at the right time.

If you have spark and you have fuel in the cyclinders at the right time, there is no way that the engine is not going to run. SO obviously, you do not have spark or fuel.

A problem with the TFI ignition module (people have told me they are mounted on the firewall on 3.8L engines) or the breaker module (located inside of the distributor) could cause the engine performance problems you have described.