[njbull]

My '93 taurus 3.0 (160K miles) ran great until it ate the distributor drive gear. I replaced the distributor and attached module and timed it to factory specs with the spark sensor unplugged. Now it starts easily, idles fine, and cruises smoothly. However, there is a huge bog on initial acceleration and the problem is worse before the engine is warmed up. I have checked for vacuum leaks and found none. Where should I start looking to find the problem?? Any suggestions would be appreciated. ( I assume it wouldn't run at all if I installed the distributor 180 degrees off. Is this true?)

 

[pawpaw]

Well did you remember to reconnect the Spout connector????

Did the bog problem come about after the distributor replacement, or after some other event, before or after the distributor problem????

Do you have a CEL lit???? If so, pull & post All of the trouble code numbes, as they can offer up good trouble shooting clues.

If no CEL lit, then look for a MAF sensor problem, maybe dirty, lazy O2 sensors, fuel pressure, or fuel pump problems, or maybe cloggged fuel or air filter, or an intake side vacuum leak, that could be anything from loose or cracked vacuum lines, to a stuck open, worn out PCV valve or connecting rubber hose, to an acting out vapor recovery system, or leaking vacuum line from it to the intake manafold.

Lots of possibilities, so we need some more details, to offer up a more focused guess.

 

[njbull]

yes, I cleaned the contacts on the spark sensor and plugged it back in. the CEL is not lit. i went over the vacuum lines but I guess I better double check. is there a way to check the MAF??

 

[pawpaw]

Did the bog problem begin after the distributor replacement????
If so, have you checked spark advance with your timing light???

Is fuel pressure ok????
Is the throttle position sensor reading ok????

The MAF sensors PID output & many other sensors output to the computer can be easily be read with a scantool like the Actron CP-9145, that'll monitor PID live feeds, or you could back probe it's electrical connector & measure it's ref & sig rtn voltage with a DVM, but the latter is a pia!!!!

I suppose if you come to suspect the MAF, maybe pull & clean it with CRC MAF sensor spray cleaner & keep it clean while reinstalling & see what happens.

BUT, before you do all that, where are you on all due past & present scheduled replacement maintenance items, like spark plugs, & wires, air & fuel filters, PCV valve ect, ect, as any one or a combination there-of could cause your problem!!!!

We just need some more clues to make a better guess!!!

 

[wjc]

There are bad rebuilt distributors, too. Check the pickup gap and forcefully try to wobble the shaft to check for lateral play in the bushings.

 

[njbull]

I removed and cleaned the MAF with CRC cleaner. Also changed the air filter. It still stumbles when cold but now runs better when when warmed up. Should I replace the MAF or keep looking??

 

[pawpaw]

Not a good idea to throw parts at a problem based on a hunch.

If we take the time to do a proper trouble shoot, get results we can believe in, Then make the repair, we're more likely to expierence joy!!!!

Anyway, there are a number of questions about things to check that could be inolved in your problem, that you've not yet aswered.

So, things like fuel pressure, O2 sensor & TPS PID's, scanning the computer & posting any set, or pending trouble code Numbers found, would be helpful.

If your diagnostic tool box is skimpy, most autoparts stores have things like timing lights, fuel pressure & vacuum gauges, multimeters & some have scantools, ect, in their "Loan-A-Tool" programs, for a refundable deposit, so you could begin a resonable trouble shoot diagnosis without having to own a lot of expensive diagnostic tools.

As I posted previously, if you can come by a scantool that'll read live PID feeds to the computer, it sure would make your trouble shoot a lot faster, easier & more accurate.

I suppose you could try disconnecting the MAF sensor & see if there is any difference in how it accelerates when cold. That'll turn the CEL on, but you'll know what it's for.

Using a good quality analog multimeter to masure the smoothness of how the TPS resistance changes as the throttle is opened, might be a worth while test.

How old, or how many miles are on the O2 sensors???? Have you checked their voltage switching range & speed with a scantool, or good quality digitial multimeter???? They belong on your suspect list if they have more than 100k miles on them.

 

[Jeff K]

93 is EEC IV and will not show live data.

Have you checked to see if the timing is advancing with SPOUT plugged in as noted above? By "attached module" I assume you mean the TFI module? If so, was it a Motorcraft unit or cheap chinese junk? Half the cheap off shore made TFIs are bad out of the box, and the other half fail within a few months. I have seen several cheapo brand new TFIs that wont advance spark in response to th SPOUT signal generated by the PCM.