Help with 93 SHO

[Bryce Minor]

i recently bought a 93 Taurus sho (manual) with 150k miles. The car runs and drives. (I’m new to tinkering with cars so my descriptions or knowledge might be annoyingly bad). The issue I’m facing now is that when I press on the gas it will bog out and die. If I lightly push the gas I can actually make my way up in revs but if I just push the throttle down to the floor it hogs out and dies. There doesn’t seem to be a misfire. Any advice would be greatly appreciated

 

[sperold]

Check for codes, both current and stored, preferably using the paper clip method, that you can research on this forum.

As a guess, the Throttle Position Sensor (TPS) going bad can give you this symptom, but the codes will answer your question.

 

[Bryce Minor]

Thank you for the response, I should have mentioned that there is no check engine light currently on, would the paper clip method still give me any information. Another thing is the throttle body seems to be functioning properly. I took the intake hose off and moved the throttle and the blade inside moved like it should. Could the TPS still be bad while the throttle body itself is working?

 

[luigisho]

Yes it is possible there are codes stored in the computer without a current check engine light on.

TPS is used to monitor the airflow/opening of the throttle butterfly valve. it does not interfere with the throttle body opening as it is controlled mechanically via cable. So yes it can and be faulty without any visual signs.

I would do easy things like check for codes, clean the MAF sensor element, check plugs and then look at other air/fuel/spark mechanical and electronic causes. Codes first.

 

[Bryce Minor]

Okay thanks guys.

 

[Bryan]

I agree with sperold. Check the codes before throwing parts at it. Old Tauruses have many electrical gremlins that will make you pull your hair out trying to diagnose and solve them.

 

[Bryce Minor]

Okay, I ran codes. The numbers I got were weird, I wrote down the numbers as they came out and then I wrote my interpretation of what codes those numbers could have been on the next line. Here are the codes I got and what those codes stand for. Nothing about the TPS. Let me know what you think

 

[rubydist]

please shoot a little video of the blinking light so we can decipher it for you.

 

[Bryce Minor]

I posted a video of the codes as well as my main issue that I’m having, here are the links to the videos.

(codes)

(Bog)

Let me know what you think! Thanks

 

[krednjen]

MAF is the one that jumps out at me. The computer combines Maf and TPS to get a value for "load". It uses "load" as the prime determinate for fuel delivery. If the "load" calculation is wrong, the fuel injector pulse width (fuel delivery to engine) is wrong.

 

[krednjen]

Of course, it is always good to start by checking for vacuum leaks, on these motors in particular. Also, I was taught to never diagnose a driveability issue without putting a fuel pressure gauge on the car.

 

[Bryce Minor]

Okay I will look into that. I have another update / issue / new info that might help diagnose. Yesterday I decided to let it warm up and get it on the road briefly. Once it’s warmed up, it does not bog out, it just revs up very slowly. Anyways I pulled onto the road and went full throttle in first gear. It started feeling a little more peppy up top (still bad) but then around 3000rpm maybe a little higher. The tone of the engine changed to a deeper tone and when I turned off the road I noticed it was running fairly hot right after the acceleration, and I know there is coolant in the system.

 

[rubydist]

ok here are the codes:
current
114 IAT out of range
stored
157 MAF signal grounded
211 crank sensor signal erratic
542 fuel pump secondary circuit

(It reads the current codes twice, then a 1 flash separator, then it reads the stored codes twice)

You MUST fix the IAT out of range first. This engine will never run right with that code showing up. It may be the IAT is bad, but more likely a wiring issue, since the MAF is on the same power circuit and you also have a MAF code.

You will need to address the crank sensor issue since that will continue to get worse until one day you are stranded on the side of the road.

The 542 can be ignored, since that code is set whenever the engine dies or stalls.

 

[Bryce Minor]

okay. Thanks for the help. I’ll let you know if anything interesting happens

 

[Bryce Minor]

Okay. I looked at it. I had a hard time understanding what exactly to start doing to try and address this possible wiring issue. First off I’m assuming that the IAT is on the intake manifold right after the throttle body. Assuming this is the correct sensor. I unplugged it and tried running the car. It started and died shortly after. I don’t know if this means it would be a bad sensor, because the car can actually run with it plugged in, just not well. If I were to start checking wiring where should I start? I have not ever messed with wiring on a car. Should I test voltage through some of the wires. Just I need some sort of general place to start. Thanks

 

[sperold]

I think the IAT is in the airbox and the MAF is the first component in the tubing when you leave the airbox.

I see a lot of butt-connectors in the wiring in that zone, so it has been molested and could be untrustworthy.

Move those wires around when the engine is running and see if anything changes.

Use a meter and see if all those connectors are continuous.

There is a chance it could be the components themselves, but the wiring is an economical place to start.

Although not absolutely necessary, the Electrical and Vacuum Troubleshooting Manual (EVTM) for the 93 Taurus would be a great help and they are usually available on E-Bay for around $15.00. It removes all the mystery of the wiring and components.

 

[Bryce Minor]

Alright. Thanks

 

[Stevenj444]

Okay I will look into that. I have another update / issue / new info that might help diagnose. Yesterday I decided to let it warm up and get it on the road briefly. Once it’s warmed up, it does not bog out, it just revs up very slowly. Anyways I pulled onto the road and went full throttle in first gear. It started feeling a little more peppy up top (still bad) but then around 3000rpm maybe a little higher. The tone of the engine changed to a deeper tone and when I turned off the road I noticed it was running fairly hot right after the acceleration, and I know there is coolant in the system.

You were hearing the secondaries kick in this happens between 3800 to 4000 rpm. It's a good thing and how it makes all that power also check the intake hose (behind the MAF) for cracking if it gets air the MAF dosen't know about it will run rough

 

[BaySHO Performance]

My code interpretations are a little different:

114 ACT (Air Charge Temp , aka IAT) higher or lower than expected. This is the sensor plugged into the air box.
157 MAF circuit below minimum voltage
211 PIP (Primary Induction Pickup, aka CPS: Crank Position Sensor) circuit failure
542 Fuel Pump secondary circuit failure.

I've never know an ACT Sensor to go bad.
I had a car that bogged down under heavy acceleration but was fine under light acceleration. Cleaning the MAF fixed it. But could also be a vacuum leak or bad MAF.
The CPS will short out and make the engine die if the water pump leaks on it, shorting it out. Car won't start again until the CPS dries out. However, those don't seem to be your symptoms. The car either runs fine, or doesn't run at all.
542 caused by stalling at a light.

So I second going after the MAF, as well as looking for a vacuum leak.

 

[Dale Leonard]

Before you go too much further you need to check the cats as they will break apart inside and not let the exhaust get out and it will cause backpressure and cause the engine to run hotter. Also you may be loosing fuel pressure from a clogged fuel filter or from a weak fuel pump. On all the early sho's that I have owned I have cut holes in my cats and gutted them and tehn welded the cats back up. Have owned 6 sho's from the 1989 to the 1963 and have found 4 of them with bad cats.