Engine Codes, What to Believe!

[stuartporter]

For the last couple of months the check engine light has been coming on periodically, it will come on for varying lengths of time, i.e. seconds to minutes, I have also noticed on occasions that under heavy acceleration sometimes the engine hesitates, you ease up on the gas pedal a bit and it catches and progresses smoothly, there doesn’t seem to be a connection between this happening and the engine light coming on, although if the engine light comes on and you let the gas pedal up abit, to take some of the load of the engine, it usually goes off.

I bought a code scanner and pulled the codes, I got a code 33 followed by a long pause, another blink, another long pause and then code 33 again, according to the Haynes manual, the code indicates the EGR Value as being the culprit. Armed with this knowledge I took the car across to the local shop, and mentioned my findings, initially they had wanted to change the o2 sensors on the car, But they couldn’t determine which one was bad using their computer, I suspect that if an Explorer comes in with a ‘check engine light’ problem, that’s the usual practice!

Anyway turns out that his computer was actually fried by another car and couldn’t pull codes, so he pulled the codes using a screwdriver with a bulb inside, in a manner similar to using the volt meter, I watched him pull the codes and he got 3 codes, the first one being a 53 (Throttle Position Sensor) followed by a 86 and I forget the last one.

While looking at the car I noticed that there was a split in one of the tubes leading to the Differential Pressure Feedback Sensor (DPFE), (this was replaced but doesn’t seem to have made any difference).

I took the truck back home and pulled the codes again, I got code 33 twice (no 53)

What would be the symptoms of a deflective EGR valve or Throttle Position Sensor? And do they match the ones I have described above?

Can anybody recommend a good shop in the Scottsdale/Phoenix area?

Thanks in advance

 

[Phantom]

I had a similiar problem. I got an EGR fault and changed it but it didn't kill the light. I pulled the DPFE/PFE sensor off and found the hose nipples full of junk. One of the hoses was completely blocked. I cleaned out the hose, replaced the sensor, reset the computer and the light is gone.

 

[stuartporter]

Were you having similar symptons with the car or did you just have the same code?

I'll check out the hoses and nipples this weekend.

Thanks

 

[Phantom]

Similar symptoms. I had the codes read at a shop and they just told me it was an EGR fault. But like I said , this is a generic fault as I am told by them and Ford, and it took a bit of digging to find the actual problem. It could be BS but it's fixed now.

 

[stuartporter]

I checked for split hoses and made sure the nipples were clean, I also did a couple of diagnostic test with a voltmeter and everything appeared fine,

I put it in the shop to get the Oil, Transmission and a general tune up done, I also asked them to diagnose the engine light, They tried to hook up their computer but couldn't pull any codes, he seems to think that the computer might be faulty!

On the other hand he did say that from the way the truck is running and the mileage I'm getting (16.5-17mpg, with AC on full blast) he doesn't think it can be anything major.

any ideas on what I can do next?

Just a though, I ususlly use ARCO gas(on the way to work) I have just read a post where a guy was getting his light come on due to bad gas! Would this be true? how big a difference is there between gas types over here? (I come from Scotland, where gas is gas).

Thanks

 

[Triton46]

Im getting a check engine light too. I havent read the codes yet but assumed it was a FPR going out do to a heavy gas smell (read Check Engine Madness!!!!!! for details).

I have a 1991 Ford Explorer, I know I dont have OBDII, so what do I have and what do I need to get to read the codes as I dont want to pay Ford $50.

The O2 sensor was replaced a few months ago, and the check engine light went away but now its back. The only change is a K&N air filter. Were heading back to NC tomorrow and I just reset the computer. What else can I try?

 

[stuartporter]

Well, I'm not sure how much faith I would put in reading your own codes, I ended up putting my Exp into a ford shop, the local shop said they couldn't read the codes, the scanner I bought was saying 33 (ERG Fault).

Ford hooked up the car and one O2 sensoe was totally dead, the other was out of range, The hesitation problem on acceleration was traced to a faulty wire.

I got it back and everything seems to be running fine, no lights and no hesitation problems.

I don't understand why I was getting a code 33 and the local shop got a code 53 when it was the O2 sensors!

 

[Triton46]

Hey, thanks for the response. You may have missed the second set of codes. I'm not sure about the 94's but on my 91 there are two sets of codes. The first set said it was my transmission sensor, then there was a code of 1 which meant the computer was going into continuous memory and I received another set of codes. These codes pointed to the O2 sensor and a lean running condition on the fuel pump. Turns out the two were related. I took out the old O2 sensor and it was totally shot, put in a new one and reset the codes (by using the jumper method) and have not had a problem yet.