Codes: 33, 41, 63, 91 Car running like crap (maybe 3G alternator to blame??)!!

[Ishman 306]

Upon initial startup after I installed my 3G alternator, I noticed that my car has run like crap. Here are the symptoms:

At Idle:
Car will idle at like 600 rpm barely staying alive shaking the car back and forth (E303 cam)...then sometimes it will raise back up to 850rpm which is what its set at and idle perfectly.

Accelerating:
Car will accelerate very roughly (slight bucking) then on top of that if you give half to full throttle the car starts sounding like its completly missing (popping in exhaust sometimes), very hard to climp in rpm........then sometimes it will clear up all the sudden and snap your head back and run perfect....

I pulled code 33 KOEO test all the time and in continous memory 63 (TPS below voltage)...

Then KOER test pulls code 63(TPS below voltage)sometimes 41(left o2 lean) sometimes, 91(right o2 lean) sometimes...or even all of them sometimes...

What is the deal, My theory is that the added current from the 3G alternator fried a weak power wire that goes to the TPS(code 63) and the EGR (code 33)....both of these sensors are fed 5V off the same wire. I figure I'm getting 41 and 91 because the computer looses TPS reading and doesn't know how much gas to dump in.

Also the car used to have an external regualted alternator, i took all this off when installing the 3G (internally regulated right), could this cause an issue?

Can anyone help with this? I've already tried a new TPS and it did nothing.

 

[jrichker]

What is the deal, My theory is that the added current from the 3G alternator fried
a weak power wire that goes to the TPS(code 63) and the EGR (code 33)....both of these
sensors are fed 5V off the same wire. I figure I'm getting 41 and 91 because the
computer looses TPS reading and doesn't know how much gas to dump in.

Can anyone help with this? I've already tried a new TPS and it did nothing.

The TPS & the alternator are on two entirely different circuits. Most of your theory
is inaccurate. Here's a book that will get you started with how the Ford electronic
engine control or "computer" works.

The TPS 5 volts is provided by a regulator inside the computer. Fry it and none of the engine controls work .

Ford Fuel Injection & Electronic Engine Control 1988-1993 by Charles Probst :ISBN 0-8376-0301-3.

It's about $20 from Borders.com see http://www.amazon.com/ . Select b...nded mine to one of the intake manifold bolts

 

[Ishman 306]

I wonder if the rough drive is from a vacuum leak....but why would I be getting code 63 (TPS below min voltage)?

 

[jrichker]

You are going to need a good DVM, so I hope you have one.

The 5 volt VREF voltage is sourced from inside the computer to provide a precision reference voltage for several of the sensors. The TPS, EGR & Baro sensors all use the 5 volt VREF. It is supposed to be 5 volts DC, +/- .25 volts.

Look for 5 volts on the orange/white wire for the TPS. The connectors and wiring are subject to damage and corrosion. Look for 5 volts on the orange/white wire for the EGR sensor. No 5 volts there, and you may have some dirty connections in the 10 pin salt and pepper shaker connectors. Look for 5 volts on pin 2 of the white connector. No 5 volts there, look for 5 volts at the orange/white wire on the Baro sensor mounted up near the windshield wiper motor. No 5 volts there and you have wiring problems inside the wiring harness or computer. The tip off is often a code 22 for a failure of the baro sensor along with the other codes. A faulty baro sensor will cause all kinds of idle/driveablity problems. They are expensive, so don't replace it unless it has really failed.

 

[302RollinHard]

Are you properly grounded for yor 3G upgrade (upgraded grounding with alt?)? I know that grounds can mess with you like that from time to time

 

[Ishman 306]

I've checked all the grounds I could think of. Does this sound more like a vacuum leak to anyone, and the TP below min voltage is just another seperate problem?

 

[jrichker]

Number 1 troubleshooting principal: Fix what you know is broke first. Then once it is properly fixed, chase other rabbits.

You'll be suprised how many other problems go away when you follow this path.

If the TPS voltage is incorrect, it will affect the idle. Fix that problem first and then look for vacuum leaks. My last post gives you the information you need to troubleshoot the problem.