'95 T5-r Misfiring 3 way Cat Codes

warmblood58 · Post by **warmblood58** » 31 Mar 2016, 16:15

Well, the good news is my car smogged today after sourcing EVAP leak and bad purge valve. The bad news it began running badly and threw CEL codes 544, 545,554, and 555 which show up as 3 way CAT damage. My thinking is, this car sat for 4 years with bad fuel, I drained tank and cleaned pump basin and then ran two tanks of Techron Complete fuel treatment. Could misfiring be due to partially clogged fuel filter? I am wondering if my fuel treatment freed up all kinds of junk and that perhaps the filter which has maybe 5-600 miles on it is already clogged and causing some misfiring? I did the following - replaced plugs (copper), cap and rotor, replaced vac lines, front 02 sensor (it threw a code for faulty) CBV, replaced fuel pump, oil change, air filter and cleaned throttle body and MAF. The plugs wires are Bougicard and were represented as almost new by owner and indeed, they appear to be new. It seems like I see a lot of threads where other owners replaced their wires and had no result so I am hesitant to replace wires - tonight I will mist to see if I have bad wire(s). So far, I am having a love hate relationship with this car as it seems to go through stages of running well and then badly . . . . Any thoughts?

Post by **rspi** » 31 Mar 2016, 16:19

Is it a wagon or sedan? The wires have a date stamped on them, in yellow.

warmblood58 · Post by **warmblood58** » 31 Mar 2016, 16:40

Thanks Robert, car is a sedan. Now I wonder if plug wires were new 4 years ago and then just lost continity from time. I will check date. Seems like this condition came on somwhat gradually, car had been sitting for a week with 6 gals in tank. It really seemed fuel starved at low speed as I returned home on a low speed limit street. I parked car for about 10 mins and upon startup, it had more reliable power

Post by **abscate** » 31 Mar 2016, 20:52

Fuel problems tend to be digital, not intermittent.

Cars with low power aren't fuel starved, they usually have vacuum leaks or ignition faults.

Do you know the engine has good compression?

warmblood58 · Post by **warmblood58** » 31 Mar 2016, 21:43

I was thinking that the fuel filter was slowly clogging . . . changed filter, blew through old (very new filter) and feel that it is not an issue. I did notice that when I relieved fuel pressure at bleed valve there seemed to be very little pressure and gas blow off as I pushed in bleeder . . . fuel pump may be underperforming . . .I will check pressure tomorrow. Per Robert, I checked Bougicard plug wire manufacture date - if I read wire codes correctly (yellow script) the wires date back to 2001 - not so new afterall unless PO purchased new old stock. I am going to go back outside when it gets darker and mist the wires to see if I see any arc-ing. I pulled plugs, they looked super clean and dry (maybe 300 miles on them since install) Vacuum seems good, elbow under PS pump has plenty of vac and other connections are tight. I suppose I will check compression tomorrow to see what I see - top end was rebuilt about 40,000 to 60,000 miles ago so I expect to see some good readings, car when boosting and in general has good power, feels strong and no blowby coming off oil cap. I am starting to suspect the coil, wonder if it cuts out when heating up??? I have a back up coil that I may swap in to see what happens. Are the coils pretty interchangeable for 94-97 cars?

warmblood58 · Post by **warmblood58** » 01 Apr 2016, 09:35

No arc-ing of wires when misting with water . . . think I will swap out coil today and see what effect that has. What port on the A box (this is a '95 car) tests for ignition faults?

warmblood58 · Post by **warmblood58** » 01 Apr 2016, 16:20

I put in some autolite coppers when I first fired this car as they were they only copper style plug that my FLAPS had but having read way too much about plugs being the cause of misfiring under load - I had removed some ngk iridiums that I cleaned up, I think I will pop those back in this afternoon to see if the misfiring changes - car runs well at lower rpms, fast startup, good idle

warmblood58 · Post by **warmblood58** » 02 Apr 2016, 11:43

no change with the iridiums . . . going to check for any vac leaks and swap out coil today - I have some new bougicard wires arriving monday. Going to check crank sensor as well along with temp sender connections

Post by **JDS60R** » 02 Apr 2016, 14:25

the codes you listed are for random and specific misfire.
Its always good to make sure plugs, wires ( cap and rotor especially) are working correctly and not covered with corrosion or oil. (Clean the contacts inside the cap and on the rotor)

But random misfires point to systemic issues.
Either it can't fire because of lack of spark (coil) (common failure)
or the air/fuel ratio is so far off it can't fire whats in the cylinder (MAF(very common), oxygen sensor)
then there is the rare electrical fault on timing (cam sensor starting to fail)(uncommon - usually works or doesn't)
and the even more rare (timing belt slip)(semi common if over 100 k without belt maintenance)

The failures com on like this - If its fuel - it will be a analog/liquid/soft fail ( you are driving but it can't accelerate - you are stopped and it slowly stalls -even if fuel pump is failing on and off -once off the remaining pressure drops and then it stalls. )

If its electrical - its like turning a light switch on and off. You are accelerating and all of a sudden its jerky or kicking. (coil is arcing out A/F is way off)

PS - some 95s have obd under coin holder next to cigarette lighter in front of shifter.

If you run a wire from the positive side of batt ( or any positive like cig lighter ) and run a ground to the ground/signal side of the coil and then put a 12v bulb (small - or led) between them you can monitor the events at the coil -

This way you can see whats going on immediately If its misfiring while the coil is being pulsed regularly then we would lean towards a AF issue. (given we know the coil is good). If the signal is not constant we go to cam sensor and square wave converter at coil. I have a known good coil I trouble shoot with.

Wish you were closer . I'm in MN this week and back in TN next week. I would have you diagnosed in under an hour.

let me know how it turns out. I can take calls today and tomorrow but busy most of next week.

warmblood58 · Post by **warmblood58** » 02 Apr 2016, 15:03

Hi, thank you for such a complete description. The good news is, I think I may have discovered the issue, the fuel pump pressure at the rail is only 34 psi. My understanding is the fp is supposed to be in the low 40's, correct? If this is true, it explains why the car drives so well around town but misses when you start to put your foot into it. I purchased this fuel pump used just to get this car running . . . On to a compression check next. I am curious to see if fuel pressure holds for the next half hour while car sits. Thanks again for your advice!