Newbie here,help!!

[edy figueroa]

Hello to everyone!!

I am new to the forum and with my 97 GTP.
The car losses all acceleration power when charger kicks in at wot.
These are the codes;
p0300
p0102
p0141
p0135

Have changed;
MAF,MAP,plugs and wires(ac),ignition module,fuel filter,air filter,charger pulley,coolant sensor,tstat,cleaned throttle,iddle sensor,pcm reset
But no luck!
The car feels very slow during hard acceleration and the charger is boosting nicely.It is stock but no cat and no ubend(still has the 2 o2 sensors) It just began all of a sudden!!
I will appreciatte any help!
Thanks,
Edy.

[edy figueroa]

I forgot to mention that the fuel pump is making a hizzing sound and the car is working at hotter temps in traffic.Can it be the fuel pump?

[GTP Dad]

Welcome to AF!!

It appears you have a fuel delivery issue. I suggest you search the forum or check the maintenance section on how to bypass the fuel pump resistor. This may be preventing the fuel pump from going into the high output mode at WOT. Also check and clean the injectors. The code 300 indicates random misfires and you may need to clean or replace the injectors to get this to go away. As for the O2 sensors you need to replace the one on the downpipe and get an O2 simulator for the rear one. The PCM may be sending too much fuel to the engine causing it to load up since the sensors are not working properly as indicated by the codes. Finally, if you used a reman MAF sensor spend some money and replace it with an OEM one from AC Delco. The reman units have a lot of issues especially those from Autozone. This could also be part of the issue.

Good Luck!

[04GTP-WhatLAG?]

don't waste your money on an O2 Sim!

I have an easy solution that i running on my car and it works... when I got my highflow cat, even with a O2 extension harness, I still set a SES light(common problem on '04+ GPs running magnaflow highflow cats)... for a while I would just use my OBD-II scanner to clear the code and I was waiting for a vendor to release an O2 Sim for the '04+ GPs(right now all they have is one for the '97-'03s, which is not interchangeable for us)... But then, on another car board I found a post that was too good to be true, but it works, its going to sound ridiculous, but it works, trust me, I installed the mod, cleared the code and it has NOT returned in 6 months, so its as good as gone... Here is the solution:

go to Autozone and buy a pack of sparkplug anti-foulers, they are $3.99... You will need a drill and a 1/2 bit which can be used in drilling metal... on one end of the antifoulers(there will be two pieces in the pack, they are identical) there is a small opening, what you want to do is take the 1/2 drill bit and hollow this small opening out to the size of the drill bit, drill all the way into the antifouler so the whole piece has a hole with a circumference 1/2"... now do not modify the other piece, leave it as it is... now screw the modified antifouler onto the unmodified antifouler so you have a single device, should look like this:





(as you can see where you drilled is the top of this piece, that is what you want to screw into your O2 bung, then plug your O2 harness into the bottom of the unmodified antifouler, clear the SES light and it won't come back... As unbelievable as its sounds, my car is living proof it actually works, so what they charge you $90 for, you can make with a $4 piece and a 1/2 drill bit, an electric drill, and a vice(to hold the piece while you hollow it out)...

[BNaylor]

Originally Posted by 04GTP-WhatLAG?

don't waste your money on an O2 Sim!

I have an easy solution that i running on my car and it works... when I got my highflow cat, even with a O2 extension harness, I still set a SES light(common problem on '04+ GPs running magnaflow highflow cats)... for a while I would just use my OBD-II scanner to clear the code and I was waiting for a vendor to release an O2 Sim for the '04+ GPs(right now all they have is one for the '97-'03s, which is not interchangeable for us)... But then, on another car board I found a post that was too good to be true, but it works, its going to sound ridiculous, but it works, trust me, I installed the mod, cleared the code and it has NOT returned in 6 months, so its as good as gone... Here is the solution:

Sounds like an interesting fix. Has anyone done this to a '97-'03 model?

I would hold off on the rear 02 sensor probem until the other issues and DTCs are resolved first. The problem I see is the DTC he is getting for the rear post CAT 02 sensor is not a typical DTC due to a CAT convertor efficiency problem. That DTC is typically P0420. P0141 is a 02 sensor heater circuit problem which means additional troubleshooting is warranted like checking the 12 volts to the heater portion of the O2 sensor and PCM 5 volt reference signal. However, it is possible to get a P0141 DTC if the rear O2 sensor itself is bad and the fix mentioned or a 02 simulator/emulator should work. The O2 simulator costs around $40 or less so thats not too bad if you're lazy and don't feel like doing any additional work. Simple plug-in at the electrical connector.

I had my Intense PCM module custom programmed to inhibit any possible post CAT DTC(s) and I run a Magnaflow Hi-Flo CAT. The extra programming charge was around $10 and that was done before installing the aftermarket CAT.

[edy figueroa]

Great to be a part of this forum.Many persons willing to help.I haven't have the chance to do more to follow your advices to fix this but what i did notice is the fuel pressure at iddle is 42 psi with a gauge i installed,is it normal? Or it has to be 52 or so?

I will be posting any findings or fixes..

[BNaylor]

Fuel pressure is checked in different ways which will not only check the fuel pump output but flow and the fuel pressure regulator, therefore it varies. What is your reading with the vacuum line to the fuel pressure regulator disconnected? It should be higher than the 42 psi.

Also, you check it at fuel pump prime which is with ignition to on not start. Look for the highest reading (spike) on the gauge even if you have to repeat it a few times. This should be in a range of 48-55 psi.

[edy figueroa]

Originally Posted by bnaylor

Fuel pressure is checked in different ways which will not only check the fuel pump output but flow and the fuel pressure regulator, therefore it varies. What is your reading with the vacuum line to the fuel pressure regulator disconnected? It should be higher than the 42 psi.

Also, you check it at fuel pump prime which is with ignition to on not start. Look for the highest reading (spike) on the gauge even if you have to repeat it a few times. This should be in a range of 48-55 psi.

I just did a couple of tests:
While iddle i disconnected regulator vacuum and it only reached 46 psi! Then i connected back and went to 40!? Then i put the car ignition at the on position a couple of times and it only went to 40 or 41psi.
So it is telling me that needs a fuel pump replacement? And this is a possible cause for the huge loss of power? I did the maf test (disconnected it) and no difference in performance.
Ed.

[Scrapper]

yes sounds like fuel presure is to low..i'm pretty sure 50-55 shold read on fuel pressure..even some run 60 on other cars or trucks as well..good luck.

[edy figueroa]

All right,
the car just died on me on start up this morning! I checked and the fuel pressure goes down first and then the car shuts off.Guess i will be looking for a new pump...

[04GTP-WhatLAG?]

Originally Posted by bnaylor

Sounds like an interesting fix. Has anyone done this to a '97-'03 model?

yes, I know for a fact it works on '04 Grand Prixs, '00 Grand Prixs(so I would assume all of them), Nissan Sentras, 350z, and S10 trucks... I'm thinking it will work on just about anything, it must confuse the PCM or something, that is the only thing I can figure out, it makes absolutely no sense as to why it would work, but whoever figured it out, is a freakin' genius, I can take no credit for it, I saw it on another board, but it does work, I can vouch for that...

[edy figueroa]

Follow up!
I just did the fuel pump resistor bypass (bent the 85 clip on the fuse box relay)as i learn from this forum and the car is up running again with the fuel press reading 55psi! But still lagging acceleration at wot.
What do i do next?
thanks.

[edy figueroa]

Fixed!

The problem with the loss of power was a bad coil.
Had put 3 new ones and the car runs like a champ now,
thank you guys for your help.

Edy.