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-   -   97 gt pi engine swap problems (https://www.allfordmustangs.com/forums/4-6l-tech/1074169-97-gt-pi-engine-swap-problems.html)

Khenji 06-15-2018 04:21 PM

97 gt pi engine swap problems
 
Had the 99-04 automatic engine swapped into my 97 manual gt at a shop and they swapped over bolt one from the 97 like long tubes, pulleys and cold air intake. Also they had to order a new flywheel for it to bolt to the automatic engine. First time driving out the shop the car seemed to be misifring especially at low rpms, but never threw a misfire code. Under full throttle it would spit/stutter and be very hesitant to go. The shop said it would need a tune because of the modifications and it being the pi engine instead of the npi. Bama sent a custom tune so it's on 87 performance however I'm running 93 octane gas. Only have been driving it tuned for a day there was a little improvement in the spitting but it's still hesitant on full throttle. Also threw codes for

Evaporative Emission Control System Vacuum System – Purge Control Valve,

Catalyst System Efficiency Below Threshold,

insufficient switching of oxygen sensor bank 1,

A Heated Exhaust Oxygen (HO2S) sensor indicating lean at the end of a test is trying to correct for an over-rich condition

Astangthang 06-15-2018 05:54 PM

Hey brother, I'm a 97 Gt owner myself. Pi swap cars run just fine without a tune, and most people don't get a tune unless the have seen other work do e at the same time. I know that the diagnostic codes say the O2's, but how you're describing the problem sounds like that's what it is. Sometimes it's just that simple and some other times it will tell you something totally different from what is actually wrong, like let's say a good ole' vacuum leak. But that's not your problem. You definitely need to dive into the O2 sensors problems and make sure everything is plug up correctly, and give it a once over. Was there anything wrong before you swapped?

Khenji 06-16-2018 09:16 AM

Quote:

Originally Posted by Astangthang (Post 9190391)
Hey brother, I'm a 97 Gt owner myself. Pi swap cars run just fine without a tune, and most people don't get a tune unless the have seen other work do e at the same time. I know that the diagnostic codes say the O2's, but how you're describing the problem sounds like that's what it is. Sometimes it's just that simple and some other times it will tell you something totally different from what is actually wrong, like let's say a good ole' vacuum leak. But that's not your problem. You definitely need to dive into the O2 sensors problems and make sure everything is plug up correctly, and give it a once over. Was there anything wrong before you swapped?

No problems at least anything that was throwing a code before, same exhaust as before the swap too, could the o2 sensor be the cause of the misfiring symptoms under low rpms and full throttle?

Astangthang 06-18-2018 02:25 AM

No problems at least anything that was throwing a code before, same exhaust as before the swap too, could the o2 sensor be the cause of the misfiring symptoms under low rpms and full throttle?[/QUOTE] yes my friend the 02's will definitely make it run lime doo doo. The purge valve won't have anything to do with performance, at least in my experience when mine when out I didn't notice any I'll effect, and I've owned a my 4.6 for 18 years now. I can tell if I don't get fresh gas. Cars are like wemon. One thing I hate is a check engine light. If your car has around 100k, and you haven't changed them, they are due.

Astangthang 06-19-2018 08:53 AM

Any progress yet bro?

Khenji 06-22-2018 03:39 PM

[QUOTE=Astangthang;9190959]Any progress yet bro?[/QUOTE just got some quotes from exhaust shops to see how much to fix the o2's, just having a hard time believing that the o2 sensors would cause it to drive rough like that

wmburns 06-22-2018 04:48 PM

Quote:

Originally Posted by Khenji (Post 9191621)
just got some quotes from exhaust shops to see how much to fix the o2's, just having a hard time believing that the o2 sensors would cause it to drive rough like that

Do you want PROOF that the problem is related to O2 sensors? If so, you will need an ODB2 scanner capable of monitoring operational PID's. Look at the Long Term Fuel Trims (LTFT) for bank 1 and 2. IF there is an exhaust leak, THEN the O2 sensors will "think" that AF mixture is LEAN and will add fuel (positive LTFT's). However the AF mixture is likely OK. The additional fuel will make the AF mixture in fact RICH.

Sooooooooooo the next step is to examine the spark plugs to see if in fact the combustion has been RICH.

Then you will know for certain one way or the other.

Here's some information on an affordable Windows based ODB2 scanner with graphing capabilities.

ForScan ODB2 scanner w ELM327 USB
https://www.stangnet.com/mustang-for...elm327-usb.57/

Khenji 06-22-2018 05:00 PM

Quote:

Originally Posted by wmburns (Post 9191625)
Quote:

Originally Posted by Khenji (Post 9191621)
just got some quotes from exhaust shops to see how much to fix the o2's, just having a hard time believing that the o2 sensors would cause it to drive rough like that

Do you want PROOF that the problem is related to O2 sensors? If so, you will need an ODB2 scanner capable of monitoring operational PID's. Look at the Long Term Fuel Trims (LTFT) for bank 1 and 2. IF there is an exhaust leak, THEN the O2 sensors will "think" that AF mixture is LEAN and will add fuel (positive LTFT's). However the AF mixture is likely OK. The additional fuel will make the AF mixture in fact RICH.

Sooooooooooo the next step is to examine the spark plugs to see if in fact the combustion has been RICH.

Then you will know for certain one way or the other.

Here's some information on an affordable Windows based ODB2 scanner with graphing capabilities.

ForScan ODB2 scanner w ELM327 USB
https://www.stangnet.com/mustang-for...elm327-usb.57/

oh yea you sent that on the other forum that thing does like very helpful, but what you said makes sense. So it sounds like the best bet is to check for exhaust leaks and replace the o2 sensors? Should I replace all 4 or just the upstream on bank 1 since the code only referred to bank 1? Should I go ahead and replace the cats too?

wmburns 06-22-2018 09:00 PM

Quote:

Originally Posted by Khenji (Post 9191629)
oh yea you sent that on the other forum that thing does like very helpful, but what you said makes sense. So it sounds like the best bet is to check for exhaust leaks and replace the o2 sensors? Should I replace all 4 or just the upstream on bank 1 since the code only referred to bank 1? Should I go ahead and replace the cats too?

Note. I haven't advocated for you to change a single part. The operative word here is to TEST/CHECK.

IF there is an exhaust leak the O2 sensors can't work correctly when outside air is allowed to enter the exhaust stream. Therefore the true state of the O2 sensors is UNKNOWN.

Consider that the rear O2 sensors do not affect HOW the car drives. So why replace a part that is not known to be bad? Especially since it won't improve driveability.

Regarding the cats. There's a saying that cats never die. They are murdered. Which means that IF the cats are bad, THEN something caused them to fail. Soooooooooo if you were to replace the cats and did not fix the reason, then you should expect the new cats to fail as well.

Your reply indicated that you did not believe O2 sensors could cause the poor driveability. Those of us that work frequently on our own cars know quite well that O2 sensor problems can cause all sorts of driveability issues. My intent was to give a thought experiment to help you come to your own conclusion.

But don't focus on an O2 problem and ignore any other possible causes for misfires. In general, start trouble shooting with any misfire DTC codes.

90lxwhite 06-23-2018 08:19 AM

226 Attachment(s)
Is there a difference between an automatic’s ecu and a manuals?
If it’s the O2’s, it’d be the fronts.
Many, many, things can cause a misfire, the O2’s just happen to fall into that “list.” It might fix your problem but probably not since they worked previously. If you want to change them it’s not hard if you have an O2 socket.
I didn’t check the size but this is the kind you’re looking.
https://www.walmart.com/ip/Wilmar-W1...&wl13=&veh=sem

neuron 06-23-2018 02:35 PM

[QUOTE=90lxwhite;9191727]Is there a difference between an automatic’s ecu and a manuals?

They list a seperate one for the GT and 3.8 with different trannies.


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