Poping sound at idle, help..

[LuminousX]

Any updates?

yeah, sorry I took so long for a follow up.. I went with a PCM from eBay FlashMasters, found a 97 Manual VIN and had them programmed it.
I have 2 Major problem with the car now.. Car seems kinda lazy on the throttle, it won't even rev match properly because it's so lazy/delayed..
my next issue is, when I'm coming to a stop with clutch in, the car dips in power as if the engine slowed all the way down and the alternator just falls flat on it's face, not sure what's up with that.. I still have that #2 misfire but I think it as something to do with the fuel, and the delivery to the injector... I have a gauge on the Shrader valve and it's just bouncing all over the place once the car is hot.. not sure what could be causing that.

it idles fine for the most part, you don't hear the popping anymore, but I can tell it's still there.. it's that #2 that's causing it..
and spark is just as low from when I had put that Original PCM back in as a test. turns out it wasn't -4 degree it was just 4 degree

Original.97.Tune.Manual.7.10.2024.hpt

24-07-10 21-17-49.hpl

https://youtube.com/shorts/FslLebz6Ddw when engine is hot
https://youtube.com/shorts/pOC0pVxEpOY when engine is cold

P.S Vacuum line is disconnected, it's running a Delphi FP10016 FPR - KEMSO 340LPH Fuel Pump, Fuel Filter is 4 years old.

[LuminousX]

Car seems to run quite a bit hotter since the new PCM installed, before I could maintain 185 degree in traffic (180 thermostat installed) with the fan on (fan on switch) but now it creeps up to 205+ guess it's time for that 3 inch aluminum radiator upgrade.

[SiriusC1024]

Wait the vacuum line to the FPR is disconnected? The data isn't setup for that. You should reconnect then get a good log. Get a new reg while you're at it if the pressure is all over the place. See if we can figure anything out.

[SiriusC1024]

I just watched the vids you posted. There shouldn't be that much variation in pressure with the line disconnected. Are you sure the factory regulator can bypass enough to regulate that fuel pump, or is it acting like a restriction and raising pressure? An aftermarket FPR may be in order. Same for the return line size.

That jitter in the needle is from the injectors firing. Usually on a vacuum-referenced system the FPR will damp that. On returnless there's a damper on the rails.

If this remains with the new FPR then one of these will fix it. I have one and it certainly made a difference. Problem is they require aftermarket rails.
https://www.radiumauto.com/Fuel-Pulse-Damper-Direct-Mount-Kits-P759.aspx

[LuminousX]

I just watched the vids you posted. There shouldn't be that much variation in pressure with the line disconnected. Are you sure the factory regulator can bypass enough to regulate that fuel pump, or is it acting like a restriction and raising pressure? An aftermarket FPR may be in order. Same for the return line size.

That jitter in the needle is from the injectors firing. Usually on a vacuum-referenced system the FPR will damp that. On returnless there's a damper on the rails.

If this remains with the new FPR then one of these will fix it. I have one and it certainly made a difference. Problem is they require aftermarket rails.
https://www.radiumauto.com/Fuel-Pulse-Damper-Direct-Mount-Kits-P759.aspx

Well it's normal for the most part. looses pressure and fluctuate a lot when hot, doesn't sound like a FPR issue... that thing is only 3 years old.. it does it with the vacuum and without..I might start with the power going to the fuel pump.. if that checks out then fpr it is.. I thought the data you gave me was supposed to work on a 4 bar rail.. didn't know it made a difference if referenced or not.. if I attach the line then I'm at to 43 psi cold and around 39 hot.. do you have any changes for that or just do a log?

[SiriusC1024]

That's the way it's supposed to work with the vacuum-referenced reg. Set a pressure with the vacuum line disconnected. When it's reconnected the regulator will maintain that pressure across the injector. Manifold vacuum pulls fuel through the injector (in the case of boost the force is reversed) just as pressure in the rails pushes. That's why all the fuel injector data in the tune has the same values for every column of kPa.

In your case it's really a 3.8bar (55psi or 380kPa) vacuum-referenced reg. Line unplugged that's what should show on a gauge measuring rail pressure. Plug it back in. Start the car. Manifold vacuum is 37kPa in the last log. That's also vacuum to the reg. 380kPa-37kPa = 343kPa = 49.74psi.

The regulator is not regulating to the correct pressure. That or the fpr on those cars is 3.3bar (48psi) to get 43psi idle? Like I said earlier in Post #7, I figured those were regulated lower.

Anyway, that data is converted over from GM data that was valid for 4bar. Going to 3.8bar won't make much of a difference. Going anywhere near 3bar is going to. Looking at RockAuto, GM uses another type for some 3800's. Fortunately, you can switch to it and get the 3.8bar reg. That's what I recommend doing.

1995-2002 Chevrolet Camaro:
https://www.rockauto.com/en/catalog/...regulator,6124

1997-2003 Pontiac Grand Prix GTP (3.8bar):
https://www.rockauto.com/en/catalog/...regulator,6124

updated fpr.png

[LuminousX]

That's the way it's supposed to work with the vacuum-referenced reg. Set a pressure with the vacuum line disconnected. When it's reconnected the regulator will maintain that pressure across the injector. Manifold vacuum pulls fuel through the injector (in the case of boost the force is reversed) just as pressure in the rails pushes. That's why all the fuel injector data in the tune has the same values for every column of kPa.

In your case it's really a 3.8bar (55psi or 380kPa) vacuum-referenced reg. Line unplugged that's what should show on a gauge measuring rail pressure. Plug it back in. Start the car. Manifold vacuum is 37kPa in the last log. That's also vacuum to the reg. 380kPa-37kPa = 343kPa = 49.74psi.

The regulator is not regulating to the correct pressure. That or the fpr on those cars is 3.3bar (48psi) to get 43psi idle? Like I said earlier in Post #7, I figured those were regulated lower.

Anyway, that data is converted over from GM data that was valid for 4bar. Going to 3.8bar won't make much of a difference. Going anywhere near 3bar is going to. Looking at RockAuto, GM uses another type for some 3800's. Fortunately, you can switch to it and get the 3.8bar reg. That's what I recommend doing.

1995-2002 Chevrolet Camaro:
https://www.rockauto.com/en/catalog/...regulator,6124

1997-2003 Pontiac Grand Prix GTP (3.8bar):
https://www.rockauto.com/en/catalog/...regulator,6124

updated fpr.png

I opted to go with one of those adjustable FPR that has the screw at the back, got it at around 60psi.. but I am still having that issue where the car just goes limp when I'm coming to a stop and I push the clutch in

24-07-15 21-10-48.hpl

[SiriusC1024]

Excellent choice on getting an aftermarket FPR.

It's definitely going to need tuning. I'm seeing in the log that B1S1 O2 isn't responding. That's the unplugged/disconnected voltage.

I've watched your videos on youtube of the car. Sounds really good, and it looks like a lot of fun. I've always wanted to do a turbo 3800 fbody. Worried a little by the AFR under boost. I'd like to help tune this if you'd like. Mind posting the latest tune? First gotta get that O2 working, though.

[LuminousX]

Excellent choice on getting an aftermarket FPR.

It's definitely going to need tuning. I'm seeing in the log that B1S1 O2 isn't responding. That's the unplugged/disconnected voltage.

I've watched your videos on youtube of the car. Sounds really good, and it looks like a lot of fun. I've always wanted to do a turbo 3800 fbody. Worried a little by the AFR under boost. I'd like to help tune this if you'd like. Mind posting the latest tune? First gotta get that O2 working, though.

Yea, I unplugged the O2 because it's not reading right.. don't know if it's because I have an extension on it or if it's the O2 itself.. I can clean up the MAF for the most, but it's all the other issue getting in the way

Original.97.Tune.16.hpt

This is the tune file on the car right now..
P.S I've been meaning to post an update video but the car just won't run right.. but I think I'm close

[LuminousX]

24-07-16 08-08-17.hpl

Log of me driving this thing to work... thing rocks the car side to side at idle like it as a big cam in it, and I'm sure I bought this thing fully stock lol.
this is the same tune I posted a log from yesterday, see how it's closer to the commanded AFR compare to last night.. all I really did was adjust the FPR a bit, it was off from where I set it when I first installed it.

[SiriusC1024]

Looks like both O2's are working. I think the problem here is it's setup to basically ignore B2, so when trims are logged it skews max negative.

Go to Engine>Fuel>Oxygen Sensors. Set it for Y-pipe, 2-bank, CL Enable to 131F. Then Fuel>General>Flow Rate to 37.3. Set the FPR for 58psi on the money with the vacuum line disconnected. Reconnect after setting pressure.

Configure the DTC's to match your O2 setup.

Write the changes then use VCM Scanner>Vehicle Controls & Special Functions to clear LTFT's. Post another log.

[LuminousX]

Looks like both O2's are working. I think the problem here is it's setup to basically ignore B2, so when trims are logged it skews max negative.

Go to Engine>Fuel>Oxygen Sensors. Set it for Y-pipe, 2-bank, CL Enable to 131F. Then Fuel>General>Flow Rate to 37.3. Set the FPR for 58psi on the money with the vacuum line disconnected. Reconnect after setting pressure.

Configure the DTC's to match your O2 setup.

Write the changes then use VCM Scanner>Vehicle Controls & Special Functions to clear LTFT's. Post another log.

24-07-17 08-17-43.hpl

alright, so I made the changes... drove to work.. I even stopped on my way for some Mc Donald's.. looks like I'll need to fix that small crack in the exhaust manifold on bank 2, I think it's the reason I'm off on that bank..
P.S it drives good for the most part, doesn't seem as lazy like it did before.

[SiriusC1024]

Running high octane exclusively?

[LuminousX]

Running high octane exclusively?

Only stuff I use.

[SiriusC1024]

It probably still seems lazy, and it shouldn't be shaking while idling. 4.5* at idle can't be correct. Seems more like excess airflow is being compensated with reduced timing. First check for vacuum leaks. This could also explain the spread between B1 and B2 trims. Second would be to adjust the throttle body closed a half turn at a time to see if spark comes inline. Don't forget TPS relearn.

From the looks of the log bigger injectors will likely be required. While you're making runs pay attention to wideband and injector duty cycle to make sure things don't lean out.

Plugs right gap and heat range?

I made MAF corrections and included suggested spark and PE. 24* under boost is going to be destructive. PE wasn't rich enough. I didn't include the previous changes because you didn't post a tune, and I don't know what all DTC's you worked on. Clear LTFT's through Scanner each tune revision.

I'll be on vacation for a week. Check back with you after?

[SiriusC1024]

How's it going? Any progress?

[LuminousX]

How's it going? Any progress?

hoped that vacation was good man..

Tuning wise.. can't tune in closed loop, wideband and narrowband not on the same wavelength.. I've just been tuning in OL for the most part.. I had a huge problem before with knock, once I got move air to flow throughout the intercooler and the IAT went down and that doesn't seem to be a problem anymore.. still missing on 2/5 during my drive but I don't feel or hear it, I'm thinking I have a lower intake leak on that bank 2 because I'm always 3% lean on that bank..

24-07-29 17-13-20.hpl

@ 5psi I'm up to about 90% duty cycle which sucks because the car is setup to run about 10-12 PSI

[SiriusC1024]

Great vacation thank you.

Are you certain about the narrowband vs wideband? Look at the log in post #52.
good o2's.png

Wideband indicates stoichiometric fueling. In other places when the wideband showed a little lean that was reflected in the O2 voltages as well. During PE, when closed loop is deactivated, wideband showed very lean. Last tune I compensated for that (comparison from tune 16 to 17 here).
maf updated.png

B1 and B2 O2's were showing matching trims except at idle. B2 was adding more fuel, indicating a vacuum leak there like you mentioned. I'm pretty sure everything is good with the narrowbands and wideband.

Would you mind loading that last tune I sent and post a log?

And for 2 and 5 have you checked the plugs? RockAuto has Hitachi coil packs for your ride. They produce the strongest spark of all OE's by far.

[LuminousX]

I'll load that tune in the morning and and try to get as much data has I can... I'm running 3 brand new duralast coil pack.. I've since switched them around, no change.. might be the plug but I've looked at that and it's burning good, not coated in oil or fuel.. I'm thinking L.I.M leak because with closed loop I get the popping out the exhaust when the O2 tries to adjust the fueling, but in OL I'm seeing 14.6 for the most part.

[SiriusC1024]

Yes the fueling adjustment is part of it. The other part is the retarded timing at idle. The burn is delayed and combustion continues past the exhaust valve. That heat in the exhaust port is why the ECT is higher since the new ECU. I mentioned closing the throttle blade. Then again the timing could be due to the vacuum leak and extra air flow there. The ECU is keeping idle in check by pulling spark. Seems that getting new gaskets is a good idea. Nvm loading the old tune just yet. Do it after.