“VOLVO MAF” conversion 1997 to 1998 3.4, supercharger upgrade,

Yes, the scanguage website has 4 different sets of choices for codes, defined as bank 1 through 4. They don’t know which of the 4 set of codes work for the 3.4 or if it works for the early ECU. It’s a pain to program each one.
They name them bank 1 through 4 for reference only, NOT for the engine bank.
I programmed the bank 1 info and nothing happens.

If I figure out the correct codes and IF it works for the early ECU I will post a thread.

 

I totally understand where you’re coming from. I didn’t have a problem I was trying to solve. I thought the mod seemed cool and was cheap so figured why not get rid of the restrictive MAF (I run a SC) and see how it runs. I figured it might screw with the fuel trims some, which kind of bothers me but I figured I’d still test it out. I could easily swap back to my old MAF (which worked fine) if I wanted.

Open loop afr seems about perfect right at around 11.2-11.5 when I really hammer it. But I can also tune open loop so it would be easy to change even if it did screw with it in a negative way.

On another note I also noticed on my way to work I averaged about 20.5 mpg and on my way back I averaged 21.5 mpg. This seems a little higher than normal (1-2 mpg). This is also only one days worth of data, but It seemed “easier” to achieve these numbers. Usually I would have to drive it a certain way to get up to 21.5 mpg. But I didn’t even focus on mpgs and just drove it normally..

I’ll keep monitoring and see what my mpgs average over the week.

 

Thanks for the thoughtful post, it makes sense to me. I've been staring at a higher LTFT since the swap, around 12-14 at idle vs. the original ~4. I also have not noticed any gas mileage increase. Since there was nothing wrong with my original MAF (I did the swap mostly out of curiosity), I may go back to that setup.

 

How can you say that when you don't even know the value of and have never monitored your LTFTs? You're spraying meth without engine management. These 3.4's do not like to be in open loop during any kind of boost. Ask me how I know. So your ECU is fighting to maintain stoich AFR while you're spraying to drop it down. What do you think that's doing to your fuel trims? Not to mention what @Speedytech7 said above about open loop conditions. I suppose ignorance is bliss.

 

I don't think you're giving @1997tacomav6 a fair shake here though, he does monitor his AFR and he is targeting ideal AFR for WOT boost. His meth kit likely fills in the lean chunks of part throttle boost. You want to be in open loop boost as these trucks don't have any real knowledge of part throttle enrichment for boost conditions.

 

I agree with you that these trucks don't have any knowledge of part throttle closed loop conditions.

I've done many many hours of logging and monitoring of open and closed loop on these trucks and even in full boost, it likes to stay in closed loop. I've tuned other boosted cars before and I've never seen a car act like this. So that's why I use the AEM FIC 6 so I can skew MAF voltage and address the part throttle closed loop areas of the map.

 

Your funny, “ignorance is bliss” I seriously would not have a supercharged 3.4 with almost 600,000 miles of actually supercharged miles and not know what my motor is capable of.
I had a speed shop setup my methonal kit and tune it for what the motor needs for added fuel.
It runs with perfect AFR that is shown on the dyno graph.

I have the larger 3.4 injectors, bored throttle body, ported supercharger, and. 2” pulley, and the added Volvo MAF. I will see if I can get my trims checked, but I’m sure they will be higher because off the added air flow I have compared to most.
Either way keeping my AFR correct has been with the methonal kit all the way up the rpm range.
The AEM FIC 6 is probably the better way to go if you know how to adjust your maps.
The AFR reads the actual reading from the exhaust where as the fuel trims are read from the MAF I thought. So your 7th injection or methonal additives are not actually seen in the fuel trims so I thought so I have not looked to see fuel trims because they would not be telling me the whole truth unless I had an engine issue

 

Worth note here, higher airflow alone wouldn't throw off trims if it is being measured correctly. Only things that aren't being accounted for properly mess up trims (hence the need to trim anything). Which is the whole reason I disagree with this MAF mod

 

But if you measure the Tacoma MAF and Volvo MAF they are the same distance across inside.
It’s just the front part of the MAF tube that is smaller on the Tacoma and then gets larger where the actual MAF sensor is that continues to the throttle body side.
Maybe that 1.5” section out of the 5” makes a difference?

 

Running "perfect AFR" means nothing when you're in closed loop and your ECU is fighting to maintain stoich. You're not getting my point. It's ok. Rock on with your 600,000 mile truck. I'd love to see it roll over to a million. That would be awesome.

And no, fuel trims still use the OEM O2/AFR sensor to calculate AFRs and adjusts trims accordingly.

 

That small discrepancy is more important that you may think.

Are you monitoring MAF/grams? The reason I ask is that mine have actually gone down. This seems counter intuitive, but my theory for this is that it's not the volume of air that has gone down, rather the velocity. The airflow has obviously increased, but the ECM sees it differently now. I believe that would also cause a change in fuel trims. My LTFT is still in a range that I'm willing to accept, but I watch it like a hawk. If I could get my F/IC to cooperate, I feel like I could settle everything down nice and easy, but so far that's a dead end.

I may be way off on this, just adding my own observations.

 

Wow.... all this jazz is getting above my head ..... I don't know about any of the measuring MAF/grams or LTFT or what they are supposed to be for my Tacoma. However I know that this MOD made my trucks engine seem to run smoother, Have noticeably more pep and for the price it was worth it. Still say great mod @1997tacomav6

 

So after listening to your input about fuel trims and others about the difference in the air box mouth being smaller on the OEM MAF tube, I decided to go further to find out my numbers with the swap installed for everyone to know the results done by the dealership with their professional tools.

I actually found the xguage codes for the scanguage and that was bank 3 codes and input the info and got the guage to work.

The Long term fuel trims were in the 8-10 range at idle showing on the scanguage.
So I’m thinking something is wrong and took the truck to my master tech Toyota guy that knows my truck inside and out and told him to find out what’s going on.

Got the truck back a few hours ago and the scanguage apparently is not giving me the correct info.
The Toyota master tech said that a lot of these type aftermarket guages don’t always tell you the correct numbers when compared to a Toyota dealerships tool.

So @JonRambo I DO have ALL the facts and my numbers are perfect for my setup.

Long term fuel trims are “ZERO” at idle
Short term fuel trims are “ZERO” at idle

Long term trims on HEAVY acceleration are 7-10
Short term trims on HEAVY acceleration are 7-10


Toyota Tech said that the fuel trims stayed right around zero at closed loop until HEAVY acceleration,

Heavy acceleration would be open loop and when the methonal is spraying and my dyno AFR numbers are perfect there on my print out below.

Anyways the master tech said these fuel trim numbers are all normal.

SO for me this swap is perfect.

More power, more boost, long term fuel trims in close loop at ZERO, better gas mileage.
Below is the dealerships invoice on the trims with this swap to back up my results.

So this swap did not really change my trim numbers

 

If what your tech reported is indeed true than that's freaking awesome man

 

The proof is in the pudding, with the paper work, and a 75.00 bill charge

 

That's some inexpensive peace of mind my friend...
I've always been impressed with your resolve, even after all these years with it, to keep/get that 3.4 and her blower running at its absolute best.

 

It would be expected that trims be at 0 at idle when you have no vacuum leaks. If you're LTFTs are 0 while you're boosting in closed loop then that's awesome. I'm assuming your tech did take a reading during partial throttle boost and not just idle and heavy accelearation? Like the time between from when you start to boost to before you start to spray...that closed loop area under boost.

 

Just wondering what tool the Toyota tech used? Techstream?

 

I’m sure he did, That’s why I took the truck to the dealership as I wasn’t confident with the scanguage numbers being correct, which they weren’t. I was very specific that I wanted ALL of my trims inspected and explain to him what was going on. He’s a old school master tech.
He said in a nut shell that my fuel trims were all normal. I was actually very surprised with the his results. I can give you the dealerships number if you want to talk to him about my results.
Anyway I know the stock ECU is a pain as it stays in closed loop most the time until full acceleration.

I’m curious to know how much power I’m giving up by not having the AEM FIC6 setup.

Can you post a photo of your rear wheel dyno horses and AFR numbers with the FIC6 to see the curve?
What boost are you running and your rear wheel horses and torque.

 

Thanks for doing this!! I feel like I should send you some money or something!