mousiee

1. Can anyone who uses a programmable engine management system, such as Uni-Chip, tell me if that eliminated the hesitation on your SC400?

2. Has anyone come-up w/ a template for the air box when making a BFI?


Thanks for your help
Mousiee

Blizzy

iTrader: (-1)

A template for the airbox is the least of your worries with the BFI....just cut the damn thing as big as possible. A template is most necessary for the top plate that dissuades hot ambient air around the engine from being sucked into the engine via the intake. The easiest way to make a template is with old cereal boxes, cutting sections at a time and using tape to secure them together. Then, you can transfer this to whatever material you are using for the top cover.

As for the Unichip comment, I can't answer the question. You probably need to define "hesitation" first.

mousiee

Thanks for your response.

The hesitation I was referring to is the common problem 400s have around the 1500 rpm mark and 40 mph mark. It only seems to happen when pulling off from a stop gradually, and when trying to keep your speed around 40 mph.

Thanks
Mousiee

mkorsu

I wouldn't call it common. Some have mentioned some hesitation here but not an overwhelming amount. My SC400 with 201,000 miles has no hesitation.




And Blizzy, I think Mousiee is also referring to a template for the creation of the high pressure box you need to make behind the headlight.

No template per se, but as Blizzy said use cardboard to find your shape. Then transfer to your construction material.

mousiee

Did you ever have hesitation? What year is your 400?

Since the hesitation seems to be AFM or ECU related, from what I have read, would a programmable engine management system clear it up?

About the template, thanks for making what I was trying to say clearer.

ScottURnot

iTrader: (33)

Yep, My tepmplate came from thin poster board.

I have a detailed top plate, feel free to copy it. Here it is.

I might add this is a complete write up on it.

https://www.clublexus.com/forums/sho...d.php?t=131460

mousiee

Thanks

And, love your 400. Your vids are crazy.

Mousiee

mkorsu

1992, and never had any hesitation.

If your hesitation is AFM related, a stand alone EMS could clear it up. I would be more interested though in finding why there is hesitation in the stock setup.

MAF clean? Check throttle body gasket? All vacuum lines connected and unworn? things like that

Blizzy

iTrader: (-1)

That is one hell of a write up. I did not even know that existed. That URL needs to be bookmarked and referred to for every BFI question.

mousiee

Thanks again.
I'll check into those things for sure. My mechanic tried to clean my MAF sensor at my request, but that messed it up (CEL and Trac Off lights) . I bought a used one from Ali a few months ago and the lights went off, but I still have the hesitation. The hesitation seems to be more fequent on 95 400s for some reason.

It gets annoying from time to time.

I would love to drive another members 400 in my area to compare because mine seems like it's corked up, but my mechanic says it's fine.

Mousiee

ScottURnot

iTrader: (33)

Thanks Mark! Yeah that’s an old thread. At that time I was going to make up a run of these cut on a Flat laser and sell them here on CL but the thread got quashed because it was against the rules, actually after I posted it I sent a note to one of the mods asking about it and as I expected it wasn’t allowed. No big deal, It’s not like I was going to get rich off the CL members making BFI's. LOL

cody468

I have a '95 400 as well and I have the same hesitation issue too. Seems to happen closer to 45 mph for me. It is more prevalent with the power switch off. There is no RPM fluctuation when it happens, just a feeling like it isn't getting fuel correctly. I have had a thorough fuel system cleaning performed, and it doesn't seem to do it at any other speed. I guess it isn't a big deal, but it is a bit irritating at times.

mousiee

Yeah, there are several post on this forum about the mysterious 400 hesitation issue. Members have tried everything from changing fuel filters, plugs, wires, coils, AFM, etc to no avail.

There has to be someone who is running a aftermarket engine management system who a 95 400 that can answer this for me.......

Mousiee

cody468

I was just reading on another thread about torque converters, and how they lock up around 40 mph on our cars. So, I wonder if we are maintaining a speed right around 40 if what we are experiencing is the torque converter locking and unlocking repeatedly as we alternately accelerate and coast to maintain that speed. I'm not a mechanic, so I'm not sure if this is possible, but seems plausible. Any experts out there can weigh in on this and if there is anything we can do about it? Or need to do anything about it? Thanks

mkorsu

Nah. Doesn't work like that. When the TQ "locks", all they are referring to is a "direct" link from engine to trans to rear.