Chip tuning didn't get too far for FD's. On the 2nd gen cars the Rtek ECU let you change fuel and timing and retain stock ECU functionality.

If you have a 90s Honda or an old 5.0 Mustang there are really good options for chip tuning, including realtime tuning, not just burning Chips.

I haven't experienced the 3000rpm hesitation on my stock 95. If enough of the stock ecu were reverse engineered I'm sure you could tune air pump deletes and a lot of other factors. It just never matured like it did on say an Eclipse GSX.

 

I haven't experienced the 3000rpm hesitation on my stock 95.

Disconnect your double throttle vacuum line (so they snap open) and give it some beans before the engine is warmed up and you will experience the 3,000rpm hesitation. The stock ECU is trying to keep the double throttle closed and provide less throttle pump enrichment for cold start emissions.

 

Honestly, I'm not that curious as to try and induce it.

I practically wrote the book on tuning modded FDs ECUbut I enjoy driving this car on the stock tune with all the stuff working, including the air pump and double throttle.

Engine runs way better with an air pump. The recirculated port air improves the combustion. That doesn't make the air pump and ACV any less of a pain in the ***, but it's there for a reason beyond satisfying a government regulator.

 

they do run way better. 1st hand experience. not hard to get the connectors to make it a plug in either.

 

Stock '93 here, and I remember back in the day many times I'd have the 3000 hesitation and engine was always warm (i.e. had been running an hour or more). Had it at the dealer one time, and mechanic went for a ride with me but I couldn't replicate it. Thinking back when it did happen it was always during rather light throttle; seems it was most common slowly climbing through 2nd gear.

 

Go on....

Aware of anyone pulling off this conversion?

 

I'm sure that I've seen a 16 bit to 8 bit ECU harness adapter for sale on RHDJAPAN but it's not on there at the moment.

 

I have one, just have to make time to do it.

 

It would be cool to run the later Japanese ECU but going with a PowerFC will get you a 16-bit ECU that plugs right in and is fully tuneable. Maybe if you were going for an "ulimate OEM" car or something it would be worth messing with.

Dale

 

I got both .... but I like the versatility of OEM ecu.

 

I know we are talking about OEM ECU swapping partly because of the 3000 rpm hesitation. I suspect the 3000rpm hesitation is mostly a '92 to '93 thing. Anyone else here with a mostly original '94 or '95 have a problem with it? The ECU part numbers changed as the model years passed.

Today if you have a driveability problem on a modern car they can reflash the stock ECU at the dealer. Back then you usually had to manufacture a different ROM chip, so changes were made only at model year start of production.

 

I never had the 3K hesitation in my 94. Most likely it was a 93 model problem that got resolved the next year.

 

Sorry to say, my 1995 with 1995 ECU has a slight hesitation around 3,000rpm. Not every time, but many times. No hesitation with PFC though...

 

See this is where having no easy way to datalog the stock ECU makes it difficult. I wonder if it is a torque drop as the turbos switch, or fueling, or spark, or what.

 

Running an N3G1 ecu on an earlier car will raise the boost also. I love my car on the late stock ecu, it's so smooth compared to other FD's I've owned.

 

I bought my car in '04 with 68,000 miles on it, had just a downpipes and a cat-back. 94 R2. I had the 3000 RPM hesitation, it was never the neck-snapping hesitation of some 93s I've driven, but it was a little "bump" in the rev range, especially at part throttle.

It has to do with the injector staging, it's a bug when the secondary injectors transition.

I added the extra ground strap from the battery negative terminal to the frame, it was SLIGHTLY better, but nothing exciting. PowerFC went in and it all disappeared.

I don't think I've ever driven a stock FD that didn't have the hesitation. Again, some cars are worse than others.

Dale

 

Love this thread...
Here's to 25 years of 3k hesitation threads!



Although, I think the discussions were more passionate on the net mailing list...

 

generally it got better as the car got newer. my friends 95 did it badly, but only if the engine wasn't fully warmed up, and it was cold outside.

cleaning the grounds did help, my 93 basically didn't do it at all.

 

Yes. '94 built in November '93. Under light acceleration only. However, have not seen this lately with new engine installed by Yoshiya at Neptune Speed. (Original ECU, so will probably see this later on.)

 

if you want to go down the rabbit hole the stock ecu DOES output data. its 90's data though, so you might need a walkman or a teletype or something to read it

 

92 JDM here and I haven't experienced any hesitation.

 

Following on the 16-bit into an 8-bit car thought; Japanese premium fuel is 100 octane RON, roughly the equivalent to 94-95 US AKI. I imagine that the JDM OE ECU's are tuned to utilize the higher octane fuel, but who can say for sure. If the OEM tune is for 100 RON, then it may not play well with US premium fuel.

I do know my old R33 GTR ran like crap on 91 AKI and there was even a sticker on the inside of the fuel door that said to use 100 RON fuel.

Maybe someone with a JDM FD can comment on whether their car has a caution to use 100 fuel, also.

 

Mine does say 100 but it doesn't run bad on 93.

 

Good to know. Do you ever premix race gas with pump or just run 93 pump typically?

 

Negatory, just 93 pump. 😎