Harsh bucking when off the pedal abruptly

[PaulPDX]

91 1G with stock 14b, 83k original miles. Swapped out all the IC pipes with DeJon bits along with a K&N filter. The car runs strong but whenever I let off the gas in say... second gear abruptly, the car bucks pretty hard. It still runs fine, and doesn't stall. It's just a very harsh transition. Is this because of the limitations of the stock MAF? or is it something else being out of whack?

 

[PaulPDX]

Anyone?? Bueller?

 

[IronnFisTT]

do you have an aftermarket bov? if you let off the gas in second gear in vacuum, ill assume the car doesnt buck?? probably only happens in boost? could be compressor surge, soften your bov settings (if aftermarket).

-attia
94 Tsi AWD
98 Supra Turbo

 

[PaulPDX]

Yup, I do have a aftermarket BOV. HKS SSQ. Sounds like a good plan of attack. I'll loosen it up some.

But, if I remeber correctly, the BOV was on the loose side right after it was installed. I drove it like that for a few days and noticed that it bucked under the same conditions.

Another thing is I'm used to BOVs like the Greddy. The SSQ sounds so different so it's kind of hard to figure out how to set it properly. It chorttles rather than the "Ppshooo" I'm used to hearing from the Greddy and the stock 1G bov.

 

[IronnFisTT]

too loose, youll have trouble building boost... too stiff, youll get compressor surge like youre currently experiencing.. youll just need to play with the spring stiffness a bunch of times until you find a good spot. alternatively, you can take a vacuum hand pump to it and set it exactly to what you want.

-attia
94 Tsi AWD
98 Supra Turbo

 

[leet]

If your venting your SSQV, you WILL have stuttering issues like you described. Get a Recirculation Kit for it.

Venting is bad on stock MAS.

 

[PaulPDX]

It isn't being vented to atmosphere. I have a recirc kit on it.

 

[szewczyd]

Originally posted by PaulPDX
It isn't being vented to atmosphere. I have a recirc kit on it.

Where did you get the recirculation kit. Do you have any pics of your setup. I alos have a 91 and I only see the kits for the 2g please let me know. Did you jsut use the fitting and run your own hose?

 

[PaulPDX]

? The recirc kits are all over the place. Check DeJon. All it is is an adapter for the BOV. You use the stock recirc hose... you just have to cut it to make it shorter. Don't go crazy on cutting... do it little by little until you get the right length. Cut it too short and you're looking at spending $30 at the dealer if you want a new one.

Still having the bucking problem... wondering if it's the tranny or bad caps in the ecu... possible?

 

[TSiAWD666]

Did you replace the intake tube just prior to this all happening, or just the i/c piping?

 

[szewczyd]

could the bucking be caused by poor engine mounts? It just seems like bucking do to the worn out engine mounts? just a guess?

 

[PaulPDX]

The IC pipes are new from DeJon. The mounts looked good when I took them out to sand off the rest and repaint. I may replace the mounts just for the hell of it. Any recommendations? Have heard the Prothane inserts don't fit well.