Oliver from Canada writes:-

Re: A problem when I accelerate ?

"Hi,

Got to say your website is remarkable, so much info.

Still with all the info available on the 2.8l 18v engine I still can't figure out my problem after spending hours after hours of checking sensors wires timing etc. etc.

I have a problem when I accelerate, the car feels as if I hit the cut off and it just won't go... then if I stay on the gas the car will backfire. It won't go over 2500 rpm if I go hard on the gas. Then if I accelerate very easy it will go very fast as long as I keep the rpm low (change gears at 2000 rpm ) and when I give gas car stopped it accelerates good.

I have ran the car with a fuel pressure tester and it is good. I checked the wires and distributor cap and rotor arm, and they are good.

I feel as if the mixture is not correct under load conditions. Don't know if what I am writing makes sense but that is the point I am at. After changing my fusebox making everything work perfect (electrically) in the car this problem has overwhelmed me.

PLEASE!!! If you have any ideas as to what my problem might be please let me know.

Thank you in advance,

Oliver."

"Hi Oliver,

Thank you for your email.

My advice is to join the Biturbo Zentrum discussion group at http://autos.groups.yahoo.com/group/BiturboZentrum/

They are a very friendly and knowledgeable group.

Regards,

Enrico."

Reply from Reg on the Biturbo Zentrum:-

Re: A problem when I accelerate ?

"Is it worth changing the crank sensor ?

Reg."

Reply from Mike on the Biturbo Zentrum:-

Re: A problem when I accelerate ?

"Check all your the vacuum lines and test the MAP sensor. It sounds like the fuel pressure regulator rising rate adjustment is not working properly so the engine is starved of gas under load because the regulator is not compensating with increased fuel pressure when under boost.

I redesigned the vacuum routing using a little vacuum system manifold and fresh lines and it sorted out this problem.

Any leak in the intake system is going to cause this problem.

Mike."

Reply from Terry on the Biturbo Zentrum:-

Re: A problem when I accelerate ?

"It is probably that vacuum sensor thing on the firewall with three hoses it is typical problem for this. It will cause the motor to cut out around 2500 rpm. You cant bypass it either.

Regards,

Terry."

Reply from Joel on the Biturbo Zentrum:-

Re: A problem when I accelerate ?

"I also have an 89 2.8 Spyder with literally the exact same condition. Over the last 10 years, I have hardly driven the car, but take it out every few months for a short exercise run.

It ran great every exercise run until a couple of years ago where out of the blue, it developed this very frustrating condition.

While fiddling with the sensors, I disconnected the air temp sensor that is in the plenum where the two turbo hoses meet and the car idle picked up, so I took it out for a drive with the sensor disconnected - The can ran almost perfect with that sensor disconnected.

I ordered a new one off MIE and installed it - unfortunately, its the same situation - the car still runs as described in Oliver's outline below.

The good news being that the car at least runs fine with the sensor disconnected. Very bizarre. You guys gave me some items below to look at next time I get a chance to fiddle with the car - thanks.

Any other input would be welcome - I am sure Oliver would appreciate additional comments as well.

Regards,

Joel."

Jan from the Czech Republic writes:-

Re: Problems at low RPM ?

"Hello Enrico,

I have a problem on my 1983 carburettor Biturbo S.

Cornell from the USA writes:-

Re: Sensitork differential ?

"Hello Sir -

My name is Steve, from Fremont, CA, USA.

Thanks for your site.

I have a 1985 Biturbo (VIN ZAMAL1102FB310868) which I purchased three months ago with about 79,000 miles on it; overall, it runs well, especially after changing many of the vacuum lines, spark plugs (ancient) and installing a new mag pick-up in the distributor.

Sorry for all that.

My question: "How do I know if I have the Sensitork differential?"

Thanks for your time.

Steve."

Cornell from the USA writes:-

Re: Bypassing the intake manifold coolant line

"Hello Enrico,

Any thoughts about bypassing the intake manifold coolant line on a 1984 carburetted Biturbo?

It's a pretty basic thing we did for the v8 street rods and race cars (although it was a little more difficult to block off the passage in the casting). I'm not sure if Maserati went to the effort to heat the bottom of the intake plenum for easier low temperature operation or if the Weber is subject to carb icing.

I also picked up an intercooler that will go on sometime. It seems that even an air to air cooled intercooler would be warm enough let alone a non-intercooled version. The car is in the Seattle area; a northern humid climate.

Thanks,

Cornell."