512 BBi ignition problems

Coach,

If you decide to go down the MSD route, I have alot of experience in this area. There are a few posts, for reference, in the Technical Section concerning BB ignition issues, tune-up etc...

I've been running an MSD unit in my BB for the last 18 years...They work very well, but selecting the corect one for your application is important.

Regards,
David

David, JRV and anyone interested: The problem with the backfiring and poor ignition is NOT the digiplex nor the fuel pumps...after six hours of testing today, it finally dawned on me what was wrong: remember, I had said that I had one bank rich (with fouled plugs) and the other perfect? Well, there is too much gas going through on that one bak, it is way too rich, and unburnt gas is accunulkating in the exhaust and backfiring there. I am sure of it. I had that FD rebuilt and probably it was not rebuilt to specs. I have tried to back out the mixture screw to lean out the mixture but it does not good. So I keep my gipilex and look for the gentleman who rebuilt that FD, return it to him and have his rebuild it again..the darn thing is sending too much fuel into that bank. Pure and simple...that bank really is rich. It can backfire so much and then also it will quit firing..and the car dies. I think you will agree with my anaylsis...please tell me if I am wrong

Interesting, indeed.

One bank rich...FD rebuilt and no response to mixture adjustments. A hunch would be either:

-Stuck/sticking FD plunger
-Warmup regulator toast

...with the FD plunger being the most likely candidate.

With CIS pressure gauges, you could confirm the operation of the regulator...

Even if the FD turns out to be the problem, you'll still need an exhaust gas analyser to set it up properly.

Regards,
David

>>-Warmup regulator toast <<

Before I would go any farher, it would definately be Fuel Pressure Test Time.

Also....it is important to know if the warm up regulators still have the factory crossover tube.

The problems here can easily be tracked down by some careful methodical checks of several different things to isolate and pinpoint the exact problems.

1- Fuel System Pressure Test.

2- Distrib cap &amp; Rotor condition check.

3- Depends on results of fist two

Also, have to know if FP crossover tube is in place or not, first &amp; foremost, by a simple visyal inspection..

All the answers aren't in yet, but I don't see how one side can shut the engine down at 60mph.

Seek and more shall be revealed to us..

Regards, JRV

Can you give me a brief description of how to check fuel pressure on each bank?

Coach,

to test the Fuel Pressure on cars with the CIS type system like Boxers and many others requires a CIS Fuel System Pressure Tester that plumbs in between the warm up regulator and the Fuel Distributor.

I think there is a pic of one below at: well I can't find the pics, which means we need some in the permanent tech archives so that they can be found easily. I'll take some pics today and post tonight. In the mean time maybe someone can post links of where to get the tester.

Here is a link to what the Warm Up Regs. look like on a TR (basically the same n Boxers). Scroll down, circled in yellow.

http://www.ferrari-talk.com/discus/m...tml?1062705546

The tester just plumbs in and reads Fuel Pressure which is the critical factor in determining CIS operating condition.

another interesting question: my FD on the left bank (driver;'s side) has an electric connection to it as some type of control, but the right bank (which is the passenger side and the rich culprit) does not have one nor did it ever have one. I will try and find a pressure gauge and try to hook it up to my FD. Thanks...I will post

Hi Coach,

that electrical plug situation is normal.

Only one side has the Fuel System Safety Switch wired in. It is an electrical circuit that shuts off the fuel pumps if the engine doesn't start to prevent flooding.

Coach,

I still need to know if your engine has the crossover pipe between the 2 Aux. Fuel Press. Regulators.

Thanks, JRV