Ferrari Mailing List: Problem with the 308 GTSi

[georgedodson (georgedodson]

I wrote earlier that I had a problem with my 81 308 GTSi. I was pushing a bit 
and the engine died and I am debugging the problem. I forgot, or was too 
embarrassed to mention that, being used to the very narrow shift gates in my 
Miata, I missed an upshift and ended up downshifting.  The engine revved high 
but I think it stayed below 8K before I got the clutch back in. She coasted to 
a stop and after cooling down started with a very lumpy idle which is not 
stable. It wants to die, then surges up to ~2500 RPM. The engine has 
essentially no power. I did not hear any bad mechanical sounds during the 
incident.  The engine spins freely and has good oil pressure. I did a 
compression test and got about 160 on the 1-4 Bank, but it was hard to get the 
long tube into the 5-8 Bank due to the 5? of clearance to the body but I will 
try again. If I get reasonable compression I will assume that the valves are 
OK. 

Initially, I assumed that I had some kind of ignition problem.  

Preliminary test showed that 1-4 Bank fires driving the engine to a rough lumpy 
idle with periodic surges to ~2500 RPM, pulling the Coil HT kills the engine 
and pulling the 1-4 Bank Coil HT lead has no effect on performance.

I cleaned the Ignition Control Module (ICM) and cables  ? no effect

I swapped the 1-4 Bank and 5-8 Bank ICMs ? No effect

I swapped the Ignition Coils/Leads ? No effect. 

I examined the 5-8 Bank Distributor. It  looks ?OK?. Cleaned and scraped 
deposits and ?ohmed? leads. All ?OK?. Replaced ? No Effect

Measured Spark Voltage;   > 30KV on 1-4 Bank but less, only ~20KV on 5-8 Bank, 
both measured from coil to ground with spark gap tester.  Also, with HT lead 
off I saw internal arcing in 5-8 Bank Coil, so I replaced 5-8 Bank Coil. ? No 
effect but didn?t expect one after the coil swap had no effect.  Spark from HT 
leads to ground is ~ 1?. I tested for rotor breakdown by placing HT lead on 
each rotor at the center pickup point. No significant arc to rotor, therefore 
no rotor breakdown to ground.

>From the flywheel timing inspection port, the marks are hard to see but I see 
>some kind of mark with a timing light with spark pickup from 1-4 coil and 5-8 
>coil. Timing marks run off to the right with spark advance, as expected. This 
>would seem to exonerate both of the Flywheel TDC pickups. 

Odd things-
?       The more warmed up the engine is, the harder it is to start

TDC scribe marks on the back (engine side) of the intake cams drive pulley seem 
~90 degrees apart but that is qualitative, they could be 1-2 belt teeth off.

Pulled individual spark plug leads. Removal of each of the 1-4 Bank plugs 
causes similar engine stumble. None of the 5-8 Bank plugs have any effect. The 
5-8 Bank exhaust manifold does not heat up.

Measured fuel pump pressure at the Fuel Injection distributor. Initial surge 
was to ~40 PSI but after ~ 1 second came up to ~120 PSI.

Sprayed starting fluid into the air cleaner with only the 5-8 Bank Spark plugs 
installed. No hint of starting. 

Swap Ignition Distributor and Spark Plug Wires and sprayed lots more starting 
fluid past the Fuel Injection (FI) plenum and got one backfire. 

I do not see how in a throttle body Fuel Injection system there could be 
delivery to only 4 of the 8 cylinders, all 4 being in one bank of the V-8. I 
tried to loosen an injector but it started to twist the delivery tube, so I 
chickened out. 

Conclusion: I have skipped/slipped a tooth or teeth on the timing belt on the 
5-8 Bank (at least)   

Questions: 
        A) Am I missing something obvious?
B) With the plugs out, can you turn the engine by hand once you have the belt 
covers off?
        C) Are the timing marks obvious with the belt covers off?

I have no experience with fuel injection, just Webers and SUs, but have the 
Bentley book on order. I have no experience with Ferrari engines, short of what 
I have done and what I saw of the belt-change done at the shop when I bought 
the car. I do have about 30 years experience restoring sports cars (Jags, MGs, 
TRs, Morgans)

Regards,
George