Ferrari Mailing List: Re: Problem with the 308 GTSi

[Jeff Greenfield (coyote]

Sounds like you've covered most everything.

I'm pretty sure you'll find (if you're lucky) that the belt on the  
front bank jumped a few teeth, or you've stripped the belt and the  
valves on the 5-8 bank are toast.

Get in there and check the compression on that bank.

Good luck and let us know what you find ...

Jeff

Sent from my iPhone

On May 14, 2008, at 4:38 PM, georgedodson [at] comcast.net wrote:

> 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 5Â of clearance to the body but I will try again. If I get reaso 
> nable 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  Â 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 ÂOKÂ. Cleaned and scr 
> aped deposits and Âohmed leads. All ÂOKÂ. 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. Â No effect but didnÂt expect one after the  
> coil swap had no effect.  Spark from HT leads to ground is ~ 1Â. I t 
> ested for rotor breakdown by placing HT lead on each rotor at the ce 
> nter pickup point. No significant arc to rotor, therefore no rotor b 
> reakdown 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-
> Â    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
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