Loss of power/backfire after engine gets hot

Possible but unlikely or we certainly would have heard of this problem before. But maybe you just have a bad batch of gas? If the octane rating is lower then what it should be ....... Or if it's got contaminants??

 

I tend to agree with Andyww as well. I hope you get this sorted it's probably something simple. I'm out of ideas. Good luck.

 

look for burn marks in the lower half near the plugs -
if there is no documentation of the set having ever been changed, install a complete new set

change that second ignition module BKL3B !
(if the first failed a year ago, chances are that the second is going south now)

forget that, can`t be the reason

 

Maybe it is time for a professional shop to take a look at it.

 

Hi GG,

So, on these burnt plug leads, are they melted or actually charred? Where exactly on the wire is this happening? Is it always in the same physical spot? Close to the heads or close to the distributors? Both banks? The individual plug wires or just the coil wires or both?

Have you had a look inside the distributors? Is it all clean in there and no degradation or buildup? No arcing/black carbon?

I can't think of why the wires themselves would just fry on their own...

Do you have one of those digital infra-red thermometers? You can pick them up for pretty cheap or order one online. I would suggest running the car to get it hot and try to recreate the scenario where you start to have this failure and point the infra-red thermometer all up and down the wires, coils, timing units, etc. to see if you can localize the problem source.

Also, once the problem has occurred, and after the engine has cooled, pull the spark plugs and see if there are a any marked differences that would point to a specific cylinder(s).

The last thing I can think of is your radiator fan temperature switch. I just replaced mine because it was leaking slightly and I learned that you can also get them in a version that will turn on about 20 deg cooler. Maybe if you can get the fans on earlier you won't reach the temperature that is causing your problems. The part is inexpensive and can be changed without having to drain the radiator (took me five minutes to install).

Franny

 

The only source of heat to do that sort of damage is the forward exhaust manifold, are you sure you dont have a crack in it.
The high voltage from the coil is not going to set them on fire. Check the connections on the coil packs- i assume it has an earth connection so check its resistance to ground.

If after a long run you slow down you lose a lot of air flow through the engine bay.
Just as a way to isolate the problem, get some heat insulation tubing to make a temperary sleeve for the individual plug leads and see if it improves matters.

Are you getting any rise in the sump oil level ?
Looking at the drawings, it shows a front and top exhaust covering over the forward exhaust manifold- do you have these fitted in the right positions ?

 

The drawings can be found on the Eurospares U K web site. Depending if yours is 85 or 87 model.
1985 car, plate item 14 pt no 118632 plate item 16 pt no 118612

1987 car plate item 32 pt no 118612 plate item 51 pt no 128950 from car 77366

Get on the eurospares site, select ferrari, then 328( 85 or 87), then exhaust. The diagram can be made bigger

The plug leads should be sitting in u shaped brackets running along the top of the cam box cover if its the same setup as my old mondial, so it is surprising they are getting overheated
I am not 100% sure but i think you can work on the bulkhead exhaust by taking the fuel tank out- others on here may be more up on this as i am mondial experianced only

 

You must have an exhaust leak to get that much heat- what is fitted in the engine lid under the ventilation louvers- i think it should be just some sort of net or nothing.
Do you have the exhaust shields on the rear bank.
The outlet of the exhaust manifold goes to the link pipes ? These are fitted with a fire ring and 3 bolts at 120 degrees- they corrode under the triangular flanges, check for holes/ leakage.

You are getting a huge ammount of heat to damage the plug cables

Check the manifold gasket at the cylinder head for leaks

 

If you think it is cam timing you can check that easily if your car has the timing ref plates fitted.
Go to eurospares site, put in Ferrari /328 / 85 or 88/ engine/timing system control which is page 008.
Look for items 11 pt no 125110, item 12 pt no 125109.
If you look at this it has 2 indicating arrows on each part- these will line up with the marks on the cam shafts.

In the engine bay, look on the right hand side of the cam box cover and you will see the 4 cam sprockets, 2 per cylinder head. A small section of the cam shaft can be seen before it attaches to the toothed sprocket, this has a flat machined on on the shaft with a flat mark stamped into it.

To check the cam timing you need to remove the plugs, the right hand rear wheel and the wheel liner. This lets you see the crankshaft pulley- turn the engine over on the starter and mark the pulley with the direction of rotation.

Use a socket and turn engine in running direction so that the slot in the crankshaft pulley lines up with the mark on the engine crankcase- it is very important that you turn in the correct direction and if you go past the mark you need to go another turn- DO NOT reverse the turning.

With the crank pulley lined up with the crankcase mark, have a look at the timing ref plate arrows and the stamped marked camshaft. All 4 cams should be in line with the arrows on the indicator plates.
If nothing in line then turn crank 1 full turn and check again.
When checking the alinement it is important you are directly above the indicator plates- you have to use a torch and lie in over the engine so you look directly down.

If they dont line up i can tell you how to adjust but you need to be very carefull

 

While you are removing the heat shielding, have a look at the exhaust for leaks.
You need to ask someone for a picture of the normal run of the ht leads. It will explain the damage if you have then in a different place
As far as i remember with my mondial they were attached to the top of the cam box in u shaped clips- given the cam box is angled it is very hard to see how the heat would get to them.

 

I'm so glad I found this thread - my Euro-spec 308 GTSi is doing *exactly* the same thing. It's just come back from a service by mechanics who specialise in Italian sports cars.

I noticed it yesterday on my first proper long drive I've ever taken it on - after about 30 minutes on the road, on an uphill, it started losing power. I managed to get over the hill, and thought maybe it was just hill-related, but it did the same thing even on a downhill. I pulled over to the side of the road, opened up the back and checked to see if there was anything weird with the engine. I couldn't see anything obvious, and when I started the car it seemed fine...for about 15 minutes.

It's hard to describe it, but it reminds me so much of one of my first cars that had a spark plug issue and was misfiring. You put your foot flat on the accelerator and it's sluggish to respond, and never really gets particularly high on the rev counter. Contrast this to a cold start, where the response to the accelerator is instantaneous, brutal, and unrelenting.

I eventually discovered that if I kept the car at about 4500 RPM and didn't accelerate then it was mostly fine on flat roads. I eventually pulled into a petrol station to fill up with petrol, and the car refused to start. The engine was turning, and the spark plugs were sparking (we checked), but it wasn't "catching". This plus the occasional faint petrol smell both when driving and when I get out the car made me think that it is fuel pump related.

At any rate, after about 20 minutes I tried starting the car again, and like magic it started! I gave it a couple of revs in neutral, and then as it was idling and I was putting on my seatbelt etc. it just cut out. I gave it another 10 minutes, and then tried starting it again and voila - it started! This time I wasn't going to risk it doing on me, so I kept the revs above 3000 and managed to get out the petrol station and back on the road.

But here's the thing: I'm pretty certain this is an electrical issue. When I was driving, and it was exhibiting the loss of power, I could (whilst moving) put in the clutch, turn the ignition off and on, and then let the clutch out...and the car immediately goes back to normal behaviour.

GG, maybe try the ignition "trick" next time you're on the road to see if we have the same basic cause?

Does anyone else have any ideas as to what it could be, if it's electrical?

Any thoughts?

 

I'm so glad I found this thread - my Euro-spec 308 GTSi is doing *exactly* the same thing. It's just come back from a service by mechanics who specialise in Italian sports cars.

I noticed it yesterday on my first proper long drive I've ever taken it on - after about 30 minutes on the road, on an uphill, it started losing power. I managed to get over the hill, and thought maybe it was just hill-related, but it did the same thing even on a downhill. I pulled over to the side of the road, opened up the back and checked to see if there was anything weird with the engine. I couldn't see anything obvious, and when I started the car it seemed fine...for about 15 minutes.

It's hard to describe it, but it reminds me so much of one of my first cars that had a spark plug issue and was misfiring. You put your foot flat on the accelerator and it's sluggish to respond, and never really gets particularly high on the rev counter. Contrast this to a cold start, where the response to the accelerator is instantaneous, brutal, and unrelenting.

I eventually discovered that if I kept the car at about 4500 RPM and didn't accelerate then it was mostly fine on flat roads. I eventually pulled into a petrol station to fill up with petrol, and the car refused to start. The engine was turning, and the spark plugs were sparking (we checked), but it wasn't "catching". This plus the occasional faint petrol smell both when driving and when I get out the car made me think that it is fuel pump related.

At any rate, after about 20 minutes I tried starting the car again, and like magic it started! I gave it a couple of revs in neutral, and then as it was idling and I was putting on my seatbelt etc. it just cut out. I gave it another 10 minutes, and then tried starting it again and voila - it started! This time I wasn't going to risk it doing on me, so I kept the revs above 3000 and managed to get out the petrol station and back on the road.

But here's the thing: I'm pretty certain this is an electrical issue. When I was driving, and it was exhibiting the loss of power, I could (whilst moving) put in the clutch, turn the ignition off and on, and then let the clutch out...and the car immediately goes back to normal behaviour.

GG, maybe try the ignition "trick" next time you're on the road to see if we have the same basic cause?

Does anyone else have any ideas as to what it could be, if it's electrical?

 

Apologies for the double post earlier. GG, you may have missed my post, as it took a few days for mod approval

 

Huh? they SHOULD be on the valve cover. not on the side of the engine.