I'm having a weird problem only on extened trips

[staticpage]

I'm lost on this one.
so I'm driving along on a four hour trip and two hours in to it the engine cuts out. Partial throttle, 70mph if I stay on the gas it bucks, no back firing some times it lasts 5secs some times 10secs then it clears up and is fine. some times the engine just dies for 5secs on a 4hr trip it will do it 3 times. no CEL, does not do it on short trips. I have two ecus one re-caped one not both do it.
any ideas?

 

[RacerXJ220]

Sensor or coil pack getting hot over time? Weird man.

 

[OneJSupra]

How good is your fuel system (pump, regulator, filter, injectors)?

 

[Jayhall]

what your describing sounds similar to when my alternator was crapping out. But for me it would do it at random, not after a certian amount to driving time.

 

[staticpage]

fuel system is fine i checked it a wile ago.... maybe
alternator, did have some problems with the wiring a wile ago
should i have it tested off car?

 

[Jayhall]

its not hard to pull so I dont see it being a bad idea. If you need one let me know becasue I can get up to 160amp alternators built.

 

[Bigzavs]

def sounds like something is getting too hot, def take the alt off and have it tested out

 

[di_rosa]

what about your charcoal canister? is the tank vent plugged causing it to cavitate? i had a similar problem, but it doesn't explain why after it initially dies, it drives fine.

i think if it was alternator, your lights should dim and your voltage gauge (if you have one) should show it. and even then, i think your battery light comes on if it isn't charging

 

[staticpage]

no charcoal canister, line was removed all the way to the tank with a custom filter on it.

drove home today (4hrs) and it did not do it, it was colder out. but my lights do dim at low rpm.

 

[boostindoo]

wiring getting hot somewhere?? or loose??

 

[Jayhall]

no charcoal canister, line was removed all the way to the tank with a custom filter on it.

drove home today (4hrs) and it did not do it, it was colder out. but my lights do dim at low rpm.

Ive got a brand new Optima Red top and a brand new 160amp highout put alternator, and my lights still dim at idle. Anything above 1000rpm and they are juiced right up to the max

 

[staticpage]

I never really fixed the problem I just stopped driving the car and forgot about it. I took it for a long 17hr drive over the last few weeks and the problem returned.
I have found that it only does this over 80MPHish or (long periods of revving over 4k not sure I have a NA diff gear so in 5th @80 I’m right there) and will do it every 10mins like clockwork. When it does do it your just driving part throttle then with no change in throttle it losses power and gains power in a surging manner very rapidly.

If I let off the throttle quickly it stops then disappears right after you get off the throttle till the next time it does it.
If I stay on it I will surge until you have no speed.

If I go WOT it surges more rapidly and violently then just dies, the engine just turns off for around 5secs then fires right back up. This is wile rolling clutch out so no starter is needed, when it dies I must let off the throttle in order for the engine to start firing again

In-between 10min break-ups “surges” if I WOT it cuts up, has little power, and blows black smoke.

If I stop reset ecu it seems fine for longer than the 10min window.

I pulls fine under 80MPH or before a surge.

If you have any ideas let me know I have tried two ecus and they were both doing it.

Only thing I can think of is bad wiring, igniter, a relay. Battery was changed, new spark plugs, no bad coils.

 

[mk3_chris]

How good is your fuel system (pump, regulator, filter, injectors)?

Sounds like when my fuel pump when out. When it heated up it didn't work properly.