304 struggling at high revs.

[moco]

my vs 5 litre, is struggling at high revs.

It drives fine if im easy on the pedal, but if i go to boot it, as soon as it gets in the high rev range it just struggles. The tranmission doesnt kick over into next gear.

Its driving me mad. i just had a new cam installed, and it was doing this before the cam as well. I have a tuned memcal for a stock engine, and it ran fine.

Could it be the tune? diff? tranny?

[88GreenVN]

Define struggle? How old are the leads, dizzy & rotor button?

[hako]

No chance the catalytic converter is blocked? - an over rich mixture or excessive oil burning can block the matrix and kill high revs.

[moco]

just got new leads. dont know about dizzy or rotor button. What exactly is the dizzy? Do you mean distributor cap? whats the rotor button?

[moco]

just got new leads. dont know about dizzy or rotor button. What exactly is the dizzy? Do you mean distributor cap? whats the rotor button?

when i boot it, the engine will rev and stay at 5000rpm, gears will only change if i back off on the throttle.

[moco]

No chance the catalytic converter is blocked? - an over rich mixture or excessive oil burning can block the matrix and kill high revs.

good question. I really dont know. i just had the car serviced while the cam was done as well.

I still have a stock exhaust. i am going to get a full new exhasut system with extractors. Maybe theres too much back pressure??

[88GreenVN]

just got new leads. dont know about dizzy or rotor button. What exactly is the dizzy? Do you mean distributor cap? whats the rotor button?

Yep "Dizzy cap" and the rotor button is inside the distributor and makes contact for each lead inside the cap. This can be pitted and making poor contact. Just something to check.

[moco]

Yep "Dizzy cap" and the rotor button is inside the distributor and makes contact for each lead inside the cap. This can be pitted and making poor contact. Just something to check.

thanks. where abouts is the dizzy in the engine bay? I'm not familiar with it.

Is it something i can do myself? It seems to have only started to happen when i had my last service when they changed the ignition leads.

[88GreenVN]

thanks. where abouts is the dizzy in the engine bay? I'm not familiar with it.

Is it something i can do myself? It seems to have only started to happen when i had my last service when they changed the ignition leads.

Centre at the rear of the engine - all the leads go to it But would not expect it to fail over night as such - so if the car was running fine into the high revs before the cam - I'd be going back to the mechanic that fitted the cam.

What cam did you put in - just a mild one?

[moco]

Centre at the rear of the engine - all the leads go to it But would not expect it to fail over night as such - so if the car was running fine into the high revs before the cam - I'd be going back to the mechanic that fitted the cam.

What cam did you put in - just a mild one?

yeah thanks. it happened about 2 months before the cam. its a mild cam . It was given to me. i think its a custom grind. hydraulic and lifters as well

Heres the link to my cam specs. Let me know what you think?

Any idea how much power it be roughly making?

[moco]

http://forums.justcommodores.com.au/...cs-sheets.html

[88GreenVN]

yeah thanks. it happened about 2 months before the cam. its a mild cam . It was given to me. i think its a custom grind. hydraulic and lifters as well

Heres the link to my cam specs. Let me know what you think?

Any idea how much power it be roughly making?

Greenfoam is the fella your after on cam specs.

If a v8 is struggling at high revs - it can be with in the ignision, blocked cat/exhaust or running out of fuel at the top end. How is your fuel system - pump good? regulator, fuel filter?

[Troy5L]

maybe get the gearbox serviced. mine does that on cold starts, it doesnt wanna change into second in boost until i back off..

but ive been told that people have had simular problems, had the gearbox serviced and a trans cooler and it was fine after that

[moco]

Greenfoam is the fella your after on cam specs.

If a v8 is struggling at high revs - it can be with in the ignision, blocked cat/exhaust or running out of fuel at the top end. How is your fuel system - pump good? regulator, fuel filter?

From what i know, its all fine. Ill have it checked out on my next service.

appreciate your help, ill check the dizzy over the weekend and see how it looks and test the car.

cheers

[moco]

maybe get the gearbox serviced. mine does that on cold starts, it doesnt wanna change into second in boost until i back off..

but ive been told that people have had simular problems, had the gearbox serviced and a trans cooler and it was fine after that

the trans is due for a service, hopefully thats all it is.

cheers mate

[VrWagz1]

I was goin to suggest fuel filter, how long since you changed it, also could be the pump.

[moco]

I was goin to suggest fuel filter, how long since you changed it, also could be the pump.

will also check that out as well. Is there any performance fuel pumps? can you recommend any? I'm looking to upgrade everything also as they need replacing.

cheers

[moco]

im going to get a fuel service and tranny service from ultratune. ill see how it goes. im sure it will solve the problem.

[VrWagz1]

Noi cant recomend any in particular, I jst replaced mine with a new factory spec one when it fugged up on me. My car kept reving to about 4500rpm and dogging out on me and wouldnt rev any harder.

[greenfoam]

I just think it's not able to reach the speed it needs to reach to change gears at full throttle (it will need to go to at least 5200) so it sounds like it's a power issue rather than the gearbox, If it's not miss firing as such the top two on the hit list would have to be fuel pump or filter but mostly a colapsed cat.

The cam is the crane 260, very close to a stock cam

[sostok]

perhaps a vacuum issue or the auto

[moco]

Just changed the air intake back to the stock over the radiator one this morning.

It seems the problem has gone now. I had a pod on there before and also tried a custom cai that i made.

I believe they were sucking in too much hot air. My engine bay gets pretty hot when driving. Also noticed a massive drop in temperature on the guage and stays between a quarter and the middle. Prior to this, whe i was running with the pod and custom cai, the temp would be around the half way mark.

I gave the car a good booting this morning, and didnt struggle at all. While I was at it I saw a blue vs the rego is vs3551 , Anyone seen this guy around before? That thing was a monster

[88GreenVN]

Just changed the air intake back to the stock over the radiator one this morning.

It seems the problem has gone now. I had a pod on there before and also tried a custom cai that i made.

I believe they were sucking in too much hot air. My engine bay gets pretty hot when driving. Also noticed a massive drop in temperature on the guage and stays between a quarter and the middle. Prior to this, whe i was running with the pod and custom cai, the temp would be around the half way mark.

I gave the car a good booting this morning, and didnt struggle at all. While I was at it I saw a blue vs the rego is vs3551 , Anyone seen this guy around before? That thing was a monster

Well there you go - POD filters = fail hey. Bet your glad thats fixed it

[moco]

certainly am. appreciate the help everyone. will post again if i do find other symptoms

[moco]

damn. the problems still there. Have booked in to get checked, the fuel system, dizzy, everything. How can i check if the cat has collapsed? Is it an easy fix, temporary fix like take the internals out?

I hope its only the fuel pump or something.

I'm totally spewing at the moment, I would get thrashed by a datsun...