V6 wont rev...

[10000_fists]

Hey all having a few probs with my vp...
The story is: The car runs fine untill i hit 4000rpm then it just backfires and sputters and lacks power until it changes gears. when i watch the revs guage the needles jumps erraticly between 4000 and redline. This is in a VP V6 auto and no charger.

Any body got any ideas what it could be?
So far peopel have suggested:
fuel pump, spark plugs, ignition leads and crank angle sensor, but i dont want to go throwing all this cash around if i dont have to.

[RabidDog_12345]

pull a plug out and see what they look like.. also whack some new leads on and see how she goes.

[Emackulation]

My needle was jumping erratically and car felt like **** when I was running on 7 cyl thanks to a lead not connected to a plug.

[Dragz]

ye change ur leads, or check if they are connected propley on the spar plugs and coil pack..

[10000_fists]

Yeah i've check that all the are plugged in properly, haven't checked out the plugs yet, but i changed them less than 2 months ago...

Also if i leave the car "nuteral"(sp?) and rev it it will rev all the way to red line with out any dramas.

[immortality]

checked for a blocked air filter?

[10000_fists]

The air filter is about 4-5 months old but it was cleaned out a month ago.

[LowVp]

how old are the cat or cats, i had one break down internally and a chunk had turned sideways and yeah it wouldn't rev but felt like a crook coil pack

[immortality]

how old are the cat or cats, i had one break down internally and a chunk had turned sideways and yeah it wouldn't rev but felt like a crook coil pack

agreed, a blockage in the exhaust will cause similar symptoms. the cat would be the most likely suspect.

[greenfoam]

I'd be looking at everything to do with the ignition, crank sensor (prolly not) dfi (probably) coils (maybe), spark lead (maybe), cracked plug (bit more than maybe)

[vn calais manual]

yeah id be looking into one of your coilpacks or a plug.

[10000_fists]

How can i tell if it is one of my coil packs?
I ripped out the spark plugs and they are all in good nick and checked the gaps and they are fine as well.
I'm gonna chuck a set of new leads on this week, just waiting for the auto shop to order them in. I've had the same leads on for about 10 months but i'm not sure it they were used or not, they came with the charger when i bought it.
The computer has no faults either...

[LowVp]

checked the cat yet?

[10000_fists]

when i changed the motor over few months ago i notice that my cat had been gutted out, so i guess i can rule that out... So much for paying for a hi-flow cat, dodgy exhaust shop.

[vn calais manual]

test the resitance of the coilpacks, i cant remember what the ballpark figures are i can find out if you like? there is a certain giveway in their resistance that they need to be under, if not they will run like ****, same with leads.

[modcon]

Hey man, I had this same problem on my VN it was cutting out at 3500 rpm, it was my CAS - it didn't need replacing it just needed ajusting. The CAS has a black unit on it that clicks - one click you might be away!

[Not_An_Abba_Fan]

If your cas needed adjusting sounds like it was loose, not out. It is a fixed unit pretty much with just two screws holding it on. There is no adjustment.

When you had your plugs out, did you notice a sooty ring right where the lead finished on the plug? If there was a black mark on them, the leads are shot. Free revving with no problems, then misfiring under load would indicate an ignition problem. Look at it running in the dark and see if there are any sparks jumping between the posts on the coil pack. Also check the leads for any burn spots along them.

[10000_fists]

Didn't notice any rings or marks on the end of the plugs when i checked them. i also removed the leads and checked for any visible cracks but didn't find any. I'll have i look tonight once it gets dark see if i can spot any sparks.

Also what is the CAS? and where is it?

[LowVp]

crank angle sensor, down the passenger side of the crank, sits behind the balancer.

[10000_fists]

Ah of course, silly me, i actually am a bit suspect of that because it is slightly damaged and had a bit of trouble with it when i first put this motor in... the clip that holds the wires on is slightly damaged but i'm not sure if this could be the culprate.
If it comes down to that i'll have to boot it off for the mechanic cos i dont have the tools to remove the balancer.

[modcon]

If your cas needed adjusting sounds like it was loose, not out. It is a fixed unit pretty much with just two screws holding it on. There is no adjustment.

When you had your plugs out, did you notice a sooty ring right where the lead finished on the plug? If there was a black mark on them, the leads are shot. Free revving with no problems, then misfiring under load would indicate an ignition problem. Look at it running in the dark and see if there are any sparks jumping between the posts on the coil pack. Also check the leads for any burn spots along them.

Yes you are correct it is attached to the car with two screws, but it can also be adjusted! I adjusted mine three times before the rev limit was removed, I'll put my money on the CAS having something to do with the problem - mind you I also thought the Wallabies and All Blacks would win on the weekend!

[Not_An_Abba_Fan]

How did you adjust it? As far as I am aware, there is no adjustment. What did you do?

[10000_fists]

I'll put my money on the CAS having something to do with the problem

Thanks i'll take your money
I changed the fuel filter today at lunch and the old one was so clogged up that when i blew through it with the compressor you could just feel the air comming through.
Took her out for a drive and first time i managed to hit just over 5000... no dramas with it. i got up it a few more times and 3 of 5 times were good but twice is still backfired and ****, but not as bad as it had been.
Dropped it of the the mechanic next to my work and he tested the fuel pressure while its was under load and every time it stuffed around the fuel pressure was down, but if it revved through fine the fuel pressure was good, so he told me to change the fuel pump and clean out the tank.

So hopefuly that'll be the end of the problem.
Just one quick question i have a walbro hi-flow fuel pump in my room for when i put more boost through the charger, would there be any issues running it without the boost and stock injectors and regulator?

Cheers steve

[LowVp]

with my turbo set up i put my pump in 3 days before i hit the dyno running stock injectors and no reg.

what injectors are you putting in btw?

[Not_An_Abba_Fan]

The regulator will take care of any extra fuel anyway so it won't be a drama fitting a high flow pump now.