Another Grand (+ 1/2) Down The Tube...

[coupe72001]

One of the things that I hate most about my car is that sometimes it wont rev above 5,200 rpm. It starts of with hesitating a little above 5,200, but within a week it becomes much harsher - it just wont rev past that point and the car starts to splutter and jerk about. Oddly the car runs really sweetly at anything under 5,000rpm. You don't know the problem is there until you hit that spot. Sometimes the problem goes away, after tinkering with carbs, adjusting the timing, a change in the weather etc... but it always comes back.

When I tried swapping the engine and related parts from the rally car to my car I made a mistake. I shook up the carbies (twin 2 inch SU's) and fouled them, so I couldn't get the car to go. I pushed it to the nearest mechanic who rebuilt the carbies but wired up the distributor incorrectly, frying my Petronix electronic ignition module. So I forked out for a new one of those too, along with a new coil, just in case.

The car has never run right since then for more than a week or two. Z-spares had it going well for a fortnight after a carby balance and air-fuel adjustment, but the problem crept back again.

I decided to take the car to a carby specialist to be tuned but he convinced me that the previous reco of the carbs was a botch-up, and would need to be completely redone with all genuine SU parts by a dedicated carby professional, like himself.

After two weeks he calls me to let me know that he is finishing off the carbs and they are in immaculate shape. Unfortunately the car STILL doesn't rev above 5,200 rpm. He thinks its the ignition system. Ha. Ha. Ha.

Before I re-rebuild the ignition system to match my re-rebuilt carbies, can anyone think of something else that might cause this problem?

Thanks.

Edited October 4, 2007 by coupe72001

[giant]

maybe try to supply fuel externally via seperate fuel hose from a fuel tin into the carbies feed line just in case it is a blockage from the tank or something silly like that.

just to eliminate that as a possibilty.

russ

[V8skylineMAN]

Make sure the wire inside the ditributor is ok, and not earthing when the counterweights advance the timing

Cheers

Jason

[coupe72001]

Thanks guys - will try both of those tips and we'll see how we go. I'll be happy to see the back of this problem - that's for sure...

[T04GTR]

like does it just stop all together. or does it just loose heaps of power?

what coil you using? your electronic igntion, are you sing the "electronic" type coil or the origonal one?

[coupe72001]

like does it just stop all together. or does it just loose heaps of power?

what coil you using? your electronic igntion, are you sing the "electronic" type coil or the origonal one?

It doesn't cut out altogether - it just spasms violently between 5,200 and 5,300 rather than soaring all the way up to the red-line. You can keep your foot to the floor all day, but it wont go past that point.

I am running the original points distributor - but the points are long gone and an after-market electronic ignition module is tucked in their in place. I have borrowed a standard and working electronic distributor (from an R30) from a mate and Ill see if that makes a difference tomorrow. Maybe there is a nasty hidden in my distributor somewhere as J mentioned above.

I have tried a few different coils. At the moment it a fairly standard but new Bosch item - I got it when I changed from points to electronic.

Fingers crossed anyway - we'll see what happens tomorrow.

[blind_elk]

Have you checked the advance on the dizzy? And that BOTH retaining springs for the counterweights are still there.

[coupe72001]

The distributor is officially off the hook.

The next suspect is fuel pump/fuel pump mounting arrangement; maybe its just not sucking hard enough.

Unlike this experience in general.

[blind_elk]

Have you checked the float levels in the carbs? (who was the "expert" carbie builder?)

I'm guessing you are still using the mechanical fuel pump. Try adding an electric fuel pump as a "helper" (should be mounted near the tank so it pushes fuel).

[coupe72001]

Ok- B+M Fuel Systems in Richmond Vic have provided me with;

Carby rebuilds including jets, needles, seats, gaskets, floats, shafts... the whole box and dice.

Went to the 280zx distributor and it works way better than my Petronix system... do'h!

Fitted a piersburg(?) a very German and very expensive electric fuel pump below the level of the fuel tank to help out the neikkei(?) Japanese fuel pump in the boot.

27 - no joke - 27 attempts on the dyno to get it all going.

Final result... she goes - all the way to 7,000rpm with 88 screaming horses at the rear wheels. The question is for how long?

Cost - $1,500. Bummer about that part.

Anyway, hopefully nothing to nasty will break for a while now.

[coupe72001]

Wow - What a shock! The car got halfway home - maybe 5 kms, before the nasty came back. Today's new rev limit is 4,000rpm. The problem seems to emerge when the car is forced to sit in traffic for a while, so maybe there is some relationship to temperature.

Then I got a flat.

And the rear brakes are still grinding away for no apparent reason - having replaced the pads, machined the disks etc etc...

Honestly I am sick of the car and out of money. The project has cost easily 10 grand so far for it to look and run like an absolute piece of shit. I hate the thing.

Drew

[coupe72001]

I just got thinking about a previous post. Just because my coil is new doesn't mean its right. Should I be running a resistor type coil with a ballast resistor with the electronic distributor, or should I go for the non-resistor type (anyone got an R30 they can check?). Will a standard coil do, a GT-40, or will I need a "performance" coil of some sort? Could a faulty ancillary (eg taco) to the coil be causing me this bastard of a problem? (Not that the taco or anything else is obviously malfunctioning, for the record.)

To be honest, I think the fuel system has been pretty well sorted. Maybe I need a pro to look at the electrical side. What else can it be short of kids having stuck a banana up the exhaust?

D

[Factory 5]

SHIT!

for the price of all that you could of got a L24 EFI with a turbo setup.....

sometimes you gotta cut you losses and just drop the lot, but if it means this much to you just take it to a dat rally shop of somesort and give them a few weeks with it... let them know you'll pay by credit card adn just pay off the debt...

id fkn burn the shitter if it was mine.

[coupe72001]

SHIT!

for the price of all that you could of got a L24 EFI with a turbo setup.....

sometimes you gotta cut you losses and just drop the lot, but if it means this much to you just take it to a dat rally shop of somesort and give them a few weeks with it... let them know you'll pay by credit card adn just pay off the debt...

id fkn burn the shitter if it was mine.

I hear you... it's really starting to hurt now. I squirm to think of what I could have if I had dropped the 10G in one hit off the bat... an L28 tripple-webbered screamer, something nice through J-spec, 3,800 Big Macs...

If the coil experiment doesn't work out the car IS going of to Dat Rally Moorabbin and its staying there till its sorted. Ill never get back all the cash I've blown, so Im basically stuck with the the old girl till Im rich enough to consider another never-ending project (read basically never). You never know, maybe she's only another 2-3 years away from being all sorted.

Also I am going to replace all the rubber sections of fuel line in case there is a hidden flappy bit on the inside that is opening up and restricting the flow of fuel sometimes. Maybe $10 worth of hose could solve all my problems!

[blind_elk]

Also I am going to replace all the rubber sections of fuel line in case there is a hidden flappy bit on the inside that is opening up and restricting the flow of fuel sometimes. Maybe $10 worth of hose could solve all my problems!

Clean the fuel tank. There might be something in there that's blocking the pickup.

My R30 is just running a stock (black) Bosch ignition coil (no ballast resistor) - runs fine.

(If you want a going L24E engine, call round and take it away.)

[Factory 5]

Clean the fuel tank. There might be something in there that's blocking the pickup.

My R30 is just running a stock (black) Bosch ignition coil (no ballast resistor) - runs fine.

(If you want a going L24E engine, call round and take it away.)

hey i still got a few window motors here for ya!

what head do you have on the L24e????

and km??

[Rhys1600]

You are either running the wrong ballast resistor for your dizzy, this needs to be changed when you go from points to electronic.

Or your carbys are out oof balance at that point and onward.

[blind_elk]

hey i still got a few window motors here for ya!

what head do you have on the L24e????

and km??

Had given up on those, thought you'd forgotten

Stock as, had about 285k on it. Still started first time, every time (unlike the prissy R32)

[coupe72001]

Ok thanks - that's great news that the ballast resistor is wrong as its an easy fix. That's also a really generous offer in relation to the L24E, but hopefully I won't need to consider it if I can finally get mine up and running right.

There has been a delay in operations though... I've lost my damn car keys! Arrrrgh!

[Rhys1600]

Also you really don't need an electric (even if it is low pressure) fuel pump, the L series mechanical ones are very adequate.