Rpm started to jump badly when hot

smurfbus · 04-25-2014, 07:11 AM

Finally took the car out and it was ok at first but had to go fill it up when it really started to act bad with misfiring and bucking. After the fill up all seemed well until after maybe 30 miles it started to do this intermittend cutting no matter where rpms or throttle was? It was really difficult to get home as it was like a kangaroo and if too much throttle it would BANG like hell.

I dont think one cylinder can do this but maybe two if they are in line in firing order?

Any ideas? I'm pulling the plugs tomorrow when the engine is cold and I will check later today if it was only hot engine temp related. Maybe some fuel system cleaner too but the frequency was solid so it must be cylinder related?

wjfk32 · 07:28 AM

When cold my car was fine driving nice.. Once warmed up--started everything u said. Turned out to be my Coi/msdl--slight leak-had it upside down--Went with epoxy-msd-black. While I was in there I changed also the distrib-coil (probably didn't need it )and cleaned it up in there. All was good after that.. Did check hoses-plugs-wiring..etc..before doing the coil Hopefully nothing major.

Gl.

Walt

smurfbus · 04-25-2014, 07:38 AM

I've changed recently epoxy coild, msd superconductor wires, plugs, 123 TUNE distributor. But I did loose one spark plug earlier, the porcline part broke so my spark might be strong enough so I need to start shortening the cap? I'm hoping for fauled plugs.

Thanks

wjfk32 · 04-25-2014, 08:14 AM

I had a problem in the past with plugs--Car missing etc..etc
Went with Denso {#W24ESRU} Copper Gap .028-0.32 straight out of the box.. So far so good.
I have msd-6al- & coil.. My car didn't like .40 setup..

The only thing I recently changed/ multiple times- was my red fuel pump relay. None of the new stuff lasted more than 2-weeks or 4 plus months.

smurfbus · 04-25-2014, 08:46 AM

I run NGK8 copper plugs now after the org bosch ones. No red relays on my car anymore and both pumps are switched/fused separately from battery. I need to try the 0.03ish cap next. I also have MSD6 for extra spark even though 123ignition told me i dont need it. The spark was just not enough without it IMO.

mark houghton · 04-25-2014, 09:26 AM

Just the first two things that come to mind: Pop your distributor cap and take a look inside for any weird carbon tracks. Also, make sure you have the correct rotor in there. With MSD you need a rotor that does not have a resistor incorporated into it. They will overheat and eventually fry.
Hopefully you just have a loose wire somewhere.

mdripley · mdripley's Garage

Can original bosch plugs be used ?
I found a bad plug wire and a loose distributor cap gave me trouble like the op be has

smurfbus · 04-25-2014, 10:38 AM

Just tried it with cold engine and no jumping but I can tell it was not on all cylinders. I will check tomorrow the rotor that should be resistorless or low ohm, IIRC the resistorless part number that i bought still has some resistance?

Engine sounded like a beetle with zappin sounds. All these problems take me closer to efi everyday.

wjfk32 · 11:45 AM

Clogged fuel injectors'????? Fuel head-clogged..????

I didn't drive my car for a very-very long time.. Changed fuel pumps-cleaned gas tank-fuel accumulator--blah-blah--

I also went thru hell way-back--on missing injectors.. Changed all new. Still didn't run well... After all said and done again---fuel head was clogged-took it apart..

Poor mans way quick fix-- Marvel Mystery Oil- 3 ounces -10 gallons-- I use this stuff religiously..Techron did nada.

mark houghton · 04-25-2014, 11:16 AM

Fire her up in a very dark garage and look to see if any 'sparkage' is going on where it shouldn't be. Just another random thought....

wjfk32 · 04-25-2014, 11:29 AM

What up Mark

smurfbus · 09:12 AM

Plugs looked good in color but AGAIN one fouled plug at the ceramic part!

Anyway switching back to old stock bosch plugs did not help much so next was checking the rotor and cap. Rotor was my own made resistorless but it had some dirt on top of the middle contactor that I sanded away. Cap was clean.

Now the car works fine after one subaru moment when one plug EDIT PLUG CONNECTOR disconnected while driving. Its funny how these engines can mimic other brands.

I used 0.03 for the plugs and set the timing where it felt best and now the car runs really well. It does still sound a bit like beetle when not totally hot so there must be some leaks at the exhaust system but I'm happy until next ohnoes moment comes. I hope the bosch plugs with smaller gap can handle the heat better. Thanks for helping

JFairman · 04-26-2014, 06:06 AM

Looking at your list of happy gadgets I would try removing or completely bypassing the J&S safeguard.
You never know.. some electrical component in it could be going haywire after a certain amount of engine bay heat soaks into it.

smurfbus · 04-26-2014, 06:43 AM

I hear you but none of the electric gadgets are in the engine bay except ofcource the 123TUNE distributor. I've them all in the rear seat backrest, dunno if that firewall passage brings any other interference problems though. Oh, the J&S is in front of the shifter so i can see the lights plus the retardgauge wire was a bit short.

JFairman · 04-26-2014, 07:38 AM

I'd never heard of the 123TUNE distributor so I googled it.
How do you like it?

Maybe it has a headache?

smurfbus · 04-26-2014, 08:26 AM

It's very nice as far as tuning but it should give enough spark itself whitch it doesnt, hence the MSD 6A. I can monitor my timing as I drive and use shortcuts to increase it on the fly plus I have two maps behind a switch to fast check some adjustments. So far I have seen that this engine really likes good timing. Idle is good at 25 btdc and cruise likes around 40-45 btdc but I need to try higher. This is where J&S comes handy IMO. I can just eyeball the retard gauge for any retard and adjust accordingly.

The sad thing is I'm alone when it comes to problems as I think I'm the only person running this unit on turbo porsche so a lot of try and fail progress as with the need for MSD 6 for good spark and now this nkg quality issue with too much spark shattering the plugs. This was to delay efi as I kind of like to keep the sucky k-jet just for proving a point as everyone says go EFI all the time : )

JFairman · 04-26-2014, 08:37 AM

Wow 25*, thats a lot of advance at idle. I don't know what works best there on these things. Mine was around 12-15* BTDC at idle before and when I first start my new motor I'll retard it a little from there at idle just to be safe.

My aluminum CIS injector blocks should get to me on monday and then I have to install them and all the CIS stuff. Hopefully I'll be driving it and breaking in the new pistons and cylinders tuesday... hopefully

smurfbus · 04-26-2014, 09:03 AM

I still have stock fuel head so if I want more power its either efi or modified fuel head so cost wise i think its easier to switch over to efi. My modified alu blocks are on their way from jpnovak so I need injectors, throttle sensor, fuel pressure regulator and efi unit to swich (ok, plus lots of other things line fuel lines and so on) over but if this cis begins to behave I will delay the swich as far as I can.

smurfbus · 04-27-2014, 10:40 AM

No problems in two days. Exhaust nuts were loose on couple of cylinders and one broken stud was found that was ok last year, outch. It does not affect running so I will let it be until I remove the engine. All the beetle noises are cleared now as the exhaust is pretty tight now.