truckarms

Right I know half the people on here really like this thing and half hate it but it was the perfect solution to my problem.

I have a v6 (3.0ltr) which runs mainly on LPG (I start on petrol and once the engine is warm it flicks over and runs on lpg) The problem is that lpg likes a really big fat spark. I replaced all the components of my ignition system apart from the coil to get a decent spark and even then it was still not great and still prone to the odd missfire so i decided to try a jacobs coil to boost the standard spark.
I have hooked it all up and double checked everything about 20 times but it still wont run.
What happens is I turn the key and the engine starts to fire up and then about 1/2 a second later I blow the fuse on the negative line back to the battery from the main "pro street" box.
I have done a search both here and on the net and cant find anything. I have also called the help line and they said send the box back.
Well before I do that (as I live in the UK its not a 2 day job its a 2 months job) I was wondering if anyone on here has had a similar problem and does anyone have any advice?
I dont normally use the US forum as I am in the UK and so use the UK forum but I dont think anyone else in the UK has one of these kits hense I need your help.
If you help me get it working I will donate some cash to the forum as it will be saving me about 2 months of pain.

Many thanks in advance

Chris
1994 3.0ltr V6 4 Runner

JCM4x89pu

what is lpg? propane? methane?... where did u get the kit?

truckarms

LPG = Liquid petroleum gas

I got the kit from a company in the uk, who are the reps for jacobs but know nothing about it.

toyotatom93

Maybe just make a bigger gap.

Robert m

iTrader: (2)

why would there be a fuse on the negative side?

truckarms

Interesting,
I knew I would have to re gap the plugs a bit (I have them gapped smaller at the moment as LPG dont like big gaps) but I cant see how this will effect the rest of the system unless the small gap does not allow for a large discharge and therefore there is a build up in the coil and that is causing the short.

Will have a look at the weekend (I hate taking the plugs out)

truckarms

I dont know, on the old kits they seem to only have a fuse on the +ve side.

But mine has a 15amp fuse in both power lines.

No idea why but it confuses me even more why its the negative that blows.

Do you think its worth me putting say a 30amp fuse in the negative one and leaving the 15 on the +ve one? think that would help?

toy power

that is odd that it only blows the fuse on the neg side. i would throw a larger fuse in its place to see what happens. no harm done since they have already told you to send it back.

DeathCougar

iTrader: (23)

Talk to taikowaza, he has/had the Jacobs ignition and ended up yanking it out. Of all the people I know, he would be one of the more knowledgable.

Hilux808

I don't understand the fuse on the neg side either. I've never seen that. I don't understand the "LPG" too. Here in the U.S. it's gasoline and I thought all of europe was on "petrol" and then diesel after that. Anyway I wouldn't recommend installing a 30amp fuse if it calls for a 15amp fuse, you're just asking for more trouble, like frying the box instead of a fuse. you obviously have a short circuit somewhere which is why your blowing the 15amp fuse. Check your wiring and connections. I doubt your spark gap is your problem. I run a full MSD ignition on my rig and MSD told me to open my gap up anywhere from .10 to .15 from stock, this is to take advantage of the more powerful and multiple sparks.

DeathCougar

iTrader: (23)

LPG= Liquified Petroleum Gas aka Propane+Butane

You have to convert your truck to run on LPG, as most engines in the US run on Gasoline, or Diesel. Very few vehicles came stock equipped to run on LPG, and even then it was a spendy option.

taikowaza

thanks for the props deathcougar! it's been a love/hate relationship with Jacobs for me and I liked it a lot while it worked. Unfortunately the reliability was not good enough and it almost left me stranded while camping in a national park. Always bring enough stock spark plugs to restore your rig back to the standard coil just in case!
about your problem, one of the major issues that I had was that I was missing the secondary trigger which is required for our trucks. I also had the same problem with starting for a few seconds and blowing fuses/stalling. The secondary trigger translates our stock ignition output to a signal that the jacobs brain can understand. After installing the secondary trigger I was good to go.
The Jacobs spark is massive and I felt like I had slightly more torque and responsiveness, although this is part of the 'mod reality distortion effect' where the more you spend on a mod, the more it seems to be useful to the user.

links to the secondary trigger:


After all the people I tried to get in touch with, there was only 1 shop where someone was willing to take the time to walk me through the installs and troubleshoot- his name is Gary and he has been selling Jacobs products since the beginning. (800) 627-8800. Jacobs has been sold to Mr. Gasket and the service has descended to nil (call them and end up waiting for an hour before hanging up type of thing).

In retrospect, I learned that MSD ignitions seem to be more respected and much better supported.
Even more hindsight is that the Toyota ignitions in our vehicles are excellent and don't require aftermarket to beef them up in most cases. In your case however you are running alternate fuels and I can highly recommend the Jacobs for the size of the spark it is HUGE. My only issue is with reliability, I went through several units before giving up. At this point I need a new 'brain' which is just too expensive.

Enough ranting- I would recommend a secondary trigger! If you already have one let me know and we can proceed to the next step.

cheerio!

Belize Off Road Team

have you checked out either www.toyotadiesel.com or www.hiluxsurf.co.uk

Those are some sites to also check out for more help on the matter.

truckarms

Wow guys thank you.
taikowaza I have the secondary trigger and its all hooked up properly (I have double and tripple checked everything) Its soo simple to hook it all up but it just keeps blowing the fuses.

If I hook everything up apart from the lead to the distribution cap from the jacobs coil I get an awsome spark all the time so it would seem everything is firing ok its just once it goes into my distributer and then into the engine it all goes wrong.

For all you other guys in the uk its about 10$ a gallon for petrol (regular) now so I converted my car to run on lpg which works out about 5$ a gallon. I have 6 new injectors (which are drilled into the intake manifold) and inject gas (propane/butane sort of) into the engine (petrol injectors are turned off at this time).

taikowaza

truckarms- are you using a jacobs wire going from your coil to the distributor cap? Exactly what kind of wire are you using. I do not recommend a stock wire, you need the big mother of a jacobs (blue) wire.

check your sparkplug wires you may have them hooked up in the wrong order.
check your cap and coil, these are cheap enough I would recommended replacing them.
check the wires themselves- I melted several wires while working with the Jacobs.

doublecheck the jacobs brain power signal. It is misleading- there is a power section, and then a section where you can attach the 'full throttle' signal. This full throttle signal is provided by the optional 'off-road kit' which is a POS mercury switch as everytime you go up a hill it sends a 'full throttle' signal to the jacobs meaning that you LURCH at fullspeed into the vehicle in front of you on the hill. Luckily I disabled this (cut it right off!) before I hit anybody but let me tell you it was unnerving in a big way. If you are attaching your power signal to the full throttle leads you will blow fuses.

truckarms

Thanks taikowaza,
I will do everything you suggest this weekend and get back to you on sunday or monday.

Just reread your reply, yes I am using the really thick blue lead, but the rest of the leads are some stadard after market leads (I think 5.5 or 6mm core)

The engine still runs fine on petrol (if I take out all the jacobs bits) so cant see how I have the wires hooked up wrong.

Cap and coil I did replace about a year ago, but yes they are cheap and so I will replace them.

I will check the wires etc this weekend.


Many thanks

Flash319

Spark energy is dictated by the number of windings in the coil. The more windings on the seconday the higher the voltage. Voltage means you can jump a larger gap but your current goes down as the difference in winds between the primary and secondary gets larger.

So what you need is a low impedence (resistance, ohms) coil with a very high seconday winding count so that you can set you plug gap big and still have lots of current to make the spark "big and fat". I have not shopped around but Accel sells racing type coils for large engines with high compression (where a big spark is needed).

Another thing is that, you are actualy jumping 2 gaps. One in the distributor and one at the plug. The smaller you make the gap between the rotor and cap the less loss you will have for the plug jump. Maybe you can get a better cap/rotor set from somewhere.

PS what does a Jacobs ignition do that a stock one doesn't? Just give you some tuning ability?

truckarms

Thanks flash 319,
The jacobs takes the stanard signal from the ignition coil and uses that as a signal to a new much bigger coil, the bigger coil then goes into your stock distributor cap and away you go (or not in my case).

The jacobs sounds like what you are talking about interms of racing parts.

taikowaza

truckarms- OK if the truck runs fine on 'petrol' then your problem is not spark plug wires, neither cap or rotor. I wouldn't worry about them then. Your problem seems to be the wiring to the brain, or the fuse that you have in there. Something is causing the fuse to blow. DO you have the .pdf for the proper connections? when checking the brain, make sure that the secondary trigger is properly connected, and then make sure that the leads to the battery are properly connected, and make sure the fuse is the proper type and size.
I have written to my electronics friend and if he can't answer it (he helped me with my jacobs too), then I will contact my friend in texas who runs the jacobs distributorship

truckarms

Ok I managed to upload the picyure of what I did, its taken from http://www.jacobselectronics.com/pdf/373546.pdf

I did exactly this, I taped off the extra red and black wires (for the full throttle thing)

I cut 1 of the looped wires so it works with a v6

I set the limiter to 5000 revs

Is this the same as you did?

Oh I have just stuck a volt meter between the 2 terminals where the negative fuse sits and I have 2.5 volts going through it when the engine is turned off. Could that be the problem?