Fuel Injector Impedance - megasquirt

[TX82FIAT]

Folks, I have read a few times on forums and other resources that the L-Jet fuel injectors used on our vehicles are low impedance. I understand almost all injectors are now high impedance. From what I can gather that means 1.7 - 3 ohms of resistance built in to limit current using some type of ballast in the circuit so it does not burn out the ECU with voltage spikes similar to coil operations. I've been looking at various documents to find more technical specs on the standard stock fuel injector on an 82' spider with no luck. A couple questions, has anyone replaced low impedance with more modern high impedance in thier Fiat Spider? Were some spiders build with high impedance fuel injectors? Am I nuts and many of these cars are high impedance? My understanding of high impedance is 12-16 ohms with an internal to the injector voltage spike limiter to preserve the circuit/ECU.

The reason why I am asking is that I have turned a couple big projects over to an extremely competent FIAT mechanic. This guy works on FIATS and ALFA's all day long. Answers my questions and educates me in the process. I am extremely confident in his ability, happy with his service. I normaly struggle through things, make a few mistakes and take several months to complete smaller projects. My mistakes often cost me more than if i had someone do the work for me in the first place. For the first time I have contracted out to and expert. With that said, I am being told the injectors on my car are high impedance. The type of injector may be significant depending on what base board is used with a MegaSquirt upgrade.

I'd rather hear form a few more educated than myself before cirling back with additional questions to an expert. Appreciate the help, most likely I am already in error with some of my thought processes on the fuel injection upgrade. I don't want to come off as an Ass**** to a pretty accomplished mechanic by asking questions on something already answered.

Thanks,

[divace73]

Hi TX82FIAT

I have done just that, both turn a small job into a big one and have updated the low z to high Z. AFAIK (As far as I know ( its take me a while to figure out the acronyms)) they were all low Z. The east way to know is get yourself a multi meter put in on resistance and measure the 2 prongs inside the injector (I used an old bosch 2 pin plug with lead to make it easier). You should measure 2-3 ohms.
I have just put 220cc/min high Z units in mine and also will be Megasquirting it. I have not really tested it properly with the L-Jet system but it did start and was idling. I have attached some pics of my fuel upgrade.
By the way we learn rather quickly when we error [*]

[unplugged]

I replace my injectors with BOSCH 280 150 934 High Impedance Injectors when I installed MegaSquirt.
They are rated at approx, 308 cc/min
I did not try to run the new injectors off the L-Jet system.

[divace73]

It appears I cannot put pics if it is not my thread, is this correct?

[Daniel]

http://fiatspider.com/f08/viewtopic.php?f=18&t=12141 <<LINK

Yes you can post photos on here click on the link above to use a simple site for hosting pictures .

[TX82FIAT]

folks, thanks, I'm going to have to circle back potentially hook an Ohm meter to the prongs on the injectors. I did not switch the injectors out. However, given the information you have provided it is possible a switch to high impedance could have taken place at some point over the last 70K miles and 28 years. None of this really matters if the board used is megasquirt V3 or higher.

Good insight on injector options. I'll keep everyone posted on the efficiency of the new engine with Mega Squirt. Really looking forward to seeing how strong it performs across the RPM spectrum with better managed mixture. Should ge good low end torque qith a respectable power band. I'll see if i can post Dyno results for those interested.

Ray

[divace73]

Hi TX82Fiat

Just an update, I have had the car running around the block (about 5-10min of driving) with high z 220cc/min injectors with the L-Jetronic system, I had them at 40PSI just for straters and all went well, no problems at all. Don't know too much on the emissions side yet but so far so good.
However just after I went for a run, I went to check my oil and my dipstick broke..... It just would not be a Fiat if something didin't happen???
I will attempt to put some pics on a site shortly.

[divace73]

I have managed to figure out the way to attach pics
Please see my adjustable fuel pressure reg with gauge