peak-n-holds

[Bruce Plecan]

-----Original Message-----
From: Mike Pitts <mpitts at netspeak.com>
To: 'gmecm at efi332.eng.ohio-state.edu' <gmecm at efi332.eng.ohio-state.edu>
Date: Thursday, March 18, 1999 4:22 PM
Subject: RE: peak-n-holds 


>I have the stock ECM in my Buick GN which still has 
>the stock saturation type injector drivers installed. 
>I am however running 55# low-impedence injectors. 
>I know that this is not supposed to work, but it 
>has been working...so far.

I'd really be suspicous. of something being wrong, and your just 
borderline on it working.  Such as having a poor ground or some 
resistance in the power to the injectors.  I went from a 2 ohm load to
1, and the driver lasted just seconds, your going from 6,  16 ohms to
6,  2 ohms, and it's living?.  See if at the ecm you have any voltage
reading on any of the ground wires at the ecm, with a good DVM.
Also, key on, engine off what is the voltage at the injector drivers at the
ecm... 
>
>I have some peak-n-hold drivers (4A) that I would 
>like to install into the ECM to make it right for 
>the injectors.
>
>I am curious if doing this is going to change the 
>fuel output of the injector compared to what it is 
>right now with the saturation type drivers.  
>
>My understanding is that the "peak" part of the 
>peak-n-hold might cause the pintle to open slightly 
>quicker. If so, I would guess the total open time 
>would be slightly longer, allowing more fuel to enter 
>for a given pulsewidth.

Well, that has been mentioned, but they also close quicker,
since their is less smoke flowing thru the injector, when it's on
Bruce
>
>Thanks,
>-Mike
>
>-----Original Message-----
>From: owner-gmecm at efi332.eng.ohio-state.edu
>[mailto:owner-gmecm at efi332.eng.ohio-state.edu]On Behalf Of jsg at donet.com
>Sent: Thursday, March 18, 1999 4:01 PM
>To: gmecm at efi332.eng.ohio-state.edu
>Subject: Re: peak-n-holds 
>
>
>
>
>   In message <E299274A3F18D211B9E700600805A01D0100BFB8 at crash>, you write:
> 
>| Has anyone ever taken fuel delivery measurement differences 
>| between peak-n-hold and saturated drivers, for the same 
>| injector at the same PW and fuel pressure? 
>
>Same injector? If you have a low impedance injector, you don't want to
>use a saturation driver. You can detect an electrical insulation
>burning smell with full power on for as little as a second. If you have a
>high impedance injector, it is designed for full voltage (or full
>current). So... if you have low-z injectors, you need pnh drivers... if 
>you have high-z injectors, I don't see a need for not using a
>saturation driver nor a performance difference if one is used.
>
>| My thinking is that the P-n-H drivers may open the injector 
>| a little quicker, therefore delivering slightly more fuel 
>| for a given PW.  
>
>Using a high-z injector with a higher source voltage (like 30-40V)
>to give an initial current greater than 12V/Z_{injector}
>may make a difference, but that would require a setup power
>supply. Is that what you want to try?
>
>john
>