Techno car efs400

Propane, Butane, LPG, GPL, C3H8, C4H10
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darren
Posts: 37
Joined: Mon Jan 06, 2014 11:19 am

Techno car efs400

Post by darren »

I have a 1995 gmc 7.4 propane with a techno carb efs400 system it has a model e impco Vap
On it and wondered what the solenoid on the face of it does
Thx Darren

kikkegek
Posts: 416
Joined: Thu Nov 17, 2011 2:12 pm
Location: Netherlands, The Hague

Re: Techno car efs400

Post by kikkegek »

an photo would be really helpfull.

but if it looks likes this, then its a start assist solenoid.

Image
storage/project: 1974 GMC 25HUNDRED Suburban - fresh rebuild 350 small block - TH350-NP203 - 4.10 gears - IMPCO425 mixer
driver/project: 1977 GMC C15 Suburban - 454 big block - 4L80E- LPG VSI - 3.08 gears
sold: 1986 Chevrolet Suburban K20 Silverado

darren
Posts: 37
Joined: Mon Jan 06, 2014 11:19 am

Re: Techno car efs400

Post by darren »

Ok thanks
Is it engaged all the time?
I tried attaching a pic but it said file to large it does look like the one you pasted
Does it release after it is warm?

storm
Posts: 796
Joined: Wed Jan 10, 2007 10:10 pm
Location: NSW, Australia

Re: Techno car efs400

Post by storm »

It should only operate when the engine is cranking over to start.
Fuel flow requirements calculations
Engine air flow requirement calculation: CFM = Cubic Inches x RPM x Volumetric Efficiency (VE) ÷ 3456

C3H8
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Location: Winnipeg, Canada

Re: Techno car efs400

Post by C3H8 »

This solenoid has two purposes. Venturii style mixers do not generate enough vacuum signal during cranking or slow idle RPM's to open the secondary valve on IMPCO regulators. Because of this the engine could not start or idle without a solenoid to open the secondary valve and keep it open at idle. Technocarb added the solenoid to push the secondary valve open slightly as soon as the key is turned on. Initially they used a fixed solenoid only. They then used a solenoid that had a manual adjuster on it allowing them to adjust the solenoid at idle to control idle fuel mixtures. Later models incorporated a stepper type motor controlled by a computer that controlled the idle mixtures as dictated by an O2 sensor.

All three of these versions were meant to have power all the time once the key was turned on.

darren
Posts: 37
Joined: Mon Jan 06, 2014 11:19 am

Re: Techno car efs400

Post by darren »

Thank you for the responses
Does anyone know of the type210 digital scan tool that techno carb use to offer , what it all did and if anyone would have one available .Technocarb on their schematic for this particular system show this scan tool
Thx

C3H8
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Joined: Fri Sep 09, 2005 11:23 pm
Location: Winnipeg, Canada

Re: Techno car efs400

Post by C3H8 »

This is the scan tool used to check fault codes and operation parameters of all the Technocarb systems that use AEB computers for fuel control. The scanner can measure O2 readings, Stepper motor function on the regulator and stepper motor function of the electric power valve. I'm not sure if timing modification readings are available on the tool. I believe it also allows the operator to reprogram the ECU if necessary along with manual adjustment of the stepper motors for testing. Availability, not sure. I'll see what I can find out.

C3H8
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Location: Winnipeg, Canada

Re: Techno car efs400

Post by C3H8 »

Check this link out. It is the EFS600 which is the next generation after yours but quite similar in operation. You will note the stepper motor on the reg vs the solenoid on yours.

http://documents.rasoenterprises.com/Te ... Manual.pdf

darren
Posts: 37
Joined: Mon Jan 06, 2014 11:19 am

Re: Techno car efs400

Post by darren »

Thx c3h8
Let me know if you find a scanner
The engine gallops a bit on idle and you can feel surging on acceleration of which I would like to figure out
Thx

franz
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Re: Techno car efs400

Post by franz »

I have the Technocarb set up tool and scanner which I will sell. I'll also toss in an additional mini-scanner that has an LED that has burned out. Both for $125.00 USD and I'll include shipping here in the US. Add the appropriate shipping for non-US destinations.

When I got these scanners, they were astronomically expensive! I believe somewhere around $400.00 each. PM me if interested.

The EFS system is heavily reliant on the O2 sensor for input. If the sensor has seen extended periods of lean operation, or is more than about 60,000 miles old, its time to replace it. The same for if it has seen water submersion, salt buildup, or engine coolant.
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