Prins vsi

[darren]

Any one out there know where to source a schematic for prins vsi
Install for 2006 grand caravan dual fuel
Thanks

[C3H8]

What country are you in Darren?

This location has a pretty good generic manual but it is a 4 cylinder engine shown. Have a look.

http://www.prinsautogas.com/view_attach ... nual_prins_

[darren]

I am in canada

[C3H8]

In that case you can contact MaxQuip. They are the Canadian distributor for Canada and should be able to assist you in getting a wiring diagram. MaxQuip's main office is in Calgary but they also have branches in Surrey, Edmonton, Saskatoon, Winnipeg and Montreal. 1-866-629-7847 or 403-258-3685. Used to be Victor was the main technical assistance. Could be someone else now.

[darren]

Thanks c3h8
I will tell you the trouble I am having with my 2006 grand caravan
I have rail pressure of 55 psi , ihave spark I havesome impulse on the injector socket
But it will not start on gasoline it kind of tries
Ihave tricked it to start and run on propane fine by warming the reg heat sensor
but when I switch it to gasoline
It flutters and dies
Can I still get an impulse light to cycle on and off but not be strong enough to fire
My gasoline injector s?

Darren

[C3H8]

Whenever we diagnose any of the injection systems for a gasoline issue the main thought is to remember the propane ECU or modules are normally operated in propane mode with a 12 volt signal from the propane switch. Selecting gasoline on the switch or losing power for any reason to the ECU or modules normally causes the system to default to gasoline through normally closed relays. What this usually means is if you have the switch in gasoline mode you need to ignore the propane system for diagnostic purposes. As you stated you have used a noid light to check for injector pulsing (driver operation). You say you have some pulsing on the noid light. The most important check you can do initially is to check all your ground connections on the system. Also locate the main relays that operate the system and remove them and reinstall them. It is common for the main relays to get corrosion on the posts. Removing them will allow inspection and break off the corrosion.

The fuel pressure spec calls for 58 PSI +or- 5 PSI so your ok there.
Since your noid light has a fairly weak pulse there are several things to check. Proper power to the injectors. Make sure there is 12 volts. Check the connections at the LPG injector modules which also provide the injector simulation for the gasoline RCU while on propane. Although I said to ignore the LPG side the injector modules could be faulty or disrupting the pulse width on gasoline and starting on propane since the system starts on gasoline in both modes. If the injector simulators are easy to get at you could temporarily reattach your gasoline injectors to the factory install and see if it now starts on gasoline. If so the problem is in the simulators or the simulator wiring.

One last thing. You can verify this is a gasoline fuel delivery problem by squirting a few ounces of gasoline into the intake manifold and seeing if the engine fires. If it does you have a likely gasoline injector issue or a problem with the simulators installed to shut off the gasoline injectors.

The injector simulator has 4 wires going to it. 12 volts from bat. A trigger wire going back to the LPG ECU. The other two wires are the factory gasoline driver wire that was cut and routed through the simulator. Either a poor power wire or a poor ground on the LPG ECU could be causing issues with the simulator.

[C3H8]

Sorry. I should have stated the injector simulator could have as many as 14 wires. Power in, trigger wire to the LPG ECU, 6 "in" for the factory cut and 6 "out". Depends on how many simulators were used at that time. Could be one or two.

[darren]

Thanks again c3h8
A couple more questions , when I pull out the asd relay (this is what feeds the
Injector 12volts) and using dvom I put it on dc volt setting and prob the positive terminal on the injector socket and the other lead on the positive batt post I get a reading of 12volts , keep in mind I
have not removed any of the other injector sockets . Now does reading tell me
I have a short to ground or is it feeding through the other injectors and sourcing
a ground through them from the pcm? Is there supposed to be ground from the pcm
When engine is off ?
Darren

[C3H8]

My time working on the Prins system was fairly short. IMPCO came out with the BRC system shortly after we installed some Prins systems and being an IMPCO distributor we immediately stopped doing Prins and went to the BRC. I didn't get a lot of diagnostic time on Prins. That being said your test may or may not make sense. If the key is off I would expect the power to be interrupted to the injectors however that interruption is done by the relay. If you bypassed the relay in performing the test there is a good chance the computer grounds would function with at least one driver being grounded. A test I would consider in this situation is to put a jumper across the relay socket connections to reconnect the power to the gasoline injectors. Then test the gasoline injectors with your noid light and see if you get a proper pulse. If the pulse is still weak you need to go after the simulators as the second most likely culprit. I am assuming you have checked the grounds as I first suggested. By this either physically loosen them or even use a jumper from the ground position to the battery ground. I once grounded a GM system to the factory welded post on a firewall you find on the newer pick ups. The vehicle wouldn't start but I ruled out the ground since it was welded to the firewall. After a time I hate to disclose I finally attached a jumper to the post and battery ground and all the issues disappeared. The weld was no good for some reason. Grounds on these systems are critical.

[darren]

Just let everyone know I got the van running on gasoline again .
The injector simulator was not properly switching internally
when gasoline was was selected . I found it by jumping the factory injector leads that
we're cut and spliced into the simulator as c3h8 had suggested THX again
c3h8