Trigger Points, chasing my tail Options

[tdgray]

I am still chasing down my FI problems. Got a new realy board seems to have solved the fuel pump problem. when I switch the ignition on now I here the FP for a brief moment as I think it supposed to do. I have reconnected the vaccum hoses (dumb ass PO unhooked every hose (IMG:style_emoticons/default/fighting19.gif) ). I am sure the fuel is being delivered to the pressure reg and beyond, still need to measure pressure. Alas I am getting no fuel into the cylinders. Crank it for 15-30 seconds and pull a plug and it is dry. Tried 2 diff FI brains and nothing ( I am pretty sure that the new one should be operational). Sorry this is a long explanation. Tonight I want to check the trigger points. As I understand it they signal the control unit to dispense fuel RIGHT? I am wondering if they are stuck closed or bad or what. I don't know I am just chasing my tail. (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/headbang.gif)

Am I going about this all wrong?

Thanks Guys,

Todd

ps. Thanks Dave Darling the help you gave on my last post helped to diagnose the Relay Board problem real fast. new one is in and working (IMG:style_emoticons/default/clap56.gif)

[redshift]

Trigger points... uhhhhhuhh..

Hey, yank an injector out, and shoot it in a bottle, save you 25 seconds, and you won't have to foul the plugs, or shoot gas out of the pipe to tell..

Pressure regulator and 'beyond'?

(IMG:style_emoticons/default/huh.gif)

Step out of the car please....

Could you give us a summary of your fuel line layout?

(IMG:style_emoticons/default/smile.gif)


M

[tryan]

try brad banders website and follow the logical sequence. jousting at windmills is expensive.

[ArtechnikA]

...I am getting no fuel into the cylinders. ... Tonight I want to check the trigger points. As I understand it they signal the control unit to dispense fuel RIGHT?

i shouldn't be trying to help with /4 FI problems but i will... somewhere you'll find a reference to Brad Anders' page on D-Jet principles of operation and troubleshooting; i don't have the link but i'm sure it won't be long before someone adds it to this thread. it's excellent.

yes, trigger points signal when to inject fuel. if they're bad, no regular injection...

things to try: 1: go to the engine with the ignition on and manually work the throttle. you should hear a series of clicks (10?) as the throttle-position sensor does its enrichment thing. do that enough times and there -will- be fuel in the cylinders -if- there is pressurised fuel in the loop.

you -can- drive the car with no TPS so if this doesn't work all is not lost (although it'll be a pig under acceleration and you''ll want to deal with it...)

2) if you make the ThermoTime Switch think it's *REALLY* cold (< 40F, i believe) the aux cold-start injector should operate while cranking - again - if there is fuel in the loop.

good luck !

[Brad Roberts]

All good advice...

but he should check fuel pressure first.

checking the injectors is easy... do like Rich above me said: turn the key on and work the throttle... listen carefully for the injectors... they will click as you move the throttle (and squirt gas) I unplug all but one injector when I'm testing like that (so I dont foul plugs or cause a back fire when it does start)


B

[tdgray]

Ok here goes (thanks for the injector suggestion lot easier than pulling a plug, will try (IMG:style_emoticons/default/beerchug.gif) )

Fuel lines come up from pump. Two lines. The delivery goes across back of engine compartment into pressure regulator on one side of the "T". Line comes out other side of T to fuel rails. A line also comes out of stem of the "T" this is fuel return back to fuel pump I assume. That is as far as I can follow. Am I missing something? Like I said the PO removed all lines so I hope I am following the diagrams correctly. I have downloaded the D-Jet manual and the tech articles from PParts web site. I guess at this point I'm not ignorant just Stupid (IMG:style_emoticons/default/blink.gif)

Thanks

Todd

[tryan]

dd posted a fuel line routing recently. pop a fuel line loose at the pump and put it in a jar. hit the key a couple times and see what you have. i look for daves schematic.

[Brad Roberts]

Denied.

The fuel flows from the passenger side rail across the front of the engine thru the drivers side fuel rail then to the regulator. Think of it this way: the regulator bleeds off the pressure you DONT need into the line running across the back of the engine (the return line).

Which is how/why you can test pressure from both fuel rails.


B

[tdgray]

Thanks Brad. (%(*#&$((#Y$)*Y#)Y)#$ dumb ass PO why do people do sh*t like that. Ok will reroute fuel lines tonight and see what happens. I will look for DD's fuel line diagram.

To Do list.

1. redo fuel lines
2. check pressure after reroute
3. check injectors for "click"
4. have beer
5. pull injector and check for gas.
6. try to start car
7. have beer and shoot myself if none of this helps.

You guys are great thanks for all the help

Todd

[ArtechnikA]

... dumb ass PO why do people do sh*t like that.

there are many reasons, of course, not to dampen your righteous rant :-) ...

here's a scenario i know too well: begin a project over a weekend with great zeal. discover Monday morning you're on the 1-wk layoff list. suddenly that restoration project you've waited so long to begin fades in priority ... i remember very clearly taking -something- apart and thinking to myself "i don't have to document this, it's so obvious i could -never- forget how it goes back together." fast-forward 20 years and guess what -- i forgot !

'bout all you can do is make the best of what you've got -- and make NO assumptions about anything...

[tryan]

is there a possibility the po had carbs on it and stuck the fi back on when it was sold? have ammo. will travel. (IMG:style_emoticons/default/wink.gif)

[tdgray]

I am pretty sure that this an unmolested car. Has 52K on it everything appears to be orginal. Just been sitting for 5-7 years. The PO was just a wanna-be dealer who "stole" the car from the orginal owner ( I have all his paperwork) and tried to make it run to sell it for more money. I agree that people do things just as "art" said, hey when I got my MGA it was in five thousand pieces with panels cut of where they shouldn't have been etcetera. Got that back together should be able to do the same with the 914. I know.... patience grasshopper.

Todd

[redshift]

I say this thing runs on the next start after the fuel lines are moved..

You may have other stuff, but I think this one will be done.

(IMG:style_emoticons/default/smile.gif)

G'luck! Crossin' my fingers!


M

[Bleyseng]

Yes, the fuel lines from the fuel pump are High pressure which go to the fuel rails and injectors then go to the fuel pressure regulator which bleeds excess pressure off to the return to the gas tank line.
All fuel lines should be brand new PORSCHE high pressure fuel injector hose. Don't use anything else as it won't be rated for high pressure or the high heat from the engine. That's why crappy FI line cracks and sprays at a high pressure gas onto the hot engine. The result is a burnt up 914, see there are lots of pics of those cars posted here. The VW stuff is not rated either.
Please use a the FI fuel line clamps that Porsche used too, they don't pinch the fuel line like the cheap carb fuel clamps do.


Geoff