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Rebuild/Swap No Start Situation- Now solved

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Old 07-23-2011 | 09:30 PM
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So I pulled the fuel hoses and turned the motor without the dme relay in and there was no geyser. I'll probably still try and find something to test the cooling system with tomorrow

I have 72lb siemens injectors with a 'marren' sticker on the side. Number on the side says 3145 so they are 72's.

However when I look at the little pin on the nozzle it seems to be pressed in just a smidge, is this how they should be? Considering all 4 are like this I'd assume so, unless someone was trying to sabotage my project.

I'm using a chip made by rogue for this size injector.. Think he may have made a mistake and these could be geared for stock chips and are being told to squirt more than they should?

And for a dumber question, I am supposed to run these straight without caps, right

Last edited by 1987Porsche944WithRealLongName; 07-23-2011 at 10:14 PM.
Old 07-23-2011 | 10:34 PM
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That is a good!! If you don't have fluid with the injectors pulled then it may not be a head gasket. You need to contact Rogue and confirm the map. Also check you have the chip installed correctly in the DME. Most run the larger injectors without the caps.
Old 07-23-2011 | 11:59 PM
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Originally Posted by 1987Porsche944WithRealLongName
I'm using a chip made by rogue for this size injector.. Think he may have made a mistake and these could be geared for stock chips and are being told to squirt more than they should?
You have a PM. If I missed the injector size in your order, then yes the injectors could be injecting too much fuel.
Let me know (PM) and I will double-check your setup.
Old 07-24-2011 | 02:16 AM
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There a way I can test the injectors to see how they act when under pressure? I don't think they'd hold in the rail if I pulled it and turned on the fuel pump would they
Old 07-24-2011 | 03:32 AM
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If they have the retaining clips, then they should be ok.
Old 07-24-2011 | 03:28 PM
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Nobody around here has a coolant pressure tester..

So I tried turning the motor over a few times with plugs in to see if the vacuum would suck in some water. Risky I know, but it was only a few bursts. When I pulled the plugs the elements on all of them were bone dry.

I'm starting to think about giving it another go. I regrounded the dme and the fuel stopped going into geyser mode, well at least I think that's what did it. Will it flood again if I try turning it over normally with spark just to get it to start? I think enough pressure has been built up in the motor from last time to not have to bother with pressurizing the oil system again.
Old 07-24-2011 | 08:48 PM
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Aaaand now I'm not getting spark or rather it's the first I've actually been able to worry about it

I've got 87, 87b, and 30 jumpered on my dme relay, and the fuel pump fuse removed with dme hooked up. The dme would still allow the plugs to fire with this, right?

12v coming from the coil, I tested with the 'ol screwdriver in the ignition wire near the body of the car. Had to use a camera to record it while I turned over since nobody is here...
Old 07-24-2011 | 09:05 PM
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That should work. Power for the coil comes directly from the ignition switch and is a direct feed, no fuse or relays in the path. You need to have the DME relay (or junpers) installed to get power to the DME. The speed and ref sensors send the timing signals to the DME and the DME sends a ground pulse to the coil to fire it. If the sensors are working, the tach should bounce a little while cranking.
Old 07-24-2011 | 09:16 PM
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Wasn't the tach going through a different set of prongs on the relay?

Although these sensors worked for me before the swap and tested proper resistance I suppose there could still somehow be something wrong. And yes, I have them connected properly.

I think I may try readjusting them for the hell of it

Last edited by 1987Porsche944WithRealLongName; 07-24-2011 at 09:38 PM.
Old 07-24-2011 | 09:43 PM
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The tach is driven by the DME directly, the signal doesn't go through any relay. If it bounces, it shows that the sensors are generating and the DME is processing the timing signals. Next I would put a 12VDC trouble light on the coil and see if it is getting ground pulses from the DME.
Old 07-25-2011 | 01:22 PM
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Well the speed and references sensors were pretty off, I got that sorted and still no rpm signal.

But you know when I turn the key to accessory all of the needles on the gauge panel jump just a hair except for the tachometer.

Connected a sparkplug to the wire coming from the coil and tapped a ground wire where the green wire goes in and it sparked where I touched, nothing at the plug itself... It's reading 0.8-0.9 ohms from point to point

Last edited by 1987Porsche944WithRealLongName; 07-25-2011 at 02:40 PM.
Old 07-25-2011 | 04:46 PM
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So... I take it sparks coming from the coil ground when I tap it is a good sign of a bad coil?
Old 07-25-2011 | 06:47 PM
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Yup. the green wire goes to pin 1 of the DME and the Black is 12VDC power. If you tap the green wire to ground you should get a spark with the ignition on.
Old 07-25-2011 | 06:58 PM
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I can get a wimpy looking blue spark through to the plug, but it also sparks where I contact the ground on the coil itself.

I'm getting 12vdc through both prongs.. Is something amiss?
Old 07-25-2011 | 07:11 PM
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Nope, you should get 12V on both prongs since the coils resistance is close to a short (less then 1 ohm). The coil takes about 5-10 amps of current to work so the arc on the green lead is expected. If you get a spark by tapping the coil terminal to ground, you should get a spark while cranking the car if the DME is generating a ground pulse to the coil.

Last edited by Bri Bro; 07-25-2011 at 07:34 PM.


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