Oil leak fixed...now it won't start.

Flitzr951 · 10-08-2007, 08:44 AM

So it's been a couple weeks since I've posted any updates on my 951 project. I finally had it idling when the freeze cap at the rear end of the main oil galley popped out. I went to Jamaica, came back and pulled the engine. I installed a new freeze plug, the approriate 55lb injectors and the venturi delete hoses. I have tried starting the engine but it won't fire up. It cranks but there is no fuel pressure or spark. I never had this issue before so I'm a little lost as to what it could be. The DME is plugged in, the relay is good (I'm getting the 12v switched power to my MAFterburner) and I have swapped my chips to see if that could be the issue, nothing seems to be wrong. Any input would be greatly appreciated. Thanks,

soxnail · 10-08-2007, 02:00 PM

But is the relay switching on (and turning the fuel pump on) ??
Sox

Flitzr951 · 10-08-2007, 03:40 PM

When I turn my ignition to "on" I don't hear the fuel pump. My MAFerburner is powered by the 12v switch wire off the DME, and it lights up when I turn the ignition to "on". It still seems like the issues has to be at the DME, since I'm also not getting any spark either. I've had some issues trying to get this thing started in the past but both of these issues are new.

soxnail · 10-08-2007, 03:49 PM

you can test the dme relay by pulling it and jumping pin 30 to pin 87b on the socket this will cause the fuel pump to run all the time. (just use it for testing and emergencies).
Sox

Flitzr951 · 10-09-2007, 06:26 AM

I'll be sure to give that a try when I get home this afternoon. If that causes the fuel pump to turno on, does that mean the relay was bad, despite the fact that I got power to my DME?

2Tight · 10-09-2007, 07:14 AM

Make might sure you didn't get the reference and speed sensors crossed. It's easy to do after pulling a motor. Even with them not swapped a bad connection at the male end of the ref. sensor will do the same thing. The fuel pump should only run in the 'start' position and remember there's a fuse also on the pump. I hope you find it, I'm sure it's something simple.

soxnail · 10-09-2007, 07:33 AM

Dme power does not come from the dme relay...it is wrongly named it should really be called " power for fuel and other necessary stuff after dme says its ok" but that may be too long

Sox

Flitzr951 · 10-09-2007, 07:59 AM

I did remove a sensor from my bell housing. I didn't touch the reference mark sensors but the 3rd sensor (the one that runs the output end to a mount on the back of the cam tower) was destroyed so I pulled it out. I assumed it was only used for testing purposes so I didn't think it would matter too much

2Tight · 10-09-2007, 08:08 AM

Quote:

Originally Posted by Flitzr951

I did remove a sensor from my bell housing. I didn't touch the reference mark sensors but the 3rd sensor (the one that runs the output end to a mount on the back of the cam tower) was destroyed so I pulled it out. I assumed it was only used for testing purposes so I didn't think it would matter too much

I was thinking more about them getting swapped at the connectors at the rear of the intake manifold when you pulled the motor. That 3rd diagnostics sensor is pretty useless and won't effect anything. I assume you removed the sensor bracket then to pull the bellhousing off and if so did you regap the ref. sensor? That gap is pretty critical. If you have slotted your belhousing sensor opening and just left the bracket alone ignore all of the above.

Flitzr951 · 10-09-2007, 08:40 AM

I loosened the mark sensors enough to slide the bell housing off, and then pushed them back into place once I put the bell housing back on. I didn't have any ignition issues before I pulled the engine out so I tried not to mess with anything.

soxnail · 10-09-2007, 01:18 PM

I would recommend you chase down the fuel pressure (lack off) first before chasing ignition.
My 0.02
Sox

Flitzr951 · 10-09-2007, 01:24 PM

I'm going to short out the DME relay point first and formost, and see if that charges the system. I'm also concerned about the amount of fuel left in the tank (I'm thinking that if I was out it would certainly cause a problem). Would the Reference sensor gapping cause a lack of spark if it was incorrect?

soxnail · 10-09-2007, 01:29 PM

I reckon if you don't have fuel in the tank, getting fuel pressure would be difficult

Either ref or speed sensor gap or any other problem (with the sensors) will cause no no spark.
Sox

Flitzr951 · 10-09-2007, 01:30 PM

can the reference sensor gaps be set with the engine in the car? Which sensor is which?

soxnail · 10-09-2007, 01:33 PM

Yes here is an excellent write up from Clark's site.
http://www.clarks-garage.com/shop-manual/ign-02.htm
Sox

Flitzr951 · 10-09-2007, 01:35 PM

beautiful, thanks.

Flitzr951 · 10-09-2007, 05:18 PM

Let it be known: You must have fuel in your tank in order to attain fuel pressure.

With that being said, I'm still getting no spark. I suppose my next step would be to gap the reference and speed sensors. If anyone has any other ideas please chime in.

soxnail · 10-09-2007, 05:53 PM

before you dig the sensors out, you may want to hook a scope up to the sensor's out puts and test them in place. Hook up the scope to each one in turn and crank the car you should get the following wave forms.

Reference mark sensor

Speed sensor
Sox

Flitzr951 · 10-14-2007, 04:42 PM

So I had a friend test the speed sensor and it wasn't relaying a signal. I replaced it with one that checked out and I'm still getting zero spark from my coil. I'm going to get my hands on a multimeter, although I don't know how to go about checking for connectivity. I'm guessing that I have some sort of bad conection on the #1 wire off the DME. So if anyone knows how to continue troubleshooting, I'd appreciate the help.

soxnail · 10-14-2007, 05:22 PM

First confirm that it is the speed sensor that is bad and not just its positioning on the fly wheel. Ditto for the reference sensor. I am not doubting that your friend is right but I have seen a lot of hall effect sensors and they is not much to go wrong in there. The way they go bad is with physical damage, running into the teeth of the fly wheel etc.
Having said that you can ohm out the sensor it should be about 1000 ohms say 600 to 1600 ohms, but to really test it you need to look at its output with a scope as I posted last time. you need to look at pins 8 and 27 for speed sensor on the dme and pins 25 and 26 for the reference sensor.
Sox