No spark, no start

gt350mike · 07-16-2006, 05:07 PM

I'm about to call the suicide hotline..........I've replaced everything in the fuel system now I can't get any spark. I tried to by-pass the coil (putting power to the coil straight from the battery) but didn't have any luck.

The PO had problems starting the car because of the fuel issues. He was able to start the car, but he did so by running a propane line to the air clear (not recommended). Could we be having a problem with the sensors? If so, I need a link that has a pictorial on how to fix them.

Thanks in advance!

Razorback1980 · Razorback1980's Garage

It could be a lot of things including but not limited to the sensors. Do a quick search for no spark and SoCal will probably have a list of things to check and in the right order. Follow that and you will do well.

Schumi · 07-16-2006, 06:00 PM

Find SoCal's five minute test (I think he called it that) in this thread:

The Neverending

Do Hugh's test, report back with findings.

gt350mike · 07-16-2006, 06:09 PM

five minute quick test.

Check for power at the coil and at the injectors with the key on.

No power at the coil it's the ignition switch or related wiring.
No power at coil...tried to by-pass, using jumper from battery to coil & still would not start.

No power at the injectors it's the DME relay.
I have power at the injectors
Power at the coil and injectors points to a bad reference sensor. The connector may be corroded and/or not plugged in all the way or cracked and may have broken the wires inside.

Could be the second set of contacts in the DME relay. These are for the fuel pump. The fuel pump should run for a half second after you stop cranking. Have someone listen for it behind the passengerside wheel well. Check the fuse for the pump too.
Fuel pump works
On the early 944's you can use an alligator clip jumper between Aux fuse #2 and #3 to run the fuel pump directly. Count from the drivers door. Don't leave the clip on.

Come back with your findings.

_______

SoCal Driver · SoCal Driver's Garage

I'm almost stumped. Just got back from a long drive. Need to think on this.

Schumi · 07-17-2006, 09:31 AM

This is exactly what we did to Ed's 944 with the same results. Even with trying to bypass by jumping the coil we got nothing. We replaced the coil to make sure the coil was good and still no result.
We also bypasses the distributor while jumping the coil from the battery by hooking a sparkplug into the coil output wire yet we still got no spark, even when we were sure we had a good coil.

asudds · 07-17-2006, 12:34 PM

I ended up haveing a cold soldier joint in the DME... I also had an intermittant wire loom issue in the engine compartment. Try either or both... tapping on the DME while starting helped the first... running a jumper from the firewall connector to the injector gnd help the other.

gt350mike · 07-17-2006, 02:13 PM

Quote:

Originally posted by Schumi
This is exactly what we did to Ed's 944 with the same results. Even with trying to bypass by jumping the coil we got nothing. We replaced the coil to make sure the coil was good and still no result.
We also bypasses the distributor while jumping the coil from the battery by hooking a sparkplug into the coil output wire yet we still got no spark, even when we were sure we had a good coil.

How did you fix the problem?

gt350mike · 07-17-2006, 05:59 PM

I talked with the PO today and he had some DME issues (If he remembers correctly, injector problems). He also told me that he swaped out the coil so that should not be problem. I have an extra DME so I'm going to swap it out tomorrow. I'm at a loss as to what the problem is so I'm going to start w/it and hope the car starts.

Schumi · 07-17-2006, 06:17 PM

Quote:

Originally posted by gt350mike
How did you fix the problem?

The jury is still out on that. We're still working on it.

Razorback1980 · Razorback1980's Garage

If you put a jumper between the battery and the coil, then you should have power to the coil. The thing that makes the coil fire is the other side completeing a ground. Could you have a wire not making contact between the DME and the coil. I think there is a test on Clarks garage to help diagnose if this is the problem or not.

asudds · 07-18-2006, 05:49 AM

try the DME swap with a known good one... You can have the DME re-built as well. The wires have to be traced either from the DME Connector or the Firewall connector through to their terminations at the injectors, Sensors, etc.

I had a broken injector grd wire in the harness.

Nothing a DVM and a wire diagram can't trace out.

gt350mike · 07-19-2006, 05:07 PM

Swapped the DME out tonight.....no change. I do have a question regarding the two plugs that mount just outside the DME plug; one plug had two black wires with strips and the other plug had a brown or blue wires. The black wire plug was plugged in but the other plug wasn't. What is there function??????

SoCal Driver · SoCal Driver's Garage

Changes fuel mapping for other world locations.

gt350mike · 06:12 PM

Hugh.....Any ideas on what I should work on next? I have two more evenings to work on the car before I go play soldier for two week (heard of Camp Shelby, MS?) and I'm hoping for a miracle!

SoCal Driver · SoCal Driver's Garage

All of the pertinate points have been touched on. Just have to eliminate them one at a time.

Slam · 07-21-2006, 12:13 PM

Does the car have a factory alarm or a coil disable alarm?

gt350mike · 07-21-2006, 12:42 PM

Don't think so.......I'm going to replace the coil this evening and see what happens. If it doesn't start tonight, then its going to sit for 2+ weeks.

Schumi · 07-21-2006, 09:32 PM

Slam- what all do you know about these coil-disabling alarms? How do they work?

eresner's car has what we believe to be a dealer-installed alarm and it might be one of these types.

Slam · 07-23-2006, 06:42 AM

Schumi, all I know is that my car had some sort or alarm on it when I bought it. The alarm was set up to ground the coil when it (the alarm) was activated and it gave me trouble until I removed absolutely all of its wiring. Frankly, I wish I knew much more about wiring because at my car's age, it's becoming a recurring issue.