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View Full Version : no start, no fuel pressure, no spark



Slysc
06-21-2007, 10:16 PM
Just left the dyno and got about 50 ft. down the road when the car coughed and died. I check and found that there was no fuel pressure. I jumped the fuel pump relay and the pump came on and fuel pressure was normal. Yet, when I crank with the relay jumped, still no spark.

I unplugged the tuner, no change.
I swapped out the DIS module, no change.
I checked and the cam sensor is turning correctly.
The dampner and crank sensor look OK.
The upshift light is not on when I crank it.

WHAT IS GOING ON!!??:confused:

XR7 Dave
06-21-2007, 10:38 PM
Just left the dyno and got about 50 ft. down the road when the car coughed and died. I check and found that there was no fuel pressure. I jumped the fuel pump relay and the pump came on and fuel pressure was normal. Yet, when I crank with the relay jumped, still no spark.

I unplugged the tuner, no change.
I swapped out the DIS module, no change.
I checked and the cam sensor is turning correctly.
The dampner and crank sensor look OK.
The upshift light is not on when I crank it.

WHAT IS GOING ON!!??:confused:

It's your throttle body. I knew that thing was going to cause problems sooner or later.

mnwhatley
06-22-2007, 12:50 AM
Maybe the EEC is bad.

Tickler
06-22-2007, 03:40 AM
Ignition switch or some kinda relay? check yur fuse box yo'

deepbluesc
06-22-2007, 06:10 AM
All of those at once means something common to all is out of wack. Try pulling codes, if you can't retrieve any data, EEC relay is the first place I would look. I know the EEC and FP relay are interchangeable, but not sure if you can swap in the headlight or other relay to get it to a safe place.

Slysc
06-22-2007, 09:40 AM
Dave,

I tried reclocking the throttle body 180 degrees clockwise and guess what!! :rolleyes:

Where's the EEC relay?

I have a Z1Z EEC. The car is a 91 5 speed. What EEC modules will work with my car? I have two other EEC boxes on the shelf but only one has the right plug. Its the COES or something like that. When I try that box, everything is messed up so I'm thinking it's not compatible.

Raymond
06-22-2007, 02:17 PM
I have same problem. Feul pump wireing harnes is shoot. Can not find one.

Slysc
06-22-2007, 02:20 PM
Would that allow the pump to work when I jump the fuel pump relay? I get good fuel pressure when I do that. Also, would the harness problem prevent me from getting spark?

Do you mean the fuel pump harness that goes under the back seat or a different one?

David Neibert
06-22-2007, 03:50 PM
Another vote for ignition switch.

David

CMac89
06-22-2007, 04:42 PM
Sounds to me like it is some type of safety cut-off switch doing it. If you are getting multiple units malfunctioning at the same time then it seems there should be something that controls them all, henceforth, it may have shut them all down at once.

It would have to be something like the inertia switch. Although, I do think that is fuel pump shut-off only. Could be wrong.

Slysc
06-22-2007, 10:31 PM
I'll check the ignition switch. The radio and stuff comes on when the key is on. Would the ignition switch be failing and still turn on the interior electrical stuff?

XR7 Dave
06-22-2007, 11:28 PM
Absolutely. There are several seperate power feeds from the switch.

Certain things work with the key backward. This includes the radio and power windows.

Other things work only with the key forward. This includes your heater, the ABS, ignition, and others.

Then there are some things that drop out during crank and some things that continue to have power during crank. Your ignition (and EEC) is one of very few things that retain power during crank.

For this reason it is completely possible to have everything in the car work including the starter but have a faulty ignition switch prevent the car from running.

ThunderDave
06-22-2007, 11:34 PM
Absolutely. There are several seperate power feeds from the switch.

Certain things work with the key backward. This includes the radio and power windows.

Other things work only with the key forward. This includes your heater, the ABS, ignition, and others.

Then there are some things that drop out during crank and some things that continue to have power during crank. Your ignition (and EEC) is one of very few things that retain power during crank.

For this reason it is completely possible to have everything in the car work including the starter but have a faulty ignition switch prevent the car from running.


Took the words right out of my mouth. :rolleyes: ;) :D I too think it's your ignition switch Dan.

dwinthrup
06-22-2007, 11:43 PM
I found that if you remove the cooling fan relay box behind the passenger side head light the fuel pump don't work maybe check that?

Slysc
06-23-2007, 06:17 PM
I swapped the ignition switch with another car and it was the same.
I also swapped the box behind the passenger headlight (IRCM?) and that didn't change anything.

One thing I did find is that the O2 sensor wires were melted on the header. (funny there wasn't a check engine light.) I'm thinking that if the power to the O2 grounded out, it would blow a fuse (or an ECM). I'll check that next.

David Neibert
06-23-2007, 09:34 PM
I swapped the ignition switch with another car and it was the same.
I also swapped the box behind the passenger headlight (IRCM?) and that didn't change anything.

One thing I did find is that the O2 sensor wires were melted on the header. (funny there wasn't a check engine light.) I'm thinking that if the power to the O2 grounded out, it would blow a fuse (or an ECM). I'll check that next.

Dan,

That happened on my daughters explorer and it blew the EEC fuse and caused it to go into limp home mode. I think you've found the problem.

David

Slysc
06-23-2007, 10:02 PM
I looked in the fuse box and the ignition coil fuse was blown.
I replaced the fuse and the fuel pump cycled. However, when I tried to start the car, I got one little pop and then nothing. I checked the fuse and it was blown again. I think I found the initial problem but now I have to fix the cause. It's probably the O2 sensor wire like I described before. I hope thats it cause I don't have any other ideas.

Tickler
06-24-2007, 03:19 AM
Could be a bad fuel pump, check its impedance with a multimeter? I'm not sure what fuse that would blow though. I've had a bad fuel pump blow fuse after fuse, upon removal of pump the wires were charred.

CMac89
06-24-2007, 11:03 AM
Well, I had the concept right atleast.:)

Anyways, the only possibilities for a fuse to blow is if wires melted together, grounded out, or if the fuel pump motor is bad. If the pump motor is bad then it start to draw more and more amps to override resistance. I doubt this is the case, but possible.

Slysc
06-24-2007, 06:27 PM
I re-wrapped and re-routed my 02 sensor wires and replaced the fuse. It blew as soon as I started the car. Something else is blowing the fuse.

It is an ignition coil fuse. Would a fuel pump blow the ignition fuse or would it be a bad coil pack?:mad:

David Neibert
06-24-2007, 06:31 PM
I re-wrapped and re-routed my 02 sensor wires and replaced the fuse. It blew as soon as I started the car. Something else is blowing the fuse.

It is an ignition coil fuse. Would a fuel pump blow the ignition fuse or would it be a bad coil pack?:mad:

There is probably another short/burn in the wiring...I would start by tracing the o2 sensor wire that burnt, back up into the harness.

David

seawalkersee
06-25-2007, 03:07 PM
I think that when you melted the o2 wires, they shorted something upstream. When you have key forward is it blowing, or is it only when it is cranking? If it is popping when it is cranking, I would look for the hot wire to the starter being smashed or melted from the selonoid.

Chris

Mike8675309
06-25-2007, 07:53 PM
Which fuse, specifically is blowing? Position F in the power distribution box?
Here is the diagram for what is off of that fuse from a 93 sc. I'd pull the coil pack control wiring and see if you can key on without blowing the fuse.

Slysc
06-25-2007, 10:19 PM
It was the ignition coil fuse. I found that the spade connector which connects to the little resistor next to the coil was bare and grounding out on the bolt that holds the coil down. Apparrently, that comes directly from the coil power.:o I guess God decided that I needed to learn that piece of trivia through this hassle.

Thank you all for your help.:D

seawalkersee
06-26-2007, 02:32 PM
Augh....that was my NEXT guess...

Chris