Pulling my hair out troubleshooting intermittent no start. Sometimes starts no problem, when it doesn't start, there is no fuel pressure and no spark. Problem is as I continue to troubleshoot - the car will start. Has done this a couple of times making troubleshooting difficult.

I checked and replaced all the critical relays - EZ, LH & Starter

I hooked up a test rig so I can read the signal to the coil of the relay and a switch to by pass the relay to help troubleshoot.

EZ-F relay pin 85 is grounded - that checks, pin 86 gets +12V from 15 bus - ignition switch +12V in the run and start position - checked OK, though I think for a second, in the start position I saw the voltage dropped to 0 when I was troubleshooting.....

Fuel pump relay gets ground from LH, checked pin 86 on relay - 15 bus - +12V in run and start position checked OK.

I believe the LH gets an RPM sign from the EZ-F telling it that the engine is spanning, then the LH grounds the fuel pump relay turning the fuel pump on.

I replaced the crank position sensor in '09. I am leaning to the ignition switch being the problem, but that too was replaced in '09.

Am I missing something? Hate to drive the car anywhere and shut it off.

 

I am in the midst of troubleshooting an intermittent non-start, (see below) and pulled the X-Relay - the car started and runs with the relay pulled. What is the X-relay powering? It looks like it only feeds the fog lamp relay. Is it a standard "53" relay?

 

X-relay in position IV? Looks like it's for a flash-to-pass bypass of the fog lights.



Problem with ignition switch?

 

Ken, that's what I'm thinking even though the electric part was replaced just 3 years ago. Wondering if the cam part is worn a bit causing problems too.

 

its possible you got one of the bad ig switches that were sold a few years ago.


try this first,
when it wont start see if your getting power through both sides of the fuel pump fuse.

Read the next part carefully.....

I had an issue with one of these connections... the fuse was showing 12V on both sides but the part that plugs into the CE panel pin was corroded and the power stopped at the fuse so you really wanna check the wires after the fuse on both sides of it,
this means dropping the CE panel down to investigate

 

Stan, good tip, will look at that, but every time I jumped the FP relay, the pump ran but the car still didn't start, no spark, but before I could jump the EZ relay, the car would start.

Leads me to think it is the ignition switch, but I will pull the CE panel to peak at the connections.

 

I just had the same problem.Turned out the brand new fuel pump relay was faulty.Stuck the old one back in and problem solved.Prior to that the green wire that sends the hall signal to the injector control was the problem.Used a noid test light to find that problem. 14 pin connector, grounds, bad fuse conductivity no end of things to play with.

 

Glen,

Sounds like you're on the right track, but you are making some assumptions. You said the CPS was replaced in '09 and the same for the ignition switch so you're kind of ruling those out.

The CPS may be new, but if the wiring going to it is faulty, loose or corroded, it will give the same symptoms as a bad CPS (which I think is what you're describing).

Stan's suggestion is interesting and one I hadn't thought of. Of course if the voltage is getting through the fuse the next check is to see if it's getting to the places it's supposed to be so that would lead you back to the CE eventually.

The worst kinds of problems are the intermittent ones, especially if they only show up when you're not in a position to work through the variables.

Sounds like this one will take a while but keep posting the scenarios on here if for no other reason than that they will be documented for you to refer back to later. I'm sure a pattern will emerge.

 

Mike, thanks for input. I will double check the wiring on the CPS and the CPS, see if I can borrow a scope from friend and check pulses at EZ connector.

I am focusing on ignition switch....forgot 2 weeks ago I had a no start, starter wouldn't engage, called for a tow home from parking lot of store, when tow showed up, tried to start again, starter cranked and fired up. Seems like the more I try starting, turning the ignition switch will have the car start.....

I'll keep posting and hopefully find the true cause.

Thanks to all

 

Happy fathers day to all you fathers out there.

Went out to see if car would start today - no go.

Here is what happened - car did not start, tach not moving at all. Plugged in my new relay test rig pictured below. Turned key to run position - relay pin 86 has 12V, which is connected to 15 bus which gets energized from ignition switch. Turn key to start position, crank, no tach movement, voltage on pin 86 goes to 0 volts (should be 12V in start position also), then climbs to 7-8V still no start, flip switch to on position...vrooom car starts.

I think this points me to the ignition switch as the culprit. I may have gotten one of the problem ignition switches back in 2009.



If that doesn't solve it I may make up a panel with individual switches and a push button to start car alla a race car......

 

I'm still convinced these 85's have an endemic bad ground splice in the harness that carries all the electronics. Manipulating the hell out of mine, after 19 months of doing all kinds of parts replacment, finally cured the beast. Same symptoms. Sorry, I was too lazy to rip it all out to verify the final solution.

 

Cool test rig.

Well, keep us posted on the new keyswitch. I'm convinced that a lot of these issues fall into the category of: "If it hasn't happened to you yet, it will." So I follow the rare cases where I haven't had the same problem very closely...

 

That started me thinking - not always a good thing...

I would like to have a more complete test rig for "53" relays.
This would be a relay base that plugs into the relay socket, and allows the relay being tested to plug into the relay base, piggyback fashion.
Coming out of the relay base would be a ribbon cable, with leads tapped onto each of the pins in the relay base, plus a couple of extra leads with alligator clips.
The ribbon cable would connect to a PCB in a small box. The box, placed where you can easily see it from the driver's seat, would have labeled LEDs.
These LEDs would show presence/absence of:
- Power on each of the relay terminals.
- Ground on each of the relay terminals.

Think of how useful that would be! Pull the start relay, plug the tester into the socket, plug the start relay into the tester, and turn the ignition key to the start position. You instantly know whether the ignition switch is sending the start signal, or whether the neutral safety switch isn't grounded, etc.

There are quite a few "53" relays in the panel. This makes troubleshooting the fuel pump system (on later cars), start system, X-Relay, fog lights, LH, HVAC blower, defrost, and EZK a lot easier.

Someone want to make/sell these? I get a couple of free ones for the idea...

 

Wally, I like the way you think. I am in for a couple too.

 

To close out the thread, installed the ignition switch , 3 days now and 8 or more starts without a hitch. The old ignition switch looked fine, opened it up and didn't see anything that would have caused the problem, but its working now. Side benefit of replacing the switch was replacing the "D" lamp in the tach which was burned out while the pod was out.