Weird Issue: Not turning over... Tried everything
 

As the title states wont start but here's the details.

So i bought a 98 with a bad motor and swapped a good one in (both 2.5 ect). Everything worked fine for a few weeks while in the garage but after pulling it forward and back a few times it wont start at all now. I replaced my ignition switch (the mechanical and electrical) with a known working one out of my old wrecked car. I can jump the starter and it turns over (doesnt fire) and sparks so its not the starter.

Is there a fuse or relay for the starter? would it be the clutch sensor not working (meaning it thinks the clutch isnt engaged?). I just dont understand how everything works fine then nothing.

Interior lights all work, headlights ect, the battery is charged. snt

Any ideas on what to check? it started easy before and now jumping the starter isnt starting so im thinking the fuel pump ect isnt kicking on. I never replaced the black electrical box on the ignition, i think its the immobilizer. Could that be the issue as its the same original one.

Thanks guys and if you can help and need parts let me know i have a wrecked one i parted out that id be willing to help you out in return.


Thanks Brian

Do you have fuel pressure? You can pull the fuel QD at the lower left firewall and you should get squirted with gas, if you don't you have a bad fuel pump.

And the title says it wont turn over, but the post says it does. That is a little confusing.

So the starter turns when 'jumped' but not when you turn the key?
Fuel pump- you should hear it start after turning key on and there's a Schrader valve fitting on the right fuel rail for a pressure tester.
The main DME relay is in the trunk and I think this can cause 'silence' with key-on.

Can you change the clutch interlock with another?
Often the first think to let us down is the last thing we fixed. IE- a loose ground or other wire/ connector.

Yes correct it only turns over when jumped

Yes i hear a humming when the key is to the ignition on selection
and I dont have a clutch interlock as the wrecked one was triptronic


Other thought: it seems like a anti theft or kill switch b/c everything worked (approx 10 starts over 2 weeks) and did nothing different or changed anything to make it not start. Everything seems correct except it does not turn over. I have to double check the fuel pump though as the humming noise could be something else.

I did close the top from the service position before it quit starting but i then tried it with it back in the service position, up down and all positions out of desperation but still no click or noise from the starter.

Also this may help, when it was starting it had a bad mechanical ignition switch and didnt spring back once started so the starter was still engaged while it was running. Would this of fried a relay? It was never running more than 5 minutes.


Tomorrow morning i will bridge the clutch micro switch to see if thats the problem. Does anyone have a relay diagram so i can check the starter relay

My guess would be the clutch switch. This happened to me once and it was just the floor mat stuck under the pedal. :rolleyes:

Just tried the micro switch. 1 holding it down... nothing, and then i used a wire to jump the two posts and still nothing so this seems to be good.


So Summary:
- Doesnt start, no click or noise what so ever, all interior/dash lights work fine
- If the starter is jumped it will attempt to start but wont fire (acts like dosent get gas)
- Ruled out ignition switch (mechanical and electrical), battery and clutch microswitch

Possibilities:
Immobilizer, key?, ground wire? (although i checked all the ones i could find),

Prior to problem:
-Engine was replaced, then worked fine for a few weeks after new engine was put in(started first time everytime)
-Ignition mechanical switch was bad, wouldnt spring back after started
-Before the engine replacement everything worked as should with the starter just didnt fire

Sounds similar to my issue only mine is intermittent. When my problem occurs I am able to roll the car and pop start it in second gear.

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Update: replaced the fuel pump relay (13 in foot compartment), dme relay and the start lock relay (1,7 in trunk)
Still nothing, I also checked for any error codes with my obdII and nothing

Also the fuel pump is not kicking on (why i changed the relay)

Does yours start after the initial rolling start?

Yes mine starts when push started then subsequently starts with the key fine until it decides not to.

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What method did you use to "jump" the starter?

I actually connected wires to the positive and solenoid, ran them into the cabin with a momentary switch. Works well to crank the starter over but when my car is experiencing the condition the starter spins but it still won't fire. But the car will still roll start.

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I used a screw driver to make sure it was getting juice and worked.
Its not getting fuel as well though b/c it fired 1st time every time before that, jumping it doesnt even try to fire other then turning over

got schematics and a voltmeter?

I know its been awhile but it was a rough winter here and didnt get much time to get to the garage.
Yes i have a voltmeter but i dont know where to start.

If the immobilizer when bad what would happen? I'm thinking this is what went bad, or the ecu itself. The person i bought it off of said it was rechipped with a performance chip but i find it odd why it worked fine for a couple weeks. Changing the original trans from this engine from auto to manual shouldn't of made a difference since the engine part#'s are the same.

This weekend i'll try the rolling/pop the clutch to see if that starts it but i kinda doubt it since the fuel pump didnt seem to be kicking on either with the starter

When you swapped ignition switches, did you swap keys as well? If so, did you swap the innards of the keys?

If you changed the entire ignition switch (not just the electrical part) and the keys, you need to remove the metal key from the fob and install the metal key in your old fob (remote control).

I kept everything original in the car except the engine, after that it started and ran fine for a couple weeks and now nothing

Do the exu's go bad? I had a 3000gt and had one go bad once, opened it up and it was busted capacitors but didnt think this could happen to boxsters.

I'm thinking either the ecu or immobilizer, Id hate to buy an immobilizer if its the ecu, if it was the ecu I'd just replace the 3 units and locks with a used instead of paying the crazy dealer price for one. Maybe i'll post in the parts to see if someone has a set i can rent to see if thats the problem and if so I'll just buy it from them. But this wont tell me if its the immobilizer or the ecu.

Also to clear the confusion, the car wouldnt try to start before i replaced the mechanics lock on the ignition.

Just bought and replaced all three components of the computer, ignition switch and key. Still nothing, and now the dash lights only come on for 10 seconds once the ground is connected then off to never return until the battery is disconnected again, the key fob still works and door lights but nothing else.
I went over the wires and the grounds and didnt see anything and when it did start nothing was changed or moved so i dont think it could be that but what else is there other than the wires and computer?
I replaced all the relays under the dash and in the trunk out of my parts car which i knew worked.
Checked the ground in the trunk, the big one from the engine (on opposite side of the maf). What other grounds should i check? I also checked the battery one of course, the one under the seat.
I'm so frustrated with this car, i keep throwing money at it and nothing, the car is out in the country with the nearest dealer a couple hours away and no indy shops near by.

Just my logical thinking if everything worked and ran then didnt start. It would have to be electrical so ruling out, relays, clutch switch, ecu/immobilizer/key, starter, ignition switch manual&electrical, short of replacing the whole wiring harness and engine wiring harness what else is there?

Ok so out of desperation i started from the battery/fuel pump and started tracing wires hoping something would jump out at me and noticed the rubber plug on the wire harness wasnt pushed in the hole on the outter wall b/c the jackass before me ran his own wires from the speakers to the amp. Anyways there was stuffing around it and then i pulled the front carpet out and low and behold there was an old mouse nest.

Now I'm thinking one chewed a wire inside the dash since the plug wasnt sealed tight. Also the fuse e1 and b1 (interior cluster, radio, convert top ect) fuse was both blown which might explain why they only come on for 10 seconds and go off until battery reset. I replaced the fuses and they no longer blow but the dash lights still only come on for 10 seconds and go off. The hazards, and other lights not on those 2 fuses above work but I would of assumed if they are still shorting they would blow again or am i wrong.

If the weather is nice this coming week I'm just going to take the whole dash apart and trace the wires I cant see.


Another thing, when i was changing the ignition column a long wire fell out. It had a stiff plastic shield around it and what looked like a anteanna on the end. Any idea what this is? I didnt have it on my 99 trip, and i thought the radio was around the windshield.