944 not firing

[Aurora's 944]

Hi everyone- I am new to the forum and hoping you guys/gals can help me with my Porsche issue.....why do blogs always deal with issues? anyways....I have a 1988 -944. sweet car....just being very naughty right now. We have had it stored for the winter and went to start it up for a nice days drive and it didn't start...never has this ever happened. We discovered the negative wire on the battery was melted....the one laying on the engine so we replaced it. Now we have lights, radio, etc.

Just will not turn over. no ticking no fire.........nothing. can you please help?

[txhokie4life]

when you try to turn it over

1) does the starter turn?

(why was the battery wire fried?)

might be worth going over the various grounds in the system and cleaning them up

2) does the tachometer move (even if just a little)

if the crank position sensor is not working or is not picking up a signal, you will not get a spark.

The tach is will jump if you are getting a signal.

Note I'm not 100% sure if the tach is connected to the signal, or gets a pulse from the DME.

It is possible you are getting the sensor signal but your DME is bad.

3) is your fuel pump running? you should be able to feel it when the key is turned on.

There is a relay (which when pulled can be jumpered) that runs your fuel pump.

4) is your timing belt good.

if something happened to it and you are out of timing, you will not start the engine.

this should at least give you a good starting point.

Mike

[Aurora's 944]

when you try to turn it over

1) does the starter turn?

(why was the battery wire fried?)

might be worth going over the various grounds in the system and cleaning them up

2) does the tachometer move (even if just a little)

if the crank position sensor is not working or is not picking up a signal, you will not get a spark.

The tach is will jump if you are getting a signal.

Note I'm not 100% sure if the tach is connected to the signal, or gets a pulse from the DME.

It is possible you are getting the sensor signal but your DME is bad.

3) is your fuel pump running? you should be able to feel it when the key is turned on.

There is a relay (which when pulled can be jumpered) that runs your fuel pump.

4) is your timing belt good.

if something happened to it and you are out of timing, you will not start the engine.

this should at least give you a good starting point.

Mike

Hi Mike-

Thank you so very much for your quick response. The weather will be nice today so I am going to go out and tinker....

I will check everything you just mentioned....I hope its not the DME, those things can get expensive. Is there a way to check the DME without sending it to the shop? The one closet to me is over an hour away and the towing alone could cost a fortune.....It seems this should be something I could do at home, just not a mechanic....I am just learning...This car was gotten last year, ran GREAT! Not sure what happened with the ground wire and why it was bad. When we replaced it, it was laying on the engine. I am wondering if the heat alone just melted the plastic casing and over time, it just melted through and arced out. We drove this car often last summer and fall......it was perfect when we put it in storage.

Thanks again Mike- I'll be back later to update what I find.....

Aurora-

[txhokie4life]

when you try to turn it over

1) does the starter turn?

(why was the battery wire fried?)

might be worth going over the various grounds in the system and cleaning them up

2) does the tachometer move (even if just a little)

if the crank position sensor is not working or is not picking up a signal, you will not get a spark.

The tach is will jump if you are getting a signal.

Note I'm not 100% sure if the tach is connected to the signal, or gets a pulse from the DME.

It is possible you are getting the sensor signal but your DME is bad.

3) is your fuel pump running? you should be able to feel it when the key is turned on.

There is a relay (which when pulled can be jumpered) that runs your fuel pump.

4) is your timing belt good.

if something happened to it and you are out of timing, you will not start the engine.

this should at least give you a good starting point.

Mike

Hi Mike-

Thank you so very much for your quick response. The weather will be nice today so I am going to go out and tinker....

I will check everything you just mentioned....I hope its not the DME, those things can get expensive. Is there a way to check the DME without sending it to the shop? The one closet to me is over an hour away and the towing alone could cost a fortune.....It seems this should be something I could do at home, just not a mechanic....I am just learning...This car was gotten last year, ran GREAT! Not sure what happened with the ground wire and why it was bad. When we replaced it, it was laying on the engine. I am wondering if the heat alone just melted the plastic casing and over time, it just melted through and arced out. We drove this car often last summer and fall......it was perfect when we put it in storage.

Thanks again Mike- I'll be back later to update what I find.....

Aurora-

I race a 924S which is a 924 with a 944 engine.

I'm knowledgeable but I am not an expert.

I do wonder about what could have caused your ground wire to fail and if it did any damage along the way.

Good luck -- and I'm happy to help.

Mike

[Aurora's 944]

when you try to turn it over

1) does the starter turn?

(why was the battery wire fried?)

might be worth going over the various grounds in the system and cleaning them up

2) does the tachometer move (even if just a little)

if the crank position sensor is not working or is not picking up a signal, you will not get a spark.

The tach is will jump if you are getting a signal.

Note I'm not 100% sure if the tach is connected to the signal, or gets a pulse from the DME.

It is possible you are getting the sensor signal but your DME is bad.

3) is your fuel pump running? you should be able to feel it when the key is turned on.

There is a relay (which when pulled can be jumpered) that runs your fuel pump.

4) is your timing belt good.

if something happened to it and you are out of timing, you will not start the engine.

this should at least give you a good starting point.

Mike

Hi Mike-

Thank you so very much for your quick response. The weather will be nice today so I am going to go out and tinker....

I will check everything you just mentioned....I hope its not the DME, those things can get expensive. Is there a way to check the DME without sending it to the shop? The one closet to me is over an hour away and the towing alone could cost a fortune.....It seems this should be something I could do at home, just not a mechanic....I am just learning...This car was gotten last year, ran GREAT! Not sure what happened with the ground wire and why it was bad. When we replaced it, it was laying on the engine. I am wondering if the heat alone just melted the plastic casing and over time, it just melted through and arced out. We drove this car often last summer and fall......it was perfect when we put it in storage.

Thanks again Mike- I'll be back later to update what I find.....

Aurora-

I race a 924S which is a 924 with a 944 engine.

I'm knowledgeable but I am not an expert.

I do wonder about what could have caused your ground wire to fail and if it did any damage along the way.

Good luck -- and I'm happy to help.

Mike

Hi Mike-

I'm so glad someone is happy to help. OK- here is the update.

1. We have a connection from the battery: The lights work, the door dinger works, the radio works......

2. We had the starter tested and it works fine.

3. We found out the DME relay is BAD....We did a jumper on the relay and that kicked in the fuel pump so we know we need a DME...we are ordering that. When we used the jumper it still didn't crank at all.....

4. We have checked every fuse we can find and they are all testing good........

Now......we have NO clue were to begin.

ANY ideas???

Thanks SO much!

PS- the ground wire was laying on the engine....by the looks of it, it got hot, dried out and cracked the outer layer...but thats all better with that now, we have lights....oh yeah, the gauges move/react/jump when we turn the key over & all the dash lights come on as if it should be turning over.

[magcuda]

you can not really check the DME until the engine cranks, the speed/reference sensor wakes up the DME to ground the main relay.

need to get it cranking before you start throwing expensive parts at it.

I have attached the wiring diagram for the starting system

get it cranking first

what is your email? the diagram, even page by page is too large to upload

[Aurora's 944]

you can not really check the DME until the engine cranks, the speed/reference sensor wakes up the DME to ground the main relay.

need to get it cranking before you start throwing expensive parts at it.

I have attached the wiring diagram for the starting system

get it cranking first

what is your email? the diagram, even page by page is too large to upload

Oh - THANK YOU!

Crystal@mcneelymedia.com

[magcuda]

Check your email

[Aurora's 944]

Check your email

Thanks so much Macuda! Just to run something past you, I was thinking, what about the electronics on the ignition? That can keep a car from cranking since it needs the signal from the ignition to the starter, right?

As for the battery cable, looks like it got hot and dried out laying on the top of the engine. It was the original cable. I had my starter checked and it is good. We took the starter to advance auto and they did a free check for me....

Thanks again for the diagram. This is gonna come in handy.

Aurora

[magcuda]

2 different circuits, the only thing they really have in common is the ignition switch

get it cranking first, then we can concentrate on any running problems

if you have a volt meter check voltages of battery and components

[wvicary]

Is it a automatic or manual gearbox vehicle?

[Aurora's 944]

Is it a automatic or manual gearbox vehicle?

Manual.

[Aurora's 944]

Any thoughts on the possible issue being a "Neutral Safety Switch"? If so, were is it located?

Thanks again for everyone's help!

Aurora

[magcuda]

old school, no safety switch

check for power be sent to the small post on the starter

also I sent the 88 wiring to you, sent the earlier version earlier

[txhokie4life]

sorry I have been traveling -- does the tach bounce (like 1/4")

when you crank it.

if not -- then there is an issue with the crank position sensor to dme to tach.

On our race car -- we sometimes swap the two connectors (NOTE to self label the **** connector!!!)

anyways -- I can tell immediately because the tach doesn't move.

Mike

[Aurora's 944]

sorry I have been traveling -- does the tach bounce (like 1/4")

when you crank it.

if not -- then there is an issue with the crank position sensor to dme to tach.

On our race car -- we sometimes swap the two connectors (NOTE to self label the **** connector!!!)

anyways -- I can tell immediately because the tach doesn't move.

Mike

The tach does bounce. All the gauges come to life when I turn the key over.

[magcuda]

so it is cranking now?

[Aurora's 944]

so it is cranking now?

No, nothing. No noise, no crank, no action from the starter.....nothing.........We jumpered the starter and it kicked in but did not crank the car. The fly wheel looks great. The teeth are in perfect condition. We have blown a fuse now.....When we ran a jumper on the DME it blew a fuse and it also blew yet another relay....still trying to remember which one. My notes for which one is in the car and I am at work....so I will look and post it later...But now we have no crank, and 2 relays blown and a 30 amp fuse blown.

thanks again for all your help....

[magcuda]

Great you have it cranking, I will send you step 2 on crank / nostart

[Rdward]

so it is cranking now?

No, nothing. No noise, no crank, no action from the starter.....nothing.........We jumpered the starter and it kicked in but did not crank the car. The fly wheel looks great. The teeth are in perfect condition. We have blown a fuse now.....When we ran a jumper on the DME it blew a fuse and it also blew yet another relay....still trying to remember which one. My notes for which one is in the car and I am at work....so I will look and post it later...But now we have no crank, and 2 relays blown and a 30 amp fuse blown.

thanks again for all your help....

Have you tried to turn the engine over by hand at the front crank pulley? When you said that the starter was jumpered and the engine didn't turn over but did engage, it sounds like something is locked up. Was the car outside during the winter? It could be possible that something froze and cracked. Just an idea. I live in TN., and have owned 4 944s and worked on all of them. If you are close then i would be willing to come look at it.

[Aurora's 944]

so it is cranking now?

No, nothing. No noise, no crank, no action from the starter.....nothing.........We jumpered the starter and it kicked in but did not crank the car. The fly wheel looks great. The teeth are in perfect condition. We have blown a fuse now.....When we ran a jumper on the DME it blew a fuse and it also blew yet another relay....still trying to remember which one. My notes for which one is in the car and I am at work....so I will look and post it later...But now we have no crank, and 2 relays blown and a 30 amp fuse blown.

thanks again for all your help....

Have you tried to turn the engine over by hand at the front crank pulley? When you said that the starter was jumpered and the engine didn't turn over but did engage, it sounds like something is locked up. Was the car outside during the winter? It could be possible that something froze and cracked. Just an idea. I live in TN., and have owned 4 944s and worked on all of them. If you are close then i would be willing to come look at it.

If something had frozen and busted, could all the fluids still be intact. We have a full reservoir of fluid. We will check the oil and turn the motor over by hand today.....I will let you know how that goes. I am also going to check all the grounds hopefully when I get a chance this weekend. It has been really busy and I don't get to work on it as much as I would like to....

[magcuda]

I thought it was cranking, another thing to check if it is locked up is slip the alternator belt off

with the burnt cable the alternator could be fried, I have seen them lock and stop a running engine

I almost replaced an engine because of it

[Aurora's 944]

I thought it was cranking, another thing to check if it is locked up is slip the alternator belt off

with the burnt cable the alternator could be fried, I have seen them lock and stop a running engine

I almost replaced an engine because of it

Thank you Magcuda- I will try it. Looks like the rain is setting in here so I won't be able to get out and tinker to much. I don't like the cold weather.... :) I will let you know how it turns out. Let's all cross our fingers!

Talk to ya soon-

Aurora