Ok so, I did some searching in the forum in this is the only thread I could come across where people are talking something that moderately relates to my problem.. --- http://www.saabcentral.com/forums/showthread.php?t=137380&highlight=light ---


c900 says "As soon as you turn on the ignition (key in 'run') the check-engine light should come on and stay on, which indicates that the ECU is getting power and that it's power-up self-tests have passed ok. When you actually crank the engine to start it, the check-engine light should go out after no more than a couple of seconds after the engire fires unless there is a fault that it's detecting."

As soon as I turn the ignition key in 'run' the light doesn't even come on at all. So theoretically, this means the ecu isn't getting power for some reason..

 

so crank the engine, but no fire up.
check earths. have you got the crankcase sensor, or do you have the wires coming out side of distributor. Is the connection(s) on ecu etc all good(could be vibration and come loose, if spring clips that secure are missing.
have you an alarm system, could be failed/failing

 

Ok so, I did some searching in the forum in this is the only thread I could come across where people are talking something that moderately relates to my problem.. --- http://www.saabcentral.com/forums/showthread.php?t=137380&highlight=light ---


c900 says "As soon as you turn on the ignition (key in 'run') the check-engine light should come on and stay on, which indicates that the ECU is getting power and that it's power-up self-tests have passed ok. When you actually crank the engine to start it, the check-engine light should go out after no more than a couple of seconds after the engire fires unless there is a fault that it's detecting."

As soon as I turn the ignition key in 'run' the light doesn't even come on at all. So theoretically, this means the ecu isn't getting power for some reason..

Sorry to hear your car is giving problems.

There is one relay (the 'system' relay) which controls power to the ECU. It's mounted in a little relay holder above the ECU (the fuel pump relay is there also) behind the carpet under the right hand side of the dash. There is a fuse in the fuse/relay panel for the ECU circuit as well (can't recall off-hand what it's labelled as). You'd probably need to remove the lower dash to get good access to the two relays unless you have elastic arms.

Before you suspect the system relay itself, make 100 percent sure all the fuses are ok. If you suspect any of them, pull the suspect fuse out and make sure that it's properly fitting into it's pair of spring contacts in the fuse/relay panel. Check the relays in the fuse/relay panel too. Just pull out the relevant ones and push them back in.

I have had one instance where the A/C fan relay's ground contact spring-finger dropped out of the fuse/relay panel causing the A/C fan not to run. Probably fairly rare though.

It's also possible the CEL lamp may be blown but if you had the car running recently and the CEL was coming on, that's unlikely.

The system relay also switches power to the air-mass meter, and if the AMM is not getting power the ECU will not get any signal for airflow, which would force the ECU into 'limp' mode. This can prevent the engine from starting and running, though it might start and run very rough. The air mass meter in your car will have +12 volts from the system relay showing up on pin 5 of it's harness connector. I think the problem is something more fundamental though.

Did you accidentally break or disconnect a ground connection for a device in or around the engine bay? Did you accidentally leave a connector unconnected which could be touching something that is grounded and causing partial or temporary short circuits?

Is the crank sensor, if mounted behind the engine near the crankshaft, in place and connected properly (harness connector for it hides under the throttle valve end of the intake manifold)?

Craig.

 

to get at relays above ecu, I removed the screw that secure the ecu in place and could then get them out

 

so crank the engine, but no fire up.
check earths. have you got the crankcase sensor, or do you have the wires coming out side of distributor. Is the connection(s) on ecu etc all good(could be vibration and come loose, if spring clips that secure are missing.
have you an alarm system, could be failed/failing

So the crankcase sensor could have failed? The ignition system is ok because I took the distributor cap off and cranked it, and sure enough there were sparks.. I'm fairly certain this is some sort of fuel/ecu related issue.. The loose connection on the ecu makes sense but at the same time, how was the car able to drive 6 miles whist having stumbling problems before it went kaput? It's like something was in the process of failing while I was driving..

Did you accidentally break or disconnect a ground connection for a device in or around the engine bay? Did you accidentally leave a connector unconnected which could be touching something that is grounded and causing partial or temporary short circuits?

That's a possibility. The only other thing I did was, I took out the entire air intake housing to clean around down there and to check the filter. And when I replaced the thermostat, I also cleaned out the AIC with WD40, something I did when I first bought the car. Btw, when I put the ignition in start mode, the AIC makes a very strange humm noice..

Something else that could help troubleshoot the problem, When I get the car moving by having friends help push it, push starting the engine with the clutch does not start it. There's no activity at all when this happens.

 

After examining the car and thinking back to what on earth I could have done to cause this, I noticed that the thermostat is adjacent to the ignition coil. There is a pretty good chance that I could have gotten water all over the ignition coil because of how I cleaned the engine.. I didn't even consider it (EDIT) I took the ignition coil back home and tested the resistance.. it came back perfectly normal.. GAH!

Could this problem I am having be related to the ignition system? When I thought I tested the ignition last night, I actually just took the distributor cap off and had a friend crank the car, I saw the rotor spin.. Prolly not a good ignition test lol.

I read an other post online that stated if the check engine light is not coming on when the key is turned, there is a problem with the ecu receiving power. This is general for most cars.. I have having serious trouble getting to the ecu and relays in the passenger side of the cabin.. How on earth do you get to it?

 

Can anyone tell me if there are any important grounds near the airbox and throttlebody/intake manifold? I'm thinking perhaps I knocked one of those loose.

Also, when I first bought the car, my buddy and I rigged up a temporary switch that connects the engine diagnostics jumpers under the rear seat permenetly, with the press of a switch. The switch kind of dangles from underneath the rear seat. I had been checking the enginecodes somewhat regularly so, I have been reaching back and tugging on the wire. Is it at all possible that one of the wires to the jumpers may be touching another jumper than could be sending a bad signal to the ECU? What else could be intrupting the power to the ECU upon engine startup?

 

There is a pretty good chance that I could have gotten water all over the ignition coil because of how I cleaned the engine.. ..

Could this problem I am having be related to the ignition system?

Remove and dry out the Spark Plugs. Dry out the Cap, Rotor, Wires., and the Coil (mounted on top of the Radiator).

 

Remove and dry out the Spark Plugs. Dry out the Cap, Rotor, Wires., and the Coil (mounted on top of the Radiator).

Thats a great idea but, would that be causing the check engine light not to come on? Because since the ecu isn't performing it's diagnostics like it's suppose to, the fuel pump is not turning on..

 

I'm with Jim. Retrace everything you did the day it died. Especially the electrical system. Cap/Rotor, Plugs, Plug wires. Put dielectric grease on the plugs, and cap when you put back together. If necessary use a blow drier and get everything dry.

Don't start ripping into areas you weren't working in until you've made darn sure it's not there. You could create more problems. I'd bet a dozen donuts the problem is related to water on an electrical connection.

The fact that you have a "dim" CD light sounds like a short (the kind excess water would cause), not a direct zap to ground.

Good luck!

 

The fact that you have a "dim" CD light sounds like a short (the kind excess water would cause), not a direct zap to ground.

Good luck!

Forgive my total ignorance of electrical basics but, what exactly causes this kind of short? Like water got onto the ground wire or something of the sort? And how could I fix it? I feel that when I find out what is causing the issue with the CE light, I will have found the issue with the whole car not starting..

 

WHen you were cleaning the engine area did you get the air mass meter wet? It will run like **** or not run at all if that is not plugged in. Also if the wire is broken.

There is one relay (the 'system' relay) which controls power to the ECU. It's mounted in a little relay holder above the ECU (the fuel pump relay is there also) behind the carpet under the right hand side of the dash. There is a fuse in the fuse/relay panel for the ECU circuit as well (can't recall off-hand what it's labelled as). You'd probably need to remove the lower dash to get good access to the two relays unless you have elastic arms.

in the states its on the drivers side (left side) and the ECU is on the right side passanger side. to remove the knee bulster you need to pop the hood and look int he fender wells. move the wires out of the way that go to power door locks windows and mirrors. you will see a scew on one side (driver) and a nut on the passanger side fender well inside. you need to remove those and then the ash tray 10mm and then there is a 13mm brass thing in there that needs to be removed. all the relays on the drivers side and ECU is under passanger carpet

 

WHen you were cleaning the engine area did you get the air mass meter wet? It will run like **** or not run at all if that is not plugged in. Also if the wire is broken.

Nope, the meter couldn't have gotten wet because I removed the whole airbox/filter system from the car while I was working on the thermostat. That's why I'm thinking that maybe I bumped or broke the connection to a ground while I was removing it or replacing it..

 

shine a flash light inside the AMM and see if the wire is attached. Otherwise you will need to test it via the bentley. also check the ECU/computer to see if it is faulty. I dont know why/how it could be. as it is inside the car.

When I wash my car the damn door locks dont work for a while But thats about it.

Try disconnecting the AMM and try starting the car to see if it is the same. Or borrow or go to a junk yard and see if they have any 900's with AMM ECU's and any other component that could cause this problem. And get a return voucher so you can return what didnt help. Or take it in to a mechanic to diagnose. Or someone here with a lot of experience could try to walk you through diagnosing whats what.

Hope you get it going again soon.

 

Ok, here's the latest update. I checked the ignition system today.. No spark what so ever. The ignition coil is reading perfectly normal, however.

So basicly, I have no fuel pump action, no fuel delivery action, no ignition action, no check engine light on start up.. Sounds like a computer problem. Has my ECU or ignition control unit failed? At this point, it's either the system relay, the ignition control unit or the ECU.. Unless you guys have any other ideas..?

My first thought is, how the heck could 1 of those 3 things failed while I was changing my thermostat.. wtf?

 

Ok, here's the latest update. I checked the ignition system today.. No spark what so ever. The ignition coil is reading perfectly normal, however.]

When you say reading correctly, does that include input voltage? Is the coil ground clean and properly grounded to the vehicle. I have the older 2.2 ignition system in my 87' so I'm not sure how you coil is grounded. In my car the coil and thermostat are in fairly close proximity, so I could see how a wire or water could cause a problem.

No spark could definitely be a ground problem, either shorted or opened. Meaning water is causing the positive voltage to go directly to ground (path of least resistance). Or open meaning a ground wire is broke and there is no path to ground leaving the 12v as potential.

I would work my way backward from the coil using the Bentley manual as guidance.

 

When you say reading correctly, does that include input voltage? Is the coil ground clean and properly grounded to the vehicle. I have the older 2.2 ignition system in my 87' so I'm not sure how you coil is grounded. In my car the coil and thermostat are in fairly close proximity, so I could see how a wire or water could cause a problem.

No spark could definitely be a ground problem, either shorted or opened. Meaning water is causing the positive voltage to go directly to ground (path of least resistance). Or open meaning a ground wire is broke and there is no path to ground leaving the 12v as potential.

I would work my way backward from the coil using the Bentley manual as guidance.

Yeah, that darn coil is perfectly fine. If only that was the problem.. Easy fix! But anyway, from looking at Mr Bentley's manual, the next step is the Ignition Control Unit.. I have no idea how that could have just died but, if it did it looks like a pretty cheap fix. I will defenitly look around for any grounds or other wires that may have gotten wet or otherwise. Something I noticed that was odd was, under the boot of the ignition coil was a condenser.. I looked through the manual and I did not find anything that talked about a condenser.. Any ideas what that may be for?

 

So it looks like I will be testing the Ignition Control Modual, the System Relay and the actual ECU itself..

Wish me luck!

 

a ng900 similar issue...

Having trouble similarly, the one constant is that if my CEL doesn't come on, my car won't start. Sometimes I'll hear that main relay click, and the CEL comes right on. Car starts right up, may drive for 400 miles, may drive for 10 feet without stalling. Most guides point to a faulty ground, since the ignition sends signal to fuel pump and starter, dash, etc...

 

Having trouble similarly, the one constant is that if my CEL doesn't come on, my car won't start. Sometimes I'll hear that main relay click, and the CEL comes right on. Car starts right up, may drive for 400 miles, may drive for 10 feet without stalling. Most guides point to a faulty ground, since the ignition sends signal to fuel pump and starter, dash, etc...

what car

does it turn over or nothing?

nothing suggests probably bad ign switch, if it turns over but doesn't fire and there is no warning CEL light maybe ecu

 

mr fundira

engine is not starting and engine check light off