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Discussion Starter · #1 ·
I hope I am placing this in the correct forum, my apologies if not. I own a 1998 saab 9-3 and recently it fails to start when hot. Reading up on the issue I thought neutral switch. But it wasnt. It happens everytime its hot and I use it as a delivery vehicle(not best car for this)which forces me to start/stop it over and over so its always hot. If I pour warm/hot water on it I can get it to start(sometimes) or if I open the hood and allow it to cool for 30 mins I can get it to start. I have discussed this with alot of local forum guys and even a few "master" saab mechanics but nobody has any ideas. I tried 2 different bypass switch bypasses(paperclip and at the fuse box)

Heres a list of new parts, this was happening before these parts were installed

Rebuilt the Neutral safety bypass switch
Newer Di cassette
New vacuum lines
New fuel pump(cant remember if it was doing it before this)
New starter
New thermostat
Newer radiator
New fuel pressure regulator
New injector seals
New postion sensor
New front break pads

I am in a huge bind with this issue and any help is greatly appreciated.
 

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Discussion Starter · #2 ·
I should add that I have 2 days to figure this out before I will be forced into trading it off. I enjoy the car and its looks but not having it running 100% of the time is unfortunately costing me more than I can stand to lose.
 

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I hope I am placing this in the correct forum, my apologies if not. I own a 1998 saab 9-3 and recently it fails to start when hot. Reading up on the issue I thought neutral switch. But it wasnt. It happens everytime its hot and I use it as a delivery vehicle(not best car for this)which forces me to start/stop it over and over so its always hot. If I pour warm/hot water on it I can get it to start(sometimes) or if I open the hood and allow it to cool for 30 mins I can get it to start. I have discussed this with alot of local forum guys and even a few "master" saab mechanics but nobody has any ideas. I tried 2 different bypass switch bypasses(paperclip and at the fuse box)

Heres a list of new parts, this was happening before these parts were installed

Rebuilt the Neutral safety bypass switch
Newer Di cassette
New vacuum lines
New fuel pump(cant remember if it was doing it before this)
New starter

New fuel pressure regulator
New injector seals
New postion sensor ....interesting ?...the CPS , I take it....note the deletions....these are just regular maintenance items, even the radiator.

I am in a huge bind with this issue and any help is greatly appreciated.
Quite the parts throwing party:cheesy:
Exactly what does she do during the "no-start" ??
Does the engine crank using the starter ?
So, if she starts OK when cold...I'd check out things that are affected by heat; the CPS specicially...then the DIC...the the FP...
Both the CPS and the DIC have to swelter and sweat it out; this cuts their lifespan to ? 7 years, 100K miles or so.
The fuel pump (FP) is cooled by the gasoline....assure that this is so...try not to run low to empty.
Do the battery, charging system service....at least 11 volts are necessary during start up.
One of the first things most mechanics will do is check engine compression.....at the same time, the spark and fuel are observed.
Assume nothing:D:):lol::eek:;oops:
 

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Discussion Starter · #5 · (Edited)
All the parts were replaced either do to age or because they were failing. Not throwing parts at it in an effort to fix this issue. The car was abandoned by its previous owner and I am trying to give it a second life. The compression was good(leakdown). When the issue is present, it does everything but actually start. The cps is new and the Di was tested on 2 other saabs prior to me purchasing(was a spare for a local saab guy who owns several saabs and was willing to put it on his to prove it worked). I keep the fuel level at almost full(I want to make a quick get away when the zombi apocolypse comes). The battery is also less than 2 days old. I am thinking maybe a wiring issue but I dont know where to begin. Someone suggested maybe a wiring insulation issue.

When I bought this it was barely running. After diagnosing the Di was bad I first swapped it out. It ran alot better and thats when I started addressing other issues that were suggested should be looked at. The entire time I was still having this issue. I was hoping one of the new parts would solve my problem but thats not why they were changed. The radiator had a pin hole in it and a local guy had a cheap one so I swapped it and the thermostat as well as flushed the system. The fuel pump went out 2 weeks after I was using it as a daily.
 

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All the parts were replaced either do to age or because they were failing. Not throwing parts at it in an effort to fix this issue. The car was abandoned by its previous owner and I am trying to give it a second life. The compression was good(leakdown). When the issue is present, it does everything but actually start. The cps is new and the Di was tested on 2 other saabs prior to me purchasing(was a spare for a local saab guy who owns several saabs and was willing to put it on his to prove it worked). I keep the fuel level at almost full(I want to make a quick get away when the zombi apocolypse comes). The battery is also less than 2 days old. I am thinking maybe a wiring issue but I dont know where to begin. Someone suggested maybe a wiring insulation issue.

When I bought this it was barely running. After diagnosing the Di was bad I first swapped it out. It ran alot better and thats when I started addressing other issues that were suggested should be looked at. The entire time I was still having this issue. I was hoping one of the new parts would solve my problem but thats not why they were changed. The radiator had a pin hole in it and a local guy had a cheap one so I swapped it and the thermostat as well as flushed the system. The fuel pump went out 2 weeks after I was using it as a daily.
Could it be maybe a new (bad) CPS? This really sounds like a quirky CPS sensor.
 

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Discussion Starter · #7 ·
Are faulty new CPS's a common occurence? I understand anything is possible but is it common? Any real way to test? My issue is compounded by the fact it only happens when I get the vehicle hot. If it takes me awhile to run through diagnostic things, the car will cool and be ready to start thus never really knowing if I am making any progress.
 

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I personally ran into this. Bought a new CPS seemed to help fix the problem for a day or so, but problem came back. So, Im figuring great....its some goofy issue that would cost 1500 to replace. Ended up replacing it again and sorted it out. I dont know of any voltages or any way to test it, but hell any component can have issues. Even brand new.
 

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Discussion Starter · #9 ·
Now how do I convince the auto parts place that there might be something wrong with the sensor and swap out a new one?
 

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Check the connector to the CPS. They rot and rip with age. If "pouring water" gets it to start, it might be completing the ground wire insulation or something. Also, don't jump things with paper clips at the fuse block. That's a good way to destroy the ECM or melt a wire.
 

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Discussion Starter · #11 ·
I didnt use the paperclip at the fusebox just on the harness at the switch. I hardwired afused jumper at the fusebox. Can I wire in a new connection for the CPS?
 

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I didnt use the paperclip at the fusebox just on the harness at the switch. I hardwired afused jumper at the fusebox. Can I wire in a new connection for the CPS?
When looking at the CPS in the block, check the wiring right at the connector to see if it's peeling away and exposing metal insulation/ground wire. If it is, replace the wire. If the CPS is bad, replace it at the same time. Don't think you can "rewire" that. Best bet is to find a replacement, but make sure it's actually bad 1st.
 

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Discussion Starter · #13 ·
First off thanks for the help everyone. I am no mechanic if there are steps along this process that I am missing, or something rings a bell that could cause this starting issue please let me know.

Got back into this thing today. I noticed that at least one injector is misting fuel where it should be seated tightly, I will try to pull the rail and make sure everything is seated properly. The CPS is new and it has a long wire attached that plugs in on top of the motor. I checked the wires at this union and everything looks good.

Another issue I am having is the fan never kicks on. I forced it on by putting power directly to the motor and it does work. The temp gauge on the dash never rises either. Is it safe to assume that a temp sensor might be the culprit? If so where is it located and can it be tested? Also how can I tell if the water pump is actually pumping? I assume it would have overheated if it wasnt but just want to make sure. Is it as simple as feeling for pressure in the upper radiator hose or a more accurate way of telling?
 

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When looking at the CPS in the block, check the wiring right at the connector to see if it's peeling away and exposing metal insulation/ground wire. If it is, replace the wire. If the CPS is bad, replace it at the same time. Don't think you can "rewire" that. Best bet is to find a replacement, but make sure it's actually bad 1st.
This CPS is posing quite the mystery..
IMO, new parts have a 99.9 % plus reliability ...
Thats good advice; do check the CPS connection (strong lite and mirror); then do an inspection of the harness to the connection.
A Saab turbocharger = hellish under hood heat; insulation suffers..
Back to the diagnosis of the problem...
I take it that she spins over fast during the start operation cold or hot...
I'd even redo some of the work.....Do we have good electrical connections ?
Do we have OEM or China parts ?
Sorry, China, reputations exist....
 

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First off thanks for the help everyone. I am no mechanic if there are steps along this process that I am missing, or something rings a bell that could cause this starting issue please let me know.

Got back into this thing today. I noticed that at least one injector is misting fuel where it should be seated tightly, I will try to pull the rail and make sure everything is seated properly. The CPS is new and it has a long wire attached that plugs in on top of the motor. I checked the wires at this union and everything looks good.

Another issue I am having is the fan never kicks on. I forced it on by putting power directly to the motor and it does work. The temp gauge on the dash never rises either. Is it safe to assume that a temp sensor might be the culprit? If so where is it located and can it be tested? Also how can I tell if the water pump is actually pumping? I assume it would have overheated if it wasnt but just want to make sure. Is it as simple as feeling for pressure in the upper radiator hose or a more accurate way of telling?
You seem to be "more mechanic" than a great many I have read about..:cheesy:
The rad fan...it must kick in during this heat wave (90s).
Its controlled by the ECU; the sensor for the gage is on the short side of the engine cylinder head, above the trans bell housing...
Feel the force from the WP at a hose, I am sure that it works....there are those (newer ones) where the impeller fins wear down, degrade, causing a mystery overheating condition..
 

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Another issue I am having is the fan never kicks on. I forced it on by putting power directly to the motor and it does work. The temp gauge on the dash never rises either. Is it safe to assume that a temp sensor might be the culprit? If so where is it located and can it be tested? Also how can I tell if the water pump is actually pumping? I assume it would have overheated if it wasnt but just want to make sure. Is it as simple as feeling for pressure in the upper radiator hose or a more accurate way of telling?
Hmm. When the engine has cooled off enough to start, does it start and run normally, or is it unhappy with stumbles/rough running/dying?

If the former, then that points to a component that either works or doesn't work (e.g. CPS).
 

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My apologies if you already stated this (I didn't see it), but, when it fails to start, does the starter crank and the engine just doesn't start, or does nothing happen? If it is cranking, then the non-start and the non-running fan could be related (coolant temp sensor).
 

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Discussion Starter · #19 ·
The starter does attempt to start the vehicle it just doesnt. What exactly would be the reasoning behind the fan causing the issue? I forced the fan on in an attempt to cool the engine bay but it didnt help. When the day starts its cool and will start right up, sometimes it takes a few turns of the key but no real issue. As the day warms up it becomes harder to start it could be after the first 5 min trip and I have to let it sit. After I let it sit it gets harder and harder to start each time. Once I finally start it, it runs rough very rough, for the first few seconds and then evens out, doesnt sound/feel perfect but still fairly good. It runs fine at this point, actually unusually good considering what it took to get to this point.

If I cannot get this fixed by friday and I get the transmission swapped out and running in this little honda my sister has, I will be forced to just sell it. Its to bad as I have really got it looking nice and all cleaned up. I put a decent amount of money in this, far more than I should have. I will just have to cut my losses. Any more ideas? Thanks
 

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You mentioned a misting at one of the injectors. I would run a fuel pressure test to see if you aren't losing pressure when the engine is shut off (possibly a faulty check valve at the fuel pump). This won't keep the engine from starting while hot but will certainly delay it 5-10 sec until adequate pressure is reached.

While you may have just replaced the CPS it could still be faulty out of the box (you can take a multimeter and take an ohm reading across the terminals to determine if it is functioning properly, I will see if I can hunt down the spec for it).

I had the same problem with my fan at one point as said above it is controlled by the ECU (the in-dash temp sensor hardly moves in my experience). I have a OBD scanner that can take direct readings off of the sensors and it appears to kick on at 185F roughly. I would investgate the relay in the box adjacent the brake booster (mine was faulty).

Given the engine design (i.e. turbocharged and having the CAT in the engine bay) they suffer a tremendous amount of heat soak (when the engine is shut off it actually will continue to rise in temp). I installed a 'delayed' relay instead of replacing the stock. When the ignition is shut off it kicks my fan on for 2 minutes to try to cool the engine down a bit more (no more than 10F or so).

my bet is on the CPS
Sorry for the long post .
 
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