SaabCentral Forums banner

1 - 15 of 15 Posts

·
Registered
Joined
·
1,887 Posts
Discussion Starter · #1 ·
so i got in my car to leave for work this morning and it wouldn't start. it'll turn over fine but it won't catch it just backfires. it even backfires a few seconds after i've stopped turning the key. it can't be the fuel pump because i just replaced that about 2 weeks ago. i'm thinking maybe the direct ignition cassette? anyway i can easily check it before i go and replace it?
 

·
Registered
Joined
·
4,293 Posts
If you post the history and what has been done to the car, you will get better information. Is this the same car that had the low hwy MPG, and the white smoke from the exhaust a few weeks back, and a possible oxygen sensor failure (and some mods)?
 

·
Registered
Joined
·
1,887 Posts
Discussion Starter · #3 · (Edited)
well it's the 2.0 liter turbo, it has a newer turbo but i haven't gotten around to seeing what turbo the previous owner put on he also said that he put the stage 3 nordic ecu in. a modified exhaust, and a different intake, but other than some suspension mods it's pretty much stock, i took off the mbc. and oh yeah highway mpg was fine, around 25 mpg
 

·
Registered
Joined
·
21,583 Posts
turbojohnny said:
so i got in my car to leave for work this morning and it wouldn't start. it'll turn over fine but it won't catch it just backfires. it even backfires a few seconds after i've stopped turning the key. it can't be the fuel pump because i just replaced that about 2 weeks ago. i'm thinking maybe the direct ignition cassette? anyway i can easily check it before i go and replace it?
Where to start ?
All of the service requirements must be up to date.
Backfiring ? and no start ?
Codes must have been thrown...
The ECU is not above suspicion - even the fuel pump....
Nothing can be assumed..
Have you checked out your timing chain and the tensioner ?
Were the spark plugs wet or dry upon their removal ?
 

·
Registered
Joined
·
1,887 Posts
Discussion Starter · #7 ·
man i knew i never should have bought this car. i already put more money into it fixing the stupid thing than i paid for it. and it's still giving me problems. i'll take my old carb'd v8 anyday over all this computer controlled bologna.

anyway, i haven't had a chance to check anything yet except i put a bottle of dri-gas in the tank to see if maybe there was just water in he gas lines, it is getting to be that cold, but that wasn't the case. tomorrow i'll go out and check the plugs and regap them but if it is getting fuel what's the proper way to check and see if i'm getting spark from the di cassette?
 

·
Registered
Joined
·
21,583 Posts
I'd crank her over for 5 to 10 seconds, allowing the plugs to become saturated with fuel IF the fuel delivery is good..

Then quickly remove them(have your tools handy) and see if they are wet or dry - for now, forget the regap and cleaning/replacing.
Just examine the plugs....

This is just one diagnostic step of many. The first is the battery/charging system..

The third step involves inverting the DIC; connecting grounding leads to the plugs and spinning over the engine.
The DIC will either work or not. The proof will probably be visual and audible.
 

·
Registered
Joined
·
4,293 Posts
turbojohnny said:
...i'll take my old carb'd v8 anyday...
People who like playing around with these engines do it precisely because it is not a "carb'd V8"... :D

I would need a complete list of your engine modifications and prior symptoms to even start to make a guess about what is going on with it. You will get better advice on the performance board, especially if you post your mods and history.

Personally I don't understand how this particular engine can backfire from a cold start, unless there is both fuel and spark at least initially. My car has never done that, regardless of how I managed to screw it up playing around.

Just scanning the different posts about this car, I see a different turbo, modified intake, possibly a failed O2 sensor (?), low hwy mileage, possibly reflashed ECU (with a manual boost controller!), white smoke out the tailpipe...

Reflashed ECU w. MBC (20 psi?) is not a common setup here. Almost sounds like the previous owner modified the car without understanding how the T5 system works, trying to remake it into something the car isn't. To do that kind of job on this engine properly is more $$ than a typical cost of a 12-year-old Saab.

With that record, I would say that the ignition module is not a likely culprit, and it may take some REALLY knowledgeable people on the performance board to sort this all out. (not a couple guys who like to play mechanic on sunny days like me and earthworm, <chuckle>)

Running this engine at high boost, with a possibly fouled O2 sensor providing the only closed loop feedback to the ECU is a prescription for engine problems, just for a start. At this point, the engine may not have enough compression left in the cylinders to give proper feedback to the ECU to set the cylinder firing order during start, and that is just one of the things I can think of.

Don't take this the wrong way, I think just about anything you can do with a car is fun, and worth trying at least once, especially under the hood, BUT it better not be your daily driver, and you also have to consider the engine a disposable accessory of your hobby.... Which, in my opinion, makes it all the more fun... :cheesy:
 

·
Registered
Joined
·
1,887 Posts
Discussion Starter · #10 ·
i'm about to go and check a few things, but i think you're right about the previous owner. he said he was a mechanic and he probably is, but not a saab mechanic. when i went through the car more thoroughly after i got it home i noticed a few things that i did not like at all and the job he did doing it was very shoddy. but as i said before, i removed the mbc about a month ago and reconnected the stock controller, now it runs at about 10 psi in first and 15 max in 2-5. i haven't done anything crazy to this car for the fact alone that it is my daily driver. i'll post in the performance board and i'll see what i can come up with. thanks for your help so far
 

·
Registered
Joined
·
1,887 Posts
Discussion Starter · #11 ·
well i dunno what the hell the problemm was, but i took the DIC out and checked to see if i had spark but i didn't see or hear anything, i had plenty of fuel to the cylinders so that wasn't a problem, and i even pulled off the valve cover just for the heck of it. checked out the cps and that looked to be good, so i assumed it was the DIC. went and looked at GS to order it but before i did i went and put everything back together and tried it one more time. and it started up. and it's been runing and driving fine for a few hours now. i'll probably order the DIC just to be safe though. any chance a t7 DIC will work in place of the t5 DIC?
 

·
Registered
Joined
·
26 Posts
It sounds like you may have an intake valve problem. Try doing a compression test followed by a leak down test to determine the source of the problem. Post the results if you don't know what they mean.
 

·
Registered
Joined
·
1,887 Posts
Discussion Starter · #13 ·
turns out the spark plugs were bad, i didn't think they would be because they weren't that old, but whatever
 

·
Registered
Joined
·
1,887 Posts
Discussion Starter · #15 ·
thanks for your help guys. and thank god i found out it was the plugs before i went and spent the money on a new DIC, i might need one sooner or later though. just not now.
 
1 - 15 of 15 Posts
Top