Odd no start issue... car seems to want to start
12-05-2011, 08:25 PM
#1
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Odd no start issue... car seems to want to start
It's been awhile since I last posted on here, let alone worked on my 944. I recently had the time to finish a head gasket job a started a couple yrs back. Got everything bolted up properly and it doesn't start.
It seems to want to start, when I crank it, though the engine sputters, and it'll afterfire, but doesn't come to life.
When I try to start it:
Tach needle bounces normally, but will occasionally bounce all over the RPM range.
Car has compression, timing was checked a million times, and have checked with a compression tester.
Smells like it's getting plenty of fuel, tank was drained, and new fuel is in.
Firing order is correct.
Pretty much every component of the ignition system is new, and the DME has been tested.
I think I can smell fuel from the pressure damper, when I inspect the vacuum line. Would that cause a no start issue? The regulator is new.
I'm not sure if it's getting spark, but I'm going to try and test that this evening. I'm also thinking of buying http://www.9xauto.com/servlet/the-14...ressure/Detail to check the fuel pressure.
I figured I post up on here, to get some opinions on what to test, and to see if y'all have any ideas at what could be causing my no start issue.
It seems to want to start, when I crank it, though the engine sputters, and it'll afterfire, but doesn't come to life.
When I try to start it:
Tach needle bounces normally, but will occasionally bounce all over the RPM range.
Car has compression, timing was checked a million times, and have checked with a compression tester.
Smells like it's getting plenty of fuel, tank was drained, and new fuel is in.
Firing order is correct.
Pretty much every component of the ignition system is new, and the DME has been tested.
I think I can smell fuel from the pressure damper, when I inspect the vacuum line. Would that cause a no start issue? The regulator is new.
I'm not sure if it's getting spark, but I'm going to try and test that this evening. I'm also thinking of buying http://www.9xauto.com/servlet/the-14...ressure/Detail to check the fuel pressure.
I figured I post up on here, to get some opinions on what to test, and to see if y'all have any ideas at what could be causing my no start issue.
12-06-2011, 10:40 AM
#2
Rennlist Member
You might want to pull and clean your injectors, if they sat that long without use.
(gleaned from another forum)
1. Pull injectors out of car
2. cut a length of fuel hose aprox 12" long
3. hose clamp one end to the injector.
4. hold hose straight up and fill with carb cleaner.
5. hose clamp other end to air compressor blow gun.
6. regulate air compressor to 45-60 psi
7. take a battery charger that has a 2 amp charger setting.
8. turn on the air and touch the battery charger + and - across the 2 electrical terminals of the injector. ON AND OFF!!!!!!
"DO NOT HOLD THE BATTERY CHARGER TO THE TERMINALS PULSE THE INJECTOR JUST LIKE IT WOULD BE DONE IF IT WERE IN THE CAR"
refill the hose as many times as you like.
If you are real ****!!
You can build your own injector manifold to hold all 4 of your injectors using hose and brass T fittings from Lowes or home depot. Snag a 4 cylinder wiring harness from a salvage yard and test the spray pattern of your injectors, by visually comparing one injector to the other.
And if you are Really Really ****!!!
You can measure the amount of carb cleaner you put into the manifold and put 4 beekers to catch the carb cleaner as it passes through the injectors and measure the difference of each injector. YOU HAVE JUST NOW BALANCED YOUR INJECTORS OR YOU KNOW IF THEY ARE OR ARE NOT BALANCED.
Kevin
PCM Injection
Hope this can help someone!!
Brian
(gleaned from another forum)
1. Pull injectors out of car
2. cut a length of fuel hose aprox 12" long
3. hose clamp one end to the injector.
4. hold hose straight up and fill with carb cleaner.
5. hose clamp other end to air compressor blow gun.
6. regulate air compressor to 45-60 psi
7. take a battery charger that has a 2 amp charger setting.
8. turn on the air and touch the battery charger + and - across the 2 electrical terminals of the injector. ON AND OFF!!!!!!
"DO NOT HOLD THE BATTERY CHARGER TO THE TERMINALS PULSE THE INJECTOR JUST LIKE IT WOULD BE DONE IF IT WERE IN THE CAR"
refill the hose as many times as you like.
If you are real ****!!
You can build your own injector manifold to hold all 4 of your injectors using hose and brass T fittings from Lowes or home depot. Snag a 4 cylinder wiring harness from a salvage yard and test the spray pattern of your injectors, by visually comparing one injector to the other.
And if you are Really Really ****!!!
You can measure the amount of carb cleaner you put into the manifold and put 4 beekers to catch the carb cleaner as it passes through the injectors and measure the difference of each injector. YOU HAVE JUST NOW BALANCED YOUR INJECTORS OR YOU KNOW IF THEY ARE OR ARE NOT BALANCED.
Kevin
PCM Injection
Hope this can help someone!!
Brian
12-06-2011, 11:59 AM
#3
Burning Brakes
Join Date: Jun 2004
Location: Livonia, Michigan
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I ran into a similar situation with my early car, it turned out to be the reference sensor connector. Without the reference sensor signal, the DME doesn't know where in the cycle the engine is, so it cannot fire the ignition at the right time. It does fire the injectors and ignition, but the timing is off.
In my case, if I held the throttle wide open, after 15 seconds of cranking or so, the engine would sputter to life and run, albeit very poorly. It would slowly build speed, the start running better and better until it got to around 4k rpm, at which point it was running almost normally. It would get worse again after that.
After replacing both sensors and the harness side connectors, the car ran great.
In my case, if I held the throttle wide open, after 15 seconds of cranking or so, the engine would sputter to life and run, albeit very poorly. It would slowly build speed, the start running better and better until it got to around 4k rpm, at which point it was running almost normally. It would get worse again after that.
After replacing both sensors and the harness side connectors, the car ran great.
12-06-2011, 02:14 PM
#4
Former Vendor
FYI:
If you're going to replace the reference sensors have a look here first:
http://www.pontiacperformance.net/Te...efSensors.html
The BMW Part is cheaper and the same item as the 944 ref sensor, just has an extra 1" of cable.
If you're going to replace the reference sensors have a look here first:
http://www.pontiacperformance.net/Te...efSensors.html
The BMW Part is cheaper and the same item as the 944 ref sensor, just has an extra 1" of cable.
12-06-2011, 04:26 PM
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Thanks sca037, I might give that a try. The injector seals are new, but I never sent the injectors out for a clean/rebuild when the car was down.
I had a no start problem before this, and after replacing almost all ignition components, including the speed/ref sensors, I got my hands on an oscilloscope, to find that the bracket that holds the 2 sensors was out of adjustment. Adjusted it and it started right up. I'm going to check the adjustment on the sensors again, and try to test them with an oscilloscope.
I need to check a couple other plug wires, but I am getting a spark at at least one of them.
Thanks so far for the input guys!
I had a no start problem before this, and after replacing almost all ignition components, including the speed/ref sensors, I got my hands on an oscilloscope, to find that the bracket that holds the 2 sensors was out of adjustment. Adjusted it and it started right up. I'm going to check the adjustment on the sensors again, and try to test them with an oscilloscope.
I need to check a couple other plug wires, but I am getting a spark at at least one of them.
Thanks so far for the input guys!