No Start Issue / 944 NA 1984
#1
No Start Issue / 944 NA 1984
Hi Everyone,
I'm a longtime lurker in there, just recently signed in and this is my first official post. Sadly it's not an happy one.
I own a 944 Na 1984 since August 2017. I was looking for one for a while and this one was the perfect match I was looking for. The Idle was never really smooth but it was running and I was happy. Until November, when the car started to run only on 2-3 cylinder when cold to finally run ok when hot. The only event I could recall before those symptom appeared is driving in a rain storm for 300km and stalling in a parking lot. I stored it for the winter and when I started it the following Spring, she was running fine like when I got it.
Then I changed the oil (Brad Penn 20-50) and the filter and suddenly, she don't want to start anymore. Here's the list of what I did or replaced so far:
-Tested reference sensor (ok)
-Replaced Oil and Filter
-Replaced 4 injector
-Replaced DME Relay and Fuse
-Replaced DME (went that far...)
-Inspected and tested Distribution Cap (has spark)
-Inspected and replaced Ignition wires for BERU
-Replaced and gapped spark plugs (copper)
-Cleaned ground
-Inspected every vacuum line
-Replaced Alternator for a Bosch unit
-Replaced battery
-Replaced fuel pump (cleaned the strainer while I was in there)
-Replaced fuel filter
At this point, she is cranking, I've a tach bounce and a smell of petrol when I do. But when she do try to start, it's only on two or three cylinders... I'm puzzled and I'm a little bit tired to trow parts at my car for zero result.
Any inputs?
Thanks!
C
I'm a longtime lurker in there, just recently signed in and this is my first official post. Sadly it's not an happy one.
I own a 944 Na 1984 since August 2017. I was looking for one for a while and this one was the perfect match I was looking for. The Idle was never really smooth but it was running and I was happy. Until November, when the car started to run only on 2-3 cylinder when cold to finally run ok when hot. The only event I could recall before those symptom appeared is driving in a rain storm for 300km and stalling in a parking lot. I stored it for the winter and when I started it the following Spring, she was running fine like when I got it.
Then I changed the oil (Brad Penn 20-50) and the filter and suddenly, she don't want to start anymore. Here's the list of what I did or replaced so far:
-Tested reference sensor (ok)
-Replaced Oil and Filter
-Replaced 4 injector
-Replaced DME Relay and Fuse
-Replaced DME (went that far...)
-Inspected and tested Distribution Cap (has spark)
-Inspected and replaced Ignition wires for BERU
-Replaced and gapped spark plugs (copper)
-Cleaned ground
-Inspected every vacuum line
-Replaced Alternator for a Bosch unit
-Replaced battery
-Replaced fuel pump (cleaned the strainer while I was in there)
-Replaced fuel filter
At this point, she is cranking, I've a tach bounce and a smell of petrol when I do. But when she do try to start, it's only on two or three cylinders... I'm puzzled and I'm a little bit tired to trow parts at my car for zero result.
Any inputs?
Thanks!
C
#4
Hey Carl,
It sounds like you might be well beyond this, but I usually find it helpful to verify the absolute basics if my engine won't start. Have you verified that the injectors are delivering fuel to all cylinders? Have you verified that each plug sparks at the correct time? And finally have you verified the the AFM is delivering the correct air flow measurement to the DME? If you have air, fuel, and spark (at the correct time, as Van points out) then your engine should at least fire on all four, if not start roughly.
It sounds like you might be well beyond this, but I usually find it helpful to verify the absolute basics if my engine won't start. Have you verified that the injectors are delivering fuel to all cylinders? Have you verified that each plug sparks at the correct time? And finally have you verified the the AFM is delivering the correct air flow measurement to the DME? If you have air, fuel, and spark (at the correct time, as Van points out) then your engine should at least fire on all four, if not start roughly.
#5
Drifting
Smell of petrol? Whatever you do, pull the fuel pump fuse while diagnosing
Get a cheap little 12v LED from an electronics supply and use it to test for injector pulse for each cylinder plus ignition coil
Get a cheap little 12v LED from an electronics supply and use it to test for injector pulse for each cylinder plus ignition coil
Last edited by Dan Martinic; 07-12-2018 at 07:07 PM. Reason: Added video links
#7
Rennlist Member
Check if the DME is collapsing the 12V at the coil to produce the high voltage spark or if the spark plug is firing. Clark's Garage has procedures
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#8
Rennlist Member
Hi Carl -
I have to vote with Van on this; check the plug order. If that doesn't work, take a look at the distributor again. Mine had a nearly invisible crack in it with a faint carbon trace that was causing a misfire. It's not an expensive part and it's pretty easy to miss even after you think you've inspected it. Definitely check and recheck, then check again, the plug wire sequence. It's really easy to get backwards.
PS: Rain storm and stalling in a parking lot. There's a clue that points to the distributor. Humidity and water will make a marginal distributor turn bad on you.
Best Regards,
I have to vote with Van on this; check the plug order. If that doesn't work, take a look at the distributor again. Mine had a nearly invisible crack in it with a faint carbon trace that was causing a misfire. It's not an expensive part and it's pretty easy to miss even after you think you've inspected it. Definitely check and recheck, then check again, the plug wire sequence. It's really easy to get backwards.
PS: Rain storm and stalling in a parking lot. There's a clue that points to the distributor. Humidity and water will make a marginal distributor turn bad on you.
Best Regards,
#9
Perfect! I'll recheck this morning. But the thing is that before, I was able to start it after some time and it was running fine. Now I can't start it without keeping my foot on the pedal.
#11
Rennlist Member
Sounds like you have a AFM is in failure mode, sending a signal to ECU/DME that falsely indicates more airflow than actual, pulsing the fuel injectors more frequently, causing a rich A/F ratio. Holding the throttle wide open compensates for the rich fuel mixture and adds more air. Contact Bavarian Restoration
#12
Here's the updates.
I replaced the AFM for another one and the problem is still there. I replaced the Distributor cap and rotor and there's still a problem.
My car start when it's cold in the morning but never once the temperature hit above 80F. ICV? I made sure that I had no vacuum leak again. I'm just throwing parts at it right now....
I replaced the AFM for another one and the problem is still there. I replaced the Distributor cap and rotor and there's still a problem.
My car start when it's cold in the morning but never once the temperature hit above 80F. ICV? I made sure that I had no vacuum leak again. I'm just throwing parts at it right now....
#13
Rennlist Member
Hi Everyone,
I'm a longtime lurker in there, just recently signed in and this is my first official post. Sadly it's not an happy one.
I own a 944 Na 1984 since August 2017. I was looking for one for a while and this one was the perfect match I was looking for. The Idle was never really smooth but it was running and I was happy. Until November, when the car started to run only on 2-3 cylinder when cold to finally run ok when hot. The only event I could recall before those symptom appeared is driving in a rain storm for 300km and stalling in a parking lot. I stored it for the winter and when I started it the following Spring, she was running fine like when I got it.
Then I changed the oil (Brad Penn 20-50) and the filter and suddenly, she don't want to start anymore. Here's the list of what I did or replaced so far:
-Tested reference sensor (ok)
-Replaced Oil and Filter
-Replaced 4 injector
-Replaced DME Relay and Fuse
-Replaced DME (went that far...)
-Inspected and tested Distribution Cap (has spark)
-Inspected and replaced Ignition wires for BERU
-Replaced and gapped spark plugs (copper)
-Cleaned ground
-Inspected every vacuum line
-Replaced Alternator for a Bosch unit
-Replaced battery
-Replaced fuel pump (cleaned the strainer while I was in there)
-Replaced fuel filter
At this point, she is cranking, I've a tach bounce and a smell of petrol when I do. But when she do try to start, it's only on two or three cylinders... I'm puzzled and I'm a little bit tired to trow parts at my car for zero result.
Any inputs?
Thanks!
C
I'm a longtime lurker in there, just recently signed in and this is my first official post. Sadly it's not an happy one.
I own a 944 Na 1984 since August 2017. I was looking for one for a while and this one was the perfect match I was looking for. The Idle was never really smooth but it was running and I was happy. Until November, when the car started to run only on 2-3 cylinder when cold to finally run ok when hot. The only event I could recall before those symptom appeared is driving in a rain storm for 300km and stalling in a parking lot. I stored it for the winter and when I started it the following Spring, she was running fine like when I got it.
Then I changed the oil (Brad Penn 20-50) and the filter and suddenly, she don't want to start anymore. Here's the list of what I did or replaced so far:
-Tested reference sensor (ok)
-Replaced Oil and Filter
-Replaced 4 injector
-Replaced DME Relay and Fuse
-Replaced DME (went that far...)
-Inspected and tested Distribution Cap (has spark)
-Inspected and replaced Ignition wires for BERU
-Replaced and gapped spark plugs (copper)
-Cleaned ground
-Inspected every vacuum line
-Replaced Alternator for a Bosch unit
-Replaced battery
-Replaced fuel pump (cleaned the strainer while I was in there)
-Replaced fuel filter
At this point, she is cranking, I've a tach bounce and a smell of petrol when I do. But when she do try to start, it's only on two or three cylinders... I'm puzzled and I'm a little bit tired to trow parts at my car for zero result.
Any inputs?
Thanks!
C
I believe the one part that was not replaced is the fuel regulator located on the fuel rail
You purchase without testing or you can test it by following the procedure from Clark's Garage
The fuel regulator failure mode is closed, increasing the fuel pressure above spec. When it fails, no fuel is returned to the fuel tank and the fuel rail is pressurized to the maximum output pressure of the fuel pump. Consequently, no enough mass of air flowing into intake header for the mass flow of fuel, mixture too rich. The AFM is a volume device and as the intake air temperature increases, the density of the decreases, the air volume is constant, BUT the mass of decreases
#14
I read your list of parts replacement and your other threads. Your last thread was significant because the symptom is the engine does not start when the outside temperature is not.
I believe the one part that was not replaced is the fuel regulator located on the fuel rail
You purchase without testing or you can test it by following the procedure from Clark's Garage
The fuel regulator failure mode is closed, increasing the fuel pressure above spec. When it fails, no fuel is returned to the fuel tank and the fuel rail is pressurized to the maximum output pressure of the fuel pump. Consequently, no enough mass of air flowing into intake header for the mass flow of fuel, mixture too rich. The AFM is a volume device and as the intake air temperature increases, the density of the decreases, the air volume is constant, BUT the mass of decreases
I believe the one part that was not replaced is the fuel regulator located on the fuel rail
You purchase without testing or you can test it by following the procedure from Clark's Garage
The fuel regulator failure mode is closed, increasing the fuel pressure above spec. When it fails, no fuel is returned to the fuel tank and the fuel rail is pressurized to the maximum output pressure of the fuel pump. Consequently, no enough mass of air flowing into intake header for the mass flow of fuel, mixture too rich. The AFM is a volume device and as the intake air temperature increases, the density of the decreases, the air volume is constant, BUT the mass of decreases