Is it the fule pump?, Spluttering and stalling! |
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Is it the fule pump?, Spluttering and stalling! |
chrispovoas |
Apr 8 2023, 04:00 AM
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#1
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Member Group: Members Posts: 61 Joined: 8-April 23 From: New Zealand Member No.: 27,285 Region Association: Australia and New Zealand |
Hi guys, Chris from New Zealand here....finally bought myself a 914! Shes a '73 2.0 with original FI. Had her about a week, after standing for 8 years.
Previous owner spent some time and money getting her on the road as part of the sale to me, but still a bit of work to be done! I'll try and attach a picture. Took her for a shakedown run today for about 3 hours but then she started coughing and spluttering then stalled at about 60mph. Coasted to a halt, ignition on/off and away she went again for about half an hour.. Same thing again, ignition on/off and all was well for another 20 min.. This went on and on and the intervals between spluttering and stalling got more frequent until i just about made it home. Felt like fuel rather than electrical... Could it be the fuel pump, or any other ideas? I have a feeling I'll be using the forum quite a bit (IMG:style_emoticons/default/smile.gif) Nice to meet everyone! |
emerygt350 |
Apr 8 2023, 10:14 PM
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#2
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Advanced Member Group: Members Posts: 2,136 Joined: 20-July 21 From: Upstate, NY Member No.: 25,740 Region Association: North East States |
At cold start (20 c) it should jump up to 12-1400 rpm. As it warms it will rise to 1400 but shouldn't go higher. That is the aux air valve. As the filament in the aav heats it will bring the idle down. As the heads heat the sensor the ECU uses to enrich the air fuel ratio will eventually tell the ECU to knock it off. At this point the idle should be about 850. This can take a long long time in cold temps. Temps less than 20c.
The system the type 4 uses to control airflow over the oil cooler and heads is really interesting and important. Besides insuring that you are not running lean, you need to make sure that is working as intended. Do you have a Chilton's or clymers manual? |
chrispovoas |
Apr 8 2023, 11:11 PM
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#3
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Member Group: Members Posts: 61 Joined: 8-April 23 From: New Zealand Member No.: 27,285 Region Association: Australia and New Zealand |
At cold start (20 c) it should jump up to 12-1400 rpm. As it warms it will rise to 1400 but shouldn't go higher. That is the aux air valve. As the filament in the aav heats it will bring the idle down. As the heads heat the sensor the ECU uses to enrich the air fuel ratio will eventually tell the ECU to knock it off. At this point the idle should be about 850. This can take a long long time in cold temps. Temps less than 20c. The system the type 4 uses to control airflow over the oil cooler and heads is really interesting and important. Besides insuring that you are not running lean, you need to make sure that is working as intended. Do you have a Chilton's or clymers manual? Just went out for a 30min spin and the idle etc seems to line up as per your comments above. The first 10 minutes of the drive it was coughing and spluttering, no power etc.. But after about 15 minutes of warm up that went away and it ran fine. This is how it was yesterday, but on an extended run (a 3 hour drive) with more time is when it stalled a number of times. No, dont have either of those manuals.. |
r_towle |
Apr 19 2023, 05:55 PM
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#4
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Custom Member Group: Members Posts: 24,586 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
At cold start (20 c) it should jump up to 12-1400 rpm. As it warms it will rise to 1400 but shouldn't go higher. That is the aux air valve. As the filament in the aav heats it will bring the idle down. As the heads heat the sensor the ECU uses to enrich the air fuel ratio will eventually tell the ECU to knock it off. At this point the idle should be about 850. This can take a long long time in cold temps. Temps less than 20c. The system the type 4 uses to control airflow over the oil cooler and heads is really interesting and important. Besides insuring that you are not running lean, you need to make sure that is working as intended. Do you have a Chilton's or clymers manual? Just went out for a 30min spin and the idle etc seems to line up as per your comments above. The first 10 minutes of the drive it was coughing and spluttering, no power etc.. But after about 15 minutes of warm up that went away and it ran fine. This is how it was yesterday, but on an extended run (a 3 hour drive) with more time is when it stalled a number of times. No, dont have either of those manuals.. You seem to have a temp issue. Three things I would do to troubleshoot this. I would remove the vacuum line to the AAR and put tape over the hole in the plenum and tape over the AAR. These rust inside, it’s a steel spring, and I can get stuck in one position. Second Get a brass, male male 5/16 barbed fitting Remove the fuel line from both sides of the cold start injector and connect them together with the fitting. These cold start injectors sometimes fail open and will add too much fuel no matter what the temp is. Third, measure the output of the CHT when it’s stone cold. Measure again once it’s nice and hot. These are your three temp related items. Finally, clean and regrease the advance plates on the distributor. Old grease no longer allows them to move freely. This can cause the advance plates to stick in full advance when warm, thus increasing the idle speed. If you cannot change or make an impact on the idle speed with the idle adjustment screw, you must find the root cause of either a vacuum leak, or timing issue. You mentioned the hose fell off the AAR very casually, but that is a massive vacuum leak. Rich |
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