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> Bog down after warm up, Bog down after warm up
tsvo
post Nov 29 2016, 07:22 AM
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I am looking fsome help. I have a 1973 1.7L. I have replaced the points and wires as well as general tune up. It starts fine and seems to idle OK. However after 30 - 45 Min of running it starts to bog down. The car loses power, idle drops then backfires. The car gets a quick power surge at the time of backfiring. THe cycle then repeats. I let the car cool down for a little while and it usually goes away.

Any sugestions?
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76-914
post Nov 29 2016, 10:12 AM
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Did you replace the condenser also. Have you checked the coil's resistance? (IMG:style_emoticons/default/beerchug.gif)
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BeatNavy
post Nov 29 2016, 10:54 AM
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Fuel injection or carbs? Initial thought is you're running way too rich or your timing is over-advanced. If FI, there are a couple of potential causes including blown MPS, fuel pressure too high, wonky CHT, etc. When you replaced the points, did you set dwell and timing? You need to adjust timing after changing or adjusting points...

If it is FI you may want to start getting familiar with this site: http://members.rennlist.com/pbanders/djetparts.htm
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tsvo
post Nov 29 2016, 12:38 PM
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QUOTE(BeatNavy @ Nov 29 2016, 10:54 AM) *

Fuel injection or carbs? Initial thought is you're running way too rich or your timing is over-advanced. If FI, there are a couple of potential causes including blown MPS, fuel pressure too high, wonky CHT, etc. When you replaced the points, did you set dwell and timing? You need to adjust timing after changing or adjusting points...

If it is FI you may want to start getting familiar with this site: http://members.rennlist.com/pbanders/djetparts.htm


Thanks, it is an FI. I did set the timing, but perhaps I need to recheck it. Any other thoughts are appreciated.
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tsvo
post Nov 29 2016, 12:39 PM
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QUOTE(76-914 @ Nov 29 2016, 10:12 AM) *

Did you replace the condenser also. Have you checked the coil's resistance? (IMG:style_emoticons/default/beerchug.gif)


I did not do the condenser. I will check that as well.
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rmital
post Nov 29 2016, 01:17 PM
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QUOTE(BeatNavy @ Nov 29 2016, 11:54 AM) *

.... If FI, there are a couple of potential causes including blown MPS, fuel pressure too high, wonky CHT,


solid advise...over the last 10 years of 914ing, the above was a good start and most of the time, the cause(s).
money's on the MPS of course, the most expensive solution (IMG:style_emoticons/default/dry.gif)
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IronHillRestorations
post Nov 29 2016, 05:28 PM
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Check the MPS, CHT, and the distributor.

I worked on a car that had a similar problem, when it got hot the advance plate in the distributor wouldn't move freely.
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BeatNavy
post Nov 29 2016, 06:40 PM
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QUOTE(Perry Kiehl @ Nov 29 2016, 06:28 PM) *

I worked on a car that had a similar problem, when it got hot the advance plate in the distributor wouldn't move freely.

Good point, Perry. A good dizzy cleaning is also a worthy idea. The old grease gets sticky and dirty over the years. Relevant thread: http://www.914world.com/bbs2/index.php?sho...232335&st=0. Dizzy cleaning starts around post #36.

Rich would approve.
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tsvo
post Nov 30 2016, 06:47 AM
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QUOTE(rmital @ Nov 29 2016, 01:17 PM) *

QUOTE(BeatNavy @ Nov 29 2016, 11:54 AM) *

.... If FI, there are a couple of potential causes including blown MPS, fuel pressure too high, wonky CHT,


solid advise...over the last 10 years of 914ing, the above was a good start and most of the time, the cause(s).
money's on the MPS of course, the most expensive solution (IMG:style_emoticons/default/dry.gif)

THank you, I will give it a try
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BeatNavy
post Nov 30 2016, 06:58 AM
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Be methodical and follow the directions on that link I gave you for identifying the possible causes and eliminating them one by one through testing. You can do it, and you'll learn a lot about how to maintain it going forward. D-Jet is a pretty cool system, given its age, but if it hasn't been maintained something, or some things, will go wrong. If you have questions, let us know. Lots of good FI knowledge here on the World.
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Ansbacher
post Nov 30 2016, 11:23 AM
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Had similar problem and turned out to be bad coil. Try a known good coil. Even if your existing coil checks out good cold, it might be bad when hot. I wasted a lot of time and money before I zeroed in on the coil. Good luck.

Ansbacher
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tsvo
post Nov 30 2016, 02:08 PM
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QUOTE(Perry Kiehl @ Nov 29 2016, 05:28 PM) *

Check the MPS, CHT, and the distributor.

I worked on a car that had a similar problem, when it got hot the advance plate in the distributor wouldn't move freely.

Thank you
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tsvo
post Nov 30 2016, 02:09 PM
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QUOTE(Ansbacher @ Nov 30 2016, 11:23 AM) *

Had similar problem and turned out to be bad coil. Try a known good coil. Even if your existing coil checks out good cold, it might be bad when hot. I wasted a lot of time and money before I zeroed in on the coil. Good luck.

Ansbacher

Thank you, I will give it a try.
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tsvo
post Nov 30 2016, 02:10 PM
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QUOTE(BeatNavy @ Nov 30 2016, 06:58 AM) *

Be methodical and follow the directions on that link I gave you for identifying the possible causes and eliminating them one by one through testing. You can do it, and you'll learn a lot about how to maintain it going forward. D-Jet is a pretty cool system, given its age, but if it hasn't been maintained something, or some things, will go wrong. If you have questions, let us know. Lots of good FI knowledge here on the World.

Thank you again
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