 D-Jet difficult to start when hot |
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| andreic |
 May 8 2018, 09:52 PM
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#1
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Member  Group: Members Posts: 172 Joined: 21-December 15 From: Madison, WI Member No.: 19,479 Region Association: Upper MidWest  |
My new (to me) 1972 1.7L has the original D-Jet. I have not started to troubleshoot it (I am very familiar with the L-Jet, but I know almost nothing about D-Jet) -- the main reason being that it actually runs very well -- when it runs. I.e., it starts very well cold, on the first key, and after that it runs perfectly. Except that after I turn it off hot, and try to start it after a few minutes, it will require 3-4 tries to get it going.
Is this is a common issue? What is causing it? Thanks, Andrei. |
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| iankarr |
May 8 2018, 10:05 PM
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#2
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The wrencher formerly known as Cuddy_K Group: Members Posts: 2,473 Joined: 22-May 15 From: Heber City, UT Member No.: 18,749 Region Association: Intermountain Region 
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Where is your fuel pump located? If it's in the original location it's possible (but not highly likely in WI this time of year) that you're getting some vapor lock. Is your starter still turning over strong when hot?
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| andreic |
May 8 2018, 10:12 PM
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#3
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Member Group: Members Posts: 172 Joined: 21-December 15 From: Madison, WI Member No.: 19,479 Region Association: Upper MidWest |
The fuel pump is in what I believe is the original location -- on the firewall, engine side, low, passenger side. The air temp today was in the 70's. I did think about vapor lock, but not sure at what temps I should start worrying about that.
The starter cranks as strong as ever. |
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| Dave_Darling |
May 9 2018, 12:16 AM
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#4
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914 Idiot Group: Members Posts: 14,986 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California
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Read through Brad Anders' D-jet Bible. http://members.rennlist.com/pbanders
That contains just about everything currently known about D-jet. He wonders if there may be heat-soak issues with the CHT sensor. The mixture may also be a bit off, or there may be other issues. --DD |
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| BeatNavy |
May 9 2018, 04:24 AM
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#5
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Certified Professional Scapegoat Group: Members Posts: 2,924 Joined: 26-February 14 From: Easton, MD Member No.: 17,042 Region Association: MidAtlantic Region
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I think it's a pretty common issue even for generally well-tuned D-Jet cars. Starting after a brief stop (say to get gas or run a quick errand) can be a bit difficult. Mine always starts, but I normally have to crank it a few seconds longer while depressing the accelerator. Then it idles really low and runs lean for 20 or 30 seconds before all is good again. As Dave says, I think it is exacerbated if there's something not quite tuned right.
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| erwindv |
May 9 2018, 06:40 AM
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#6
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Newbie Group: Members Posts: 46 Joined: 17-June 16 From: Belgium Member No.: 20,119 Region Association: Europe |
QUOTE(andreic @ May 9 2018, 05:52 AM)  My new (to me) 1972 1.7L has the original D-Jet. I have not started to troubleshoot it (I am very familiar with the L-Jet, but I know almost nothing about D-Jet) -- the main reason being that it actually runs very well -- when it runs. I.e., it starts very well cold, on the first key, and after that it runs perfectly. Except that after I turn it off hot, and try to start it after a few minutes, it will require 3-4 tries to get it going. Is this is a common issue? What is causing it? Thanks, Andrei. Last month I had the same problem but worse: had to let it cool down for about half a day. Turned out to be the cylinder head temperature sensor which was not properly tightened. |
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| dr914@autoatlanta.com |
May 9 2018, 08:20 AM
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#7
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914 Guru Group: Members Posts: 7,864 Joined: 3-January 07 From: atlanta georgia Member No.: 7,418 Region Association: None |
the three main ones are
leaking pressure sensor vapor lock defective head temp sensor that of course is assuming that the dwell and timing are perfect, the fuel pressure is coming up right away you do not have a vacuum leak, the valves are in adjustment, the compression is even, the air filter is not clogged, etc QUOTE(andreic @ May 8 2018, 08:52 PM) My new (to me) 1972 1.7L has the original D-Jet. I have not started to troubleshoot it (I am very familiar with the L-Jet, but I know almost nothing about D-Jet) -- the main reason being that it actually runs very well -- when it runs. I.e., it starts very well cold, on the first key, and after that it runs perfectly. Except that after I turn it off hot, and try to start it after a few minutes, it will require 3-4 tries to get it going. Is this is a common issue? What is causing it? Thanks, Andrei. |
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| andreic |
May 9 2018, 08:30 AM
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#8
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Member Group: Members Posts: 172 Joined: 21-December 15 From: Madison, WI Member No.: 19,479 Region Association: Upper MidWest |
Well, this is a bit more than I expected... The valves are properly adjusted (just done). I was planning on checking the timing and dwell today or tomorrow, and also the compressions. I'll replace the air filter anyway. Vacuum leaks -- that's a bit harder to check, other than to visually inspect it.
If I don't find anything unusual in these tests -- should I dig deeper? As I said, the car runs fine and this is not a big issue, it just requires cranking a few times. I just would like not to be left stranded somewhere... |
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| JeffBowlsby |
May 9 2018, 09:06 AM
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#9
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914 Wiring Harnesses Group: Members Posts: 8,510 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None
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Not hard.
Attached image(s) 
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| sechszylinder |
May 9 2018, 09:55 AM
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#10
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Member Group: Members Posts: 247 Joined: 9-April 03 From: /earth/europe/germany/berlin Member No.: 545 Region Association: None
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QUOTE(andreic @ May 8 2018, 07:52 PM) My new (to me) 1972 1.7L has the original D-Jet. I have not started to troubleshoot it (I am very familiar with the L-Jet, but I know almost nothing about D-Jet) -- the main reason being that it actually runs very well -- when it runs. I.e., it starts very well cold, on the first key, and after that it runs perfectly. Except that after I turn it off hot, and try to start it after a few minutes, it will require 3-4 tries to get it going. Is this is a common issue? What is causing it? Thanks, Andrei. Hey Andrei, I've been through all of this issues with the D Jet in my 2.0. Actually after nearly replacing all parts of the system, including the system itself (I've switched to megasquirt) I had the same hot start issues. The remaining parts where the injectors and after checking them I realized, that these old injectors where leaking, after shutting down the engine, which means , when hot starting the engine, I had an extreme rich mixture, which fails to start the engine. Give it a try, and let them be checked and cleaned ... BR Benno |
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