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Posted by: andreic May 8 2018, 09:52 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.

Posted by: cuddy_k May 8 2018, 10:05 PM

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?

Posted by: andreic May 8 2018, 10:12 PM

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.

Posted by: Dave_Darling May 9 2018, 12:16 AM

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

Posted by: BeatNavy May 9 2018, 04:24 AM

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.

Posted by: erwindv May 9 2018, 06:40 AM

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.

Posted by: dr914@autoatlanta.com May 9 2018, 08:20 AM

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

Posted by: andreic May 9 2018, 08:30 AM

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...

Posted by: Jeff Bowlsby May 9 2018, 09:06 AM

Not hard.




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Posted by: sechszylinder May 9 2018, 09:55 AM

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