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> Djet running way too rich... Still!
Halfnelson
post Jun 20 2024, 03:33 AM
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Had a previous thread starting in 2022 about my 73 1.7 standard D-Jet running way too rich and flooding to the point where it wouldn't start. It's been an ongoing issue. I've had a go. 2 garages have had a go. I'm at the point where I'm beginning to lose hope.

A recap. Bought the car 2021, had a problem with intermittent flooding. So far have:
Checked MPS - holding vacuum.
Replaced CHT sensor and tested. Working when flooded.
Replaced fuel pump and tested pressure.
Replaced all vacuum hoses and tested for leaks.
Valves set and rechecked.
New 123 distributor.
New injectors.

Each time I think I've cracked it and it runs and drives - sometimes for a month or so. Then I'll go to start it and it'll flood again to the point where it contaminates the oil. I feel like I've never managed to get to the bottom of the problem. Just keep replacing parts. Thinking maybe a return line that intermittently blocks? I'm kind of at a loss.
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JeffBowlsby
post Jun 21 2024, 05:32 AM
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While the idea of swapping in 'known good' parts like the ECU is noble, I have seen some 'known good' ECUs be functionally defective in some mode even though they seem to work OK. No harm in trying the swap as a first step as it may get one closer to any issue and solution. But that process is not definitive.

I have the equipment to test the ECUs, D-Jet or LJet, but I don't do repairs. Or send it to an ECU repair shop for their analysis and any needed repair. Verify functionality of every ECU function and take the guess work out of the equation.
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ClayPerrine
post Jun 21 2024, 07:19 AM
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QUOTE(JeffBowlsby @ Jun 21 2024, 06:32 AM) *

While the idea of swapping in 'known good' parts like the ECU is noble, I have seen some 'known good' ECUs be functionally defective in some mode even though they seem to work OK. No harm in trying the swap as a first step as it may get one closer to any issue and solution. But that process is not definitive.

I have the equipment to test the ECUs, D-Jet or LJet, but I don't do repairs. Or send it to an ECU repair shop for their analysis and any needed repair. Verify functionality of every ECU function and take the guess work out of the equation.


(IMG:style_emoticons/default/agree.gif)

But the downside to bench testing and ECU is that is is not subjected to engine heat and vibration when you do this. So intermittent connection issues won't show up.

If there is a break in the CHT circuit, the ECU is designed to go full rich. So a solder joint inside the ECU in the CHT circuit, broken due to vibration or heat, could cause a intermittent flooding condition.

Another could be an old wire in the CHT circuit the harness that is old and brittle. Vibration causes it to move enough to break the circuit, and it goes full rich.

Or the connector between the CHT and the harness is corroded or making a bad connection.

The last two can be resolved with a new harness. The ones Jeff makes are excellent and resolve a LOT of running issues with D-Jet, or even L-Jet. So if you have not bought one of the new harnesses, I would suggest it.

Jeff. You can send my sales commission to me via paypal. (IMG:style_emoticons/default/biggrin.gif)
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Posts in this topic
Halfnelson   Djet running way too rich... Still!   Jun 20 2024, 03:33 AM
emerygt350   Have you removed the cold start valve from the equ...   Jun 20 2024, 04:20 AM
Halfnelson   Have you removed the cold start valve from the eq...   Jun 20 2024, 04:51 AM
JeffBowlsby   The MPS holding vacuum is not a definitive test. ...   Jun 20 2024, 06:01 AM
Halfnelson   The MPS holding vacuum is not a definitive test. ...   Jun 20 2024, 06:31 AM
Halfnelson   The MPS holding vacuum is not a definitive test....   Jun 20 2024, 06:33 AM
JeffBowlsby   Also would that present as an intermittent issue...   Jun 20 2024, 07:11 AM
Halfnelson   Also would that present as an intermittent issu...   Jun 20 2024, 07:19 AM
JeffBowlsby   The MPS holding vacuum is not a definitive test....   Jun 20 2024, 07:10 AM
emerygt350   It could. Just depends on how it is cracked. I k...   Jun 20 2024, 06:40 AM
emerygt350   If you get the rebuild kit from Chris it is super ...   Jun 20 2024, 08:35 AM
StarBear   If you get the rebuild kit from Chris it is super...   Jun 20 2024, 09:16 AM
emerygt350   I wonder about the ECU... They rarely go but perh...   Jun 20 2024, 08:37 AM
rjames   I wonder about the ECU... They rarely go but per...   Jun 20 2024, 09:10 AM
rjames   double post   Jun 20 2024, 09:10 AM
emerygt350   I have a known working extra 037 from my 73 2.0. ...   Jun 20 2024, 09:15 AM
FlacaProductions   What MPS do you currently have? I believe a 73 1....   Jun 20 2024, 09:34 AM
914_teener   What MPS do you currently have? I believe a 73 1...   Jun 20 2024, 11:02 AM
emerygt350   What MPS do you currently have? I believe a 73 ...   Jun 20 2024, 03:06 PM
JamesM   [quote name='914_teener' post='3152016' date='Jun...   Jun 20 2024, 04:18 PM
Ishley   It sounds a lot like you're having ignition a...   Jun 20 2024, 11:55 AM
FlacaProductions   Agreed on MPS tuning - that's a whole differen...   Jun 20 2024, 12:47 PM
emerygt350   My point was, he could borrow my ECU.   Jun 20 2024, 04:26 PM
JamesM   My point was, he could borrow my ECU. If you wa...   Jun 20 2024, 09:45 PM
914_teener   I'm with Jeff. This is a common failure mode o...   Jun 20 2024, 10:01 PM
rjames   The ECU is the easiest thing to test first. Move t...   Jun 20 2024, 11:09 PM
emerygt350   The intermittent cht is an interesting idea but it...   Jun 21 2024, 05:14 AM
ClayPerrine   For years the rule of thumb was "The ECU neve...   Jun 21 2024, 05:28 AM
JeffBowlsby   While the idea of swapping in 'known good...   Jun 21 2024, 05:32 AM
ClayPerrine   While the idea of swapping in 'known good...   Jun 21 2024, 07:19 AM
emerygt350   If cost is no issue, definitely send it out for te...   Jun 21 2024, 06:31 AM
emerygt350   Just a quick mention on the TPS, although I really...   Jun 21 2024, 06:33 AM
dr914@autoatlanta.com   substitution is your friend. That is what we do he...   Jun 21 2024, 08:22 AM
Halfnelson   Thanks so much for the suggestions. I’ve been th...   Jun 22 2024, 04:27 AM
Halfnelson   I’m not sure if this is relevant but when it doe...   Jun 22 2024, 04:32 AM
ClayPerrine   I’m not sure if this is relevant but when it do...   Jun 22 2024, 04:39 AM
emerygt350   Ahh, Cornwall, just noticed that. Can you descr...   Jun 22 2024, 04:53 AM
Halfnelson   Although the cht has been changed and I’ve teste...   Jun 22 2024, 05:13 AM
ClayPerrine   Although the cht has been changed and I’ve test...   Jun 22 2024, 06:27 AM
technicalninja   What he's describing appears to be fuel foulin...   Jun 22 2024, 03:47 PM
technicalninja   Made me think... An ECU that did short the inject...   Jun 22 2024, 03:59 PM
emerygt350   Pressure Regulator on these is static. The wet pl...   Jun 22 2024, 04:03 PM
Halfnelson   Do you recommend pulling a plug, checking, and the...   Jun 23 2024, 05:08 AM
emerygt350   Yeah, check first and then after if it doesn't...   Jun 23 2024, 06:01 AM


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