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Fueling Issues - Looking for opinions on PPR
#16
6 jam jar test, through full range of movement from the venturi flap.
Rissy
(Forum Member 288)
(DOC Member 663)

May 1981 vin#1458 "LEX"
Grey, Flapped, Black
Chassis: #1073
Engine: #2839

Main Car(s):
2005 BMW M3 in Velvet Blue
2010 Honda Civic Type R in Sapphire Blue (1 of 115 made)
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#17
I prefer peanut butter myself, but I'll keep you posted on the results when I get a chance to do the test. I'll probably film it for reference Smile
VIN 4494, Grey interior, 5 speed, October 1981
DOC 757
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#18
When i needed to do such a test, i didn't have any jars (Constantly recycling you see). I had to go to Tesco (other supermarket variants are available) specially to buy the cheapest tall jam jars i could lay my hands on. As soon as i was home, the first thing i did was to empty all the jars and clean them thoroughly.

I was left with a whole heap of jam i had no fear of ever getting through (or even using - since i hardly ever eat jam). Unfortunately, the whole lot went to waste.

I learned from that day forward to always keep a healthy supply of tall jam jars for unforeseen circumstances.

They've proved useful time and time again since.

(Peanut butter jars *may* work just as well)

8-)
Rissy
(Forum Member 288)
(DOC Member 663)

May 1981 vin#1458 "LEX"
Grey, Flapped, Black
Chassis: #1073
Engine: #2839

Main Car(s):
2005 BMW M3 in Velvet Blue
2010 Honda Civic Type R in Sapphire Blue (1 of 115 made)
Reply
#19
Be interesting to see the results, I 'still' thing it's a metering head issue however!. You could always try the jam jar test without injectors to see if there is any difference in flow without the injectors causing a restriction. And then try with the injectors also.
Chris
Membership Secretary DOC UK
2021's DeLorean event: http://www.deloreans.co.uk/forum/showthr...p?tid=6056
VIN#15768 Ex VIN#4584
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#20
Updates! I had time to put the in-tank bits back together today. Plumbed it all back in, ran the test again with no shims. Same result. In sorting through my box of parts I found a spare (but rough looking) DeLorean WUR. Decided what the hell, swapped it on instead.

The good news; cold tests I get 20 psi control pressure and 70 psi primary pressure. Warm I get around 50 psi control pressure, just over 70 psi primary pressure. So the swapped in WUR has made some difference, though still looking to be at the lower end of the primary pressure scale. Haven't tried adding a shim to the distributor again though.

The bad news; No impact on my initial problem I was trouble shooting when I started looking at the fuel pressures. If anything it seems slightly worse.

I'm time limited today for further trouble shooting, but I at least decided to hook up my dwell meter and get a reading from lambda system. I stress that I did not touch the mixture screw, but it has been touched in the past (previous owner/s, then by a former volvo tech, then by Ed last summer). So I wanted to get a reading on that, but oddly instead of somewhere around the 40-50 mark and fluctuating it was sitting at 85 degrees.

I didn't opt to adjust it as I don't want to add another unknown to the situation as it stands but I figured I'd share the information rather than not in case it makes a difference.
VIN 4494, Grey interior, 5 speed, October 1981
DOC 757
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#21
Weekend update! I bought a refurbished CPR/WUR and Fuel Distributor as my readings just seemed too wacky and no other reference online for this oddness. Fit them today and getting textbook fuel readings AND much much improved sounding engine. Ran her up to temperature and she was a little hesitant, but no stalling out. No MOT or tax right now so only a stationary test. Idle is now sitting at around 1000rpm and a little sticky once warmed up, but only to 1100, I think that is likely a separate issue.

My dwell readings are stable when cold then the needle swings straight to 85 degrees once warm so I think my o2 sensor is hosed. I'm bought a second hand exhaust gas analyser that should arrive this week so I'll get the co2 down to 1.5, fit a new o2 sensor and then tune using the dwell. Then we'll see where I'm at! Will check injectors after this.

Thank you all for the continued assistance Smile
VIN 4494, Grey interior, 5 speed, October 1981
DOC 757
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#22
Great news. a few good trips will do it a world of good also!
Membership Secretary DOC UK
2021's DeLorean event: http://www.deloreans.co.uk/forum/showthr...p?tid=6056
VIN#15768 Ex VIN#4584
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#23
I think your on the right track with replacing the O2 sensor. I had one fail on my car and the dwell meter acted in the same manor.

Don’t forget to reset the Lamda counter.

Nick
DOC 650
Jaguar X-Type
Range Rover Sport SDV6 "Rufus" (Mrs H's motor)
DeLorean DMC 12 Vin#2862

My other hobby...
http://www.lccuk.org.uk/
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#24
Video 
Weekend again so finally some time for an update. Captured a video of the engine before adjusting the CO2;

 



Message split in two due to video limits...

Using the analyser I was only able to tune her in to 2.7% CO2, but it's a second hand meter so I'm not sure how good the calibration is to begin with. Video of after;





Dwell reading still wrong in the same way. Mostly it was leaning out the engine, so she smells much less rich. Unplugging the O2 sensor does make a noted difference in the sound but being an idiot I didn't record that part Smile

Now the complicating thing for me is that she _just_ got the UK SS Exhaust put on before I had all these troubles. So the first video she sounds more like she did before all this AND before the exhaust, where as the second video you can hear a gurgle in the exhaust note (despite the bad mic on my phone) but I'm not sure if that's how she's meant to sound now.

She does not stall under load anymore though, but seemed to be slightly lacking in power. I think I may have leaned her out too much due to the CO2 tester. However I am taking her for an MOT next Saturday and can get some good readings there and see. Will replace the O2 sensor this weekend with a spare, once the exhaust has cooled down that is.
VIN 4494, Grey interior, 5 speed, October 1981
DOC 757
Reply
#25
Good news, I have a valid MOT again Big Grin I had leaned out the mixture too far but we were able to adjust it in the garage and get her much happier again. She still needs some fine tuning, but overall a much happier car. Took her out for a good long drive to celebrate (and test) and it was great fun. Other issues with her to fix still, but glad to be mostly over with this one.

Will still do the jam jar test when I have time to confirm that part also!

Thanks for all the advice and assistance Smile
VIN 4494, Grey interior, 5 speed, October 1981
DOC 757
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