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Hesitation when Aircon on
#1
Not sure if this should be in the engine or aircon section.
Has anyone come across this issue when the air con is on?

You step on the gas the car bogs down and surges in an unsmooth manner when under load at higher revs.


With the aircon off the car revs smoothly in all gears. 


Any suggestion gratefully received

Cheers
Nick H
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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#2
I would suggest (as you have guessed) down to the load when the A/C is on!  Seems strange that it causes such a huge issue when on, is there a possibility that your A/C compressor is on it's way out? Or even alternator struggling under extra load?
Chris
Membership Secretary DOC UK
2018's DeLorean event: http://deloreans.co.uk/forum/showthread.php?tid=5715
VIN#15768 Ex VIN#4584 1972 Bond Bug.
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#3
Try using the best possible fuel you can find, example: shell V-power or race power.
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#4
Air con compressor is relatively new. Alternator is original (Motorola). I have a new 120amp special T to fit. 
 After further testing. I think you might be on to somthing with the Alternator Chris. As I have recently fitted the solid state fan fail and fan relay the fans run for 20 seconds after you switch off the air con.

The car hesitates/slight judders under load ( at idle or unloaded its fine) until the fans cut out. At that point the compressor clutch is already disengaged.  So I don't think it's the compressor. 

So alternator maybe on the way out or could it be load on the front harness effecting the fuel pump?

I'll try some V-power as well.

Cheers
Nick H
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/
Reply
#5
Quote:could it be load on the front harness effecting the fuel pump?
Ohh, good call didn't think of that. Could well be worth a check on the earths in that area.
Chris
Membership Secretary DOC UK
2018's DeLorean event: http://deloreans.co.uk/forum/showthread.php?tid=5715
VIN#15768 Ex VIN#4584 1972 Bond Bug.
Reply
#6
(12 Aug 2017, 13:39)Chris Williams Wrote:
Quote:could it be load on the front harness effecting the fuel pump?
Ohh, good call didn't think of that. Could well be worth a check on the earths in that area.
Chris

Got a chance to have a look at the front frame ground point tonight. Definitely looked a bit crusty.
Removed the bolt and cleaned up the electrical connectors. Then gave it a good spray of contact cleaner. 

Also removed the inertia switch (fuel pump ground runs through this) connector and gave it a spray of contact cleaner. 

Noticeable increase in voltage on dash voltmeter.

Not sure if this has solved the issue yet but will give the car a run when I get the chance to test.

Nick H
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/
Reply
#7
Update

Replaced front earth point bolt and hardware with stainless version and used dielectric grease.
Voltmeter reads a fraction higher Smile .
Test run revealed slightly better running when fans are running.
Hesitation/chugging was less severe.


Installed new Special T alternator. Voltmeter considerably higher Cool .
Test run revealed it's 90% better. Just a very slight hesitation/chugging.

So I think it is definitely an electrical issue causeing the fuel pump to reduce pressure. 
When the cooling fans are running. 

I think it's time to fit the new low draw fans. 


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/
Reply
#8
Quote:I think it's time to fit the new low draw fans.
I have them and think they are great! I have these: http://www.deloreanindustries.com/11-hig...d-upgrade/  but I'm sure Ed's/others are just as good
Chris
Membership Secretary DOC UK
2018's DeLorean event: http://deloreans.co.uk/forum/showthread.php?tid=5715
VIN#15768 Ex VIN#4584 1972 Bond Bug.
Reply
#9
(18 Sep 2017, 20:16)Chris Williams Wrote:
Quote:I think it's time to fit the new low draw fans.
I have them and think they are great! I have these: http://www.deloreanindustries.com/11-hig...d-upgrade/  but I'm sure Ed's/others are just as good
Chris

I'm just about to fit mine. I need to get some new rubber/silicone hoses - I believe that 32mm is the correct size and would prefer to use silicone tube. - maybe somebody could confirm the size?
I also have a full set of (fully) stainless steel jubilee clips.
Vin 11789 (probably #50 of the Middle East batch of 50)
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#10
Quote:somebody could confirm the size?
Mine came supplied (from Ed) with new pipes so I did not have to buy them, sorry did not measure them either.
Chris
Membership Secretary DOC UK
2018's DeLorean event: http://deloreans.co.uk/forum/showthread.php?tid=5715
VIN#15768 Ex VIN#4584 1972 Bond Bug.
Reply
#11
(19 Sep 2017, 09:55)SpudMurphy Wrote:
(18 Sep 2017, 20:16)Chris Williams Wrote:
Quote:I think it's time to fit the new low draw fans.
I have them and think they are great! I have these: http://www.deloreanindustries.com/11-hig...d-upgrade/  but I'm sure Ed's/others are just as good
Chris

I'm just about to fit mine. I need to get some new rubber/silicone hoses - I believe that 32mm is the correct size and would prefer to use silicone tube. - maybe somebody could confirm the size?
I also have a full set of (fully) stainless steel jubilee clips.

I'm a bit confused. I thought people were talking about fans and current draw, but you seem to be referring to coolant system pipework hoses. lol!

The pipework hoses are 1 /14 inches diameter (32mm is close enough). I'f you buy a straight length of 2m (or 2 x 1m), this is enough to do all the straight portions of the pipe joining (obviously by cutting it up into sections for installation). the exception is the passenger side (RHS) of the pipework where it changes direction by 30-45 degrees as it heads up to the RHS of the engine bay.

I bought what's required for my car from this website some years ago (I've used them for quite a few things over the years - I'd recommend them). Here's the links to what I bought.

https://www.carbuildersolutions.com/uk/b...tre-length

https://www.carbuildersolutions.com/uk/b...h-4in-legs

unless of course you're talking about A/C pipework. In that case, I can't help i'm afraid. I've been running my car for 8yrs with no A/C. It's a bit of a sore point actually. lol!
Rissy
Chris M. Morionem qui loquitur multus sine cogitatione.
(Forum Member 288)
(DOC Member 663)

May 1981 vin#1458
"LEX" aka "Wonkey" - Officially used in Britain's Greatest Machines (80's episode) with Chris Barrie.
Grey Wheels
Grooved, flapped Bonnet
Black Leather Interior
Chassis: #1073
Engine: #2839

Main Car(s):

2005 BMW M3 E46 Shape 3.246 Straight Six in Velvet Blue
1999 Honda Civic MB6 Shape 1.8VTi VTEC in Pirates Black
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#12
... all linked up (pardon the pun) in the scheme of things.

So let's get me some 32mm silicone hose - seems cheap enough.

I have the link to a great site for the hose on my home computer and will post it here later.
Vin 11789 (probably #50 of the Middle East batch of 50)
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#13
(20 Sep 2017, 13:44)SpudMurphy Wrote: I have the link to a great site for the hose on my home computer and will post it here later.
the link is ...
http://www.autosiliconehoses.com/?utm_ca...0431610616
Vin 11789 (probably #50 of the Middle East batch of 50)
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#14
(20 Sep 2017, 18:45)SpudMurphy Wrote:
(20 Sep 2017, 13:44)SpudMurphy Wrote: I have the link to a great site for the hose on my home computer and will post it here later.
the link is ...
http://www.autosiliconehoses.com/?utm_ca...0431610616

There's not much in it, but the wall thickness is a bit smaller than the ones I bought. more prone to "bubbling" under heat and pressure? Let us know how you get on for comparison. (I'm sure they'll be fine - and cheaper than mine)
Rissy
Chris M. Morionem qui loquitur multus sine cogitatione.
(Forum Member 288)
(DOC Member 663)

May 1981 vin#1458
"LEX" aka "Wonkey" - Officially used in Britain's Greatest Machines (80's episode) with Chris Barrie.
Grey Wheels
Grooved, flapped Bonnet
Black Leather Interior
Chassis: #1073
Engine: #2839

Main Car(s):

2005 BMW M3 E46 Shape 3.246 Straight Six in Velvet Blue
1999 Honda Civic MB6 Shape 1.8VTi VTEC in Pirates Black
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#15
yup I'll do that - as long as the engine fires up lol
Vin 11789 (probably #50 of the Middle East batch of 50)
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