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Hesitation when Aircon on - Printable Version

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Hesitation when Aircon on - Nick H - 11 Aug 2017

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

RE: Hesitation when Aircon on - Chris Williams - 11 Aug 2017

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

RE: Hesitation when Aircon on - Future - 11 Aug 2017

Try using the best possible fuel you can find, example: shell V-power or race power.

RE: Hesitation when Aircon on - Nick H - 11 Aug 2017

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

RE: Hesitation when Aircon on - Chris Williams - 12 Aug 2017

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

RE: Hesitation when Aircon on - Nick H - 14 Aug 2017

(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

RE: Hesitation when Aircon on - Nick H - 16 Sep 2017

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

RE: Hesitation when Aircon on - Chris Williams - 18 Sep 2017

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-high-flow-fan-stainless-fan-shroud-upgrade/  but I'm sure Ed's/others are just as good
Chris

RE: Hesitation when Aircon on - SpudMurphy - 19 Sep 2017

(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-high-flow-fan-stainless-fan-shroud-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.

RE: Hesitation when Aircon on - Chris Williams - 19 Sep 2017

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

RE: Hesitation when Aircon on - Rissy - 20 Sep 2017

(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-high-flow-fan-stainless-fan-shroud-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/black-32mm-1-14-id-1-metre-length

https://www.carbuildersolutions.com/uk/black-32mm-1-14-id-45-degree-elbow-with-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!

RE: Hesitation when Aircon on - SpudMurphy - 20 Sep 2017

... 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.

RE: Hesitation when Aircon on - SpudMurphy - 20 Sep 2017

(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_campaign=Brand+-+Auto+Silicone+Hoses&utm_source=google&utm_medium=ppc&utm_term=autosiliconehoses.com&utm_content=1875135x823925430431610616

RE: Hesitation when Aircon on - Rissy - 21 Sep 2017

(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_campaign=Brand+-+Auto+Silicone+Hoses&utm_source=google&utm_medium=ppc&utm_term=autosiliconehoses.com&utm_content=1875135x823925430431610616

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)

RE: Hesitation when Aircon on - SpudMurphy - 22 Sep 2017

yup I'll do that - as long as the engine fires up lol