RE: [DML] Re: Strange acceleration problem ( For Rob Grady)

[<rob@xxxxxxxxxxx>]

Hi Harold,

That’s strange because I've seen very few of these check valve failures but
it is a possibility. A loose vacuum line to the CPR is a much more common
cause and the vacuum hose routing label should definitely be checked.

Rob Grady

-----Original Message-----
From: dmcnews@xxxxxxxxxxxxxxx [mailto:dmcnews@xxxxxxxxxxxxxxx] On Behalf Of
Harold McElraft
Sent: Saturday, October 22, 2005 6:30 PM
To: dmcnews@xxxxxxxxxxxxxxx
Subject: [DML] Re: Strange acceleration problem ( For Rob Grady)

I am really surprised that no one seems focused on the delay valve 
that is THE functioning piece for cold acceleration. If that delay 
valve is out of spec you will have cold engine hesitation. I have 
had three DeLoreans and two failed. I have used a white cap delay 
valve as a replacement - my preference, as it has been closer to 
specs than OEM. Solved my hesitation problems instantly.

Harold McElraft - 3354


 
--- In dmcnews@xxxxxxxxxxxxxxx, "dmc_5180" <dmc_5180@xxxx> wrote:
>
> Rob,
> 
> I too have a very similar experience when I Start my engine cold 
and then immediately try 
> to take off at a quick pace without letting the car warm up for a 
minute.  As I get to a 
> certain rpm under acceleration the engine will suddenly fall off 
and backfire pretty loud.  I 
> let up on the accelerator a bit so it stops and continue at a less 
agressive pace. it usually 
> only happens once when cold. it generally goes away a half mile 
further down the road.
> 
> I replaced my fuel filter 4-5 years ago and even then my fuel 
system was quite clean inside 
> the tank.  I was in their this spring and everything was quite 
good. I could understand  
> changing the filter if you went into the tank found rust and 
disintragated rubber 
> everywhere.  But mine is clean. I won't rule out changing it, but 
I would like to know what 
> the other things are I should look for the other 40% of the time.
> 
> One thing I should also point out is that I have  the Houston 
exhaust which does not have 
> provisions for the heat riser duct . I just have the pipe tucked 
loosely on top of the right 
> header so it can draw in any heat heat generated in the area. 
> 
> Other than this, the car runs perfectly. It always starts 
instantly and idles smooth @ 775 
> unless it is really cold say less than 50 degrees out then it 
might idle hunt a little for 3-4 
> ups and downs before being constant.
> 
> On a diffenet note:
> 
> I have a friend who's car will not hot start, even if he just 
turned it off and goes to restart. 
> Although it will restart if you do the CPR connector swap on the 
cold start valve. I was 
> under the car a month ago and did a test where we ran the car with 
the  small return line 
> running into a jar to see if the accumulator was bad.  After the 
initial start-up 
> pressurization of the system, which of coarse pushed fuel out of 
the spring side of the 
> accumulator, the flow almost stopped but did continue to drip 
albeit very slowly  but was 
> constant. I just can't imagine that this would make the car not 
restart after shutting it off 5 
> seconds earlier. He has replaced the fuel pump and the O-rings in 
the fuel distibutor. The 
> only thing left is the accumulator ,which he has, but hasn't 
gotten around to changing yet. 
> Are their any other possilities? 
> 
>  He also has cold weather hesitation although it is much different 
than my symptoms. His 
> car will stumble slightly when  when accelerating say for the 
first 10 minutes after the car 
> has been started cold. it feels more like a mis in the engine than 
an all out lean situation 
> he's done an ignition tune up with no change. He runs a can of B-
12 thru it every few 
> months, with no change. I even swapped my CPR for his to try see 
if that might be the 
> problem. no change their either accept he thought the car didn't 
accelerate as well with my 
> unit than his. so we switched them back, and his car ran fine 
again. My car runs fine with 
> my CPR so I'm not sure what the deal is their either.Many times he 
has to depress the 
> accelerator half way to the floor and then it will eventually 
start. His car has been that way 
> since he's owned it (5 years) it almost acts like it's flooded. On 
the other hand my car 
> always starts immediatley by just turning the key. We have been 
chasing this mystery quite 
> some time now.
> 
> Rob, any suggestions would grately appreciated. 
> 
>   Dennis 

[very long quote trimmed by moderator]




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