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-   -   1800: P1800ES fuel injection (https://www.volvoforums.org.uk/showthread.php?t=315949)

VolvoRoyS Apr 10th, 2021 09:24

P1800ES fuel injection
 
Hi everyone,
Just bought a 1973 P1800ES (to accompany my 2001 V70 T5) and trying to sort out the fuel injection. Can anyone tell me where the thermal timer for the cold start valve is situated? A previous owner has seriously messed about with the cold start system. I am having trouble starting the car from cold. So far established that the cold start valve is not working and doesn't seem to be getting any power, but there has been a lot of rewiring which I'm trying to sort out but don't even know where the thermo timer is. Any help much appreciated.

Roy

cassell Apr 10th, 2021 12:14

Hi Roy,

It's to be found screwed into the right hand side of the engine block just below the exhaust manifold close to the bulkhead if that makes sense. It has two wires, one white and one black from memory both held in place with screwed connectors.

They are no longer available new and difficult to source second hand. If yours has failed it is possible to wire a manual switch to activate it when cold and deactivate it when the engine is sufficiently warm to no longer need the cold start injector.

Hope that helps?

Paul

cassell Apr 10th, 2021 12:31

1 Attachment(s)
Here's a PDF picture for you...

VolvoRoyS Apr 10th, 2021 13:06

Thanks for the prompt reply. I spent an hour this morning unravelling lots of taped up wires and eventually concluded that a switch has been installed to do as you suggest. I still can't see the thermal timer but there is a hole where it might go so wonder how it has been blocked off.

VolvoRoyS Apr 11th, 2021 08:37

Found the switch to activate the cold start under the dash and have tidied up the wiring; removed at least 4 feet of wiring and several connectors and an in-line fuse. Unfortunately the previous owner chopped off the connector to the valve and made his own push connectors. I wonder why he didn't just cut the old wires and solder in the new wires to the switch. Anyone know if the male part of the connector is available so that I could make a better connection to the valve?

142 Guy Apr 11th, 2021 17:41

Beck Arnley used to sell the plastic plug body and internal spade connectors (female terminals) at a very nice price. However, that ship appears to have set sail.

These guys offer complete terminal kits for the 1800E with new boots, housings and terminals and the special tool for removal and insertion of the terminal in the plug body.

https://www.djetparts.com/english?lang=en

They also offer the individual boots, plugs and connectors. I believe the Volvo uses the generic D Jetronic spade connector which is about 1/8" wide.

Since you are new to the world of vintage Volvo and D Jetronic ownership, go here

https://volvo1800pictures.com/sweden...in_page_en.php

and download copies of the 1800 ES service manual and the all important Fuel Injection Fault Tracing manual for the D Jet. Knowledge will be your friend because you are going to be largely on your own when it comes to working on the D Jet system.

As a D Jet owner (actually a Megasquirt - D Jet hybrid) my guidance to any new D Jet owner is to carefully check the D Jet wiring were it enters the connectors at all of the engine connected 'bits' (fuel injectors, sensors ......). After 50 years, I expect that you will find that the insulation on the wires has hardened and may have reached the point where it has crumbled and is falling off which can lead to outright shorts or low resistance bridging causing erratic performance. On my car I ended up stripping the harness back about 20 - 30 cm to replace all the wiring at the plug ends of the harness. Replace with high temperature rated wire. TXL cross link is good (125 C rating). PTFE insulated is really good; but, expensive and can be hard to source unless you want 1000' of the stuff. You can replace the stripped harness cover with stretchable silicone rubber jackets or wrap the harness with self amalgamating silicone tape.

https://www.gardnerbender.com/en/p/H...-inch-x10-inch

The self amalgamating tape makes a very nice looking custom harness cover if you are careful with the wrapping and it is extremely chemical and heat resistant. The down side is that once wrapped you cannot unwrap it so if you goof you need to cut it off and start over. Do not use heat shrink tubing for replacement harness covers.

c1800 Apr 11th, 2021 17:59

Also parts available here.

https://www.finjector.com/eng/search?s=Djet&t=all

VolvoRoyS Apr 11th, 2021 22:17

Thanks for those links. I've had the car only two weeks and am working my way through a service. The car had no hose linking the vacuum retard to the inlet manifold (it was blanked off at the manifold), the inlet air hose was ripped apart and the air filter very dirty. So far I have fitted a new air filter, inlet air hose but when I fitted the vacuum advance hose there was a very noticeable drop in engine revs so don't why that would be. I have also had the distributor off to check the trigger contacts (completely new concept to me), set the point to 18 thou (they were 12 thou) and checked the ignition timing (set to 10 deg BTDC). Also set valve clearances to 16 thou (some were OK some were tight and others loose) but find the valve gear quite noisy and wonder if I should set them to perhaps 12 thou. I then found it wouldn't start when cold (and it has been cold here the last week) but then discovered the hidden switch for the cold start valve. However, idling is quite rough so now plan to focus on the fuel injection starting with the throttle valve, throttle valve switch and idle adjustment. Any suggestions as to why the idle would be rough especially when cold would be welcome.

Laird Scooby Apr 11th, 2021 22:38

Quote:

Originally Posted by VolvoRoyS (Post 2727936)
Thanks for those links. I've had the car only two weeks and am working my way through a service. The car had no hose linking the vacuum retard to the inlet manifold (it was blanked off at the manifold), the inlet air hose was ripped apart and the air filter very dirty. So far I have fitted a new air filter, inlet air hose but when I fitted the vacuum advance hose there was a very noticeable drop in engine revs so don't why that would be. I have also had the distributor off to check the trigger contacts (completely new concept to me), set the point to 18 thou (they were 12 thou) and checked the ignition timing (set to 10 deg BTDC). Also set valve clearances to 16 thou (some were OK some were tight and others loose) but find the valve gear quite noisy and wonder if I should set them to perhaps 12 thou. I then found it wouldn't start when cold (and it has been cold here the last week) but then discovered the hidden switch for the cold start valve. However, idling is quite rough so now plan to focus on the fuel injection starting with the throttle valve, throttle valve switch and idle adjustment. Any suggestions as to why the idle would be rough especially when cold would be welcome.

If memory serves you should have an AAV - Auxiliary Air Valve - for cold start idle speed increase. Going by what else you've said, chances are this is filthy inside and so gummed up it's not opening. Usually they are a bimetallic strip that opens the valve when cold and when heated with an ignition switched supply, the bimetallic strip bends (or straightens, depending how you view it) closing the valve. With the valve open, it admits extra air past the throttle body to increase the idle speed.

As a temporary measure, try just touching the accelerator enough to just take up the slack in the cable and a little more to bring the cold revs up slightly - should start easier if my guess about the AAV is correct and idle nicer. Cols start idle speed is generally about 1000-1200rpm depending on make/model etc but will be around that for your P1800. Others will likely confirm the correct figures but if it's idling slowly when cold (6-700rpm) that would be my first port of call.

c1800 Apr 12th, 2021 04:31

A few comments.

The AAV is not electrically powered, it gets heat from the block/coolant that is designed to close the valve as it warms up. You can block off the air connections, the only thing you’ll need to do is feather the gas for a minute or two when you start it cold. That’ll take the AAV out of your troubleshooting, if it is stuck open, you’ll have too much air and difficulty getting the idle down to where it should be.

The vacuum retard, apparently an attempt to improve emission performance. Most leave it disconnected and the port in the intake manifold plugged. Purportedly runs better without it.

The thermo time sensor in the block adjacent to the oil filter is what triggers the cold start injector. You appear to have that missing, hence the switch under the dash. It can suffice but don’t leave it “on” too long, I recall the time is something only about 10-15 secs. The hole in the block where the thermo time sensor resides is a blind hole, no need to seal or block that.

I trust your setting on the trigger points is as per published spec. They don’t require any filing like ignition points, in fact that may damage them. A simple swipe through with some clean brown paper or thin cardboard is all that is needed. A little distributor grease on the rubbing block is helpful.

In terms of setting the valve clearances, stick with the specs, these engines are noisy and that’s just the way it is, and part of the charm.

In terms of your rough idle, go through the fuel injection fault tracing manual step by step to iron out problems.

To set your TPS I found this link most helpful.

https://vcoa.org/forum/9-P1800-1800S...onic-FI-system

Also check and clean the ground wires that attach to the rear of the intake manifold

Good luck and do report back your progress.


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