1800: P1800ES fuel injection

[Ron Kwas]

Roy;

I don't have a problem with 142Guy's technique of positively charging the Intake Manifold then using the old soupy water trick for locating points of exit, in-fact I might even like it better than the old carb-cleaner-sprayed-at-junctions-and-note-idle-changes-technique, but positive pressure on the Manifold Pressure Sensor of the D-Jet is a decidedly BAAD thing, so I'd like to reiterate and point out in no uncertain terms, that the MPS should not remain connected during this test!

See also: http://www.sw-em.com/D-Jet_Manifold_...hanical_Checks

Cheers

[VolvoRoyS]

Originally Posted by Ron Kwas

Roy;

Adjusting the Throttle Position Sensor (correctly!, see: https://www.sw-em.com/D-Jet_Idle_Adj..._Stop_and_TPS: ), is not a bad thing, but its setting can and will never cause a raised idle like that...that can only be caused by allowing additional air to enter the Intake Manifold, either by an intended path (like the Aux Air Valve, whether correctly operational or not, and I see you have been working on it...), or by an unintended path (like a loose or cracked hose to the AAV).

With Idle remaining raised after your motorway run, after TPS adjustment, I'd recommend checking for false air (after engine is warmed to operating temp and TStat has opened, AAV should be fully closed and out of the picture, so its tubing can simply be pinched closed to eliminate AAV and its associated plumbing as a cause of the raised Idle), also returning of Throttle Linkage and Ign (Centrifugal Advance) Timing to the Idle positions...

Good Hunting!

I hadn't thought of air leaks. When I tried another test run after the latest tweak on the TPS I noticed an alarming rattle from the back of the car so cut the test run short and made for home. The next day I shuffled my cars around so that I could get it on my lift to see if I could find anything loose. While I was shuffling cars I let the 1800ES idle so by the time I got it on the lift the engine was quite warm. There was no wild fluctuation of revs that has plagued the car before and idle speed was around 1000 rpm. If I revved the engine it would take a few seconds to settle back down to the 1000 rpm but was not racing away at 1800 rpm anymore.

With regard to the rattle I discovered that the bodger had been at work again. The exhaust has had a tendency to bang on the body work and I have tried to move the centre box before without success. This time I noticed that the rear hanger bracket was quite loose with metal-to-metal contact. By consulting the parts diagram I found that an extra L-shaped bracket had been fabricated to locate the rear hanger; no such bracket should be there. So I removed the extra bracket but found I couldn't hook what was the correct bracket over the spigot that projects from the rear bodywork. For those not familiar with this exhaust bracket, it comprises a circular part into which fits a circular rubber with a central hole that can be slipped onto previously mentioned spigot. The exhaust system was sticking too far out of the back of the car - hence the extra bracket. I tried to force the rear silencer box further on without success but found I could get the centre box to move forward far enough to get the rear bracket on. So it looks like someone went to the trouble of fitting the extra bracket instead of installing the exhaust system properly. The exhaust system now feels well located. It's raining today but should be drier later in the week when I can get another test drive in to check both the running of the engine and the fixing of the rattle.

Roy

[VolvoRoyS]

Originally Posted by Ron Kwas

Roy;

See also: http://www.sw-em.com/D-Jet_Manifold_...hanical_Checks

Cheers

Good to know that repair kits are available. I have bought a spare pressure sensor.

Roy

[VolvoRoyS]

Originally Posted by 142 Guy

Ron's comment about false air and high idle speed are correct. The setting procedure in the service manual is based upon an assumption of no manifold air leaks.

The injector holders are a common source of manifold air leaks as are faulty hoses attached to the intake manifold. I chased a high idle problem on my B20E gradually eliminating all the unofficial sources of manifold air. The last source was a leak around the throttle plate shaft (shades of an SU carburettor!) - there is a felt bushing around the shaft which is not shown in parts diagrams. I also had a broken strand inside the throttle cable which was causing it to hang up; but, that is easy to spot if you can manually force the throttle plate to closed and eliminate the high idle.

I found the best way to find manifold leaks was to use a shop vacuum connected in reverse to slightly pressurize the intake manifold and then to do a soap bubble test to find the leak spots. Block off the lines to the MAP sensor and the distributor servo to avoid the risk af damaging the diaphragms.

I've had the injectors out and used new seals when I replaced them. But there could be a leak in the hose from the AAV to the manifold - I haven't checked it. When warm the AAV is closed; I can tell by looking down the inlet hole, so it wouldn't matter if there was a hole in the hose leading to the AAV. On the parts diagram the AAV is shown with the inlet pointing downwards; in the manual it is shown (in isolation) with the inlet upwards. Doubt if it matters which way up it is. Anyway I will check the hose leading from the AAV to the manifold.

Roy

[JP 1800]

Don't apply positive pressure to the MAP as stated above. For pesky leaks I use a cheap fog machine to locate leaks. A mini vacuum pump the type you get with brake bleeding kits are good for checking the integrity of the map. Apply a vacuum and make sure the vacuum does not drop over 30 seconds

[142 Guy]

The seal around the injector pintle is not the only place where there may be a vacuum leak. The O ring at the base of the injector holder can be a leaker, particularly if the engine has been retrofitted with the phenolic washers to address the hot restart problem. With the washers in place there is a small gap between the holder and the head surface and if the large O ring is not perfect that interface will leak.

Having done it, the shop vac in reverse is a pretty simple process. Unplug the hose to the distributor servo and the MAP sensor and plug it with a screw. That eliminates any possible concerns about damage, although that is likely 'over blown' since vacuum cleaners don't do a very good job of generating significant air pressure. They are very good at generating a lot of low pressure air flow and with 5 cents worth of dish soap solution it should take you a maximum of 5 minutes.

Attached a photo of my ultra sophisticated test set up

[VolvoRoyS]

Originally Posted by 142 Guy

The seal around the injector pintle is not the only place where there may be a vacuum leak. The O ring at the base of the injector holder can be a leaker, particularly if the engine has been retrofitted with the phenolic washers to address the hot restart problem. With the washers in place there is a small gap between the holder and the head surface and if the large O ring is not perfect that interface will leak.

Having done it, the shop vac in reverse is a pretty simple process. Unplug the hose to the distributor servo and the MAP sensor and plug it with a screw. That eliminates any possible concerns about damage, although that is likely 'over blown' since vacuum cleaners don't do a very good job of generating significant air pressure. They are very good at generating a lot of low pressure air flow and with 5 cents worth of dish soap solution it should take you a maximum of 5 minutes.

Attached a photo of my ultra sophisticated test set up

I replaced 2 O rings for each injector, one small and one larger and thicker.

Not sure how you are getting a seal with your vac hose at the manifold and my vacuum cleaner sucks only.

Roy

[Ron Kwas]

Roy;

Domestic vacuum cleaners are typically not set up to be able to use the blowing output side, but "shop vacs" often are...

[VolvoRoyS]

Putting leak testing on hold I took the car for a test drive today (it's not raining here). With the exhaust now secured properly there was no rattle so took the car down the motorway one junction and tried engaging the overdrive again. Really pleased that the overdrive works and noticed that the green light on the dash came on - it most likely did before but I didn't notice as it is partly hidden by the steering wheel.

But joining traffic the engine was still idling away at 1800 rpm. Back in my garage I tried adjusting idle screw, screwing it in a little further until I got an idle speed of around 900 rpm. I then took it out for another drive round the block and this time it seemed much better with the idle speed settling between 800 and 900 rpm. I'll take it out again tomorrow and see how it behaves. I did check the AAV again and it is definitely closed when the temperature gauge is beyond the second white mark on the green background. Also noticed I could here the fuel pump running while sat in the car, not loud but a distinct hum when the engine was idling. Is this normal?

Roy

[142 Guy]

Originally Posted by VolvoRoyS

I replaced 2 O rings for each injector, one small and one larger and thicker.

Not sure how you are getting a seal with your vac hose at the manifold and my vacuum cleaner sucks only.

Roy

There are three rubber rings associated with each injector. There is a small thick cross section O ring around the tip of the injector and there is a very large square cross section ring that is really just a cushion to hold the injector tight in the holder. The square ring does no sealing. Those two rings are the ones that typically get replaced when the injectors get serviced.

The third ring is a more conventional O ring that fits between the base of the aluminum injector holder and the surface of the head. You have to pull the injector holder off the head by unscrewing the bolt retaining the injector holder to see this ring. This is the O ring that I was referring to that can develop leaks with age, particularly if the holders have been retrofitted with the phenolic washers. Do not remove the holder to inspect unless you have replacements because once disturbed they are unlikely to reseal. The replacement O ring is different in cross section depending on whether you have the washers retrofitted or not.

A 2.5" -1.25" hose adapter and some duct tape work nicely to seal the hose to the manifold inlet. As Ron notes, I had stated shop vac, also referred to as wet/dry vacs on this side of the big water which almost always have a 1.25" or 2.5" discharge outlet allowing them to be used as a blower. If you don't have a shop vac then refer to one of the other methods for diagnosing manifold leaks.