P1800e: Source for replacement coolant temp sender 028013001

[142 Guy]

I was just looking at your other post. What vintage is your 1800E? If it pre 1972 you do not have a thermal timer for the cold start injector. The cold start injector time is controlled by the D jet controller (and indirectly the coolant sensor). However, the cold start injector is still only energized when the starter motor is engaged so a problem with the 'electrics' will not cause a continuously rich fuel condition.

[ChasesDragons]

your study towards your Megasquirt conversion, clearly shows in the depth of knowledge!

You are also right regarding signs of rich running - the yard stinks of raw fuel on trying to run it, the Stainless steel exhaust tips are coated in black soot from any start I have managed. I dread to imagine the condition of the second set of new plugs installed over winter.

Today - the vehicle did not start once, after I

1. cleaned and tightened earths x2
2. Installed a responsive Coolant Sensor
3. cleaned all connectors for Coolant sensor
4. Installed new battery earth to cleaned earth
5. Refitted a loose 19mm hose running from near the distributor to the throttle body
6. Cleaned and refitted Cold Start Valve connection

I will attempt this tomorrow:

Check air filter or take off the air filter inlet completely from the throttle body (?) to bypass any air filter issue - TRY START.

Unplug the Cold Start Valve power supplyor block the CSV fuel supply off - TRY START

Point of concern: FUEL PRESSURE
When I turn the ignition on to start the PUMP, NOT the engine (position 1?), the fuel pressure rises to about 20psi, not 30. When I turn the engine over, it shoots up to about 40psi and then quickly drops back to 20psi when I stop cranking. I am not sure this is normal. I think that I read somewhere that a fast drop in fuel Pressure could be due dysfunctional non-return valves......that shouldnt be an issue in rich running.

Any bids on this?

I have a Land Rover......I have options, I keep telling this Volvo to tread softly or there would be tears.........

[142 Guy]

Pressure loss when the pump is not running may be normal for an older D jet system. Shooting up to 40 psi during cranking not so normal.

As the fuel pressure regulators get older, the valve seat in the regulator does not seal as well as it should so in the condition where the pump is not running it is not unacceptable to have some pressure loss. The fuel pump also has a check valve on its discharge which is designed to keep the system pressurized when the pump shuts down; but, on older pumps debris and wear usually conspire to result in some leak back past the valve into the pump with a loss in pressure.

It is important to measure the fuel pressure on a running engine. With the engine running at idle the fuel pressure should steady be at 28 - 30 psi. Open and close the throttle with the engine running and you should see very little movement in the pressure. That would indicate that your pump and fuel pressure regulator or working correctly (at least at lower engine loads). The fact that you are seeing a pressure spike to 40 psi during cranking makes me think that your pressure regulator is malfunctioning or is not set correctly. High operating fuel pressure will definitely cause over fueling over the complete range of engine operation.

I would be inclined to confirm your running fuel pressure before doing anything else. Fuel pressure was in my list of more complicated things; but, your observation of 40 psi suggest that you should probably fast track to confirm what the actual running pressure is.

[Ron Kwas]

CD;

I agree with 142g...the FPReg is a dumb device...it has but one job, and it does this irrespective of all else: to hold the set pressure, and direct everything beyond what is demanded back to the tank...but it can only do that if the connection to tank is not impeded or overwhelmed during low demand...that sounds like maybe the return line is partially blocked...

Good Hunting!

[ChasesDragons]

142,Ron,
Thank you again. I will have a look at altering the FPR today. I have heard 40 psi, although higher than recommended, can help P1800e. Kurt Incledon mentioned running his system @ 40psi although I bet his car is not a pile of neurotic poop like mine.

Ron - good point, I had to take the car in to have the tank flushed out due to excess debris stalling it. This was about 4 years ago. Must have only done about 500 miles since.

142 - yes my P1800E comes in as 1971. I am not sure what month, though.

Coolant sensor - I used PTFE tape on the thread as a habit. I might remove this, in case it confuses electrical Ground.

Regards
U

[142 Guy]

I have read of people who modify their engines occasionally attempting to 'tune' the D jet by increasing the base fuel pressure. Bumping the base fuel pressure from 28 psi to 40 psi would result in an approximately 19 % increase in fuel delivery. The problem is that it does it over the complete operating range, so its not targeted to where you need it. Savvy people who are handy with a soldering iron can modify the filter circuits in the D jet controller to provide some targeted tuning; but, it is a rather excruciating process. I would advise against trying to tune the D jet by adjusting fuel pressure. It is too ham fisted.

There is perhaps one exception to this. In 1972 when Volvo released the B20F as a replacement for the B20E in North America, they bumped the base operating fuel pressure from 28 psi to 30 psi (actually 29.8 psi if you want to quote the Volvo spec). I don't know whether this was to accommodate the lower compression ratio and K cam in the B20F or whether it was also applied to the 1972 B20E models that were still available outside of North America. Since lower compression and lower cam overlap rarely require more fuel I am a little suspicious that the change in fuel pressure was to fix another problem. By late 1971 or 1972 Volvo was probably aware that they had a hot restart problem with the B20E. When the B20E is shut down with a hot engine the injectors heat soak. On restart, a hot injector flows less fuel which cause a lean condition which can make the engine hard to restart and if it does restart the engine will run like merde for a couple of minutes. The problem goes away after a couple of minutes once enough fuel has passed through the injector body to cool it off and allow the correct flow. Volvo never really eliminated the problem; but they did reduce the heat soak effect by installing phenolic insulating washers below the injector holders where they mount to the head. It is not apparent that Volvo did this as a recall because my 1971 142E never had these insulating washers installed when I acquired it. I suspect that you had to complain to get the washers and probably had to pay if the car was out of warranty. I am a little suspicious that the slight bump in fuel pressure from 28 psi to 30 psi was part of the strategy to try and fix the problem by increasing fuel flow under starting conditions.

If your 1971 B20E is like my 1971 B20E the factory recommended setting for the fuel pressure regulator would originally have been 28 psi. However, if you look at that Fuel Injection Fault Tracing Manual I linked you will see that the base pressure recommendation is 29.8 psi for all 4 cylinder D jet installations. No mention of the 28 psi spec that was in the 1970 and 1971 service manuals. So, I think Volvo did a little 'fuel pressure tuning' to help with the hot restart problem on the B20E and F.

My experience with the hot restart problem is that it only becomes a significant problem when the ambient temperature is above 30C. Under those conditions if I drove the car someplace, parked it out in the sun for 5 or more minutes and then tried to restart the car it would be a problem. If you leave it for an hour things will generally cool down enough that the restart problem will not be noticeable. So, where I live (and probably you) the hot restart problem is less significant. It would have been a really big problem for Volvo in places like California, Nevada and Florida.

So, if you have incurred the hot restart problem it is probably 'fair game' to raise the base fuel pressure from 28 to 30 psi on your B20E. If the hot restart problem is not noticeable then I would leave it at 28 psi because higher fuel pressure will likely increase your fuel consumption. The bump in fuel pressure can also contribute to flooding and hard starting on cold starts. If the hot restart problem is apparent I would make sure that your car has been retrofitted with the brown phenolic insulating washers on the injector holders before increasing the base fuel pressure to 30 psi.

A couple of related observations.

1) If you have only driven about 500 miles in 4 years I suspect that the fuel in the system is falling into the skanky category. Your injectors may be gummed up contributing to operating problems. Even when stabilizers are added, gasoline has a recommended shelf life of less than 1 year in a sealed container. Less than 1 year in a 1971 Volvo with its non airtight evap system. Because of its high compression ratio the B20E doubly suffers from skanky gasoline. My 142 E is a low use car; but, I still manage to drive about 1000 - 1500 km per year. When it is parked for extended periods in the winter I top off the gas tank to the max with fuel that has had stabilizer added to it and I crimp off the evap line to try and prevent breathing air into the system during temperature changes.

2) Wrapping the coolant sensor threads in PTFE tape will not be a problem. Unlike the gauge sensor at the back of the head the D jet coolant sensor is a 2 wire device and runs isolated from ground when operating correctly.

[ChasesDragons]

OK,
Took air inlet off throttle body to eliminate any air filter issues - doesn't start

Cold start valve unplugged - doesn't start

Cold start valve itself checked - doesn't seem to be leaking

I have cleaned all the ignition leads with brake cleaner so they are clear of dirt. Same with the coil. All ignition leads removed, sprayed with electrical cleaner, brightened if necessary and replaced.

Interesting point about fuel levels - mine has only got about 1 gallon on week old fuel in it....I might add a few more to balance for the fossil of a fuel pump and it is now carrying the metal fuel filter between the tank and the pump. This shouldn't be a problem as the pressures are reaching 40psi, I think...

I am going to get an ignition coil, as mine looks ancient. I have no other way of verification for spark quality.....I am beginning to have murderous feelings towards this car.....

[Ron Kwas]

CD;

Replacement of components should not be based on what they look i.e. "ignition leads ... clear of dirt" or "ancient looking ignition coil", but their function!

I suggest you drain and replace old fuel, which at this point likely has less octane than Italian dressing, verify Cold Start Injector and Cylinder Injectors are dispensing fuel. Check and set Timing, and retry.

Good Hunting

[142 Guy]

Don't rush out and purchase a new ignition coil just yet.

Since you can't get the engine to run, you can't do an accurate measurement of the base fuel pressure. However, you can do an approximate measurement.

Set up you fuel pressure gauge to do the test. Turn the ignition key to the run position and you should hear the pump go through its prime cycle and you should see the fuel pressure rise and then fall if your check valve or regulator are allowing a little leakage. Connect a jumper wire from terminal 85 of the fuel pump relay to bare metal on the chassis (the mounting screw for the relay should do the trick). This jumper should force the pump to run continuously and generate enough fuel flow that you can measure the operating point of the fuel pressure regulator. If the operating point is not 28-30 psi, then adjust the setting point using the screw on the top of the regulator to get it to 28-30 psi. Once that is done remove the jumper.

If the operating pressure was not 28-30 psi and you have corrected it to 28-30 psi, you could try a start. However, I would not. If the pressure was really high before you corrected it, I would remove the spark plugs to see what they look like. If they are wet fouled or if they are really sooty I would dispatch them to the waste bin, purchase a new set, gap them correctly and install them. At that point I would then try a start. If you have the correct fuel pressure when attempting to start the motor; but, the engine shows no signs of firing then I would turn my attention to the ignition system.

[Laird Scooby]

Originally Posted by ChasesDragons

Coolant sensor - I used PTFE tape on the thread as a habit. I might remove this, in case it confuses electrical Ground.

Regards
U

If it is a single terminal sensor, the PTFE tape could be your problem. It will effectively isolate the metal body of the sensor from the earth of the head (ground for our stateside cousins) but also (certainly on later LH-Jetronic) on later models, even with 2-pin CTS sensors, using PTFE is a big no-no as both thermistors are commoned on one end to earth via the sensor body. It won't leak as long as it's tight, they're designed to be self sealing so no need for PTFE or any other kind of thread sealing.

Originally Posted by ChasesDragons

.

I am going to get an ignition coil, as mine looks ancient. I have no other way of verification for spark quality.....I am beginning to have murderous feelings towards this car.....

I'd hold on with that new coil for now as well, have you checked the contact breaker points are opening and closing and also the static ignition timing?

First thing to do is remove the dizzy cap and rotor arm (ignition off!) and turn the engine by hand until the points heel is on one corner of the 4-lobed cam in the dizzy then measure the gap between them. If memory serves it should be 0.45-0.5mm (0.018-0.020"), adjust if not correct. Those Bosch dizzies have a habit of closing the points gap. A light smear of HMP grease on the dizzy cam will also reduce wear on the heel of the points.

Also observe the rotation direction of the dizzy shaft when the engine is turned in the normal direction, think it's clockwise as viewd from above from memory but it's 30 ish years since i was on an OHV red block.

Turn the engine to the static timing point (think it's 5 deg BTDC) with the rotor arm pointing to #1 plug lead. Get a 12V test lamp and clip one end to the -ve terminal of the coil, the other to a good earth. Switch the ignition on, slacken the dizzy clamp and rotate the body of the dizzy in the direction the rotor arm goes until the light goes out then turn it back slowly until the lamp lights again then tighten the clamp bolts.

Refit the rotor and cap.

If the light doesn't light at any point it should during this, check you actually have a supply to the +ve on the coil with the ignition on by temporarily moving the clip from the test lamp on the -ve coil terminal to the +ve terminal. It should light, albeit dimly. If you leave it connected to the +ve terminal during cranking it should become brighter, not full brightness but brighter.

While cranking, hold the dizzy end of the king lead about 1/2" from a convenient clean earth point, nut, bolt or similar nearby but use insulated pliers so you don't get a jolt. Should see a steady stream of blue/white sparks if all is well. If you can only get orange sparks at about 1/4" or less, something is wrong. Assuming it's all good, refit the king lead back in the dizzy cap.

Remove a spark plug and reconnect its HT lead and place it so the metal body of it has a good earth so you can crank the engine and observe the spark - again should be bright blue/white.

If that's ok, check the plug is clean and dry and refit. If it wasn't clean and dry, either remove and clean all the plugs or proceed as for a flooded engine. Clutch down, accelerator pedal down (as in bury it in the carpet), crank the engine for 8-10 seconds unless it fires before that. If it doesn't fire, switch the ignition off and wait 10 seconds then repeat - keep your feet where they are, don't move them until it fires.

Sorry if any of this is "teaching you to suck eggs" but sometimes the old methods get forgotten.