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Update + EGR question-Peugeot 1986 505 2.5 lt TD sedan-cold start smoke v`s EGR


jerro

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Hi again, This is a follow on from my original post,`Peugeot 1986 505- XD3T engine 2.5 lt TD sedan--injector leak and cold start smoke` Well i`ve put the new nozzles and injector bodies back on, no leaks at all this time! I took off the `stupid` metal shield that completely surrounds the Purflux filter unit and pretty much stops you from doing a fuel filter change! I put in a new filter while i was doing that. New air filter also put in. I cannot get to the mounting bolts on the fuel pump housing to try and advance the timing a little. Put on a new v belt on the vacuum pump pulley.---Ok, so my original mission was to stop the smoke that happens on the 1st start of the day.She still smokes a lot on start up but runs much better after 5 minutes of warm up so i`m pretty happy about that! The one last thing i want to do before she goes up for sale is to clean/check the EGR system as i don`t think i can live with the smoke on start up!. I did suck on the pipe that runs to the EGR diaphram and the diaphram moves but maybe not enough (i`m guessing) I wanted to ask if it is possible to check the EGR layout and `carbon` build up when the unit is still in place without taking out the whole manifold and the other items? If i have the correct unit the EGR is the vacuum operating diaphram unit with a long rod running away from the front of the engine and vanishing into the manifold area.

Any ideas on looking and cleaning the EGR set up please or a posting that deals with it?--Thanks --See picture of what i hope is the EGR and rod running to manifold

post-1154-0-54608900-1331757546_thumb.jp

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EGR (Exhaust Gas Recirculation)isn't going to fix your smoke on start up issue. It's been said here and on Peugeot-L that it's either pump timing, or you have low compression.

If you don't have the tools needed to adjust the pump - take it to a diesel shop and ask to have it timed "by ear" - a good diesel mechanic should be able to do that. You should also make sure your valves are adjusted properly as well.

Rabin

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EGR (Exhaust Gas Recirculation)isn't going to fix your smoke on start up issue. It's been said here and on Peugeot-L that it's either pump timing, or you have low compression.

If you don't have the tools needed to adjust the pump - take it to a diesel shop and ask to have it timed "by ear" - a good diesel mechanic should be able to do that. You should also make sure your valves are adjusted properly as well.

Rabin

Thanks Rabin--appreciate that

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I've never seen a Peugeot diesel with significant carbon buildup or clogging in the EGR valve area, so chances are you're probably alright.

The electronic EGR system that was fitted to all 1984 California diesels (XD2S) and 1985 Federal diesels (XD2S-XD3T) uses a variety of sensors connected to an ECU which in turn operate the EGR valve and throttle valve.

- Air flow sensor (attached to air filter box)

- Altitude sensor (attached to tab on RH strut tower beside air filter box)

- Engine RPM sensor (bellhousing above starter)

- Engine coolant temperature thermocontact (back of cylinder head)

- Injection duration sensor (special injector body on injector #2)

The system uses these inputs to meter the precise amount of exhaust gas the engine needs "re-burn" in order to reduce combustion temperature and excessive NOx emissions while at light and partial load. The system is of course completely inactive when you're at heavy or full load or when the ECU determines that the engine needs all of the oxygen that it's trying to consume.

You mention new injectors so I figured I'd ask this--Does your injector #2 have a pair of wires coming out of it? If not, then you have no Injection duration sensor. Without that sensor (or indeed without any of the inputs listed above), the EGR system never operates. This isn't necessarily a problem unless of course you're subject to an emissions inspection and fail a test.

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You mention new injectors so I figured I'd ask this--Does your injector #2 have a pair of wires coming out of it? If not, then you have no Injection duration sensor. Without that sensor (or indeed without any of the inputs listed above), the EGR system never operates. This isn't necessarily a problem unless of course you're subject to an emissions inspection and fail a test.

Not to hijack the thread but that raises a question I've had. I have the injector pulse sensor on my #2 injector and it is leaking fuel. I understand that is a common fault and most of them have been replaced with the regular injectors without the sensor. I have an injector without the wires to replace it with. Do I need to do anything with those wires and is there any performance advantage/disadvantage one way or the other. NJ does not do an emissions test on diesel cars older than 1996, so I don't need to worry about inspection, but I would like to not pollute any more than necessary. Can the injector pulse sensor injectors be repaired? Is there a replaceable seal or washer that would stop the leak?

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I've never seen a Peugeot diesel with significant carbon buildup or clogging in the EGR valve area, so chances are you're probably alright.

The electronic EGR system that was fitted to all 1984 California diesels (XD2S) and 1985 Federal diesels (XD2S-XD3T) uses a variety of sensors connected to an ECU which in turn operate the EGR valve and throttle valve.

- Air flow sensor (attached to air filter box)

- Altitude sensor (attached to tab on RH strut tower beside air filter box)

- Engine RPM sensor (bellhousing above starter)

- Engine coolant temperature thermocontact (back of cylinder head)

- Injection duration sensor (special injector body on injector #2)

The system uses these inputs to meter the precise amount of exhaust gas the engine needs "re-burn" in order to reduce combustion temperature and excessive NOx emissions while at light and partial load. The system is of course completely inactive when you're at heavy or full load or when the ECU determines that the engine needs all of the oxygen that it's trying to consume.

You mention new injectors so I figured I'd ask this--Does your injector #2 have a pair of wires coming out of it? If not, then you have no Injection duration sensor. Without that sensor (or indeed without any of the inputs listed above), the EGR system never operates. This isn't necessarily a problem unless of course you're subject to an emissions inspection and fail a test.

Well my thanks as always, no i don`t have any wires on number 2 injector and that clears my mind a little so i`m not going to concern myself with the EGR stuff. I will get the injector pump timing set at the shop ($175) and be a happy man and Peugeot driver.

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Not to hijack the thread but that raises a question I've had. I have the injector pulse sensor on my #2 injector and it is leaking fuel. I understand that is a common fault and most of them have been replaced with the regular injectors without the sensor. I have an injector without the wires to replace it with. Do I need to do anything with those wires and is there any performance advantage/disadvantage one way or the other. NJ does not do an emissions test on diesel cars older than 1996, so I don't need to worry about inspection, but I would like to not pollute any more than necessary. Can the injector pulse sensor injectors be repaired? Is there a replaceable seal or washer that would stop the leak?

As far as I know there is no way to repair the leaky injector, at least not permanently or without causing damage to the sensor. In theory I'm sure there has got to be way to do it properly, but most any diesel shop I've spoken to looks at me as though I have three heads when I ask about it, so I gave up.

I've seen where you can still buy the injector holder with the same sensor for an old BMW 524td, but I don't know if the injector threads are the same. At any rate they are over $200 each.

There is no performance advantage/disadvantage one way or another, and a normal injector will bolt right in without any ill-effects. Since the diesel engine runs with a massive amount of excess air at light/partial load, the EGR system simply dilutes that with otherwise inert exhaust gas. Without the extra oxygen and nitrogen molecules flying around during combustion, far fewer Nitrous Oxide compounds are formed. At heavy loads, the engine needs all of that extra air and so the EGR system doesn't have to do anything. Therefore, the operation of the EGR system on a diesel is supposed to be completely seamless--you have no idea it's working except that the measured NOx concentrations in your exhaust is reduced :)

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Thanks! That's good information. Would it be prudent to plug the vacuum lines and take out the valves. If they aren't doing anything, it would be that much less places to leak, not to mention less clutter.

In North Carolina diesel cars aren't subject to an emissions inspection like a gasoline car, only a "safety" inspection. However this includes tampering inspections; Technically they are supposed to visually check to see that everything is hooked up. One loose electrical connector is easily dismissed but a disconnected or plugged EGR valve is easier to pick out. How much is this enforced? Probably not much, but it's something to keep in mind. Your state might be similar.

If you wanted, you could slip a BB or some other bit of material inside the vacuum line going to the first vacuum solenoid. The would prevent any vacuum leaks if something were to go wrong, and would also completely inhibit the EGR valve or throttle valve from operating, not that they would in the first place.

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Hi again, This is a follow on from my original post,`Peugeot 1986 505- XD3T engine 2.5 lt TD sedan--injector leak and cold start smoke` Well i`ve put the new nozzles and injector bodies back on, no leaks at all this time! I took off the `stupid` metal shield that completely surrounds the Purflux filter unit and pretty much stops you from doing a fuel filter change! I put in a new filter while i was doing that. New air filter also put in. I cannot get to the mounting bolts on the fuel pump housing to try and advance the timing a little. Put on a new v belt on the vacuum pump pulley.---Ok, so my original mission was to stop the smoke that happens on the 1st start of the day.She still smokes a lot on start up but runs much better after 5 minutes of warm up so i`m pretty happy about that! The one last thing i want to do before she goes up for sale is to clean/check the EGR system as i don`t think i can live with the smoke on start up!. I did suck on the pipe that runs to the EGR diaphram and the diaphram moves but maybe not enough (i`m guessing) I wanted to ask if it is possible to check the EGR layout and `carbon` build up when the unit is still in place without taking out the whole manifold and the other items? If i have the correct unit the EGR is the vacuum operating diaphram unit with a long rod running away from the front of the engine and vanishing into the manifold area.

Any ideas on looking and cleaning the EGR set up please or a posting that deals with it?--Thanks --See picture of what i hope is the EGR and rod running to manifold

You have loose valve guides or bad valve guide seals . All old diesels smoke cold its normal. put seals on first and try that, might work for a few weeks. Frank

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Oil smokes blue - diesel smokes white... If it's blue then Frank's suggestion is worth a try for sure. If it's white - I'd still say low compression or pump timing.

VERY curious to here what the result is once you get the pump timed.

Rabin

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  • 2 weeks later...

Oil smokes blue - diesel smokes white... If it's blue then Frank's suggestion is worth a try for sure. If it's white - I'd still say low compression or pump timing.

VERY curious to here what the result is once you get the pump timed.

Rabin

----######## Got the injector pump advanced a little (the simple method of doing it by ear not the `techno` method) NO MORE SMOKE ON 1st START OF THE DAY!!!!!!!!!!!###########################-- Thanks to all the folk on here with great suggestions and a sympathetic ear for an amateur mechanic and diesel lover

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