Smog pump bypass?

[Ton van der Sluijs]

goodmorning Fellro
I do only know the air system I.ve had on my truck. At first to Mr Blackcat I have to admit that I've made a mistake in my opinion; Indeed, the air, which was blown straight above the exhaust valves can NEVER reach the valves; the air pressure is to low... the fact here in the Netherlands is, when we have to go for the mandatory checkup every year, an air pump gives false readings when gauging the CO2. I've had a discussion with one of the guys who is allowed to give a letter of approval,(is that the same as your title?) That extra air makes a better CO2 , but he measures there's more oxygen as well what tells the computer that there's a leak!.... and that's not allowed. when I came for my first check up, they removed the hoses from the pump and blinded them off... They told me as well that the airpump is a useless thing here and that the air only dilutes what comes out the tailpipe (again, Mr Blackhat, you're right, with such high temperature just after the cat, oxygen and unburned parts will burn again!). when I dismantled the airpump, I saw, I was just on time... the bearings were heavy worn out, so I did thrown away the pump.

running on LPG.
Mr blackhat , when using LPG, the engine uses 10% more (not 30, sorry) fuel, that's a figure which all the LPGsystemsuppliers can tell... LPG is less bad for the environment (for example all the citybusses and municipal trucks and cars do run on natural gas). My truck does 1gallon to 11miles, what is a nice figure for a 5,8liter engine.
I would say Mr Blackhat, let's shake hands, and let us do where a forum is made for.... having the pleasure of learning from each other....

Best regards Ton van der Sluijs

 

[Beach66Bum]

Wow, completely missed this thread, was a lot to read but I'm glad I did. Information was an eye opener, since my truck is smog exempt from the factory('83F250) I wondered how all the pollution devices worked in the effectiveness of the engine and the relation to exhaust pollution.

 

[greystreak92]

Apologies for the length of this post...

EEC-IV: Some folks like to call it OBD-I but it was actually the fourth generation engine/emissions control system Ford engineered. Ford employed it in light trucks (1985 EFI-1995). The Thermactor system pushed fresh air into the heads just DOWNstream of the exhaust valves AND/OR into the exhaust pipe just UPstream of the catalytic converter. BOTH ports have a specific function and BOTH are indeed necessary because the EEC-IV computer USES them to control the engine's operational parameters and in so doing, reduce emissions output insofar as the system is capable.

Upstream of the catalytic converter: This port serves to introduce more oxygen into the exhaust stream to enable the OEM catalytic converter to achieve the necessary temperatures to burn-off the crud its supposed to burn off. (Adding fresh air/oxygen to hot exhaust gasses... its like opening a window in a house that was burning. The fire was out... but you just gave it a big deep breath of air). So, unless you have swapped a newer (more efficient) cat into the vehicle, the OEM cat will NOT function without the fresh air from the pump.

Downstream of the exhaust valves: This port serves to keep the HEGO (Heated Exhaust Gas Oxygen) sensor (O2 sensor) from getting a false "rich" reading before the engine fully warms up. The EGR is also closed at this point so ALL of the exhaust is headed down the pipe. This is the ONLY point in time that the Thermactor air is EVER used to "dilute" exhaust gasses. A cold engine needs more fuel and less air however, under normal operating temperatures, the fuel level is greatly reduced and the air level increased. So, until things warm up, the O2 sensor is going to get readings that are way over on the "rich" side of the ratio. Once warmed up, the EEC-IV computer shuts this air injection down so as to get accurate readings during normal operation.

TAB & TAD solenoids: The EEC-IV computer changes the flow of vacuum through the TAB (Thermactor Air Bypass) and TAD (Thermactor Air Diverter) solenoids (most frequently mounted near the ignition coil). These two electronic solenoids are nothing more than vacuum switches. They control the flow of vacuum to the Diverter Valve.

Diverter Valve: (behind the passenger cylinder head on the V8's) Redirects fresh air from the Thermactor Air Injection Pump (smog pump) between the ports in the cylinder heads and the port in the exhaust pipe. The EEC-IV computer controls this flow of air from the smog pump DURING engine operation based on temperature and throttle position.

This system is completely integrated and removing just one or two parts adversely affects engine operation. Even if the EEC-IV computer can compensate for the missing information, the LACK of this information causes the computer to alter the operational parameters of the engine... there is no way around this without rewriting the software in the EEC-IV computer. (And no, performance chips don't do this).

EGR: Exhaust Gas Recirculation is a system that is actually much older than any electronic control system. Early EGR was employed by some auto makers as far back as the late 1960's. This system uses a valve to allow a controlled amount of exhaust back through the intake in an effort to run unburned crud back through the combustion cycle to "try again" so to speak.

So, why does it matter if it isn't there? In older carburated systems, if the EGR was removed, you could simply retune the carburetor to adjust for the missing partial air/partial combustibles coming in through the intake. Simple enough. However, with a system like EEC-IV and other electronic engine control systems, if you just remove that flow of air & combustibles all together, you are taking away something that the computer was programmed to control and calculate. So imagine for a minute, that you suddenly removed a predetermined amount of air and fuel from your engine but you could make no adjustment to compensate for the loss. Well, Ford couldn't have that happen so they programmed the computer with options so it could still keep the engine running... not nearly as well as with the system functioning properly but the vehicle would run well enough to get you home. Since EGR is controlled by vacuum AND electronics the EEC-IV computer can "know" how much exhaust gas is recirculating and make fuel/air mixture adjustments accordingly. However, if the EGR is removed all together, the computer must "guess" and since it cannot control the EGR valve anymore, it spends a LOT of time trying to adjust spark timing and fuel/air mixture to compensate for the loss of exhaust gasses back through the engine. Remember the O2 sensor "knows" when the exhaust gasses are "rich" or "lean" and it snitches about 8 times per second. What you end up with, particularly in a gasoline engine, is a lot of erratic idle issues... is it any wonder?

The problem that we are dealing with here in this thread is that Ford engineered these systems in such a way that IF some part DOES fail, the computer will keep the engine running "well enough" to still drive the vehicle but it will trigger the "Check Engine" light to warn the driver that even though the vehicle still APPEARS to be running properly, there is something amiss. Running this way for extended periods of time WILL eventually cause bigger problems unless its fixed. What folks who arbitrarily remove parts of the system FAIL to accept is the FACT that just because you remove or ignore the Check Engine light (or put tape over it...which is my personal favorite uneducated maneuver) does NOT mean the engine is "running fine" and further it means that whatever the EEC-IV computer is doing to compensate WILL cause other problems that WILL be worse in the long run. Remember the EEC-IV computer controls fuel-air ratio and spark timing along with shift points (E4OD only). Anyone who knows anything about internal combustion engines knows that these settings/adjustments are critical and failure to maintain them results in terrible problems if not immediately, then definitely over extended periods of time. When you are dealing with a vehicle where the ONLY way to be certain that these adjustments are correct is to make certain the on-board computer has ALL of the information it needs, maintaining ALL of the sources of that information becomes as critical as spark timing and fuel/air mixture. These are the FACTS. Argue if you feel you must but they will not change no matter how much you want them to or how much you talk about it.

 

[Ton van der Sluijs]

EGR: Exhaust Gas Recirculation is a system that is actually much older than any electronic control system. Early EGR was employed by some auto makers as far back as the late 1960's. This system uses a valve to allow a controlled amount of exhaust back through the intake in an effort to run unburned crud back through the combustion cycle to "try again" so to speak.

So, why does it matter if it isn't there? In older carburated systems, if the EGR was removed, you could simply retune the carburetor to adjust for the missing partial air/partial combustibles coming in through the intake. Simple enough. However, with a system like EEC-IV and other electronic engine control systems, if you just remove that flow of air & combustibles all together, you are taking away something that the computer was programmed to control and calculate. So imagine for a minute, that you suddenly removed a predetermined amount of air and fuel from your engine but you could make no adjustment to compensate for the loss. Well, Ford couldn't have that happen so they programmed the computer with options so it could still keep the engine running... not nearly as well as with the system functioning properly but the vehicle would run well enough to get you home. Since EGR is controlled by vacuum AND electronics the EEC-IV computer can "know" how much exhaust gas is recirculating and make fuel/air mixture adjustments accordingly. However, if the EGR is removed all together, the computer must "guess" and since it cannot control the EGR valve anymore, it spends a LOT of time trying to adjust spark timing and fuel/air mixture to compensate for the loss of exhaust gasses back through the engine. Remember the O2 sensor "knows" when the exhaust gasses are "rich" or "lean" and it snitches about 8 times per second. What you end up with, particularly in a gasoline engine, is a lot of erratic idle issues... is it any wonder?



This is the first time , I do read something that make sense about the EGR...
My question is, If the EGR is closed at idle, how come that I do have a rough idle? When I removed the inletmanifold, thick layers of burned oil were on the valves and in the manifold... What can one do about it?
I've blinded the EGR; I consider as an experiment to open that port , to see what difference it makes..... It makes sense, what you write, that one and other has it's influence on the system...
What is your opinion about it GReystreak?

best regards Ton

 

[greystreak92]

Its most likely a case of the computer being unable to get any information back from the EGR. The EVP (EGR Valve Position) sensor sits atop the EGR valve and it sends information as to how much the valve is open, back to the computer. I say the EGR is closed at idle... I should have been more precise and said that it SHOULD be closed at idle. The valve can stick partway open and frequently does as soot tends to build up between the pintle and seat in the valve. However, the computer can compensate for this, to a certain extent and it will IF it can. In your case, if you have "blinded" the EGR, I assume you mean you have physically blocked the port from the engine back into the intake. Even if the EVR (EGR Vacuum Regulator) vacuum and electronics are still hooked up AND the EVP (EGR Valve Position) sensor is still hooked up, the computer is trying to change the flow of EGR through the system because that is what its programmed to do. If it cannot achieve the results it "expects" to by this means, it resorts to the other controls that it has which are spark timing and fuel/air mixture. This is where the erratic idle rears its ugly head. The computer cannot control EGR and even if the EGR is in fact closed during idle, if the electronics have been disconnected, it has no way of "knowing" that so it will forever "guess" which causes it to make continuous adjustments to the things it CAN still "see" and control. If you have blocked the EGER port, you would almost be better off to make certain the EVR and EVP are still connected at least electronically so the computer can "know" that the valve is closed so it won't spend a lot of time guessing because it has no information. I will not guarantee that this will work because throttle position and engine temperature also affect the opening and closing of the EGR valve.

 

[Ton van der Sluijs]

Goodmorning Greystreak92
Thanks a lot for sharing your information. I do not mind to use the EGR in the system if that's better for the environment but what concerns me is, that after years a huge built up of soot, burned oil is there in the inlet manifold and on the valves. I dismantled the cilinderrheads and I must say, the combustionchambers were clean! I did have three leaking inletvalves due to carbonbuiltup . That I've blocked the EGR is definetly not to expect more power, because I drive never faster as 60MPH and rev never further than 3200revs. The carbon comes from the damp out of the PCV and I'm seriously thinking of a filter in the hose from there..
About combustion temperature.... The EGR keeps the temperature at bay... but if one drives like me (like an old fart grin) , the product the engine produces is a certain amount of power to keep the truck at a certain speed.. but without or with crud supplied to the intake, the outcome of developing let say 90hp to stay at 55MPH gives as a result the same combustion and the same exhaust temperature? I mean, 55 is at 1600revs with O/D. Isn'tt it so, that the high temperatures do come at higher speeds and hefty accelerations?
I do personely think, that the EGR is developed as an answer to meet environmental rules and that carbon builts up in every engine? So what? In my workshop (see www.technomotion.nl ) we do built Harleys with a lot of power...We do raise the compressionratio and bigger valves for that... can you understand now why "polluting" with an inert gas sounds as "not done" in my ears?
I'm very interested in what I can learn from you and what Blackhat (if he can step over his angryness to me grinn).
sometimes people here moaning that I have a gas consuming truck... I tell the straight to shut the f... up an buy a Prius!! I drive maybe 120 miles in two weeks; I'm living next door the plant, so do I attack the enviroment? no!

Best regards Ton

 

[BuzzGun79]

Do not restrict the pcv system with anything!. it could be sucked into the engine.simply remove the hose clean out all the gunk and replace.Now im getting the impression you drive your vehicle very conservatively and thats ok.But it is not going to hurt it to kick it in the tail once in a while to get rid of the excess carbon, in fact your engine will thank you for it dont be afraid to hammer down on it once in a while, this will raise combustion temps and burn it out.Fuel additives will also aid in cleaning out carbon.If you drive short term this also will produce moisture for the engine does not run long enough to dry out the system which leads to buildup.It takes a automotive engine at least 20 minutes to get to normal operating temp from there it needs additional time to dry up condensation that engines produce.climates, weather conditions,also come into play as well.

 

[Ton van der Sluijs]

Hi Buzz
Thank you for you input... No; I do not want to restrict the PVC at all... Only what has worried me is the gunk in the inletmanifold and valves. I do not know the history from this truck, except that it came 8 years ago from Nevada to Holland . Here, one of the previous owners did put an AMpco 300 LPG under the hood and that made the ignition timing jumping back and forth.. Right now with a Prins LPG injectionset everything is fine.(they drove the truck a long period with the TPS connector loose... the guy who sold it to me the truck, told me that that made the best ride.. (bull....)
you've noticed it right; I'm a very conservative driver and even the OD is off under 55MPH! I no that it's better to rev more, but this truck is already fast like hell to me! when I use the truck, it is mostly for trips longer than one hour, so it can warm up properly . On of the reasons, I do not "drive like I stole it" is, that I do not know if it's okay for the E4OD... I've read, that it's not Ford's best part...

best regards Ton

 

[5.0Flareside]

i cant believe this thread is still going.

 

[Fellro]

Going to throw a clarification out there... EEC I-IV systems are generically considered OBD i, because it was prior to the federal mandate to make all diagnostic systems use the same plug and same scanners to make testing more consistent. Prior to tthis mandate, they were strictly called EEC I, II, II, and IV, not OBD anything, just the same as the other manufacturers did not use the term OBD I until the OBD II systems were mandated. It is only a generic reference that is not maybe "proper" but is still the reference name. All it does is specify systems that were released before the federal mandate requiring common plugs, so no need to get testy about the use of the OBD terms. I am sure the OBD II systems are not officially called that by Ford still.

In simple
OBD I = ANY system built prior the 1995-6 depending upon when the company complied with the federal mandate. Some systems were federally compliant in 95.

OBD II = all systems built compliant with the federal regulation.

These are not terms officially used by the manufacturers.

 

[greystreak92]

And as I said, "EEC-IV: Some folks like to call it OBD-I but it was actually the fourth generation engine/emissions control system Ford engineered."

 

[BuzzGun79]

Ton, Basically in short terms you have a rich air fuel mixture,grant it my experience comes from the private sector not through Ford training its self.what has been explained here by the ford techs is correct. your ecm cannot calibrate the air fuel mixture due to the Modifications made.from what ive read on this L P system it alters the design the vehicle was made to operate.Now i do know some methods along with taking smog tests in consideration,but it is going to take an investment to accomplish.and defies the technical logic of this site along with manufacture design of the vehicle.It also requires experience to get it right.therefor i cannot get into this publicly speaking on this forum.

 

[Ton van der Sluijs]

Good morning Buzz
There was a bit of struggle here on this thread, but to me personely , it has brought something good.. My truck has sometimes the hiccups with accelerating on LPG (and a rough idle ) In my new opinion, due to what I've learned here, I do think, that when accelerating, the EGR should open to tamper the exhaustemperature... Because he can't, the EEC measures high temps and tries to manage it.... Next week I'm gonna remove the alloy sheet from the EGR and find out it that's the problem. the only new troubles good be, that I get carbon again in the manifold and valves.....
Thanks a lot for your information.

best regards Ton

 

[greystreak92]

Ton,

If you get excess carbon and coke build up with the EGR unblocked, double check that the spark plugs (I think you like to call 'em sparkies) are the right temperature rating for your truck. I know it may sound strange, but a plug that burns just a few degrees too low will allow the stuff to build up more quickly.

Does anyone have OEM plug information for the truck/engine in question here?

 

[Ton van der Sluijs]

Hi Greystreak;
How are you today?
Yesterday I've unblocked the EGR and the hiccups with accelerating are gone!!
tomorrow I'm gonna pull the plugs for inspection. I do have an LPG plug in the cilinderheads ; I shall see what the colours are ...
I keep you posted..

best regards Ton

 

[ILtrash]

long time reader, first time poster.

Great info!

I have a 90 4.9 IL6 5 spd.

When I bought this beast the air pump was bypassed, black (smog thing?) cylinder was gone, even the vacuum canister is gone. I had a horrible exhaust leak so I replaced from the pipes/cat/muffler from the manis back.

W/O the air pump, should I remove the cat? Keep the EGR system in tact?
Vacuum canister....need it? I have a screw in one tube, idles higher when out.
Are there no gaskets for the mani to pipe? seems odd.

I have a new EGR valve ready to go in, just don't want to keep digging myself in further.


This is a real POS looker, but hauls the crap i need to and keeps my mustang off the road in winter. No emmisions tests, 220k miles and my wife hates this truck.

Thoughts....

 

[greystreak92]

Ok we are talking about a few different items here.

Lets start with the vacuum canister. This filters fuel vapors from the tank. It really should be there to pull vapors into the engine instead of letting them escape into the atmosphere. Fuel evaporates anyway so leaving it open, while not critical to operate the truck, puts fuel vapors into the air and allows evaporation to take place. Normally, the canister catches the vapors, prevents the evaporation, then releases them into the intake when the engine is running. If you don't replace the canister, definitely leave the vacuum line running to where it use to be plugged otherwise you are creating a vacuum leak (hence the higher idle with the plug removed). Ask yourself though, "Where are those fuel vapors collecting if the canister isn't there but the fuel vapors are still coming out of the tank and up the line that use to have a sealed canister on the end of it in the engine bay?"

If the catalytic converter is the OEM unit, and the Thermactor Air Injection Pump (smog pump) is missing, then the catalytic converter is NOT working. It can't. However, as this thread has shown, the pump provides air injection to the exhaust just downstream of the exhaust valves during cold engine operation to keep the O2 sensor from getting a false "rich" reading. If the pump isn't running/isn't there, the O2 sensor will "tell" the computer that the engine is running "rich" when its cold and the computer will "lean out" the mixture during warm up which could cause overheating of cylinder walls and spark plugs. This usually manifests as poor cold starting and sluggish behavior until it warms up along with plugs that foul prematurely especially during cold weather.

The EGR system actually helps the engine reach operating temperature quicker if it the system is functioning properly. Some exhaust gasses are recycled back through the intake to warm intake air and to send unburned crud "around again". Removing it or blocking it as Ton found out, will actually "confuse" the computer and cause all sorts of idle issues.

Ford didn't use donut gaskets between exhaust manifolds and exhaust pipes. I typically clean the flared ends of the pipes and the ball end of the manifold collector then coat liberally with high temp anti-seize lube. Tighten to OEM specs and all should be good. The anti-seize just keeps the pipes from "growing" to the manifolds as the surface rust forms.

The 300 is a torque monster and will run for freakin' ever! Maintain it well and it will be pulling just as well at 250-300K as it does at 50K.

 

[Ton van der Sluijs]

Hello both of you...
New discoveries!!
since I did brought the EGR back in action, a couple of pleasant things occured..
Better acceleration..
Faster than ever...
E4OD shifts later 2-3 and 3-4 (Before the tranny shifted up as soon as possible)
so, the EEC seems to accept that the shifts come at higher revs, thus smoother, faster run)

Greystreak... I read your statement about the Smogpump in coldstart with great interest.. I've removed it and scrapped it because the bearings were gone.. My truck starts fast, even in cold conditions.. When running cold, I smell gas; to me it seems that my truck runs abit rich when cold, BUT... right now with EGR back in business, idle is very good, but some hiccups occurs (dipping) I do haver a clean IAC valve and operates in good order...


I do have an other question.. is it possible to interfere in the shifting of the tranny? In other words, I do not like to use kickdown... is it possible to install a switch to downshift from 4-3 by hand? Is such a conversion possible?

best regards and thanks for your support. Ton

 

[ILtrash]

I should specify, it is the vacuum reservoir canister. The coffee can is gone. The charcoal can is in tact and all vac lines are good.

The cat is replaced, my header pipe was rusted out and the replacement y-pipe came with the cat. Originally I think I had two. Unfortch, 3 of 4 exh to mani bolts cracked in the manifold. I tried drilling thru and using thru bolts but it didn't hold tight enough and now i'm repairing it.

the only problem I could describe for possible egr foulup is after highway driving, i stop, going again is choking it to death.

 

[greystreak92]

Ton,

You can upgrade the E4OD solenoid pack but its pretty expensive. You can always turn off the overdrive completely with the button on the end of the shift lever. I know exactly what you mean when you say you are not liking how quickly it drops into overdrive. I've never liked that about the E4OD. But then there are a LOT of things I don't like about the E4OD so I remove them in favor of some other transmission.

As for the "rich" condition while the engine is cold, it almost sounds like it is TOO rich. Have you cleared the computer memory since you unblocked the EGR? It sounds like you may have a fault Code in memory that may be causing some errant behavior. Remember to take the truck for a drive after clearing the memory (disconnect battery for about ten minutes). Drive as you would under most conditions in town and on the highway if possible. this will give the computer the time to "relearn" the system with the EGR functioning. I know I didn't mention this before and I"m sorry I forgot it because doing this has helped me in the past especially when I have had multiple fault Codes to troubleshoot.

ILtrash,

Ah ok, my misunderstanding. The vacuum canister provides vacuum for the MAP (Manifold Absolute Pressure) sensor at startup. The canister retains vacuum but the actual pressure held varies by the barometric pressure in the atmosphere. So, if the bottom drops out of the air pressure because a storm rolls through and you go to start the truck, the MAP sensor gets an accurate barometric pressure reading at startup. Since the ambient air pressure affects the pressure inside the intake as well, the canister attempts to compensate for any change since the last time the engine was run. If starting is not affected by the missing canister, I wouldn't worry too much about it.