Spark Plugs

[t_marat]

Hi everybody!
I changed the sparks plugs on my car to Beru Ultra. I was thinking of buying Bosch, but the owner of the shop from which I bought these had the same spark plugs on his 7 series BMW and said he had no problems. Here is a link:
http://www.beru.com/english/produkte/produktfinder.php?hersteller=BMW&modell=5+(E34)&typ=520+i+24V&ktypnr=238&action=step04

Anybody have any info on these?

Since I put the sparks I only drove about 1.7km Engine runs smooth, but sometimes goes "offline" during idle. I mean it justs stops. Does not happen very often. With the old sparks I did not have problems like that, but they are very old and I had other problems with them (like one or two cylinders not working).

One guy said that the sparks need "getting used" to the engine :)

[shogun]

Beru products are a very good brand and Beru is OEM to many car manufacturers and other industries.
But for that specific spark plug I have no experience. If Beru says it is for your specific car, then I would not worry about the plug itself.

[t_marat]

Good, otherwise I was worried if its the plug.
The idle is smooth, but when you press the gas, it kind of rattles, meaning the increase in rev is not smooth. It smoothes out at about 3000 rev. But when you are in idle, and press the gas and release it fast (not very fast), the engine rattles (don't know how to describe it the other way) while gaining rev.

Maybe a fuel filter causing the fuel pressure to be too low?

[632 Regal]

try the stock bosch plugs.

[Kalevera]

try the stock bosch plugs.
Ditto.

Plugs other than those specified for these engines = stupid.

best, whit

[shogun]

orginal specs
http://www.vinesauto.com/techinfo.htm

[t_marat]

Well I understand that it is better to use the original BMW (bosch). but I already bought these, and their manufacturer seems to be a reputable company. And they actually have BMW as a client:
http://www.beru.com/english/unternehmen/kunden.php
Company background
http://www.beru.com/english/unternehmen/tradition.php

So maybe its not the plugs? Maybe something else?

Is the fuel pump supposed to work continously? Mine works nearly non-stop. After switching on the ignition it starts whizling and goes on and goes on. In other (edit: not BMW) cars I saw it start, work for a while and stop.

[shogun]

Try this: set ignition on position 2, then the fuel pum should start till the required fuel pressure of 3 bar is there and then switch off.
After it stopped again, try again psotion 2 and listen again. It should stop much faster.
Loosk like the fuel pump is the problem. I do not belive that Beru is a bad spark plug. That is a big and traditional old German company and OEM supplier to many car manufacturers , not only for spark plugs

[t_marat]

Switched on the ignition, the pump (the one under the hood) for a short time made a louder noise. But then it was making sh-sh-sh-sh noise continously. It is quiter than the first noise but it makes it continously. I started the engine, let it ran for 15 minutes, shut it down, switched on the ignition, again the same. The shshshsh noise is always there. Is this normal?

[t_marat]

I forgat to say that when I first switched on the ignition the pump was making some screeching noise (from time to time).

[bfd]

Ditto.

Plugs other than those specified for these engines = stupid.

best, whit

Can you clarify? I use NGK ZGR5A spark plugs on my 1990 535i, 5 spd, 103K miles and have NO PROBLEMS. In fact, I like the NGKs*better* than the stock Bosch ones. Further, although these plugs are the ones recommended by NGK for this car, its not officially "specified" by BMW.

One thing to consider is that Beru is the manufacturer of BMW spark plug wires, so I would think their "brand" of plugs should work fine for any BMW.

[632 Regal]

this cant be good...
I forgat to say that when I first switched on the ignition the pump was making some screeching noise (from time to time).

[genphreak]

I forgat to say that when I first switched on the ignition the pump was making some screeching noise (from time to time).Perhaps the pump is failing (intermittently). However, have you gapped your plugs correctly? Don't be offended if this is a demeaning statement to you, just have no idea of your level of mechanical ability.

If you suspect pumping problems, check if the car performs properly under load at Wide Open Throttle in 1st gear above 5000rpm. If it chokes anywhere on the way up or dies shortly afterwards it is probably fuel pressure. A full tank of gas makes it easier on the pump and harder on you to successfully diagnose. You need to check your lines, pump and Fuel Pressure Regulator if so. FPR is easy to fix, pumps are harder- but taking the old rear pump out of the tank is the first step- does it make a whirring noise in the tank? If its loud it might be having trouble, if nothing, it might be dead...

I think the front pump has proven much more durable and will make heaps of noise if the rear one fails as it can't do all the pumping on its own. Don't know of any failures yet- but no doubt this will bring out some stories...).

[632 Regal]

front pump?

[t_marat]

So there is a front pump right? I guess having only one pump at the back is not enough to provide enough pressure for the injectors to work.

Genphreak, what do you mean by "gapped your plug correctly?". I am definitely not a good mechanic, so no offence, absolutely.

I don't know if its useful, but the outside temperature is -6C. Can it make the pump to make screeching noises? Its now always, from time to time.

[Barry]

If I may add my 5 cents worth...
On cars fitted with plug wires(my 535..)It is not the greatest idea to fit a more modern "resistor" plug..Id go as far as to say that this is a definate no-no..
Resistor plugs have an impedance of around 2 to 5 K ohm..This added to the 2 odd K ohm wire just kills the spark to the cylinder..

I have Alfa Romeo`s that I race and found this out the HARD way...
I know of an instance where a Mercedes 4 cyl engine was rebuilt due to a bum diagnosed problem.Upon firing the new engine the same symtom was there(would idle but not rev over 2000 rpm as a result of a serious splutter..)
I diagnosed the plug problem and the ol Merc ran without a hiccup..

[Barry]

Replace your fuel pump Now..Mine was also screeching occasionally and finaly I got stuck on the 16th december-the dy I was to leave on holiday-and a Public holiday here in South Africa..
I now have a new pump in and the car runs better than it ver did since I bought it..
Typical broken ally housing problem..

[shogun]

So there is a front pump right? I guess having only one pump at the back is not enough to provide enough pressure for the injectors to work.


There is not a pump in the front of the car.
And only one pump is completely enough to pump all the fuel needed. The pumps are layed out in such a way that they pump more than needed. That is why there is a fuel pressure regulation inside the engine room and a return hose for excess fuel back to the fuel tank.

[genphreak]

There is not a pump in the front of the car.
And only one pump is completely enough to pump all the fuel needed. The pumps are layed out in such a way that they pump more than needed. That is why there is a fuel pressure regulation inside the engine room and a return hose for excess fuel back to the fuel tank.Yes sorry guys, Jeff, Erich, you are very right to pick me up on it. I cannot imagine why I've been living all this time thinking there were two. One inside the tank and (I thought) another somewhere further along the line... I thought in my engine bay I'd heard it a few times, but now I know this was the ICV and/or my noisy ebox fan... My apologies for the confusion, t_marat... its a very hot Christmas here in Australia.

Spark Plugs come in many types as you know but each type fits a variety of engines. Most engines have a different gap specification, so you must always check and get the gap right (or your car will run badly as the ignition will be (at least a little) advanced or retarded. If you have replaced them and you don't know what I mean, you must take them out and do this, and one should do it every time you install/reinstall plugs.

To gap the plugs;
Measure the gap with a feeler gauge- there are special ones available for plugs that are as cheap as chips. I do mine to 0.032 inches. Wherever u buy plugs u can buy them.

To adjust the gap, bend the plug's body electrode back or forth (closer or further from) the centre electrode, using an accurate hand and set of good pliers (Never touch the centre electrode OR its ceramic insulator (this can crack and the plug and it will then fail).

If I were you first thing to do is gap the plugs, torque them correctly (you have a small torque wrench?) or if you do it by hand you need to be able to feel the right amount of tightness- overtightening and undertightening are definately to be avoided.

Then tell us how the car performs... for all I know the engine management is upset by the plug gaps and causes something strange ot happen...

:) Nick

[t_marat]

What is the gap for the 520i M50 engine? The plugs that I used have two contacts.

[t_marat]

Why is the torque so important?

[dacoyote]

Why is the torque so important?

Because if you stip the block... or break one off.... it makes for a bad day....

[Bill R.]

especially for setting plugs are made by bosch and many others and they consist of a wire gauge, there's also a tool attached to the bosch spark plug gauge that you set the gap with. You don't want to use flat feeler gauges or the round disc type gauge thats available from autozone as they aren't accurate. Torque is important for a number of reasons,
first as others have stated, to avoid stripping the threads out of the aluminum head you dont want to overtighten.
Secondly torque has an effect on the gap of the plug, over torquing distorts the body of the plug and changes the gap. Theres a pic of the bosch gauge at this site, most import parts places carry it. (http://www.car-stuff.com/cs_products/mercedes_benz%7E500sel%7Espark_plug_gap_gauge%7Er-mmpp%7Ecsp436bcaa0ec1fc.html)




Yes sorry guys, Jeff, Erich, you are very right to pick me up on it. I cannot imagine why I've been living all this time thinking there were two. One inside the tank and (I thought) another somewhere further along the line... I thought in my engine bay I'd heard it a few times, but now I know this was the ICV and/or my noisy ebox fan... My apologies for the confusion, t_marat... its a very hot Christmas here in Australia.

Spark Plugs come in many types as you know but each type fits a variety of engines. Most engines have a different gap specification, so you must always check and get the gap right (or your car will run badly as the ignition will be (at least a little) advanced or retarded. If you have replaced them and you don't know what I mean, you must take them out and do this, and one should do it every time you install/reinstall plugs.

To gap the plugs;
Measure the gap with a feeler gauge- there are special ones available for plugs that are as cheap as chips. I do mine to 0.032 inches. Wherever u buy plugs u can buy them.

To adjust the gap, bend the plug's body electrode back or forth (closer or further from) the centre electrode, using an accurate hand and set of good pliers (Never touch the centre electrode OR its ceramic insulator (this can crack and the plug and it will then fail).

If I were you first thing to do is gap the plugs, torque them correctly (you have a small torque wrench?) or if you do it by hand you need to be able to feel the right amount of tightness- overtightening and undertightening are definately to be avoided.

Then tell us how the car performs... for all I know the engine management is upset by the plug gaps and causes something strange ot happen...

:) Nick

[t_marat]

If there is no pump under the hood, then what is making that noise when you turn on the ignition (not starting the engine)?

[Bill R.]

auxilliary pump running




If there is no pump under the hood, then what is making that noise when you turn on the ignition (not starting the engine)?

[genphreak]

auxilliary pump runningbtw; auxillary pump is the auxillary coolant pump (mounted on the firewall) - it is probably not on all cars- I've no idea about a 520i. Look your gap up in the owners manual (maybe), on the emissions stickers under the hood (I think so) or in a workshop manual.

[Kalevera]

If I may add my 5 cents worth...
On cars fitted with plug wires(my 535..)It is not the greatest idea to fit a more modern "resistor" plug..Id go as far as to say that this is a definate no-no..
Resistor plugs have an impedance of around 2 to 5 K ohm..This added to the 2 odd K ohm wire just kills the spark to the cylinder..

I have Alfa Romeo`s that I race and found this out the HARD way...
I know of an instance where a Mercedes 4 cyl engine was rebuilt due to a bum diagnosed problem.Upon firing the new engine the same symtom was there(would idle but not rev over 2000 rpm as a result of a serious splutter..)
I diagnosed the plug problem and the ol Merc ran without a hiccup..
Huh?!?

Bosch W8LPR/LCR, the factory plug for all US spec (and probably the world) E34 535s, is a resistor plug with a platinum or copper core, respectively.

The purpose of a resistor plug in this case is to maximize spark voltage and help minimize impedance mismatch (albeit crossfire can still be a problem on M30s with worn wires).

If it was the late 80s/early 90s mercedes 4 banger: I think Winfred and Bill will agree -- the reason it needed a rebuild was because its a shitty, cam eating motor to begin with.

best, whit

[Kalevera]

BFD, you make a valid and sound point regarding the NGK ZGR5A in the M30, although I don't think it correlates well to the M50 and later motors. I've found everything imaginable in M30s, including champions more suited for a 5hp briggs than a car. The key with the M30 is to retain the use of a single electrode resistor plug; given that the dimensions are the same as stock, anything that fits those criteria should work fine.

One variable that often gets overlooked with multi-electrode "performance" plugs, such as those used in replacement of the two electrode F7LDCR or BKR6EK, is spark position. I think Winfred was the first to point out the critical difference between the stock plugs and most "performance" parts, including the bosch platinum 4s: there simply isn't as much surface area to transmit a spark, and that area can quickly get saturated with combustion biproducts or even foul out on fuel delivery, resulting in poor performance. Hence the recommendation to use stock plugs on engines that came with multielectrodes from the factory.

One thing that often confuses the consumer is advertisement as an "OEM manufacturer". I see this all the time with WorldPac and SSF (therefore, pretty much any aftermarket parts source other than the dealer). As long as said manufacturer produces *one* part for some BMW model, it is considered an OEM manufacturer. Furthermore, many manufacturers offer multiple part lines, varying in quality (incidentally, Lemforder seems to be one of the few that only produces ONE line, so you always know what you're getting). Coincidentally, buying a part based on manufacturer name alone doesn't necessarily correlate with good/factory part quality.

best, whit

[dacoyote]

.... Coincidentally, buying a part based on manufacturer name alone doesn't necessarily correlate with ... part quality....

Unless its a car made in the states... at witch point it means its a pos

[Bill R.]

no resistance, they are solid core wires, the spark plug end has 5k ohms resistance and the distributor cap has 1k oms resistance making the total for each wire 6k ohms.




Huh?!?

Bosch W8LPR/LCR, the factory plug for all US spec (and probably the world) E34 535s, is a resistor plug with a platinum or copper core, respectively.

The purpose of a resistor plug in this case is to maximize spark voltage and help minimize impedance mismatch (albeit crossfire can still be a problem on M30s with worn wires).

If it was the late 80s/early 90s mercedes 4 banger: I think Winfred and Bill will agree -- the reason it needed a rebuild was because its a shitty, cam eating motor to begin with.

best, whit

[t_marat]

btw; auxillary pump is the auxillary coolant pump (mounted on the firewall) - it is probably not on all cars- I've no idea about a 520i. Look your gap up in the owners manual (maybe), on the emissions stickers under the hood (I think so) or in a workshop manual.

In the manual it states that the spark splugs gap is not fixed. You can't regulate it, its fixed. Two spark plugs: Bosch FO 3 DAR and NGK BCPR 7 ER. It also states these have 3 side electrodes


So there is no pump under the hood, right? Pressure in the fuel system is provided only by the pump near the tank.
But then what is that whirling sound that comes for about 3-5 seconds when you switch on the ignition (without starting the engine)? And then that shshshshsh sound which continues indefinitely (as long as the ignition is on).
Is the auxillary coolant pump always on or only when the engine is running?

ICV: Inlet Check Valve? What does it do?

[632 Regal]

theres little motors for the heat/AC ducting to add to the noise bragade.

[Kalevera]

In the manual it states that the spark splugs gap is not fixed. You can't regulate it, its fixed. Two spark plugs: Bosch FO 3 DAR and NGK BCPR 7 ER. It also states these have 3 side electrodes


So there is no pump under the hood, right? Pressure in the fuel system is provided only by the pump near the tank.
But then what is that whirling sound that comes for about 3-5 seconds when you switch on the ignition (without starting the engine)? And then that shshshshsh sound which continues indefinitely (as long as the ignition is on).
Is the auxillary coolant pump always on or only when the engine is running?

ICV: Inlet Check Valve? What does it do?
If it's a 3 electrode plug, then it has a fixed gap. It's always a good idea to inspect the plug's cardboard box for any physical damage that might suggest that the plug was dropped on the floor (thereby bending the electrodes).

The car should only have one fuel pump, in the tank below the sender. I don't know how long it's been since BMW put fuel pumps in the engine bay (E28? I forget), but it's been a while.

The Auxiliary Coolant Pump (Aux Pump) moves (hopefully warm) coolant through the heater core when the engine idles/at times when the water pump might not be providing enough flow to handle the task. It'll make noise whenever the climate control isn't off.

Think of the Idle Control Valve as a throttle bypass. It allows the DME to specify how much air the engine is getting at idle (when the throttle butterfly[or -ies] isn't open), which serves the purpose of maintaining idle. Incidentally, EML (drive-by-wire/motor controlled throttle) cars don't have ICVs because the system can actuate the throttle butterfly enough to compensate for air requirements at idle. The early (US SPEC) EML cars were the E32 750, 1990-'92 735i/L, and some '91/'92 E34 535s; it's unlikely that your car has EML -- BMW shelved the system until the ~ M54 cars. So your car probably has an ICV, and it does make noise with the ignition on/engine off.

A temporary whirring sound from the dash vicinity is usually, as others have stated, the flaps in the heater box. The recirc flaps could be making some noise (they're always opened when the car is turned off/key removed), but they're usually pretty quiet.

best, whit

[t_marat]

If it's a 3 electrode plug, then it has a fixed gap. It's always a good idea to inspect the plug's cardboard box for any physical damage that might suggest that the plug was dropped on the floor (thereby bending the electrodes).

The car should only have one fuel pump, in the tank below the sender. I don't know how long it's been since BMW put fuel pumps in the engine bay (E28? I forget), but it's been a while.

The Auxiliary Coolant Pump (Aux Pump) moves (hopefully warm) coolant through the heater core when the engine idles/at times when the water pump might not be providing enough flow to handle the task. It'll make noise whenever the climate control isn't off.

Think of the Idle Control Valve as a throttle bypass. It allows the DME to specify how much air the engine is getting at idle (when the throttle butterfly[or -ies] isn't open), which serves the purpose of maintaining idle. Incidentally, EML (drive-by-wire/motor controlled throttle) cars don't have ICVs because the system can actuate the throttle butterfly enough to compensate for air requirements at idle. The early (US SPEC) EML cars were the E32 750, 1990-'92 735i/L, and some '91/'92 E34 535s; it's unlikely that your car has EML -- BMW shelved the system until the ~ M54 cars. So your car probably has an ICV, and it does make noise with the ignition on/engine off.

A temporary whirring sound from the dash vicinity is usually, as others have stated, the flaps in the heater box. The recirc flaps could be making some noise (they're always opened when the car is turned off/key removed), but they're usually pretty quiet.

best, whit


Well, all the possible noise sources you listed are temporary ones. The noise coming from under the hood of my car is continous. I waited for 1.5 minutes with the ignition on (engine off, with engine on you can't hear that noise).
You see, it first makes whirling sound, for about 3-5 seconds. You can barely hear this from inside the car. Then it follows with sh-sh-sh-sh-sh sound which is the continous one. What that might be?

[genphreak]

Well, all the possible noise sources you listed are temporary ones. The noise coming from under the hood of my car is continous. I waited for 1.5 minutes with the ignition on (engine off, with engine on you can't hear that noise).
You see, it first makes whirling sound, for about 3-5 seconds. You can barely hear this from inside the car. Then it follows with sh-sh-sh-sh-sh sound which is the continous one. What that might be?The ICV is (often, perhaps always) continuous until the engine starts- after that you can't hear it... The other noiuse could be a noisy e-box fan like I thought I had suggested before... unless the 520i does have a fuel pump in the engine bay! (If it is hot where you are the ebox fan may come on quite readily) Also there is the wiper -arm blade adjustment motor- temporarily noisy if it gets gummed up (bnefore failiure)... Search Sean adn Johan's e32 page for solutions to that- (you have to remove and replace/repair it).

[Bill R.]

adjustment.



The ICV is (often, perhaps always) continuous until the engine starts- after that you can't hear it... The other noiuse could be a noisy e-box fan like I thought I had suggested before... unless the 520i does have a fuel pump in the engine bay! (If it is hot where you are the ebox fan may come on quite readily) Also there is the wiper -arm blade adjustment motor- temporarily noisy if it gets gummed up (bnefore failiure)... Search Sean adn Johan's e32 page for solutions to that- (you have to remove and replace/repair it).