Diesel Fuel Injection System Help Desk

[Dieseldude]

Hi DieselDude,

I seem to have a problem with my 98 BMW725 TDS...the problem is at idle...there is so much fuel knock, my question...is there a quickfix to this...like diesel fuel additives/conditions that can minimize or eliminate it. Petron's Diesel Booster might help. I've tried it.

About the fuel knock, its only present at idle around 800-900rpm. If I just tap the accelerator very lightly to keep it at 1000rpm the knock is totally gone....if I pump the accelertor several times very very quickly and let it idle it will idle without the knocking sound for about 2 seconds and the the knock returns... Knock is probably due the present cooler temperatures, as well as lower compression pressure due to normal engine wear.

I also would wnat you to know the car has no problem at all, power is good, not much smoke emited when driven hard. This seems to be normal for Rovers....

Another concern of mine, the car does not start quickly even when already hot, it will take 2 to 3 revolutions before the engine fires up...Whats your suggestion? Again this is normal, especially for high mileage cars, slight drop in compression pressure......

I believe you have a shop...are you capable of rebuilding the pump and are the parts available if ever I have it done? Could the injectors be a possibility or is it the pump, or thats just normal for older cars? Yes we are a Bosch Diesel Center, and we service this pump type. You have an EDC (Electronic Diesel Control) pump. Parts may have to be ordered from Germany though. I don't think your fuel injection system needs service; your condition is normal.

[Dieseldude]

Hi Dieseldude! Is there a reputable garage or person you may want to refer me to to have the supply pump reconditioned or maybe even a reputable reconditioned pump supplier? Any money I can save this season would be much appreciated.

I just sent you a private message.

[jpn]

Hi DieselDude,

I seem to have a problem with my 98 BMW725 TDS...the problem is at idle...there is so much fuel knock, my question...is there a quickfix to this...like diesel fuel additives/conditions that can minimize or eliminate it. Petron's Diesel Booster might help. I've tried it.

About the fuel knock, its only present at idle around 800-900rpm. If I just tap the accelerator very lightly to keep it at 1000rpm the knock is totally gone....if I pump the accelertor several times very very quickly and let it idle it will idle without the knocking sound for about 2 seconds and the the knock returns... Knock is probably due the present cooler temperatures, as well as lower compression pressure due to normal engine wear.

I also would wnat you to know the car has no problem at all, power is good, not much smoke emited when driven hard. This seems to be normal for Rovers....

Another concern of mine, the car does not start quickly even when already hot, it will take 2 to 3 revolutions before the engine fires up...Whats your suggestion? Again this is normal, especially for high mileage cars, slight drop in compression pressure......

I believe you have a shop...are you capable of rebuilding the pump and are the parts available if ever I have it done? Could the injectors be a possibility or is it the pump, or thats just normal for older cars? Yes we are a Bosch Diesel Center, and we service this pump type. You have an EDC (Electronic Diesel Control) pump. Parts may have to be ordered from Germany though. I don't think your fuel injection system needs service; your condition is normal.

Dude,

Thanks a lot for the info...I have been already searching the WEB for weeks only to find out I got the aswers from a local site....I read this whole thread from the beginning...THUMBS UP...for the time you put on to answer questions.....!!!

[batosai]

Sir DD thanks for enlightened me. So there's a purpose pala kung bakit nila nilagay ung EGR. I'll just leave it as it is..

* CJPAMA

Why not try to drop by at central diesel it is located along Quezon Ave near the capitol medical center. Mga expert tao dito pag dating sa mga Injection Pump. Hope this will help you.


Thanks and more power!!!

[jpn]

Knock is probably due the present cooler temperatures, as well as lower compression pressure due to normal engine wear.

Sir,
I notice my engine temp is always below 1/4....I highly suspect that the previous owner/mechanic probably removed or did something to the thermostat....I wonder if I put back the thermostat to maintain normal engine temp. would this probably lessen the fuel knock at idle?

By the way I did put the petron power booster and yes it did make a difference already...it silenced the fuel knock noticebly...thanks!!!

[angbatangobong]

Shempre naman pwede. Pero malaki ang gastos dahil babaguhin mo pa ang intake & exhaust manifolds, and exhaust discharge pipe.

Papalitan mo din ang injection pump nung type na meron boost compensator para magkaroon ng additional power without smoke. Adding a turbo alone will not sufficiently increase power. To truly gain power, the inj. pump will also have to be recalibrated for more fuelling as the turbo will be supplying more air to your engine.

Mga how much kaya aabutin ng lahat na yon? Kung surplus kaya na 4d56t kaya makakatipid pa ako?I heard more or less 60k yung 4d56t. How much fc ng nilagyan lang ng turbo? At sa durability? mababawasan kaya kapag nilagyan ng turbo?

Thanks again!

[carnibal]

IMO, I think the fan on the bottom is sufficent. unless walang fan dyan. besides, intercooler is not efficient on traffic/low rpms. they only get useful on heavy loads, heavy revving... intercooler tends to lag you on traffics unless vgt yung turbo.

kasi hindi vgt yung turbo namin. I wish I could make a pipe switch where I could deactivate the turbo pipe routing to the intercooler on traffics and activate it on highways.

thank you for the input.

Yes, wala standard blower yung sa amin.

curious lang po. bakit not effecient ang intercooler on traffic/low rpm?

Isn't it that cooler air is always better for the engine, probably, except for cold start?

thanks again

[carnibal]

for kia carnival 1st gen. If there is a presence of diesel fuel outside the injectors on top of the engine, is this possibly due to any washer or seal damage in the injectors? kaunti lang naman, not the overflowing type of spill/presence ng diesel.

If this is the case, can it be fixed without replacing the entire injector?

thanks

[rion]

thank you for the input.

Yes, wala standard blower yung sa amin.

curious lang po. bakit not effecient ang intercooler on traffic/low rpm?

Isn't it that cooler air is always better for the engine, probably, except for cold start?

thanks again

the intercooler makes the traveling distance from air intake to engine takes longer by millisecs, making a millisec later response from standing start. On low rpm, there is no heat generated by the turbo air friction and pressure build up. any air generated by the turbine on low rpm is directly consumed by the engine. there is no hot air that needs to be cooled.

may hoodscoop po ba yang intercooler mo?

[carnibal]

the intercooler makes the traveling distance from air intake to engine takes longer by millisecs, making a millisec later response from standing start. On low rpm, there is no heat generated by the turbo air friction and pressure build up. any air generated by the turbine on low rpm is directly consumed by the engine. there is no hot air that needs to be cooled.

may hoodscoop po ba yang intercooler mo?

Yes, meron hood scoop. iniisip ko kasi na pag traffic, papanhik yung engine heat sa intercooler therefore mag aabsorb ng heat yun g intercooler instead of giving off heat.

[Dieseldude]

Sir,
I notice my engine temp is always below 1/4....I highly suspect that the previous owner/mechanic probably removed or did something to the thermostat....I wonder if I put back the thermostat to maintain normal engine temp. would this probably lessen the fuel knock at idle? Doing this will not totally remove engine knock. But it might shorten the knocking time as the engine will reach operating temp sooner.

By the way I did put the petron power booster and yes it did make a difference already...it silenced the fuel knock noticebly...thanks!!! Good...

[Dieseldude]

Mga how much kaya aabutin ng lahat na yon? Kung surplus kaya na 4d56t kaya makakatipid pa ako?I heard more or less 60k yung 4d56t. Sorry, hindi ko kabisado ang presyo ng surplus.

How much fc ng nilagyan lang ng turbo? I don't know the resultant FC figures...... too many variables. But I think FC and power could slightly improve by just adding a turbo as you will have more air at high rpms.

At sa durability? mababawasan kaya kapag nilagyan ng turbo? Adding a turbo will not stress the engine. Durability may suffer and consumption will increase once the injection pump is adjusted for more fuel. More fuel means higher combustion temps and pressures when the engine is operated at maximum load.

Thanks again! You're welcome..

[Dieseldude]

thank you for the input.

Yes, wala standard blower yung sa amin.

curious lang po. bakit not effecient ang intercooler on traffic/low rpm? Because you don't need a lot of air at idle. And normally, the turbo is not on boost at idle.

Isn't it that cooler air is always better for the engine, probably, except for cold start? Air is expanded at high temps. The intercooler brings down the intake air temp to improve it's oxygen density. The turbo can push more oxygen into an intercooled engine at high loads when it is most needed.

thanks again

[Dieseldude]

for kia carnival 1st gen. If there is a presence of diesel fuel outside the injectors on top of the engine, is this possibly due to any washer or seal damage in the injectors? kaunti lang naman, not the overflowing type of spill/presence ng diesel. Probably a leak on the high pressure fitting to the injector, or a leak on the injector's fuel return hose connection. Shut off the engine, wipe/clean the leak, start the engine, and watch where the leak comes from.

If this is the case, can it be fixed without replacing the entire injector?
I don't think the injector/s need replacement.

thanks

[rion]

Yes, meron hood scoop. iniisip ko kasi na pag traffic, papanhik yung engine heat sa intercooler therefore mag aabsorb ng heat yun g intercooler instead of giving off heat.

I suppose putting one would be better. and your first problem is how to attach it. I suggest suction fan and located below intercooler. good luck!

[jpn]

DieselDude,

Since my car still fairly new with me, I had another observation...If I PREHEAT(it seems set at a certain time) the car 3 times then it starts right away...if preheated once it takes a few revolutions of the starter to get the engine going...it scares me I might burn the starter, so now I just pre heat it 3x all the time. Its the same even if the engine is already warmed up. Would you think changing glowplugs would help improve the starting up?

[jpn]

double post...sorry

[ttc713]

dieseldude,
ihav a prob wth my engine iTHINK.. nka muffler ako and yung sound goes like this (in words ) brrrrrrrrrrrrrrBOKBOKbrrrrBOK.. gayan ang tunog and ung rpm naglalaro w/o rev-ing. any suggestions kung ano nga ba ang prob and how to fix it. additional info pagka baba ko frm baguio nagkaganyan na and my car is honda esi 94.
tnx.
happy new year!

[Dieseldude]

DieselDude,

Since my car still fairly new with me, I had another observation...If I PREHEAT(it seems set at a certain time) the car 3 times then it starts right away...if preheated once it takes a few revolutions of the starter to get the engine going...it scares me I might burn the starter, so now I just pre heat it 3x all the time. Its the same even if the engine is already warmed up. Would you think changing glowplugs would help improve the starting up?

Check the glowplugs and its control system before replacing any part. Glowplugs are expensive. Baka naman weak ang battery mo, or faulty ang battery cables, terminals, and/or loose and connections nito.

[Dieseldude]

dieseldude,
ihav a prob wth my engine iTHINK.. nka muffler ako and yung sound goes like this (in words ) brrrrrrrrrrrrrrBOKBOKbrrrrBOK.. gayan ang tunog and ung rpm naglalaro w/o rev-ing. any suggestions kung ano nga ba ang prob and how to fix it. additional info pagka baba ko frm baguio nagkaganyan na and my car is honda esi 94.
tnx.
happy new year!

Naku, sorry. Hindi ko alam yan. Gas yata car mo. Hindi ko kabisado ang petrol engines. Try mo mag post sa ibang forum. I'm sure, meroon makakatulong sayo.

Happy New Year Din.