running problems please help

I've been driving my 528e daily for the past year like 200 miles a week but starting this last week once the car gets warmed up the car runs horrible it bogs out like it is out of gas. I know its not the fuel pumps cause i just replaced them when my tank fell off from rust. There is also aproblem the coolant keeps vanishing no leaks on outside engine and no coolant in oil, but when you pull out the dipstick while car in idle, idle gets ruf for a second then returns to normal. if anybody has any info an the problem please post it I cant figure it out

Maybe the Fuel pressure regulator or have you tried disconnecting the O2 sensor? I would try that, it might have gone bad which might cause the car to run bad.

Andy

Originally Posted by Trik

I've been driving my 528e daily for the past year like 200 miles a week but starting this last week once the car gets warmed up the car runs horrible it bogs out like it is out of gas. I know its not the fuel pumps cause i just replaced them when my tank fell off from rust. There is also aproblem the coolant keeps vanishing no leaks on outside engine and no coolant in oil, but when you pull out the dipstick while car in idle, idle gets ruf for a second then returns to normal. if anybody has any info an the problem please post it I cant figure it out

The way to check for a head gasket leak or a cracked block is to use a combustion leak tester product like "Block Chek". It detects the presence of cumbustion gases in the coolant. Fast and easy. Napa and other parts stores sell these. When you remove your dipstick you're creating a vaccuum leak. Any number of things could be causing your poor running engine; bad plugs, wires, cap, rotor, fuel pressure reg, etc. Cleaning the throttle body and air flow sensor and changing your fuel filter and air filter might also help.

Hi there, BMW 525e cylinder heads are very prone to becoming porous due mainly to lack of regular anti freeze changes and I have found through many years of experience the only positive action is to replace the cylinder head with a new one as I have seen many times people have had the heads tested and sealed only for the heads to leak within a very short space of time. Also only use high qaulity anti freeze and also replace the timing / cam belt. This problem also affects e30 320i and e30 323i and e30 325i.

I tried all the things youve said and it still acts like its out off gas when it is full could the fuel pump already be bad even though i just replaced it not even a year ago or could it just be the pump is overheating

Originally Posted by Trik

I tried all the things youve said and it still acts like its out off gas when it is full could the fuel pump already be bad even though i just replaced it not even a year ago or could it just be the pump is overheating

Which pump did you replace? Have you looked at the condition of your spark plugs? What do they look like? What about the coolant issue? Aftermarket fuel pumps are problematic. That could be your problem. Are the symptoms the same as they were before you replaced the fuel pump last year?

both fuel pumps with oem ones from BAP the plugs look clean and the radaitor needs replaced it had a hole in it

Did you check for a vacuum leak?
Check the main rubber 'boot' attached to the TB and the mass air flow unit (air filter unit). This may look 'ok' but when in drive the vacuum pressure increases and air is sucked in from the 'cracks' in the rubber 'boot' (large curved ribbed hose).
Also, carefully, spray carb cleaner around engine compartment while car is idling, in Park, and see if the idle changes...increases if leak is present.
Good luck!

dont have that rubber thing have cold air intake but i here a hiss from some where an carb cleaner dont make it idle up

Originally Posted by Trik

dont have that rubber thing have cold air intake but i here a hiss from some where an carb cleaner dont make it idle up

The hiss sounds like a vacuum leak. Check the vacuum lines carefully especially the rubber elbow that goes to the fuel pressure regulator.

put new engine in still has same problem could it be a bad IAC valve it idles real rough and starts to mess up when i put a load on engine

Hi there, Re your e28 rough running, Do you live in the UK and anywhere near Kent, If yes I'm sure that I can diagnose your problem for you, Peter

Originally Posted by Trik

put new engine in still has same problem could it be a bad IAC valve it idles real rough and starts to mess up when i put a load on engine

Take the IAC valve out and clean it with carb cleaner real well. Spray it liberally into both sides, let it soak in and do it again. Clean theThrottle body passages real well too. The IAC has it's own computer as well. Whatever you switched over or retained from your first engine seems to be the problem. Fuel pressure could be part of it.

i switched over both computers. both iacvalves are real dirty im going to switch over the fuel pomps cause thats all iv retained off first engine cause they were brand new i also just got brake parts cleaner to clean the iac and the throttle body and can u spray that on the mas air flow sensor it seems dirty also but it moves smoothly both of the ones i have seem to be good thow cause it does the same thing so far with every thing i switch and i just want to be able to drive my car again

Originally Posted by PETER NEWMAN

Hi there, Re your e28 rough running, Do you live in the UK and anywhere near Kent, If yes I'm sure that I can diagnose your problem for you, Peter

no I live in Northern Arizona

Originally Posted by Trik

i switched over both computers. both iacvalves are real dirty im going to switch over the fuel pomps cause thats all iv retained off first engine cause they were brand new i also just got brake parts cleaner to clean the iac and the throttle body and can u spray that on the mas air flow sensor it seems dirty also but it moves smoothly both of the ones i have seem to be good thow cause it does the same thing so far with every thing i switch and i just want to be able to drive my car again

Check all the vacuum lines real carefully, especially to the brake booster. It still seems like whatever is causing it is something that wasn't switched with the engine. What about the fuel filter and the fuel pressure regulator?

those were replaced with brand new parts im think it might be my fuel pump it maks wierd sound likes its shuttering and not pumping

Originally Posted by Trik

those were replaced with brand new parts im think it might be my fuel pump it maks wierd sound likes its shuttering and not pumping

There's two you know, one in the tank and one under the car. By the way, the horn and fuel pump relays are the same. Try switching those around.

it was the pumps but now the car barley runs since i put the 91 octane in the tank and now it tries to start but lopes alittle then stalls out

Originally Posted by Trik

it was the pumps but now the car barley runs since i put the 91 octane in the tank and now it tries to start but lopes alittle then stalls out

Both pumps? What caused the pumps to go bad? Maybe there's some contaminants; dirt, rust, water, dried up rubber, etc? Maybe the injectors are clogged? Can you check the fuel pressure? Back to the IAC valve. Did you clean it real well? Use carb cleaner spray liberally.