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1990 E34 535i engine problem?

9K views 7 replies 3 participants last post by  pdurand 
#1 ·
Hey guys, I've run into a problem with my 535i. The other day I was driving it normally and then out of no where the engine cut out and started sounding like diesel engine..? And after that the car would no longer accelerate normally it would lunge forward and then cut out and do the same process every time i got past 1,500 rpm on the tach. Does anyone have a clue what this could be ? I'm very new to this and stumped:thumbdwn: any help would be greatly appreciated I want my car back!
 
#2 · (Edited)
Hi there,

You've gotta check your tranny fluid levels and make sure they are ok. If you don't have a dipstick, you're best off doing this at a workshop.

Also check your engine oil levels and make sure those are ok.

Do the stomp test and see if there are any useful error codes. Youtube for the stomp test, many easy to follow videos on that there.

Unplug your engine's coolant temperature sensor and see if this problem goes away. If it does, then replace the sensor.

Clean your throttle position sensor...it should be located next to the throttle body, or just below it. Cleans its connection too. Then plug that back and see if it helps.

Check your intake hoses for any cracks or any vacuum leaks. Tighten all intake hose connections.

Download the E34 Bentley manual (google for the download links) and read through the engine troubleshooting guides to see if you can narrow down the problems.

Please read through the maintenance sticky thread at the top of these forums for more exhaustive information.

I'm sorry to be so general in this reply but your symptoms are not straightforward to diagnose (at least for the E34) and require a thorough check. Oddly enough, we've had a few of such cases in the past 2 days too.
 
#3 · (Edited)
Scratch my earlier post. This probably has nothing to do with tranny fluid. Regardless, take your car in for an undercarriage inspection to clear it of all leaks etc.

I think your problem may likely be a bad throttle position sensor. Once many moons ago, my engine just bloody cut out while i was about to negotiate a turn at high speed. The steering stiffened bigtime, but I managed to brake and turn sufficiently to avoid harm. The engine cut out once or twice again when I made U turns. The problem was the throttle position sensor.

Unplug the sensor, clean it and the connection with contact cleaner, blow dry, dab dielectric grease onto both and plug it back in. Then drive the car and see if the problem is fixed. Pull out your error codes and see if anything is reflected. After cleaning the tps (the sensor I just referred to), delete the error codes then drive and see if the problem is fixed.

If the problem gets fixed.....i would suggest that you have the sensor replaced anyway for safety reasons. Its cheap....like only $50 oem, and can be done easily by yourself in about 5-15 minutes.
 
#7 · (Edited)
Edit:

Oops wrong guy.

But that e34 in the vid is a m50 525i not a m30. Different engines... Different internals... Different situations.
Lifter Noise (I'm guessing that's what you meant) on a m50 is bad. Valve train noise from a M30 is somewhat normal.

A m30 shouldn't be quite. It should sound like a singer sewing machine.

Now cutting out and dieseling on a M30 check these things.... In this order.

Battery
Alternator
O2 sensor
Plugs
Plug wires
Distributor and rotor button
AFM
Temp sensors on the thermostat housing
FPR (I doubt it but maybe)
Fuel Pump (doubt it also but again maybe)
Crank position sensor
Throttle position sensor

Pretty much everything dealing with fuel spark and air.

The TPS on a M30 rarely is the culprit
The CPS maybe.

Battery and alternator would produce these issues for it's not feeding the car enough spark to keep running.
AFM would cause it if it is malfunctioning
Dizzy/ rotor and plugs would cause it if there is a defect somewhere in there.
Temp sensors (the black one) goes to the ECU. If going bad it will send the car into limp mode.

The fact you said it happened while turning it could be your PS pump is on the way out. But I doubt that for it would make steering when normal a bit tricky.

All these suggestions come from my recent experience.

In the end a battery, alternator, and some AFM rewiring fixed the issue.

Note: my AFM setup is different from stock for I relocated it when installing a reverse manifold. So the wiring issue will not apply to you.
 
#8 ·
I don't know if this will help figure the problem out butttt, when the car was running it would start rough and idle rough for the first minute or two then once it warmed up it was good to go. And then when turning the car off it would make a pump like sound for 20 seconds or so
 
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