1986 325i running problem

[muzz]

Hi guys need some help recently my 325 starts and runs ok for a few km then seems to splutter under acceleration just like disconnecting the afm but when I pull over turn the engine off I can immediately start it and it's fine for a km or so
I only have the basic tools so I'm looking for some possibilities
Any ideas thanks in advance

[Speedtouch]

http://www.e30zone.net/e30zonewiki/inde ... oubleshoot

[muzz]

Didn't really make any sense to me sorry anything more tangible to my problem please

[Speedtouch]

Possibly related to extreme temperature, if you're in Oz. Has the fuel filter been replaced recently?

Also check the condition of the distributor cap (look for cracks/arcing), rotor arm, ignition HT leads, and for corroded earths.

[muzz]

Thanks I will go through it all and check
Do you think the coolant temp sensor might be a bit faulty?

[Brianmoooore]

Does this car have a lambda sensor? This has the symptoms of a car which is getting wrong info. from the sensor and adapting the fuelling incorrectly, causing the rough running, and then resetting when the engine is stopped and restarted.
I should point out, that I've no idea how the early M20 ECUs adapt to the lambda signal, and whether they reset when ignition power is removed. Modern ECUs retain the adaptive settings, but this might not be the case with such an early design.

[muzz]

Brian no lambada sensor I've got a feeling it might be a bad fuel injector
Does this sound feesable
I took it for a test drive today and it did the same thing but without turning the engine off I continued to drive it 1st and 2nd gear it was bogging down and only allowed me to tickle the acelarator but in 3rd it regained its mojo and I had full power ??????? Then it bogged down again I'm very confused can you make anything out of that information cheers

[Speedtouch]

Could be that the crank position sensor(s) is/are on the way out; unfortunately, the early 325i (with Motronic 1.0) usually has at least one built into the gearbox bellhousing, so you may want to check out its resistance and connections.

http://www.e30zone.net/e30zonewiki/inde ... ion_Sensor

http://www.e30zone.net/e30zonewiki/inde ... tronic_1.0

I would suggest measuring the CPS resistance(s) at the ECU plug, in accordance with the pinout diagram given in the M1.0 guide.

[muzz]

Yep I have 2 sensors in the gearbox bel housing I know one is a cps but what is the other ?

[Speedtouch]

Crank speed sensor, perhaps, if the M1.0 pinout is anything to go by...

[Doobit]

Might be worth removing the injectors and soaking them in a solvent like brake cleaner overnight.

[muzz]

ok have changed the injectors with good proven ones from a e36 325
and i have also changed the two crank angle sensors on the belhousing with new ones
i thought i had a win with this as the car was "going like a rocket" until the same thing happened it bogged down and didn't correct itself until i turned it off and started it again
must say though before it was running a bit rich now tail pipe and spark plugs look like normal and the rich smell is not there anymore but im guessing the crank sensors would of fixed this
any suggestions this is driving me crazy

[Speedtouch]

When was the fuel filter last replaced (if ever)? Sounds like some sort of blockage causing fuel starvation.

I recently had a similar problem with a Fiat Seicento, which turned out to have about a centimetre of silt and crud in the bottom of the fuel pump - once cleaned out and fitted with a new filter, it was far better.

[muzz]

fuel filter fuel pump all new circa 6mths old i have been reading up on tps's and ive got a feeling it might be at fault mine is round plug 6 pin one
ive noticed a steel retainer on the new ones advertised for sale the one on the car dosnt seem to have one.
would this be an important thing?

[muzz]

bump

[Speedtouch]

I would guess it probably is, if they deem it necessary to fit one...

[muzz]

FYI thanks guys for all the input just thought i would share this. After months of my free time poured into fault finding i discovered the fault of the bad running was caused by a 71c thermostat being fitted to the car which resulted in the car running too cool 1/4 on the temp gauge so the primitive motronic 1.0 ran fine for about 15min then realised the engine was too cool and dumped extra fuel into the ports causing the bad running,ive changed the stat and it is back to its normal running temp 1/2 temp gauge and performs great and is not running rich happy happy days

[Speedtouch]

Interesting solution to the problem, thanks for sharing.

[muzz]

Ok scrap what I said "fixed" the running problems was not the thermostat at all it would seem the gremlins have returned if they ever went away at All at the moment I'm clutching at straws please any help or advice further to what has been said would be greatly appreciated cheers

[ah]

Ive had a Fault like this since I bought my car in 2010,mine also runs 1/4 on the temp gauge,I was really getting my hopes up.

[Brianmoooore]

Yep I have 2 sensors in the gearbox bel housing I know one is a cps but what is the other ?

One is the equivalent of the teeth on a modern crank sensor, such as used on later E30s, and the second is the equivalent of the missing tooth.
One reports that the crank is turning, and at what speed, and the other reports when cylinder 1 and 6 are at TDC.
Both sensors are identical.

[muzz]

Yes they are Brian have replaced both still looking for the problem throw some suggestions to me guys I will check anything and everything this is driving me mental my only step next would be a m50 conversion but my thinking is if it runs great for 15min why not always this is what I'm trying to find out PLEASE HELP

[paultv]

Here's a mad one - I had missing under acceleration only when hot - fine when cold - and also not always present.

Turned out to be a plug lead with a burnt out carbon suppression resistor - sparks jumped across it inside the cable - but not when hot -

Probably not your issue but as you're pulling yer hair out its worth a check - IIRC the cables should read 2K ohms approx - but they should all read the same.

good luck with it

Paul

[Speedtouch]

Ensure that the blue temperature sensor in the thermostat is working as it should, by measuring its resistance at the ECU socket, as per:

http://www.e30zone.net/e30zonewiki/inde ... or#Testing

If that checks out OK, try and borrow a replacement ECU (presumably the earlier '0 261 200 073' Motronic 1.1 type, on a 1986 325i); there may be some component or solder joint failure taking place...

[muzz]

still looking for the gremlin have changed just about everything serviceable including ecu afm icv plug leads for new set this is crazy

dont know where else or what else to do but i'm still welcoming recommendations

[Speedtouch]

Try a compression test on the cylinders - all should read around the same, at 160 psi or more.