E30 Zone

i have tried the fuel pump to rail and loads off fuel also spark at plugs ,so I think it may be at injectors or rail but what or where to check now,

What E30 type and year?

Are the plugs wet?

Check that there's power at the red/whites on the injectors.
Are plugs wet after cranking?

the plugs are dry will just check power on red and whites

ok just checked plugs going to injectors both reading power ,I think this is red and white in which to check. ,this is an 86 high compression 325i in a 89 e30 coup

Have you ever had this engine running in this car, and did you hear it running in the donor vehicle?

yep last week running sweet as put it outside for a few days to change engine in another e30 and now wont start but it as allways took a good few cranks over to start if left a while so I put a new pump on this morning and checked spark air and fuel I think it may be injectors ?

Try spraying some brake or carb cleaner, or 'Start Ya Bastard!' down the throttle body while cranking the engine over.

I tried with brake cleaner earlier and nothing what do you think,, its agro to pull injectors out ,but if its the last straw

Sounds like it could be sticking injectors (though a bit odd if it ran OK just last week!), but perhaps do a compression test first to ensure all six pots are reading around 170-190 psi.

it ran and reved up nice but a cow to start if not started for a few days it seems fuel starved or a prob getting there ..there is fuel to the injectors and live power to ,,, but plugs are dry I just put a full can of cleaner till it ran flat did not start once there was loads of power in engine and no missing ,what would a comp test do or what am I looking for

So this is purely a cold-start issue now?

This would suggest that your injectors are sticking, which means you're losing fuel pressure in the system if left for a long time so the pump has to work harder to get the fuel rail back up to pressure. If that's combined with an old pump and a clogged filter then it'll take lots and lots of cranking to get the engine running.

When you checked for power on the red/white line, where did you check? At the injectors themselves? I'm wondering whether corrosion at the C191 is preventing your injectors from working properly, or being parked outside means you're getting water into the electrics somewhere.

I checked power at the plug of injectors and put a new pump on this morning it was bone dry at ioi plug and dme I looked before it went back in garage last night.i will change filter tomorrow and give it a crank to see if its that ,if not should I pull all injectors out and clean?

Don't clean injectors yourself - send them to Injectortune (in the Traders section). Best 60 quid you'll ever spend.

You could try putting them into a jam jar one at a time to check the flow pattern.

ok I thought a lot about injectors and thought to try more on lecy side ,so I pulled first plug on injecter then connected a light to see if it would pulse yes it did then tried to fire, put plug back on and away she went once turned off it tries to fire but no luck ,itried to find 191 plug but cant where should it be traced injecter loom back and cant find it,its an electrical problem but where do I go from here? help

'86 loom probably won't have a C191. Only on facelift looms.

so where do I go from here ,I need help its seems a fault on cold start although engine was hot and would not start ,where do I test or how to check injecter electrical probs does the flashing light on plug tell you anything

if I take first plug off of injecter put a light in one of wires other to earth it will try to fire put in other wire nothing theres a fault but I don't know where to go from here,need help brain drain here

this is a preface engine loom 325i high comp 1986,put into a 89facelift coup

can you by pass blue or brown plug to see if sencer is broke it seems it tries hard to start if light is connected to plug on injecter so something is saying no the light is bright so power to injectors is strong am I right in thinking it could be sencer or am I just barking mad

Use a multimeter to measure the blue temperature sensor resistance:

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

Note, however, you'll need to find out the 35-pin ECU connections for your pre-facelift ECU if you want to measure the resistance at the ECU socket.

The brown sensor only supplies the temperature gauge, and won't have any bearing on engine operation.

Speedtouch wrote:UNote, however, you'll need to find out the 35-pin ECU connections for your pre-facelift ECU if you want to measure the resistance at the ECU socket.

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

That's the jobbie - use the multimeter between pin 13 and a ground connection.

frenchi wrote:if I take first plug off of injecter put a light in one of wires other to earth it will try to fire put in other wire nothing theres a fault but I don't know where to go from here,need help brain drain here

Assuming you have motronic 1.1 or 1.3:

One side of the injectors goes to ground (pin 14 on ECU connector )

The other end gets pulsed by the ECU.

So if as above you put your bulb across the two wires...you expect to see the light pulse.

If you put your bulb one side to chassis and the other side to the power wire...Red/White I think people are stating here...then likewise you should see the bulb pulse.

Lets assume now that you are missing the common ground that goes to all of the injectors. If you touch your bulb one side to chassis and the other side to the injector pin that should have ground...but is now missing it...you are now providing a common ground to the injectors although slightly "diluted" by the resistance of the bulb.

This could be why as you state if you place the bulb on one lead..probably Brown or Black...and the other lead to chassis the engine tries to fire.

In other words it could be that the common ground from the ECU pin 14 to the injectors may have gone missing.

If you have motronic 1.0 (ECU has only 35 pins) then +12 volts is supplied from battery (Red) to the main relay pin 30. The relay then passes this +12 volts to the injectors on the Red/White wires from pin 87 on the main relay. This main relay gets +12 volts on Pin 86 of the relay while pin 85 (Brown/Green ) goes to ground from pin 20 on the ECU.

So you need to check that this main relay is energizing when the ignition is ON and you should have constant +12 volts on each of the injectors (Red/White).

The other wires on the injectors..Brown/Yellow for three cylinders and Brown/White for the other three cylinders get pulsed to ground from the ECU on pins 15 and 14 respectively.

So in this case you should have +12 volts on the Red/White injector wires when ignition is ON but maybe you are missing the pulsed ground from the ECU to the Brown/White or Brown/Yellow wires...in this case when you touch the light bulb from these wires to ground you are supplying a form of ground to three of the injectors so the engine tries to fire.

The main reason the ECU is not supplying this pulsed ground to the injectors is that the ECU is not receiving CPS signals as the engine turns over....normally the fuel pump will also not run without CPS pulse but someone may have re-wired the fuel pump to run as soon as ignition is turned ON...this should not happen!

All the above is how I understand things to work....I may be wrong.

thanks for that I had my father in law over car electrician clever man ,he went through what you have said .but how he solved it was checked and cleaned all earths and still no go so put an extra earth on from battery to inlet manifold ,bang she fires strait up so breaking down somewhere ,many thanks for every ones help,,, once again ,,this site is the ,,,,nuts,,

As others said, the injectors ground through the ECU but the Blue Temp sensor grounds through the engine block, so the most sensible option is to get a new engine-to-body earth strap for peace of mind.

thanks ,,,,fellers,,,,

Good to hear you got it sorted in the end...