e30 won't start

[e30wontstart]

Hi everyone,

This is the most stumped I've been on an e30 before. My 92' e30 convertible always used to start on the first crank. Over the course of 3-4 weeks it started taking 2 or 3 times to start, then it finally ceased firing altogether.

Initially cold start fluid helped, but then the CPS failed causing no fuel or spark. I replaced the CPS and it started again with cold start fluid, but won't run for more than a few seconds b/c it appears to not be getting fuel.

The battery is strong. I have tested everything on the ignition side except the distributor, but assume this works since the engine fires with cold start fluid. Without cold start fluid, the engine does not fire or even cough for that matter. I have replaced the fuel pump, fuel filter, fuel pressure regulator, spark plugs, main relay, and fuel pump fuse. I have used two ECU's to test the wiring and it all seems to be working with the exception of the 'air conditioning on' test. I have jumped the fuel pump relay (I have not replaced it though) and the engine still won't start. The fuel pump is getting 12 V. I was initially getting a Lambda Control 1 check code. That went away. Now I get no fault code reading b/c the one other ECU test that doesn't work is the 'idle position' on the TPS. Without the TPS working, it doesn't register that I am hitting the gas pedal 5 times. There was a period that the TPS worked fine and the car still wouldn't start, during which time I got 1444 (no fault) on the stomp test.

In short, I am not getting fuel and do not know if it is a mechanical or electrical failure (or both). And the injectors click via the ECU test, so I assume they haven't all failed. Also worth mentioning is that some of the clicking noises from the manual ECU test do not occur when the car is on ignition 2.

Anyone have ideas on how to fix this?

[itsonlygeorge]

e30 won't start

Did you check the direction of the fuel filter when you replaced it?There's a page in the Bentley manual that tells you how to check for fuel flow rate. I believe it has you disconnect a fuel hose and check how much liquid comes out over a 30 second period of time.

You can also check your relays if you have a 9 V battery and a multimeter a few alligator clips.

[e30wontstart]

Yes, fuel filter direction is correct. Also, the old one was only about 4-5 years old and looked to be in good condition. Do not think it's a filter issue. I'll take a look at disconnecting the fuel pump hose from the fuel line and see if fuel comes out tomorrow.

I'm assuming the relay works because jumping pins 30 and 87 force starts the fuel pump and I am not getting a glowing bulb when I connect pins 85 and 86. This suggests whatever tells 85 and 86 to work is not telling them to work.

[peterman]

Do you know you are getting spark?
Pull a wire and put a plug in it. Rest it on the top of the engine and crank it over. Don't hold it while cranking. you should see a blue arc across the plug gap. An orange arc means not enough juice - ie. need a coil, cap and rotor, etc.
You need to confirm that you are not getting fuel before you state there no fuel. Pull the supply hose - the hose that DOES NOT connect to the FPR and crank it over to make sure you are getting fuel. best to have a soda bottle to pump the (assumed) fuel into.

[e30wontstart]

I do not appear to be getting fuel. I hooked a soda bottle up to the line coming off of the fuel pump, jumped the fuel pump relay (which causes the pump to make a whirring noise), and cranked the engine. No fuel came out. The fuel pump is getting 12V. If I do not short the fuel pump relay, however, the fuel pump does not make a whirring noise. The fuel pump is new. Same deal with previous fuel pump.

The ignition coil and battery were tested and work. The spark plugs are new (the car wouldn't start when old ones were in either; replaced with same model) and seem to work based on cold start fluid start. I have not tested the distributor rotor. I can test for spark later, but if the engine starts when cold start fluid is sprayed in and runs for 2-3 seconds, that would suggest spark, and at the very least that the distributor rotor works.

[e30wontstart]

Also, I changed out the TPS for a new one (drilled holes in bottom this time) and that didn't change anything, but I wasn't expecting it to fix the issue.

The fuel tank looks about half full and the level sender confirms.

What is the other access point on the rear seat well, on the opposite side from where the fuel pump sits?

[e30wontstart]

Oh and here she is....

[gath]

If the pump is new and it doesn't have the original connector orientation show, may be the polarity is reversed and it is not pumping out fuel but you will hear it spinning. Go to the fuel pump and jump it at the connectors by 12v, if there is no fuel coming out but it is running, then the polarity is reversed, try to reverse that and see what happens.

[e30wontstart]

Good news:

I did mistake the polarity when installing the new pump. Switching the two wires results in a working fuel pump.

Bad news:

The car still does not start. On key ignition 2, the fuel pump does not whir unless the relay is jumped. This confirms my belief that the problem(s) are a combination of mechanical and electrical.

A 12v, 5w bulb test across 85+86 on the fuel pump relay does not glow, suggesting there is at least one more (probably electrical) problem somewhere upstream.

Thank you for the polarity advice though.

[itsonlygeorge]

e30 won't start

The bulb should not glow without voltage. The relay is only an electrically operated switch. You need a continuity tester or multimeter.



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[e30wontstart]

Tested the sockets on car as follows:

On key ignition 2
12V between 85 and 86, 0 resistance
12V between 30 and 87, oscillates regularly between 0 and infinite resistance

On no key in ignition
12V between 85 and 86, ~32kohm resistance
12V between 30 and 87, oscillates regularly between 0 and infinite resistance

[e30wontstart]

George,

I have been testing the sockets, not the relay itself. The test results are inconclusive, but one thing suggests it is not solely the relay (if it is the relay at all): the car still won't start when the relay is jumped.

If the resistance to open the switch goes to 0, and no current is flowing (based on light bulb test), then whatever signals the relay to bridge 30 and 87 is not doing so, right?

[Yogawrench]

This sounds like it might be a fuel pressure regulator problem. I have a cabrio E30 built in December 1992. My problem was remarkably similar to yours. Turned out the FPR was failing.


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[Seawolf]

Well at least you know the CPS, DME and ignition circuits are good otherwise it wouldn't fire with starting fluid.

So to simplify the test - do you have 12v at fuse 11 when cranking ?

If you do, recheck the fuel pump plug for 12v when cranking, if yes then the pump is done.

If not then jump fuel pump pins 30 & 87 and recheck for 12v at fuse 11 when cranking.

If you are now getting 12v, the relay is done.

If not then the relay isn't getting power, you should have 12v at the red wire on pin 30, if you're not getting power then check the fusible link in the trunk.

- let us know the results eh ?