Hard Start in an '87 E30 325Ci

[nik74tii]

Hello All,
I am having some difficultly in starting my E30. The symptoms are:

1. When cool (standing for more than an hour), there is no problem.
2. When warm (say, restarting after standing for 15 minutes or so) I have to press the gas pedal to get started)
3. The car idles rough (seems to miss every tow to three seconds), and mileage is down to around 20-22 mpg.

The car has a rebuild head & new plugs. I'd appreciate your suggestions on other adjustments, etc.

Thanks,
Nik

[victory1auto]

First thing I'd check would be the fuel-pressure regulator. Pull the vacuum hose from it and see if there is fuel in it. If so, replace the regulator.

[jwhite]

The second thing to check is your fuel injectors. If you have a leaky injector the pressure in the fuel rail after you shut the engine off will cause the leaky injector to fill the area around one cylinder with fuel and will deplete the fuel in the rail. Both will make starting difficult - you can guess how I know this.

Jeff

[nik74tii]

Hi All,
I checked the vacuum hose on the fuel pressure regulator both "cold" and "hot" and I don't see any fuel either way. Dont' know if there are other diagnostics for the pressure regulator.

After looking in the Bentley manual, I also checked the resistance over the coolant temp sensor at the front of the engine. At 173 F, it was 215 Ohms, which is about 85-145 Ohms too low. I have a new sensor on order. It's around $30, so it's not too much of an investment.

I will take a look at the fuel injectors next. I suspect that they are the most likely culprit. How difficult are they to remove and clean/replace?

Also, tonight, I had a very hard start from "cold." The symptoms are sporadic.

Thanks,
Nik

[victory1auto]

The injectors are easy to remove. Remove the fuel hoses, then remove the entire injector rail, unplugging injectors as required. The injectors are held to the rail by little retaining clips. I like to change these clips when removing/reinstalling injectors.

There are several fuel-injection-service companies out there. One is Cruizin' Performance [Rich Jensen]. They ultrasonically clean the injectors and do a before- and after-cleaning flow test. Figure on a one-week turnaround, shipping time included.

Also, the Chapter Tool Box has an on-the-car fuel-injector-cleaning rig that requires a source of compressed air.

Vic

[RealM3E30]

One we use all the time is as follows for cleaning, testing of injectors. R

Marren Fuel Injection
www.injector.com
203-267-fuel

[nik74tii]

Hello All,
I continue to have issues with starting my '87 E30. So far, I have removed the fuel injectors, had them cleaned and then reinstalled. One member suggested that I check the Fuel Pressure Valve, and that seems OK. It has new spark plugs.

The symptoms are:
1. Hard start when the engine is cold (it turns over for 10+ seconds before it "catches")
2. Idle is better, but still rough. It misses periodically.

I'd appreciate some suggestions before I start replacing things at random.
Thanks,
Nik

[m20power]

It sounds like we already sent you down a fruitless path...I'd hook-up a fuel pressure gauge to verify system pressure, and also verify that pressure is held while car is not running (overnight). I think this will verify FP regulator, leaky injectors and/or FP check valve in one test.

Let's assume fuel is OK...what about spark control? Is coil/dist/rotor all OK? After what you have done to the fuel system, a rough idle is unusual unless spark is NG. Check crank sensor...gap and output. I think you've got a spark/electrical problem (easy to say now that you've refreshed you fuel system!)

Good Luck,

Bob

[NeilE30]

I had a problem with my IX idling a few years ago, turned out to be an intake manifold gasket. There is a way that it can be detected with either propane or a cigarette lighter(unlit), maybe Vic or Bob can explain how to test it that way.

Neil

[m20power]

Neil, that's a good thought. A pronounced intake leak (downstream of the AFM) could cause the idle symptoms. I would first pull the plugs and see if running lean. If so, check intake boot for tears first.

The test you refer to involves bathing the areas of the IM connections (to the head, TB, etc) with a burnable gas. Easiest is to use a non-lit propane torch. A IM vacuum leak would suck-in the gas and the engine idle would increase/change.

I would still verify fuel system pressure. After that, spark. I think that's it.

HTH,

Bob

[nik74tii]

Hello All,
I know that this will start another controversy, but what spark plugs do you recommend? I put Bosch Platinum plugs in a few years ago, and promptly got yelled at by my former mechanics in Edison.

Thanks,
Nik

[jnscaldwell]

I use NGK, nothing fancy just the OEM equivalent.

[nik74tii]

Hello All,
I have measured the resistance of the coolant temp sensor at the top front end of the engine block. It does not match the resistance ranges as listed in Bentley and I would like to replace it. This requires that I drain out some of the coolant from the engine block.

Unfortunately, Bentley is exceedingly vague on the location of the engine block coolant plug (it says "located on the right side of the engine block"). Any clues where the coolant drain plug is located?

Thanks,
Nik

[m20power]

Nik,

Coolant drain plug is a 19mm bolt under the exhaust header, near cylinder #5. I wouldn't use that drain to remover just a little coolant.

If the coolant hasn't been flushed in >2yrs, then now is a good chance to do this. (Use BMW coolant from dealer with 50% distilled water)

If it has, then you can drain some of the system more easily by using the radiator drain plug. This is a blue plastic plug on the bottom LH side of the radiator. Otherwise, you could have the new sensor (with new crush washer) ready and just swap. You may leak a little coolant. If so. rinse the area and add as needed.

HTH,

Bob

[nik74tii]

Hi Bob,
Thanks! I am going to put some paper towel aroung the area and make the switch. I don't think I'll loose too much.

On a related note--do you have any suggestions about a thread sealant? Silicone perhaps? Or maybe a little teflon tape? I am not sure if anything is needed at all.

Thanks,
Nik