Hot no restart issue?

[george graves]

I'm chasing down a gremlin. Once in a while I'll get a no-start(crank but no fire) condition. Here's what happens. After driving for 30 mins or more....

....If come back out to re-start after about 5 mins it will just crank and crank. No fire.

...If I come back in 1-2 mins, there is no issue - fires right up.

...if I come back in 30-40 mins - there is no issue - will fire up as well.

I'm guessing it's one of two things. A bad (main) fuel pump or vapor lock (heat form the exhaust is boiling the fuel). Has any one had the same issue? If you did - what resolved it? (not sure why I'm posting this - I think I just need to get under the car and check it out - I'm just being lazy)

[dnguyen1963]

I had the same problem a few years ago and it was due to a lose elbow going in the throttle body. Someone else with a similar problem installed a check valve in the fuel line as a temporary fix until they replaced the pump.

[jlevie]

The only times I've seen this the cause was one or more leaking injectors that flooded the engine while it was parked. There are other possibilities, but given the age of the injectors I'd have them cleaned, rebuilt, and flow tested first. I like to use RC Engineering and they provide a before and after report.

In one case, I sent a set in and they found two of the injectors seeping. We didn't have any evidence of a problem before hand, so it was a little bit of a surprise.

BTW, if the pump is in good condition and the filter is clean, it will only take a few turns of the engine for the pump to fully pressurize the rail even if the rail had no pressure on it to begin with.

Generally speaking, if the check valve in the pump fails, the pump is pretty worn. Adding an external check valve is just putting off the inevitable pump replacement. So you might as well fix it right the first time.

[Rouvld]

Did you ever figure out what the problem was? My car does this exact same thing, I just had my fuel pump replaced so I'm thinking that the problem is my injectors.

[TobyB]

If it's leaky injectors, try starting with your foot on the floor when it does it.

This sets 'flood clear' mode in the ECU and it will turn off the injectors.

If that doesn't do it, then I like the fuel pump relay, as a couple of minutes is about long
enough for it to heat- soak.

hth

t

[Rouvld]

If it's leaky injectors, try starting with your foot on the floor when it does it.

This sets 'flood clear' mode in the ECU and it will turn off the injectors.

If that doesn't do it, then I like the fuel pump relay, as a couple of minutes is about long
enough for it to heat- soak.

hth

t

Then it must be my injector, whenever it doesn't start after a long drive I have to press the gas and then it starts right up.

[george graves]

If it's leaky injectors......

All signs point to leaky injectors. Some rich smelling fuel at start up happening now. Once it cranks, and fires, my wideband afr shows it rich for about 2 seconds. I'm glad I have that.

After a hard pulls on the freeway the issue will go away for a bit. But I don't discount the idea of a bad pump at well (tricky problems are always two things happening at once) - like it happens less often with a full tank.

Urrr. Right now my e30 is my only personal car. So, I think I might buy a second set of injectors (this is a m30b35 out of a 635csi in my e30) - and get them cleaned by Mr. Injector on the forum.

Thanks for the help - I'll report back.

[Cephas]

BUMP

Did injectors fix this for you? Just as an aside, I had a similar issue. My car would crank for a long period and then start, but run rough for a few seconds before getting better. Exhaust was very rich and it started stumbling randomly and throwing the Lambda code...1221.

Rebuilt injectors fixed the issue for me. It might be worth putting in a new OEM FPR "while you're in there" as well as replacing any fuel injection hoses with new good high pressure stuff from BMW.

Hope it's fixed!

[george graves]

I decided to limp on it for a while - since it was really predictable.

Then just today my fuel pump went out while still in my driveway (I love how my car never leaves me stranded!). I replaced the pump with a new Delphi pump, so we'll see if that fixes it. I suspect it's not the main issue.

If not, next is injectors. I just can't decide between the new design Bosch/mustang injectors with the better nozzle design or cleaned/tested factory stock injectors.

[TimeMachinE30]

I just had mine done by MEPEH as I prepare my M30B35.

BEFORE


AFTER


Quick turnaround and under $50. Got mine painted, too.

[Cephas]

I just had mine done by MEPEH as I prepare my M30B35.


Quick turnaround and under $50. Got mine painted, too.

I used him as well. Swell guy and great prices/turnaround.

[george graves]

Just an update. Mostly too keep track of things so if others have the same issue ;(

So fuel pump replaced - still same issue.

Now after so many hard, long starts, I think I've taxed the battery. So I'll replace that, and see what's up. I picked up an e46 as a DD so that I can put the e30 under the knife. She needed it. It's time my e30 isn't my DD. Women hate it, and long trips in it suck to be honest.

One thing I really would think would be helpfull on any modified car is a fuel pressure gauge. Problem is... There isn't many sensors that are rated for fuel use (most are for oil - but I don't get that - it's all the same as far as how invasive/corrosive gas is vs oil)

So a new battery, and then I think I'll do injectors.

[TimeMachinE30]

What is wrong with the e30 for long trips?

[Kershaw]

Don't even play, lol. The list is long. You know you'd prefer your e38 for a 1200 mile trip.

[TimeMachinE30]

Don't even play, lol. The list is long. You know you'd prefer your e38 for a 1200 mile trip.

I want to k ow if it is an M30 thing.. especially as I decide mounts and bushings.

And the E38 is a nice road trip car. I'm averaging 21 MPG!