Unreliable cold starts; very long crank

[andrewwynn]

Wife's car gave the symptom of fuel pump died: crank with zero sign of ignition.

She said she also didn't hear the fuel pump whine at key on.

Fuel pump original with 185,000 miles and I had a spare ready to install so I went to put it it only to discover the new pump was apparently damaged in shipping. Worse, I put the old on my bench power supply it spun right up.

So: car was out of service about two months while I was not able to even look at it, I finally bought a knock off pump from Amazon (same brand with 12 mo. warranty I have in my car).

I installed a few days ago and not too surprised that things weren't quite right.

It took on the order of 100 seconds of crank to get the car to start. The first attempts had no sign of life at all.

I hooked up a fuel pressure gauge before I tried to start but unfortunately the gauge was defective and fuel leaked into the dial. I did get a reading of 40 psi but of course not reliable reading but non zero.

At the time the charging up from 6v from being left for eight weeks battery had under 10v so I considered low v may have been the reason for 40 psi.

So I hooked up my car to give power to the starter and did quite a number of 10 second cranks and by the 4th attempt I finally got the first sign of life a couple cylinders fired.

It took maybe a dozen very long cranks before it finally chchchugged into life. It ran ok other than stuttered a bit on heavy throttle.

I left the car running to charge the battery and work out kinks. Then over the next hour used the car to drive to HF to exchange the faulty fuel gauge bringing my son with to sit in the car because I didn't dare shut it off.

Got back home and other than a minor incident of spraying gas out a joint that needed some Teflon tape I got the gauge hooked up and the needle was right at 50-52#. Oddly bouncing between the two values im guessing at the frequency of the injectors closing and causing water hammer.

Anyhow once I got the car back where I could leave it parked in case of non start I shut it off and was able to restart without a problem.

Fast forward a day or two: cold start was a little slow took twice as long as normal but the engine turned quick not a warn starter high current low voltage thing.

I moved the car to the street where I would have to move in three days.

On the third day when I went to start it was a very hard start like starting a carburated car in WI winter. 10-12 seconds but some sign of life 6-7 seconds in.

I didn't think ahead enough to hook up the fuel pressure gauge at startup but once started it ran fine no hesitation on heavy throttle etc.

I did notice after I got it running that the short term fuel trims are quite high indicating lean condition. Lends to low fuel pressure could be a problem but when I've hooked up the gauge it's been 50-52.

So I'm suspecting fuel pressure regulator which I can get from fcpeuro for $25 or included with a filter for $65 but I couldn't find other threads on xo with similar symptoms that resolved from FPR replacement. The closest I found was a 7 year old thread that was comically long (35 pages) that tuned out to be a kinked hose from the FPR to the fuel rail (something I will definitely check on since the last thing I worked on on that car was installing some mini cats to fix a post cat error from the 20 year old cats wearing out and not being 100% efficient).

FYI worked like a charm. I installed a pair of right angle O2 adapters that just slow the feedback from post cat exhaust and it eliminated the constant post cat O2 inefficient errors. $15 to stave off a $500+ two cat replacement!

So next test will be to monitor fuel pressure during the next cold start (2-4 days sitting). I'm quite sure it will be a long hard start I'll bring my jump start 50A charger with to assist with 1/4 of the starting current or maybe just use the bolt power which can supply the entire 200+.

I will report back. Oh also I will check the hoses and make sure I didn't manage to put a kink in the line from the FPR to the rail when I did the post cat O2 upgrade.

Has anybody had an FPR fail where it only didn't work correctly when cold but worked fine once running?

Coincidentally the fuel tank is below the level where it's sucking from the left side but I will check to confirm the tank levels are ok (right side full) before I start. The right side was full when I put in the replacement pump so siphon jet not part of the equation other than depending if the FPR needs back pressure to work the pressure relief valve in the tank could have failed and that will just circle fuel back to the right tank without sucking any from the left.

While fresh on my mind I think I'll go over where I moved the car for storage while fixing this problem and do the pressure gauge start to answer that question. (if pressure is low until starting). It will be just very strange if the case. It's electric pump should not make a difference once RPM higher unless the pump makes enough overhead pressure at 14v running vs 11-12v while starting.

Anyhow. Any feedback from previous example of similar long crank runs fine will be very helpful.