Car cranks over too long before starting

[ccathey]

I have a 1992 Manual NSX. Most of the time it starts right up, but on occasion it will crank about 3 times as long before starting. This happens maybe once every 20-30 starts. Not too big of a deal, but it makes me wonder when it does happen.

Has anyone had this or have any suggestions?

I'm no mechanic, but the two things that I am considering are that it isn't getting fuel at first or no spark.
I can't imagine the spark not being there at first and then suddenly coming, so that would make me lean towards fuel.
Any ideas would be appreciated.
Craig

 

[blackna1]

Same old problem with all cars. The main relay probably has 'dry joints' that results in insufficient current fed to the fuel pump = less fuel injected into the engine. This can be replaced for about $70 at the dealer if you dont want too much trouble (dealer would most likely replace it for you if you service it and tell them about this problem). Or you can take it out (behind the passenger seat underneath the upper interior panel that says "Main Relay" on it) and re-solder all the joints yourself or even get someone who knows electronics to do it.

My x was taking a bit longer to start, especially 'warm starts' so I re-soldered it before it even 'not start' on me. And this also just happened on my 2000 3.5RL few days ago, was a 15 minute fix for me.

Do a search and you can find out more on Main Relay.

Hope this helps.

 

[HungX916]

WOW, I was just going to post this problem!...Mine is a 02 with 22k. Sometimes it cranks longer than normal, but usually it should start right up once the key is turned. Like you mentioned, It feels like the spark is out of juice or not enough fuel pumping.

 

[joove]

I had a similar issue a few weeks back. Still am not entirely sure what the deal was.

My options were.
1. Lousy battery
2. No fuel
3. Plugs
4. Filter clogged
5 Injectors clogged

However, my filter and spark-plugs are brand new (recent 60k). On further research looked like the Main relay could also be a culprit. I had put in a brand new battery and fuel injector cleaners. No luck! So I yanked the main relay out and resoldered any thing that had been soldered in 94 . Put it back in. No cigar! but it reduced the crank count.

After that, I could atleast hear a distinctive click as it relay shut off after priming the fuel pump (maybe I am hearing it now only becuase I am waiting for it). Now, I turn the key on, wait for the relay click and then start it and it starts within 1-3 cranks. There is probably something else going on as I sometimes get 3-4 cranks. My prelude on 6 yr old batteries starts in 2 cranks always. I have no idea what the NSX's cold start crank count is. Bigger engines take longer ?

The factory manual states that there is a spring loaded thingy that falls into place to retain pressure in the rail once the pump shuts off. Thats probably busted after these years and hence the need to wait for the rail pressure to build up after its been sitting a while. There is a potentially faulty fault fuel pump resistor to look at which I'll do if it gets worse.

all the best.

-vamsi

 

[Taj]

I would start with the simple fix first, the battery.

 

[drew]

ccathey: 99% chance it is your main relay.

joove: I would clean and re-grease your ignition switch (the electrical part...opposite where you would put the key in). The switch is easily taken removed and taken apart...takes about 30 minutes the first time and <15 minutes after that. Make sure you use dielectric grease.

I fought all those symptoms...the main relay cleared up most of them. The switch caused the few remaining hiccups....that was two years go and it has been 100% fixed since then.

Drew

 

[joove]

Thanks drew. Will check that one out.

-vamsi

 

[drew]

Ignition switch internals here:

http://www.nsxprime.com/forums/showpost.php?p=436339&postcount=5

 

[Larry Bastanza]

The fuel pump resistor is not used during the starting sequence. The main relay shorts it out for max fuel delivery for starting.

The idea of turning the key to "on" and waiting for the fuel pressure to build properly is the best approach. The item that seems in question in this case is the fuel pressure regulator, and its ability to hold pressure in the rails as mentioned above.

The best test for this is a fuel pressure gauge on the system. Run the engine so pressure is up at proper spec (36-44 PSI at idle) . Shut the car down and leave it over night, check the pressure in the morning. This result will tell you if the pressure regulator is leaking down.

HTH,
LarryB

 

[comtec]

Maybe you are having the same problem that surfaced when d1guy changed his air filter. Onerednsx solved his problem. Worth a look.

http://www.nsxprime.com/forums/showthread.php?t=78814

 

[ccathey]

Great information guys, I'll let you know how it goes.
Thanks,
Craig

 

[ccathey]

Well, I did the Main relay fix and haven't noticed the problem lately. I hope that was it. Thanks for all the help.
Craig

 

[NSXLR8R]

Good to hear it is fixed, seems it was your relay....but for others with similar problems.....

As Larry alludes too, when the key is first switched into the "on" potition, the fuel pump begins to build up pressure in the fuel system. It is fairly easy to diagnos the difference in these two problems....fuel relay, or impatience.

Just think back, or start to think now, is it on quick starts, when the fuel is not given time to build pressure. Or you can just take a couple of seconds between swithching on, and starting, and see if the problem persist?

I had this problem in the late 90's, but now I usually let the car have about 2 or 3 seconds or so to build pressure when it has been a while since I started it, and have not experienced this problem again since about 6 to 7 years ago. Behaviour changes are the worst, but the nut behind the wheel is where I made the adjustment. In fact, I am impressed at how well the car starts after a couple months standing on the trickle charger....it just fires right up!