1990 Infinity M30 Just cranks but wont turn over need help quick!

[90T04]

Hey guys, I was wondering if there are any common failures associated with this problem on Infinity's.

The car is a 1990 M30 and it has the 3.0L V6.

Im a technician but i dont normally work on Infinity's, I am working on it for a friend.

Here is a description of the problem:The car starts up great first time in the morning when its cold. After you get where you are going, and and lets say you go in the store and come back out, the car will not start, just cranks. Its cranking good and fast, battery has plenty of juice. You have to crank it maybe between 5 and 15 times before it will fire up. Once it does start, it runs absolutely perfect.

The problem is getting worse and worse, lately it has been taking a lot of cranking and were getting worried it will take out the starter.

I have heard some things about the "FPCU." Is this a likely culprit?

The only other thing I can think of is that it is boiling the fuel in the rail while it is sitting and the engine is hot.

Thanks in advance!Ryan

[elwesso]

First order of business is to fix the Y, theres no Y in infinit I

have you done a fuel pressure test and stuff like that? Maybe a fuel filter?

[guadofreak]

That sounds like the fuel pressure accumulator thingy. No clue on the specific term but I have seen that happen where it does not retain the pressure in the lines when you shut off the car.

That is my guess.

[90T04]

Heh, sorry, you can tell im not too familiar with these cars.

Well, on this Infiniti, is there a fuel pressure test port or do I have to tee into the supply line. I can see where the supply line comes up to the regulator in the front, but no service port there...

Also, there is a VSV on the intake manifold on the passenger side with two vacuum lines running from it to the fuel pressure regulator. I am guessing it is a fuel pressure up VSV, (for maximum fuel pressure on hot starts), the clip for the VSV is broken, and loosely sitting there. Is is likely that a poor connection at that VSV would cause it to fail to start? I have the FPU VSV completely removed on my Toyota and it still starts fine.

I will get back to you on the fuel pressure.

Once again thanks for your quick response!Ryan

[90T04]

guadofreak, that sounds very possible. Where is that accumulator located on these cars?

Sorry for my complete lack of familiarity with Nissans, I am just trying to help a friend in need.

[90T04]

elwesso, I just have to say that your Q45t is freaking sick!

Awesome that you are putting all that power through a damn auto!

I would never expect being stomped by a sleeper like that at the track (or on the street).

[elwesso]

Youll want to Tee it in.....

The FPRs arent really known to fail at least in the Qs, maybe they do in other nissans?!

What is this VSV you speak of??

Thanks for the compliments on the car, it wont run 12s any more, but it will run 13s under spray... lots have changed and more is to come!!

[90T04]

Im not sure what they are called on Nissans, but on Toyotas they are called VSVs, short for Vacuum Switching Valve. The VSV I was talking about on this car, is the one thtat controls the FPR. It basically blocks off the FPR from seeing manifold vacuum or lets it get manifold vacuum. It has a little brown 2 pin connector and the connector is broken and doesnt snap in firmy.

I took of the line that I thought was the pressure line and it was the damn return. I put the end that I thought fuel was going to come out of in a bucket and I had my wife crank the engine and I got blasted with Fuel! Not my idea of a good time. Well silly me the filter is right next to the engine and the pressure line is obviously the one comnig off of it. And yes the rail is getting lots of pressure. I dont know exactly how much because I dont have a pressure tester. But thats where I am headed right now, to go get one.

Thanks for your ideas, Ryan

[elwesso]

LOL! Gasoline baths are for auto guys... Come on, admit it, it was good! Reminds me when i did the transmission pan, ATF EVERYWHERE (even where the sun dont shine )

i dont hink theres a "VSV" thing on there for hte fuel pressure regulator, unless the VG30 is different than the Q motor...

You might just replace the filter and see what that does....

[90T04]

Okay okay, the fuel shower was pretty good, but it doesnt top antifreeze in the armpit...

Wouldnt the performance of the engine suffer when it is running and under a load if the fuel filter was clogged? Cause it runs fine once its started.

I put a fuel pressure gauge on the hose coming off the filter, and its showing about 45 psi. I dont know what I did, but now its working again. I hate intermittent problems.

Well im going to call it quits for the day. Thanks for your advise. Ryan

[elwesso]

All i know is that my old Q went to the dealer before i took delivery. It would run fine, but under a hot soak it wouldnt start.. Fuel filters are only like $10 so you might just try and replace it.. Good maintenance habits anyway... Has it been replaced???

[DominickJ30]

These and the older maximas have a problem with stuck open injectors. Short trips flood the engine. Check those out. Then I would check the computer for problems with injectors.

[M30 Steve]

Sorry for the late reply, I don't see many M30 posts here. The M30 has a recall on the injectors, call the local dealer with you VIN to see if the injectors were ever replaced. The dealer will install new ones at no charge. It was a saftey recall good for ever, plus you get a G35 to drive for the day(big fun). I have a FSM on the car if you need specific Info. about the fuel system. I don't have an electronic version of the FSM but I would be happy to look up something if needed.

Steve