Hello guys,

I'm having some trouble getting the car started after a homemade rebuild. I've got spark, fuel is coming into the engine, and compression had been tested and is OK. Managed to start the car twice and died on its own after 1 minute. Didn't run exactly great.

Car has been sitting in the garage for the last 3 years. I already changed fuel.

Brand new battery.

I think my next step is going to be to test the fuel pressure. However, I think this "not so minor problem" could be part of the problem. Have you guys seen this before? I thought I've already seen all possible problems after 12 years of ownership.

 

I haven't seen that pulsing power issue before...that is definitely weird.

Are you running the same ECU/Harness/Ignition/Fuel setup that you were prior to the engine rebuild and did anything else change when it was out?

Skeese

 

thats your flasher relay causing that. the f100 relay under the dash. if you unplug it, youll find that all those problems go away. my car does exactly what you showed but it only happens when its cold. once the cabin heats up, all those problems go away. the f100 relay doesnt have anything to do with the car not starting though. i agree with you about checking fuel pressure. start with that. when you prime the pump with the key on, it should hit 43psi and HOLD it.

 

Yeah, that's definitely related to the flasher and CPU. That is SUPER weird.

Go over the basics - no crossed plug wires, MAP sensor plugged in and getting a good reading.

Dale

 

Every day I learn something new here. I would never have connected that pulsing window to the flasher.

 

Same ECU, harness, ignition and fuel setup (except for 2 primary injectors that I replaced).

Hmmm, strange. Car never did that before. It is in the heated portion of the garage still yesterday and is still doing it. But thanks for the heads up, I'm glad it also happened to somebody else!

So I installed a T with a fuel gauge this morning. No apparent fuel leak. Does not seem to be holding pressure. At this point am I right to assume that I've got a leaking injector/bad fuel pump?

 

That's either a leaking injector or a bad fuel pump o-ring. If you pull the pump out, there's an o-ring at the top of the pump where it attaches to the hanger. Replace it or swap to a section of submersible fuel hose

 

Thanks for the fast response. However, I am not sure to understand... Can I simply change the whole pump?

Oh and I forgot to mention something: I removed the FPD 8 years ago.

 

The stock fuel pump has an O-ring at the top that fits into a "bell" on the end of the fuel pump outlet pipe on the fuel pump hanger. There are also 2 plastic pieces that locate the O-ring to keep it in place so it seals up properly.

If you haven't touched the fuel pump since the car was last running it may be fine. But, it's worth checking. Do you have the stock fuel pressure regulator?

Also if you pulled any of the injectors from the rails, it's possible for the O-rings around the injectors to leak and bypass fuel around the injectors straight into the motor. It's usually pretty obvious since many times you'll have gas coming out of the exhaust or out of the turbo manifold - it's a LOT of fuel. You should also have a strong fuel smell.

Also worth checking that you don't have the fuel feed and return lines mixed up. If you do you'll have all sorts of weird crap going on. The fuel pressure regulator is always the last part of the system before the fuel goes back to the gas tank.

Dale

 

The fuel pump is located on a hanger in the gas tank. Where the fuel pump connects to the hanger there is an o-ring.

 

Okay.

I unbolted primary and secondary fuel rails, turned key on and put my fingers underneath each injector. No leak whatsoever.

Fuel routing confirmed good (feed and return not mixed up).

I removed the fuel pump and all this felt one by one (very luckily not in the gas tank).

Now I have to understand how to put that back...

 

Well, at least you found the problem!

I think that is documented somewhere how that all goes together. Also other cars use a similar setup so you can cheat off another forum .

The metallic looking part in the middle under the O-ring, I'm not sure about that. Normally you just have the 2 plastic parts and the O-ring.

Dale

 

Cancel.

 

Yeah, you may want to post a pic of the outlet of the fuel pump.

This thread has a picture showing the order of the components at the top -

https://www.rx7club.com/3rd-generati...estion-499631/

Make sure to lube the O-ring with some WD-40 or some sort of light oil so it goes in smoothly and doesn't tear.

Dale

 

I don’t recommend lubing the o ring with WD-40. That can degrade the O ring. Use engine oil or petroleum jelly. Even dielectric grease can work.

Matt

 

Is that oring actually folded? It looks like it has a crease in it

 

Nah its the impression from the yellow-ish plastic piece to the right of it.

 

5 months later, still won't start.

New fuel pump installed, Walbro 450 LPH. Fuel pressure tested before primaries and it's good.

I don't have any clue.what to do next. I'm pretty sure that the problem is electrical, but I don't know where to start. I do have a Power FC but without Commander or Datalogit. Would it help me?

 

With a commander you could at least do a sensor check. Do you have a stock ecu to hook up to see if that makes a difference and to check for codes?

 

Try the old starting fluid trick to see if it is a fuel delivery problem. Take off elbow, open butterflies and spray starting fluid in there. If it fires then it's a fuel side issue... if that is the case I would guess stuck closed injectors from sitting.

I have also had fouled plugs trigger a timing light, but not provide a actual spark at the electrode.

 

Question didn't seem to be answered - and you may be introducing new issues doing that. Fuel pressure bleeding away in that earlier video, suggests the fuel leaks as you've investigated - or an aftermarket FPR. Hard to tell what your state of modification is, stock twins and injectors(??), but I definitely wouldn't run that big a pump with a stock FPR and it's limited bypass capacity, even one of the smaller obsolete turbosmart units went out of regulation here using a walbro.

Noid lights to see if the primaries are getting power during cranking might be my next avenue.

 

No stock ECU. I think I will buy a Commander just to help me pinpoint the issue!

Tried to spray brake cleaner, directly into the UIM. Without success. It does make some explosions sometimes, but far from enough to start the car. Primary injectors cleaned and tested a few months ago by a reputable shop.
It could be weak spark. OEM spark plugs are brand new, OEM plug wires are not that old and coil packs are old. All 4 plugs got spark (tested with my thumb).

Yes, stock FPR, FPD deleted. With the new Walbro pump, it holds the pressure much better (and gained a few PSI as well). Single turbo right now, barely hooked up to be honest (I am planning to change the turbo but I want to solve the other problems first). I have never seen how people install nold lights....

 

Definitely check to see if the injectors are getting power and if they are actually clicking open and closed. If you don't run the OEM side feeds right after you get them back from cleaning, they have a high chance of sticking close. Also, brake cleaner doesn't combust as well as starting fluid and should only really be used in absolute emergencies.

 

How do you hear a click at the injectors?

 

You really need to get some starting fluid and use that instead of brake cleaner... I would not spray brakleen into my engine.

You can hear the injectors click by using a mechanic's stethoscope or using a really long screwdriver and putting it on the injector cap and the handle to your ear. You will probably have a hard time reaching the primaries on a stock emissions car.

Not sure what the thumb test is on a spark plug, but the best way to test spark is with the plug out of the engine and a ground attached to the threads. And for god sakes - don't put your hand on them my dude. http://www.ngk-sparkplugs.jp/english.../03/index.html

Regardless, stick to one thing at a time... starting fluid. If it runs a little on starting fluid you know the problem is fuel. If it doesn't run, then move on to ignition.