Rollogic

iTrader: (1)

1993 Touring replaced motor my self from Atkins Rotary 1.5 years ago. Apexi intake, HKS DP, HKS Carbon Ti exhaust, silcon vacumm hose replacement, 2" Koyo Alum Radiator.

In the morning the car is cold I start it, let it warm up, and drive all over town say 15-20 minutes of driving. Stop at a store, I am in there for 10-15 minutes.

Come back out and when I start my car it runs for like 30 seconds and then dies. I keep trying to start it but it will run for only 3-4 seconds and then dies again.

So far my only solution to this problem is to rapidly tap the gas peddle, until I have a cramp in my right leg, say over 50 pumps of the gas to get it to finally rev above 2,000 then on up to 5,000 and let it stay there for several seconds so that I can drive it.

Another solution has been when I know that it will be hard to start is to start it and immediately drive off. The car will drive but barely and will buck around with no power at all until it works itself out to run ok. After I go through all this the car will stay running and will not die.

The longer and hotter the car is...the more difficult, longer, FRUSTRATING it is to start. If it were carburated it would imitate the same effects of fuel atomizing in the carb.

This is one of MANY problems I have with this silly car, but is the most aggravating problem of them all.

If any of you veterans have an idea, heard of or experienced this before I would certainly appreciate your opinions. I have searched this forum looking for someone else with this problem, but with no luck.

quicksilver_rx7

Put a fuel pressure gauge on the car and see what the pressure is at a cold start vs. a hot start. The car has solenoid (pressure regulator) that will increase the line pressure during a hot start. This solenoid is controlled by the ECU which takes it's reading from the Fuel Thermosensor. So, it could possibly be a problem with the solenoid, the thermosensor, or the ecu. Other possible problems could be the circuit opening relay, the fuel pump relay, fuel pump resistor, or it could be something else that I'm not thinking of at the moment.

* A note on the solenoid: There are people that have removed that solenoid and have had no problems with hot starting (at least that's what I've read on here).

You can refer to the shop manual, Section F starting on about page F-94 to see how to install a pressure gauge and how to check the fuel pressure. The line pressure should be about 36-38 psi.

Joe

Rollogic

iTrader: (1)

Thanks for the helpful ideas! That is a good point, I do need a fuel pressure gauge. That may eliminate the guess work which should hopefully point me in the right direction.

I wonder if not getting fuel pressure is causing the car to buck around when I press further on the gas?

The car will rev to 5,000 RPM and beyond when I barely push on the gas, but push the pedal harder to go faster, while driving, and it will spit and sputter and fall flat on its face and decrease in speed. It is really noticeably around 3,000 rpm. I have done three ground staps from the engine to the frame, but to no avail. This car will test your patience.

quicksilver_rx7

It could also be a clogged fuel filter as well. When is the last time the fuel filter has been replaced? If it hasn't or you don't know, I would start with that and see what results you get.

Joe

RX7_Fanatic

fuel problem lol...do what he said above.

Rollogic

iTrader: (1)

I replaced the fuel pump with one from a twin turbo Supra that was brand new. I did this when the engine was out, so I never ran the stock motor with the new pump. Also I replaced the fuel filter about a month ago. (talk about tough to get to!!)
Someone I have talked to at the drag strip that was into 2nd gen. Rx7's, said that it could be the ignitor on the inside drivers side fender. Have you heard of that being a problem?

quicksilver_rx7

With any problem like this, it could be several different things causing the problem. It could be the igniter, it could be the coils, or something else. But, from what you described in the first post makes me think it is a fuel-related problem. If it were an ignition-related problem, you would more than likely see it occur whether the car is hot or cold. Someone else on here may have a different opinion, but has yet to chime in on the subject.

Joe

DamonB

The fuel filter doesn't know the difference between a hot engine start and a cold engine start. It's not the fuel filter.

This is the place to start. Be certain the fuel pressure regulator solenoid is working correctly and that the vacuum lines to it are in good condition. I have had the FPR solenoid vac lines fail and experienced your same problems, though mine weren't nearly as bad. The car would merely idle rough during hot starts, rarely quitting.

If you find nothing there use a fuel pressure gauge to verify what the pressure is doing under different starting conditions.