I have a 88 na vert today and its is flooding out bad at start up. The unfludding procedures dont seem to work. The only way I can get it to start is to unplug the fuel pump and crank for about 10sec and then fires up. Then I can plug up the fuel pump and it will start fine. After it sits lets say for a half hour no start again. I have check the fuel presure and the fuel hold pressure and it is within specs. So that is to saythat an injector isnt leaking. The compression is good. I have also checked the water thermo sensor and the atmosphric pressure sensor and the check out fine. What else does the computer look at for start up?

 

I'm gonna say you have a leaky injector.

 

The start signal on 3B of the ECU........the output of the waterthermo sensor........rpms under 500 rpm.

AFM is not a player til over 500rpm.

Disabling pin 3B means the afm will be used for fuel and that amount will be much less than the Start Map internal to the ECU.

Downside of disabling 3B means poor COLD starting. Maybe not in the summer though.

A *made up*example is the stock fuel injector time MIGHT be like 32ms but if 3B signal is not seen, the afm is used for fuel and now the fuel injector time MIGHT be 9ms. Quite a bit less fuel during START. I made those numbers up but have have written about this in the past and shown jpgs of the injector duty cycle using the START MAP and examples of NOT using the START MAP but the afm instead.



EDIT: OK, Below are two jpg of a PALM. In the bottom left of each you see the Injector Pulse width. One jpg shows a larger value. That is with 3B connected to the ECU. The other jpg shows the lesser figure. That is with 3B disconnected. Much less fuel, MUCH less chance of flooding. See engine temps. HIgh.

Long before RTEK came out with the modified ECU and PALM, I used a FLUKE 88 to show me the same results with 3B connected, then disconnected, using its Duty Cycle feature. I disabled 3B for a hot starting problem I used to have. The sucker was flat flooding due to too much fuel. And my water thermo sensor was perfect and its signal to the ECU was perfect.

 

I recall reading a few of your posts on this subject. I think I will try disabling the 3b pin and see if start up is any easier. If that does help it still doesnt explain the amount of fuel at start up unless something screwy in the stock map. I guess i could pull the injecters and do a flow test in the car. If that doesnt help I guess it will be an unplanned tear down. thanks

 

Is unhooking the 3b pin a common thing for a fix. Ive saw that many times on here before. Seems like more of a bandaid that the fix. Im kinda new to this sight but I have had many rx7s over the years and this has (almost) beat me.

 

No need to cut 3B (Blue/Black wire on the small plug). Just depin the wire out of the plug. I'd do this when the engine is HOT, not with a cold engine.Then drive it around and stop and start quite a few times to check it out. Like I said, cold starts without 3B MIGHT be difficult. Some say that's not so, but they lived in FL.

Or making a fuel cut switch could help, OR having a switch to 3B to enable/disable it when needed. I found the 3B disable better than a fuel cut switch.

 

Thanks for the help I'll get it. I always end up with the cars a backyard mechanic screws with and then I get a good deal on it.

 

I missed this post. Yes, probably a bandaid. But I had problems with a fresh rebuild when figuring this out. Problem went south later.

The RTEK2.1 ECU now has a feature where you can adjust the amount of fuel during start. You might visit their site and look at their manual. http://www.digitaltuning.com/

If the engine is an original 88 and not rebuilt, then your problem might well be low compression. Low compression makes for hard HOT starts but not COLD starts. Go figure.