Danified

Car: 87 turbo with a 91 turbo 13b. All emissions equipment removed.

Car doesn't idle as smooth as I would like and runs a little rough when I hold it at a constant RPM. If I stomp on the gas at idle it stutters and backfires as it revs up. If I just hit the gas normal it revs up real smooth.

It won't start after it's been running anymore. I have tried turning the key on and off several times before starting to cycle to fuel pump which did no good and I tried starting it with the pettle floored and it fires a few times but doesn't start. If I wait about two hours it fires right up.

I have tried adjusting the timing and TPS but I can't make either problem better or worse.

When doing searching, if found most hot start problems were caused by low compression or dirty injectors making it flood. Any easy ways to test these ideas? What else should I look for?

FC_EDDIE

iTrader: (30)

Are you using a S4 turbo on a S5 turbo motor?
which harness/ECU are you using?

na5

you gettin good spark from coil packs

you could also have a leaky injector

RotaryRocket88

iTrader: (7)

List which ECU, harness, boost sensor, AFM and other electronics you used.

Are we talking S5 block with all S4 manifolds / electronics?

Or did you rewire half the car to use the S5 electronics?

1991rx7vert

i'm having the same problem with my 13b-re swap it happens around 4000rpms...13b-re, e6x stock turbos (twins),racing beat exhaustmy engine was rebuilt with s5 housings and rotors...

Danified

I didn't build this car. I am just trying to finish someone elses project. Its 87 car with a 91 motor in it. That's about all I know about it.

The ECU looks stock but I don't know what year it is from.
Harness is all hacked up so I have no idea.
The boost gauge on instrament panel doesn't work so I doubt the boost sensor is hooked up. It has a boost controler set at 7 psi.
There is no AFM.
The whole EGR system is gone along with several other parts I never knew I was suppose to have.

I did just replace the trailing coil because the tach wasn't working. I have another lead coil and igniter I could swap to see if that changes anything.

rotaryracer1

iTrader: (1)

holy **** man it sounds like your gonna have some fun with this one. go to autozone or some kind of parts store and pick up a repair manual to help you out with diagrams and to show you what goes where. mine is priceless to me and have had mine for almost 10yrs now. there should also be some numbers on the ecu and boost sensor, like N326 or something like that, if you let us know what those numbers are on your parts we can tell you if they are the ones you need or not

RotaryRocket88

iTrader: (7)

Well...still have the number of the original owner? It'd be nice to know what he did or intended to do to the car.

First of all, it has to have an AFM unless there is a standalone replacing the stock ECU. Are you sure it doesn't have the vane-type S5 AFM? It sounds like the harness was hacked up to accomodate S5 electronics.

If it's really not there, but somehow still runs, that's what you need to look into first.

Also, if the ecu is stock, here's the list of numbers: http://fc3spro.com/TECH/FAQ/ecutype.html. The only one I see missing is N374, which everyone seems to have problems with anyway.

Danified

The car is actually for sale because I don't have a job anymore but I don't want to sell it with issues. Here is a link to my for sale post with pictures of the engine bay so you can see what I am dealing with.

https://www.rx7club.com/2nd-generation-rx-7-1986-1992-vehicles-108/fs-rx-7-new-rebuild-785543/

Looks like most of the work was done by Krazzy RPM Racing in california. The guy I bought it from was in utah and didn't know anything about the car. Everything he touched I have had to redo.

I will try to get those part numbers tomorrow when it's not snowing. I have looked around an haven't found an aftermarket ECU anywhere on the car. Where is the boost sensor suppose to be located?

Danified

So it does have a MicroTech MT-4 ECU but it doesn't even look like they hooked everything up to it.

What a nightmare...