Hey guys, any help is welcome. I have an 89 na, that i'm starting to get lost with. It started with this free car that once I got started had a bad TPS. I replaced it with a junk yard one that had less than ideal readings(ohms). It had the brrmp, brrmp,brrmp, idle too, so I bought one from a friend. This is the one currently on the car. When first started the car would rev to 3k, like it's supposed to, then when idling down(around 2k) it had a strange brrmp, brrmp, then once warm a normal idle. I dove it for a while then it started getting weird. I would be driving to a stop- the check engine light would come on, rpms would drop to zero, engine still running. I could turn it off, start it back up- rpms would work, check engine light would be off, then a little down the road it would do it again. At the time I didn't know how to read the check engine light(flashes). I replaced fuel filter and fuel pump, and checked the psi and it was at like 40-45 psi(straight from pump). I didn't have the same engine check problem afterwards, but that seemed low compared to like 60-65 the manual said. I decide that since the car had sat for 3 yrs I should do the whole maintainance schedule. I had the injectors serviced, replaced all the hoses, everything. Put everything back togeather, and pulled the EGI fuse to get oils circulating. Put the fuse in, and It started slow but did start ran to 3k then died. It did that again, so on the third try I gave it gas to get it to the warm stage, then I let off the gas and it died. So it does run when the gas is kept on but has a crazy idle like maybe a bad TPS. The tps does read 1 at closed to 4.75 or so at wide open. The idle speed screw has no effect. I hooked up a timing light just to see and it would be way out then as the idle lowered it would come close to time then back out. Same on leading and trailing. I am going to look at the FSM to see if there is something that will help, But it might just have to go to a shop. (Anybody know anyone in Birmingham?) I 'm sorry for the long post, thanks in advance- Greg C

 

Check for an air leak at the throttle body or anywhere between the airbox and throttle body.Like tightening all connections.Check for vac leaks too.

 

I will, thanks

 

Read out the AFM plug per the FSM

If it sat for a while, the injectors might be cruddy

What's the voltage at the fuel pump? 40-45 psi does sound kinda low...

What I do now when something's really funky is gain access to the ECU, and read every pin for proper voltages per the FSM...This at the very least rules out a bunch of things...

 

I will do that as soon as fsm is back available. fc3s.org and iluvmyrx7 aren't working

 

bump

 

Is that information in the FSM as far as the ecu goes?

 

Yeh, what I did was make a little "pin #" chart on graph paper, with the connector shapes, pin locations & numbers, what they were, and what normal voltage/ resistance readings were, that way you can troubleshoot each pin at the ECU with one piece of paper in front of ya...Look at pages 4A-30 through 4A-32 in the FSM (86-88, anyway)

 

Man, that really sounds like a vac leak..

 

An intermittent vac leak? I guess anything's possible for a car that sat for 3 years...I guess gunky injectors or other fuel system component...

 

where did you get the intermittent part from?

This is what I read
Which in some sense tells me it doesnt run unless the gas is depressed.

 

Read the middle portion of his novel he wrote at the top..."worked good for while" type stuff...

 

Read above...

 

Ha ha, I read that part too, did you read my part?

 

never mind...

 

When I first put the new tps on it did run good for a while, the only idle problem I had was on the warm-up between 2300 and around 1700 rpms then it went back to a smooth idle all the way to 750- 800 rpms, where the idle sat. It is a vert that had a bad top, so the carpet was ruined and I knew I needed to get the injectors serviced. I put it in the garage where it has been for 8 months? or so. I went back through the entire service schedule per manual, and also serviced injectors, replaced vac hoses with silicone ones, installed new gaskets on VDI and upper intake manifold, installed a mechanical oil guage(directly from block), installed perma-cool fan, that is all I can think of. I have wondered if the lack of oil sending unit may cause ecu problem, but I thought if so it might just shut engine down- I don't know? I thought maybe a vacum leak- a big one, but I didn't hear one-then again it's hard to hear anything over a rotary with no exhaust other than the manifold(the new exhaust should be on soon). I've been taking a break from it this week and will try again this weekend maybe. Any other thoughts are welcome.

 

Hey, maybe J-Rat's right & it's something simple like a vac leak...The ECU doesn't care about the oil pressure gage, or where the pressure readings are coming from, unless the S5's are different...You could try the "pressurized" version of the vac leak check- use an air source to pressurize the intake/ manifold run, if you got a big leak it should be fairly easy to find...

 

sorry about the confusing early post- the rpm drop and check engine light was with the junk yard tps, not with the new/used current tps.(hope that makes more sense)

 

Could be as simple as just the O2 sensor.
I know many ppl have it disconnected, bue mine wouldn't run right until I made sure that it was well connected.

 

Where would I hook up to check for leaks?

 

I replaced the o2 sensor and tugged on the connection(I was worried about that rx7.o) I just went with a bosch universal- did I go wrong with that?

 

No, I've had no problems with my Bosch (just watched the ECU inputs on my meter the other night going home from work- working beautifully- bouncing between .4 & .5 volts in cruise)...I would hook up to the elbow right in front of the TB inlet if I was doing it- easy accessibility, should be easy enough to make a block-off plate with a nipple for air, etc...

 

thanks, I'll try that