So this past weekend I was at DGRR 2K7 beating the snot out of the 7, with no issues, she ran fine the whole time.

So I stayed last night with my in-laws in Chattanooga, and this morning when I started off home, she was acting strange.

1) The A/F Gauge is reading closed loop when it shouldn't.
2) Under light throttle it reads fine, then it quickly shoots to lean and goes blank when you accelerate harder.
3) Under light acceleration at low RPM's she sputters and bucks if you push hard.

I am thinking the O2 sensor is toasted, but didn't think it would effect any of this. The car is emissions free, no cats, and I just put an FD pump in it last week. No way its running lean (ask anyone who is behind me!)

The O2 is a universal Bosch that I put in when the motor was swapped in (rebuilt).

Or is it just maybe a random vacuum leak?

PS- No check engine light. Mods in Sig.

 

I took off the intercooler and UIM to check out the injectors and what few vacuum lines I have, didn't see anything. I did notice however that a few vacuum caps are dried up and cracking.

Took the plugs out, they look perfect.

HELP!!!

 

I'd check on your most recent mod (Fuel pump ) Make sure all that hard driving didn't knock something loose that may have originally been overlooked. I'm not in any way an expert on cars, but it sounds like a good starting point right?

 

Wideband. report back with new results.

/thread.

 

Thanks Kev. Waiting on EMS for wideband. She might be down for a month that way!!!

 

i would replace the fuel filter, plugs, and oxygen sensor and see what changes.

Ive been getting a similar problem for the past couple of months: it will hesitate in while trying to maintain speed in lower gears, low load/high vacuum type situations.. i still havent figured it out

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/hesitation-stumbling-lean-open-loop-injectors-637037/

 

Your problem sounds more like a TPS issue to me.

 

Could be. I never set it when I got the motor from you.

Another question for you Kev, maybe you know:

Will my check engine light still function given the swap? I have never seen it come on since I put the TII motor in, and it worked with the NA.

 

IT should, mine does. I have seen cars where the light would not work for unknown reasons, stock or conversion.

 

Does it start right up in the morning?

does it idle fine?

does it rev in neutral?

have you checked the timing?

to be honest it sounds like a vacuum leak or maybe a bad coil

have you checked the resistance in your plug wires?

 

Starts right up EVERYTIME.

Idles like a rock.

Revs smoothly in neutral.

Timing was set by BDC (tuner)

Coil? Maybe, but highly doubtful. Vacuum leak I'm working on.

Plug wires are brand new NGKs.

 

rub some dirt on it




check the resistance on your afm and tps maybe?

atleast you'll know then if they are suspect or not.

 

Delete this thread. It's left a bad taste in my mouth.

I'm going elsewhere to get help.

 

 

Do you have a fuel pressure gauge? Check that. Check injector clips resistance.

 

RX7clubyou

you cant blame the RX7Club for this "lack of responce"


I once had a car where the battery terminal was broken inside the battery... when tested it just looked like all it needed a charge. Sent the battery back to optima and they said the terminal was broken. point being it took me a long time to finally figure out what the problem was


typical steps would be...



re load maps into stand alone engine management. re check setup page settings


check for vacuum leaks-
*vacuum lines maybe loose, cracked or popped off
*Manifold gasket leaks (includes upper, lower, TB, EGR etc). an easy way to check is to spray all areas with brake clean (carb cleaner has a tendency to melt plastic)
*boost gauge leak @ boost gauge (check boost controller as well)
*MAP sensor leak (or MAP sensor full of oil, gas?)
*BOV diaphragm leak
*Intercooler and /or pipes leaking?


Ignition -
*Timing
*Cross firing between bad plug wires ( you can usually see a light show at nigth when you pop your hood)
*Bad coils
*bad CAS


Check TPS


Fuel -
*Correct pressure
*Correct volume
*Leaky injector / bad injector
*Bad FPR
*Replace filters
*Fouled plugs
*Cracked or fractured plug porcelain
*Water or other contaminates in your gas
*Piece of crap floating around in your fuel rail/line


Electrical -
*Bad battery
*Bad battery cable
*Bad ignition switch
*Bad alternator ( a bad alternator can wreak all types of problems which may or may not look like timing problems... especially if you have a Haltec)
*Loose wire / electrical short
*Bad ignition switch


Compression test


P.S. regardless of who or when the timing was set, it should still be part of your diagnosis

 

I just ran some codes and got a weird result.

It displayed codes:
25
30
31
32
33
34
38
All no biggies since those parts are not on the car.

But then I got code 42? WTF is that for?

 

Do you have a Haltec? or a stand alone EMS?... if so the problem can be the fact that the vehicle was tuned in cold weather and now that the temps a warming for summer, you may need to adjust the coolant temp and air temp correction maps

 

Neither. I have an S5 TII with no emissions.

Read the sig. again

 

well, from the sounds of it... it runs fine on the primaries, but as soon as you need the secondaries , it falls on it's face.....I am going to say you have a bad secondary injector. either it had a melt down or it has a big piece of crap in it

 

42 Turbo Boost pressure control

 

Hmm, couldn't find that in the FSM.

I would suspect the injectors but they tested mine about a month ago.

Also this really only happens at very low RPM's, before the sec's would come on.

I just took off the UIM and a few vacuum caps look VERY cracked and brittle. I'm going to change them all out and go from there, at least I know that will not be a problem. Also it just occurred to me that I might have a cracked TID. I will keep digging.

So I guess that code 42 would not apply either? The only thing left there is the boost sensor.