So the other day I bought a rx7, the car was claimed running and drivable. Got to drive it for the first time today after it was tailored to me. To my surprise it was in neither condition. So i am coming here for some help. Before I get flamed I understand that a rotary engine is a lot trickier to work on, but I am willing to learn I just need to be pointed in the rite direction.

Info
1987 13b N/A (was told 75,000 miles)
Spark plugs where replaced by previous owner with off brand
Injectors where supposedly replaced ( do not look new)
Throttle body was replaced or rebuilt by previous owner.
Clutch I would assume is stock.
Everything seems to be connected accept 2 outlets on the back of the throttle body Look like some kind of vacuum lines (I was told by previous owner they don't need to be, will post pictures tomorrow)
Doesn't smoke
Battery is at 12v
All ground look to be securely attached

First the car starts up fine it will idle in the cold at 1100 rpm's idle with oil pressure at 30 for about 10-15 min then it will either die or drop to 100-200 rpms.

When trying to drive the car, has a-lot of hesitation in first gear, second gear round 2000 rpm it gets better than bogs in 3rd - 5th. While on the accelerator the oil pressure rises to 60 (not sure if the oil pressure is relevant )

I have decided not to run the car until I can get a feel for what I am dealing with.
Luckily I have a spare parts 13b if it is something major.

Please I need your guys help.

 

Those two outlets/nozzles on the throttle body go to the BAC valve if I'm not mistaken. I'm not for sure where it is located on s4's.
On the s5 it is on the pass. side of the engine bay, on the VDI manifold.
Check around the manifolds and see if you see a block off plate.
If the BAC is removed that could cause your idle problems I think....

Edit:
Rotaries aren't trickier to work on; last summer I bought a miata and I swear I don't ever want to work on a piston engine again......

 

What's the oil pressure at while it 'idles'?

You should give it a good going over. Checking/setting the TPS, the timing, general maintenance like spark plugs/oil/coolant/fuel filter... Poor engine grounds are a common cause for injector problems as well.

What do you mean you were told 75,000 miles? Is that not what the odometer reads? Did the PO say anything about it being the original motor or not?

 

Oil Pressure is 30 at idle

The previous owner said it was second engine, replaced by owner before him (odometer read 163,xxx)

 

What does "after it was tailored to me" mean?

Engine idle FAQ here:
https://www.rx7club.com/forum/showthread.php?t=334730

TPS adjustment 101 here:
https://www.rx7club.com/showthread.p...hreadid=235007

 

Its supposed to say trailored to me

Car was brought up to me from out of state, it was trailored because the car I traded as part of the deal had to be trailored back.

 

As long as there is good compression I would think the engine is fine?

Im not the best with working on engines, but I do know that this will pretty much tell you how good ur engine is.

 

Engine sounds like its probably fine a compression test would be the definitive answer on that one. Does sound like there's a vac leak or non-functioning bac though, both relatively easy to fix. The sluggishness is probably non functioning 5/6th port actuators. Had the air pump been removed? Is the exhaust aftermarket?

Once u learn the terminology (which takes a little time) you'll find through searching that most of your questions have been thoroughly answered before. Welcome to the club!

 

If you have unblocked vacuum nipples, you might want to swing by the parts store and grab some caps for them.

 

The low rpms with a hot engine at idle means the BAC on the front left side of the engine either has its elect plug off or the transistor in the ECU that drives the BAC is kaput. BAC tries to maintain a 750 rpm idle speed when working.

Nipples..........are they plastic nipples on a plastic piece ? Or metal nipples on the back of the throttle body? Its unclear where these nipples are.

Hesitation in first etc.........find the pressure sensor mounted on or near the right front strut tower. Black in color and rectangular in shape with one elect plug on it's bottom and one vacuum line going to it. Make sure the vac line is getting vacuum from the engine at idle. Probably is. Remove the vacuum line from the engine. ON the end that attaches to the engine, inside that line should be a piece of plastic with a .020 hole in its middle. Its called and ORIFICE and should be in that line. If not buy one and install it to help kill the hesitaiton.

 

Cramms,
Congratulations on your purchase. Many helpful people on this forum have years of experience working on these vehicles and have developed a unique shorthand way of communicating. I suggest you purchase a factory service manual ASAP so when people suggest things you can read up further on what they're talking about. There are some FAQ's on this site that can help with the basics including acronyms in the meantime.

 

Welcome Cramms

Having a factory service manual on hand is great advice, though you really don't need to buy one. They are posted in PDF on various websites.

http://foxed.ca/foxed/index.php?page=rx7manual

 

The non-turbo's used an orifice, too?

 

Yes they do.

 

Wow thank you for all the help guys I will be checking these things today and posting pictures on anything I have questions on.

 

Ok so while I was investigating I found a-lot of things capped off and one vacuum line not connected. Hopefully this will be the fix to my problems.

 

Nah. Another honked up non turbo car.

The two yellow caps on the front of the throttle body.......bottom one feeds vacuum to the solenoid rack on the left of the engine......middle one feeds AIR to the primary fuel injector air bleed nipple located bt the two oil injectors on the intake manifold.

The two yellow caps on the rear of the throttle body go to the PURGE VALVE. Top nipple feeds the top nipple on the Purge valve and the bottom yellow nipple feeds the small nipple on the bottom of the Purge Valve.

Your very first picture is too small for me to tell what's what.

For some reason or the other theres no water hoses connected to the water thermovalve (yellow plastic jobber where you mention not connected at the other end). Odd. Self defeating with no water hoses connected.

Overall you get a B+ on the pictures. Show another larger picture of the first one. The one that seems to have a couple of blue???? in it.

 

So what your saying is that none of those are my problem causers ?

 

i would seriously check the tps adjustment.. that could be your hesitation in the 3k range .. when i bought mine it did same thing .. little adjusting did wonders im too cool for the adjuster light lol

 

I'm trying to figure out what all of those lines go to, I have a s5 so it is a little bit different.
The lines that have nothing on them on the firewall side of the throttle body are associated with the BAC system (if I'm not mistaken) and that will mess with your idle I'm pretty sure.
Also noticed that your thermowax is missing? Idk if that is only on the s5 though.
I also can't tell what hose you are saying isn't connected to anything.
If it is the hose from the rear housing that goes to the BAC valve... you'd be leaking coolant all over the place.

 

In your last pic, the highlighted part capped is supposed to run to a metal tube on the back of the throttle body which starts off in a snake like shape which then straightens out and parallels the back of the throttle body which then leads to a rubber hose no more than two inches long on the driver side of the throttle body which connects to the BAC valve. Chances are your BAC was removed or at least not being fed air from the intake tube (large plastic ribbed black tube running to the throttle body from the AFM).

 

Im going to be checking tps tonight as well as replacing spark plugs Will post video with results later

 

yeah i honestly fucked with the tps till i got it right took me a good month of ******* with it 20 minutes here and 20 minutes there

 

Sorry no pictures or videos tonight

Today I
-Replaced Spark plugs (helped overall but didn't fix dieing issue)
-Checked for vacuum leaks+vacuum cap offs (everything is ok to be removed)
-Attempted to check TPS (need pictures of location and possibly where I am supposed to put the volt meter)

Tomorrow
-Check grounds
-Properly check TPS + Adjust Idol

Questions
- Is there supposed to be a ground wire attached to the throttle body, If so can someone post a pic of its location ?

Thank you
-Steven

 

TPS is located on the front of the throttle body where the throttle linkage is. It is black and has a plastic piston that sticks out when the throttle linkage is pressed down. This sensor has three wires coming out of it and that harness is very short. Find the connector where it plugs in. Stick the red meter lead of the multimeter into the back of the Green/Red wire on the side of the connector that comes from the TPS (black meter lead goes to a ground source). With car fully warmed up, which takes a while, w/key to on take a reading of the voltage and adjust the screw surrounded by a spring that is part of the linkage until the voltage eading reads 1 volt.

There is no ground wired to the throttle body but the main ECU ground is bolted to the UIM underneath the throttle body near the driver side and closer to the back of the UIM nearest the fire wall.

Not having a BAC will make it hard to idle properly unless the engine and all its sensors and what not are working perfectly in unison. W/o it my car would idle at 500 rpm but that could be bumped up some if playing with the idle adjust screw on top of the Dynamic Chamber (top of throttle body) in addition to fine tuning the Variable Resistor found only on an S4.


EDIT: In one of your pics asking "is this supposed to be capped" illustrating the caps on the front of the throttle body look under the word "is" and there lies the TPS. Look under the word "supposed" and there lies the screw surrounded by the spring used to adjust the TPS.