150EZ

RX7 Gurus, I apologize in advance. Im in a hurry and I didnt search the archives for this kind of problem.

I just brought my rx7 back from an exhaust shop where they outfitted it with 2.25 inch dual pipes and xelarator mufflers. The car ran great all the way home. It even felt like it gained a good 10-15 hp (my estimate).

I then ordered a KN cold air kit. I let the car sit for two days while waiting on the kit. I installed the kit.

When it came time to turn on the car. It sounded magnificent. The engine revved to 3k as usual then completely died. I fiddled with the screw on top of the throttle body... made no difference. each time I cranked it, it did the same thing.

I also noticed, my TPS is malfunctioning (0.6k at WOT).

I don't know if the modifications I made to the exhaust and the air intake, or the bad tps, have anything to do with this problem (I even re-installed the stock airbox and still had the same problem). I only mention them because they are the only things that happened to car since I drove it back from the shop.

Here's what I have: 88 convertible, 13b NA, s5 standard + the mods mentioned above.

Thanks for your time!

adrock3217

You didn't plug in the AFM.


Also, that "10-15 hp gain" is just the sound. With just replacing the mufflers, you might have gained 1 or 2.

150EZ

Thanks! I dont remember unplugging the AFM. Actually, I dont know what an afm is.

My exhaust had a leak prior to having the new ones put in. The car felt a lot more sluggish and would barely peel out. Hence my estimate of 10-15. But what do I know. Im a noob.

The Wankler

iTrader: (14)

Sounds like the AFM to me.

adrock3217

The only mods to an NA rotary that will cause a 10-15 hp gain would be a FULL exhaust, standalone, porting, nitrous, or slapping a turbo on.

150EZ

cool. If i can gain another 1-2 hp Id be really cruising then! lol.

AND what's an AFM i cant find it in Haynes.

melicha8

iTrader: (1)

air flow meter

150EZ

I did take that off just to look at it. But, I double checked it. It's securely fastened to the mass air box

adrock3217

Major vacuum leak. Check all the hoses running around, make sure they are all plugged in...

The AFM is the only thing that has ever caused my car to run for a few seconds, and then die. A PLUG goes into the side of it, I didn't see you mention that.

The Wankler

iTrader: (14)

^^^^ yepper, sure does. I mean, that would be one hell of a vacum leak.

150EZ

Unless Im totally missing something. The AFm is completely inserted. Check out the pic.

Valkyrie

By unplugged we mean the wiring harness that plugs into it...

You need to pull the engine codes to make sure everything is working right, and then search for vacuum leaks...

adrock3217

Ok, this isn't meant to sound mean or anything, but, this is just the order I would personally go about solving this problem.

1: Check compression. ALWAYS check compression if you are having any sort of engine trouble before continuing with a project/buying parts to fix it, etc...it can save hundreds of dollars, and it's always nice to know the condition of your engine.

2: Check for spark. Take a spare spark plug, or one from the housing, and insert it fully into the spark plug wire. Pull off the strut tower cover, and hold the spark plug wire (the rubber part!!) with the spark plug about 1/4th of an inch away from one of the bolts, or closer. Have someone crank the car while you watch the plug. If you get strong sparks, then you have good spark. This can be done on all wires, but normally if one wire is firing, all are. Best bet is to check one trailing, one leading, to rule out a dead coil.

3: Check for fuel. Check for voltage at the fuel pump, or you can do it the super easy and visual way..pull a fuel line, insert it into an empty (clear) gallon jug (milk? water?), and crank the car. If fuel comes out, you are getting fuel.

4: Check electronics on the engine. Check the TPS, if it is within range, set it perfectly. Set the timing also. There are write-ups on the forum / maybe in the Archives, if you need any help with how to do this. Anything you didn't remove during the emissions removal, remove and throughly clean / replace with a new gasket.

5: Check for vacuum leaks. If you have the means, and want your car to be nice and reliable for years to come (DO THIS AFTER CHECKING COMPRESSION), you can replace all gaskets and vacuum hoses. Gaskets can be bought from www.mazdatrix.com, and hoses can be bought from www.hosetechniques.com. If you want reliability and to kill all future/current problems, this is the best bet. All of the RX7's that I get, I immediately tear down and replace all of the external gaskets/lines


All of these will pretty much solve any problems you can possibly have. It might take a while, but you'll thank yourself in the end, not to mention learn about how everything on the engine works :-D


Oh and..is your 3000GT for sale? :-O I'm in the mood for one, haha.



Edit: Now is also a good time to replace all belts, inspect your OMP for correct operation, thermostat, coolant filler caps, coolant hoses, HEATER HOSE (This is very important! It is known to crack! Oil drips when changing the filter and deteriorates the line, and can cause massive engine failure if it were to break off while driving!), and inspect your oil cooler lines for leaks. There is probably more that I'm forgetting, but that is most of it.

stevej88na

If the car ran fine until swapping on a new filter, I'd have to agree the AFM is suspect. My AFM wires are extremely brittle, could some have snapped on you? Another suspect is vacuum leaks - a big leak, like forgetting to connect the bent metal pipes under the main air intake hose, or not allowing the main air hose to seat properly on the TB inlet, will kill the idle like that too.

Also, a TPS reading 0.6k at WOT is basically telling the ECU the throttle plates are closed all the time - if you're sure you're testing it correctly, replace it. Another thing to keep in mind is when you turned the air adjust screw on the throttle body (did you jump the initial set connector?), the idle point changed, and it might be too low now to maintain idle even if the other problems are fixed.

PS: an '88 is an S4, not S5

lupin

iTrader: (3)

don't forget swapping the s5 intakes if not already done. Pineapple racing 5th and 6th port inserts also. Removing power steering and ac also.

gxlkinglv

The afm does come to mind first check and make shure its not bad i had that happen if you have another try swaping it out then try to crank it.

Just a thought did you check the fuses sometimes the simplest problems are the solution.

Anti-Rice-Cannon

Oh look, another turbo guy bashing on the N/A's...imagine that...


191 rwhp dyno proven

bryanfc

Somebodys a little insecere ^?

tIIsleeper

Actually an N/a can gain upwards of 30 hp from a full exhaust.

adrock3217

I don't think I bashed NA's, I spread a little bit of truth.

Removing PS and AC might free up 1rwhp, probably less. They freewheel most of the time..no real power loss.

Pineapple Racing aux. sleeves..I'd say they smooth out the airflow, and maybe promote more airflow with full intake and exhaust. But no where near 10-15rwhp gain. S5 intakes, ok, yeah, I forgot those. 10rwhp gain, dyno proven.

30rwhp from a full exhaust? Uhh, dream on..Maybe 20rwhp if you tuned it also..


The fact that you made 191rwhp on an NA does not put aside the fact that no single mod besides the ones I listed (and S5 intakes) will cause a gain of 10-15rwhp. It just doesn't happen on an NA.

150EZ

Ill try the fuses. I ordered another AFM on ebay, hopefully it will solve my problem. But honestly, I can believe that just by unplugging a sensor and looking at it you can ruin it.

Stanello

iTrader: (1)

The AFM plug doesn't look like it's plugged in all the way.

adrock3217

Well, the plug DOES seem to be a bit off, perhaps not pushed all the way on.


In my experience with these stupid AFM's, if you fool with them even a little, the inner peices can become strewn and mis-placed. If you take an exact-o (or other suitable, super sharp blade) and cut around the black plastic peice, you can get inside the AFM. Don't be afraid to pry it off, the plate is about 1/4" thick, I didn't realize this at first.

It's fairly obvious when you open it were all the connections SHOULD be, but if you need help, there is a picture floating around of the properly aligned inner peices on the forum. Search, HAILERS posted it a couple of months ago.

But yeah, I had to open mine up, fix the peices, put it back together/plugged it in, and it fired up and ran perfectly.

tIIsleeper

I didnt say rwhp. But ill keep dreamin if you want

adrock3217

Seeing as there are ALL kinds of BHP calculations, of which all are legal (hence, Mazda's ability to overrate the RX8's BHP numbers), makes talking ANYTHING BUT RWHP completely stupid.