need help dianosing this problem: no acceleration + smooth idle
 

Car
87 base
96k miles
no engine mods


The nice weather in the north east got me set to break my rx7 out from hibernation the other day. reconnected the battery and fired up first try. held idle, check for anything abnormal / leaking under the hood. nothing so i went on the maiden voyage to the gas station to top off the tires. It was then that i realized that the car had no acceleration. starting, below ~3k feels normal, but almost seemed like the secondaries or aux ports were not working. i parked it and it sat until the weekend.

Because of the old fluids i really didn't want to try really push on it during the week. yesterday i changed the following.

oil / filter
fuel filter
coolant
cleaned air filter
sea foam in the gas tank
ensured the 6pot acuators were not stuck
cleaned plugs (looked normal with carbon, not white or wet)

The engine is still in the same position. it starts up, idles fine through startup all the way to temp. but when you get in and get going it doesn't have any power. in attempt to just floor it I couldn't even hit the rev limiter?!

The gas is about 8month old 87 octane. the main reason I added the stabilizer to the tank, but do not think that it would looks octane to this extent. although i would be happy if was just the gas :(

The car ran fine before winter, although did get minimal miles in this last year do to other reasons.

is there anything that triggers secondary ports and ingectors? there any better way to diagnose this? please help.

Does the double throttle setup work?

Have you checked to make sure your secondary injectors are firing? I had this same problem and it turned out to be what I just described.

I have not check either of the two suggested points.

The cable should be easy enough to check id think.

What is the best way to check that the secondaries are firing? what was your fix?

The cables seem to be working properly. Is there an alternative way to test this?

What was your fix on this problem?

I have pulled the fuel pump and cleaned the sock. While in there i siphoned the tank and added some new fuel and a bottle of injector cleaner. Still no progress.

I am not certain how to check from the injector side. I read that i can check the ohm from one pole to the other on the injector to see if they are bad. Do not really know how to test that they are firing. Or where i would go if they are not.

I can floor it and will level out at just shy of 6k rpm.

You check for voltage at the ECU.

If that works out then take your injectors to be serviced.

So with key in with the ignition on. I should be able to use multimeter common ground for negative lead and positive lead at pin 3H should give me some voltage?

seems like a unique test.

I have tested the injectors from the ECU. All four of them are pulling 12v.

I checked the dual throttle body setup for the top two. it seems to be working properly, its flapped partially closed when cold and the outer ones open up when the engine warms up.

I am debating on the next test. I was wondering if the MAF could be making it struggle at higher RPMs. maybe disconnect the piping to the air box? Just going back to the basics Air + Fuel + Spark = Boom. perhaps im looking at the wrong variable?

I would rather not ship the injectors out for cleaning until I can reduce down other options.

I am getting frustrated and this is being such I pain to find the problem.

Any more suggestions?

Does the car rev properly when in neutral?

It does the same things in neutral as in gear. It seems about right until get beyond about 3k, or if you floor it WOT.

One thing you might want to try is to disconnect the TPS after the car has started and see if there is any change. Another thing you could do is unplug the Pressure Sensor and disconnect the vacuum hose and plug it then look for any change in performance.

Will do. I have to locate these sensors. Wish the manuals were searchable. might attempt to OCR the things and resave them.

Think I should do this after the car is up to temp, right? or at least after the start up sequence is done.

im having the same problem it just happened 2 days ago first it wouldnt go over 3800 rpms its not the ground i cleaned and remounted all grounds including ecu did absolutely nothing still the same my ecu is good and injectors r fairly new all wires r good and connections good but 2 days ago im driving home on the highway and my rpms were at about 5000 rpms in 5th gear and it maxed out at that and kept bucking and stuttering and rpms slowly dropped as it bucked and the car wouldnt pick up speed kept going slower so i had to ride the break down lane and all of sudden it dropped so low i had to down shift and once i did that rpms only went to 3000 rpms and i was able to downshift to 2nd gear and still wouldnt go over 3000 and kept bucking like crazy i had to keep shuttin the car off wait a lil then re start it i would gain like 50 feet or so then problem happened again i so long story short a 10 minute highway drive took me about 35-40 minutes to make it home so finally im home and park the car yesterday i try to start it it starts fine then when warmed up stays at 1500 rpms and keeps jumping to 2000 and so on so on so i unplugged tps didnt do nothing so thinking thats the reason but when i wot hit the gas all the way down it wont go over 2500 in neutral or in gear i noticed the butterflies werent opening at all i finally got the car 5000 rpms but struggling and still butterflies didnt open so while holding the throttle all the way down i opened the butterflies manually and car redlined right away so i kept working it and opening and closing it just thought it might be sticking so i took it around the block and car drove fine didnt have the 3800 rpms hesitation any more it had that ever since i bought the car almost 2 months ago and it ran perfectly fine so i think thats the reason now i have a question do those butterflies have anything to do with the secondaries turning on? btw sorry for the long post

http://i1156.photobucket.com/albums/...4f9b28f66e.jpg

i love how people gotta be immature first of all there was no run on sentence i was tryin to give a solution to help him out cus i have a similar problem so keep ur useless post to ur sell unless ur gonna try help someone out

On lunch break went to how and pulled the TPS. didn't seem to make all that much of a difference. I plugged my test bulbs into it and was a little bit off, but getting to to just one led on didn't seem to do much. The pressure sensor is the one that is on the right side near the air box right? a connecter and vac line that runs to uim? pulled that as well, not really any significant change with that one either?!

Maybe i should check for bad ground? It appears dual tb setup is working correct, at least as far as i can tell. when the car is off or cold the top two outer butterflies are partially closed, once warmed up the actuator extends and opens to allow the rear tb to actually allow full open.

I tried to pull the intake tube off the maf, apparently that doesnt test anything. it just stalled lol. When the engine starts running bad it gets a lower tone from around that area. might be barking up the wrong tree, but my tests on the fuel being the issue are not working out.

will see about how to post a video.

I help people out fairly often actually. However, I almost wanted to stick a knife in my eye after reading 2 lines of your post. It was a joke anyway; dont get your panties in a wad.

http://mofodot.info/2012/other/rx7-being-a-slug

Here is a quick video, not sure it proves anything at all. other than sounds fine prior the the point of sucking.

I wondering if its a problem with the afm. There a proper way to check this thing?

This seem like a possible cause?

http://mofodot.info/wp-content/uploa...d-IMAG0139.jpg

so it appears that my problem is with the temperature sensor in the AFM.

Manual says should read between 2,000-3,000 resistance at the current temp, but am getting nothing when I test the pins.

trying to locate a fix, am hesitant in trying to take this thing apart to inspect.

Did you try it on the 20K range? You would get an infinite reading if you have it on too low of a range.

Crap! You are right. Pulled 2.75 so thats within spec. I was expecting a 2000ish reading with it on 2K.

Now i am back to having no hope in getting this thing running correctly!!
Least i didnt buy one!

Lol, sorry for bringing you back to this. But glad to help.

Compression check gets my vote.

i did the poor mans one, where pull the fuel and the leading plug for front, test.. then replace front and pull rear leading. They both had 3 even pulses. guess this could not prove anything.

wonder what the dealership would charge for a compression test. probably cheaper than buying the tool to get each edges compression right?

thing that is troubling to me is that this was not an issue when last had the car out. :scratch: