91 GXL non turbo - Have a good mechanic who has tried a lot of stuff but has run out of ideas. if i stay below 3k it runs okay, above that it loses power hesitates, misses - all the good terms for not running right. Have changed or temporarily swapped out a lot of parts. plugs,fuel filter,tps sensor ( which is the only alert the computer gives for the problem), the computer, has good pressure from pump - What's going on? I posted this question the other day and got a couple of good suggestions to check the secondary injectors. My mechanic said he would go after it but he said if he turns off the ignition while the problem is occuriing - when he turns it back on it seems to go away - for a short time, could something be trying to reset? This is my first time in this forum - thanks for all the help!

 

do a search for "3800 stumble" you will find hours of good reading Info.

good luck

 

could it be as simple as the actuators? Checked those yet?

 

Ummm..No. The actuators wont cause a 3800 RPM stumble. Generally, its a bad ground.

Jarrett

 

I had this problem just a few days ago, with the help of rTED, he diagnosed it to be the crank angle sensor. We swapped it out with a new one and my car was good to go. It pulls all the way to 8000+ easy now.

Yes I also tried all the stuff you did too but to no avail. So check your crank angle sensor.

 

Checked the secondary injectors and tested a different crank angle sensor swapped from another 91 in the shop - no difference - the mechanic is ready to move on to something more profitable any more thoughts?

 

Mark,
How did you check the secondary injectors?
dave

 

I don't know - i'll ask the guy in the morning - He just told me he checked out the injectors and swapped the crank angle sensor with another one from a car he had in the shop that ran ok. What should I be making sure they are doing?

 

Maybe the mop gone bad. Car goes into a default mode when that happens. Car should hardly run, from the posts I've read on this site. I've heard it said on this site that you can turnt the key off, then back on and the car will run for a period, then fall on its face again.

That's METERING OIL PUMP or OIL METERING PUMP, one or the other. It's electrical in nature, and pumps oil into the rotor housings while the engine is on.

Your mechanic needs to download the codes stored in the computer. Go to http://home.rmci.net/panther/ecu_codes.htm and read how to pull the codes. Also how to erase the codes.

All the above is hearsay. I've never seen a 91RX-7 or a 97RX-7, whichever it is.

 

Thanks - that sounds closer to my problem than a lot of the stuff we have tried. Is a "MOP" the most expensive thing I could have busted?

 

Close. Maybe someone with a series five can confirm how a series five acts when the MOP takes a dump.

Most likely not the 3800 hesitation. That causes a bit of a buck around that figure, but runs more or less normal after 3800 rpm.

Read that site I posted above in the other post. I think you just have to jumper a single, green connector to ground. Then the check engine lite gives you codes. Pretty straight forward.

 

hey if it's the OMP I have a 90' from my jspec motor. I didn't use it cause I used a 88 ECU when I did my Turbo fb conversion. give me a PM if you want it. I'll let it go cheap.

PS: And yes, it the most expensive part.

 

Have looked at this post? This person had very similary problems with their 2nd Generation Turbo car, and got it fixed. It may help you try some other things to fix your car.

https://www.rx7club.com/forum/showth...light=3000+rpm

 

I've got a similar problem on my 87 NA. Car starts fine but as soon as I drive past 2500rpm, the car loses power. I have to shift before 2500-3000 for the car to even move. The weird thing is this only happens when the weather is hot. On cold days, it seems to work ok.

My mechanic said that the cats may be clogged. I havent gotten it checked yet so I cant say for sure. maybe something to consider.

Since it's been raining here in Southern Cal, I'm still able to get around. =) I appreciate if anyone can give me a second opinion. Tia.

 

Ok - I thought the advice about the OMP most closely matched the symptoms i am seeing. The mechanic said the part was stupid expensive and thought he should double check the oil pressure too make sure. he called me with his last rights voice and told me he was getting at least 5psi and all the way to seven if he goosed the accellerator. he says this is a blown engine - Any chnce i could get away with an oil pump? The car doesn't smoke but i have been nursing a pretty good oil leak for some time.

 

I'll bet it is the oil metering pump. Check your diagnositic codes for either code 20 or 27. I had the same problem on a 90 vert. You should be able to find a used one for $75-150 depending on who may be selling. The engine, once started and warmed up will not go above about 3000 rpm. Turn it off, and for about 1-2 minutes, it's ok, thenit falls back to the same rev limit.

 

What about the low oil pressure, how does that factor in? Could the omp make the pressure read low even if the oil pump was sound? or could they both go bad together, or could the omp be sound and if I replace the oil pump my life can go back to normal.

Also I was quoted a lot for a new omp, can i really get a used one cheap?

 

Here are some S5 Oil Metering Pums for sale (one add refered to it as a MOP (metering oil pump).

https://www.rx7club.com/forum/showth...ght=oil+or+omp

http://www.teamfc3s.org/forum/showth...p&pagenumber=5

http://www.thepartstrader.com/Single...m=369095&DCID=

 

Why is the dealer telling me the omp far a 90 is $200 and the 91 is $1,500. Can I get my pecker all the way down there on the 91?!?

 

It seems like the dealer looked up the wrong price for the 90. The 86-88 Rx7s have a Mechanical OMP and the 89-91s have an Electronic OMP.

Mazdatrix has the following prices for the OMPs.

PUMP METERING 84-88 13B 14-6000-N246 $208.84
PUMP METERING 89-92 ALL 14-600B-N350 $1,100.18

If you are going to get a replacement pump, it would definetly be best to buy a used one.

 

Yea, I called the dealer and shook him down one more time. he gave me the same info. I'll go back to the links you gave me and reconfirm.

Nobody seems to want to touch the low oil pressure part of this. Could the omp bad make the pressure read 15psi down by the regular oil pump? It would be cool to replace the right one the first time.

 

Where is your oil leak at?

If you look at the faq on Mazdatrix's website, they say that a front cover o-ring leak will cause your oil pressure to read low.

http://www.mazdatrix.com/faq/oring.htm

The low oil pressure and not running above 3,000 rpms could be two seperate problems. I would see if the oil leak is easy to fix, and then see if the oil pressure goes back up.

Did you notice where the oil gauge read before you started having problems, and where it reads now?