A new RX7 project
Hello again. Glad to be on board. My nephew gave me his '87 RX7 to work on since he got it "FREE" - has tonnage of issues with it why the previous owner wanted to let it go.
He did put new Autolite 2626 plugs in it (?) for both leading and trailing sides (is this a good idea, or I should shoot either NGK's - my preference, or DENSO plugs), but it starts okey, but has no power-just pretty flat. How does one check timing on these things for the ATDC settings per plug position? Plus, at 1k rpm idle, the motor shakes pretty good - not a smooth idle at all.. Any help would be great.. thx-Stops |
Nearly everyone uses NGK spark plugs; BUREQ7 (leading) & BUREQ9 (trailing).
For timing, there are 2 marks on the main pulley & a pin on the front cover. With a timing light on a leading plug wire, the pin should line up with the right-most mark (-5*, looking from the front of the bay). With the light on a trailing wire, the second mark should be lined up with the pin (-20*). You mentioned the idle is around 1k RPM, so keep in mind that the ECU will advance timing around ~1100 RPM. It's it's WAY off, this is probably what's going on. One big way to smooth out the idle is to adjust the variable resistor. It's going to be on the passenger shock tower, and will have "R" and "L" marks. You can turn it slowly either way to make the idle mixture more rich/lean. However before adjusting anything idle related, you need to set the initial set jumper. There's a green 2-wire plug near the leading coil. Jumper it with some wire, THEN adjust the variable resistor. Go by ear & how rough/smooth the idle is. Typically somewhere between R & L will be the happy medium. |
Hi again and thx for your help - If the timing is way off (which I suspect), then how does one adjust to correct the timing? Does one have to ground the ECU to disable it so the base timing can be corrected?
Also, on the base idle setting, dx ao I jumper the wire to ground or across the plug? A little help on this one here, if possible, or a link to a tech page would help as well. thx again - STOPS |
There is no real way to adjust timing. If it is way off, suspect that the CAS has been stabbed incorrectly.
Be aware that if you are adjusting the variable resistor with another problem in the system (ie. vacuum leak) you may just end up making it run worse. The Factory Service Manual can be found in the FAQ For FC thread. It contains all this information and more, and is an essential tool for any sort of service work that needs to be performed on these cars. Additionally, the Haynes service manual for the 1986 thru 1991 RX-7 (both turbo and NA) can be found at most local auto parts stores or purchased from any good bookstore (ISBN number 1 56392 007 7). It is only about $25 and is a great quick reference for things like this. Not only does it contain most of the information in the FSM condensed into an easy to read format, but it includes full wiring diagrams as well. These manuals will answer 99% of service related questions for the car and if you intend to do your own repair work, you will need at least one of them. Preferably both, since the FSM is a free download. |
suspect that the CAS has been stabbed incorrectly I do thank all for pointing me in the right direction on this project. Yet, ran into a small snag yesterday: It stated fine and ran good and began to do the checks. Shut it off to correct battery terminal connections since they were not the best, then got away from the project for awhile. After an hour, I went back to the project to restart and continue, but now absolutely no catch but turn over with no problem. Sprayed starter fluid in the intake and it caught immedately, then died. Pulled the plugs and all were black as sin (Autolite 2626)- wondering if these are too cold of a plug to be used since I haven't switched over to the NGK's ... Okey, now a potiental fuel problem. Does the fuel pump come on with the key, or when the starter begins to engage, plus is it fuse protected? Another thing that I noticed that I've only got the one yellow mark on the pulley for timing - not two marks - for leading and trailing - Thx for the help. |
Yes, the CAS can be stabbed incorrectly like a distributor.
With the yellow timing mark lined up, the two tooth wheel in the CAS should be at about 8 and 2 o'clock. The fuel pump will only run while the car is being cranked or the engine is actually running. To make it run whenever the key is set to IGN for troubleshooting purposes, jumper the yellow test connector on the passenger shock tower. Normally it finds its way under the airbox. |
Thx for your replies and help.
Isn't it great when nephews don't tell you the whole story: Vehicle has been sitting idle for over two years outside, so guess what kind of condition the fuel in the tank and the tank itself have been in along with being almost empty? Pump is gone and so the fuel filter... and he's gonna help me do the two changeouts before we get this thing running again... ..and now, he want's to turbo the thing to race it... thx - STOPS |
You'll probably want to read this then:
http://www.aaroncake.net/rx-7/unstore.htm |
not to thread jack here but I'm having a timing issue that I can't seem to figure out and this is the only thread going I have found that is about timing and still alive....
'89 N/A 13B - idles at 850rpms - with the car warmed up and the timing light pickup on L1, timing is showing advanced 30degrees or so. I have triple checked the CAS and even swapped CAS to see if I got a different reading but even with the CAS retarded all the way the leading timing is shows about 10degrees advanced. |
Thx for all the help. Finally got it going thx to putting in the correct NGK's.
Autolite needs to be shot in recommending their 2626 plugs as OEM replacement for both leading and trailing, for they are so super cold due to the electrode being so short coming out of the insulator, and the insulator being so forward where the plug can't get up to temperature. I gave it back to my nephew and now it's his problem now on what he wants to do with it. I have triple checked the CAS and even swapped CAS to see if I got a different reading but even with the CAS retarded all the way the leading timing is shows about 10degrees advanced. Good Luck Thx-Stops |
Autolite's 2625 I think is the actual one's I used, and they worked fine in the summer.
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Originally Posted by Aaron Cake
(Post 9942298)
Yes, the CAS can be stabbed incorrectly like a distributor.
With the yellow timing mark lined up, the two tooth wheel in the CAS should be at about 8 and 2 o'clock. The fuel pump will only run while the car is being cranked or the engine is actually running. To make it run whenever the key is set to IGN for troubleshooting purposes, jumper the yellow test connector on the passenger shock tower. Normally it finds its way under the airbox. |
Originally Posted by comrealpeace
(Post 9983645)
Can this work all the time on the fuel?
The test connector is for testing purposes only. It should not be left jumpered at all times. The AFM's fuel cut switch is there so the pump will not be pumping fuel if the car crashes. Possible side effects of leaving the connector jumpered include being set on fire. Jumping the connector will always power the fuel pump if the key is in the ON position. |
Pretty crazy that the motor would shake, rotaries usually run smooth so you're right to be asking. I'm new too so I'm afraid I can't really give any advice.
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