RX7Club.com - Mazda RX7 Forum

RX7Club.com - Mazda RX7 Forum (https://www.rx7club.com/)
-   New Member RX-7 Technical (https://www.rx7club.com/new-member-rx-7-technical-256/)
-   -   No start after rebuild. PLEASE HELP!!! (https://www.rx7club.com/new-member-rx-7-technical-256/no-start-after-rebuild-please-help-1064929/)

bojac_13b 06-01-14 11:03 AM

No start after rebuild. PLEASE HELP!!!
 
Sorry for the long post but Ive been on the search for 2 days now and Im at whits end.

Okay so I rebuilt my engine over the past couple weeks. Its an 88 NA engine with 200K on it. It ran perfectly fine before I pulled it. The reason for the rebuild was bad oil control rings making it lay down batman style smoke screens. The rebuild went smoothly no problems what so ever. I used Atkins rebuild kit and replaced all the soft seals, springs and apex seals. I had to reuse the housings and irons for financial reasons but was told that they were in pretty decent shape for a car that had that mileage. Still plenty of chrome and no step wear on the irons (verified with a dial indicator).

So I get done, fill it with fluids, check over everything a second and third time and crank if over for the first time. It started right up to my surprise. Idled high and dropped down like its supposed to. It ran perfectly fine, beautifully smooth for about a minute or so then the idle started to get rough like it was missing slightly, then worse and worse and it finally died. Tried to turn it over again and it would fire. Just cranked and acted like it was truing to fire but no dice. Tried to deflood and a little atf in the leading holes. Nothing but fog from the exhaust. I can get it to fire if I roll start it and pop it in second but it will only stay running if I keep my foot on the gas. It will not hold an idle at all. Ive tried readjusting the timing several times, took the intake off to check the vacuum lines and primaries but theyre all good. I took the plugs out to listen for whooshes and I get three pulses from each rotor. Compression tester shows three even pressures of around 80 on the rear rotor. The front shows one pulse of 80ish and two lower around 50 but even with those numbers I should be getting something right? Ive read that a fresh rebuild isnt going to have great compression right away until the seals seat properly. But Ive seen engines run on one rotor alone so surely the weak comp in the front wouldnt keep it from running at all. :banghead:

diabolical1 06-01-14 06:33 PM


Originally Posted by bojac_13b (Post 11746016)
I can get it to fire if I roll start it and pop it in second but it will only stay running if I keep my foot on the gas. It will not hold an idle at all.

realize that there are exceptions to just about every rule, but you pretty much answered your own question. no. not that question ... the REAL question. 80-50-50 is not a good sign (assuming test methods and results are kosher) - even for a rebuild. the fact is you've taken a step backwards. it fired on just the starter at first, and now it won't.

that said, rebuilds can be fickle. you can keep trying things, but you should get yourself used to the thought of having to pull it again.

Dias_Stronomy 06-01-14 06:41 PM

Well you've done almost everything I would've. THEE only things I can say that you haven't tested is your O2 sensor. The O2 sensor would help control how lean or rich the engine needs to be so be sure that its working with a Fluke meter-12V. other than that the AMV and if your not premixing the OMP. Triple check your intake manifold for leaks or a crack while the tear down process (like if you accidentally dropped it). As well as the hoses again. Good way is to spray flammable can around the parts and the engine will change rpms if there is a leak....If you tried timing it and all...those are all i can think of that could possibly screw it up.

bojac_13b 06-02-14 10:58 AM

Thanks for the fast response guys. I tried all the flammable sprays around the intake top to bottom and got nothing. It's pretty hard to check for vacuum leaks when it won't run under 1000 rpms. I'm going to get it out of te car and back apart tonight to see what the deal is. I'm still trying to wrap my head around a brand new seal not sealing. And trying to figure out what I could have done wrong. It's rather discouraging. But I'm pretty determined. One other thing I noticed. It was getting rather hot when I kept it running for more than a few minutes. What could be causing that?

bojac_13b 06-02-14 11:00 AM

And what would have caused it to run so smoothly at first before it started to run rough and die?

diabolical1 06-04-14 06:16 PM

check to see if there is water/antifreeze in the chambers.


All times are GMT -5. The time now is 12:52 AM.


© 2024 MH Sub I, LLC dba Internet Brands