Wont start... Any ideas?

[James N]

You can go quicker with a tow start! Driven it, still lumpy as hell. Bad misfire, gets really bad under heavy load, so i didn\'t nail it!

[James N]

Right, my mate has compression tested it, and apparently the rear rotor is around 7, but drops down to around 5 at one point. Thats bad isn\'t it???

[James N]

definitely low on compression.... Time to get the spanners out and see how these things work then!

[grinder]

sounds like a stuck seal to be honest - if you get 7 , 7 , 5 or 7, 5 , 7 then it might be it

have a read on rx7club.com for the ATF trick

[pdtaylor18]

It might not be all that bad, still could be just a stuck seal.  It might have been a good idea to tell us how the needle was bouncing, assuming you used a normal piston tester.  Could be any combination of either 3 even bounces, etc etc.  This might also tell you that its a water seal gone or rotor seals.  If its the rotor seals then you have nothing to lose by spending some money to see if they can be loosened up.. Theres loads of tricks  and just do a search for using ATF fluid etc etc etc.  It depends on what you want to do with it if it is just worn.  Even a basic strip and rebuild with just the seal kit can be done for £1500 if you get the engine delivered (block) or try \'restore oil\'  it does work if its down to compression generally but if you are getting a 7 and then a 5 then it does seem one of the rotor seals has gone, either stuck or damaged.  Not much you can do in this case but strip and rebuild after at least trying the above.

[pdtaylor18]

there you go, almost said at the same time eh Grinder !!  I\'m just a slow typer.    So defo worth doing.

[Mobilemick]

mmmm,  not sounding good !!

[grinder]

you did more of a full desc pete - mine was just short and sweet

[James N]

No, it isn\'t sounding good at all. It did drive nice, a seal cant be fine one minute, and knackered the next time you start it can it?? Surely it would be a slow deterioration in performance? Or is it a bit like a piston ring that can snap? I thought they just wore out?

[grinder]

dont take my word on this - but - i think this is the whole reason for red lining them every time you use it - it stops the carbon build up on the housings

what might have happened is that a small peice of carbon has come loose and wedged the seal/tip and its not following the curve of the housing

the ATF trick - this eats carbon therefore might "unstick" the seal

its worth a shot at the end of the day - what have you got to loose

you can also do it with a can of coke - but im not sure about this method !! - there is a vid somewhere of a guy with an engine on the floor with bad compression - im sure he pours a can of coke into it - then spins it over with a compressor and frees the engine up

[Mobilemick]

Have you tried new plugs,  or just bump started it ?

Mick

[James N]

It has new plugs, i\'ve just woken up (work nights) so i\'ll go try the ATF trick now.

[DMDRIFTING]

Did you try the ATF Trick if so what was your method?

I found this too on rx7club.com very interesting:

                          (QUOTE Eric) Water instead of ATF for decarboning          
                                                                                  Hey y\'all, I was talking to Rob Golden at Pineapple Racing last weekend and asked about his experience with the ATF treatment. He said that he prefers to use water.
1) works well, steam is very effective at breaking up carbon. Gives a noticable power gain.
2) easier and quicker, just pull a vaccuum hose at the dynamic chamber and pour 2 liters of water in (no kidding) while the car is reved up and down above 4k rpm. Just pour it in as fast as you can without killing the motor.
3) doesn\'t fowl plugs, O2 sensor, or clog the cats like ATF (actually cleans them).

I gave this a try last weekend and here was my experience:

I pulled a vacuum hose off of the dynamic chamber and placed a fresh hose in it and submerbed that
hose in 1 liter of water. The motor sucked up the water over about 3 minutes or so. I had to give the car gas to keep it running; about 4 k rpm most of the time, but I varied this quite a bit between 2k and 6k rpm. Obviously the car ran rough during the treatment. Towards the end of the treatment I noticed smoke coming from the side of my car near the back wheels and a burning smell. I looked under the car and to my suprise the cat and muffler pipes were glowing orange hot! (it was about 30 minutes before dark) I don\'t know wtf was going on but it got my adrenaline going! I shut the car off and let things cool down.

After things cooled down I took it for a spin. The car runs better, idles better, and has a bit more power (feels like 10-15 horsies, but this us just a guess). It also has noticeably better response at part-throttle. Feels more torque-y. So, it works, but I\'m worried about what all that heat could do to my new mufflers and cat, although everything seems fine now.

Anyone else ever try this?

-Eric (Quote Eric)

Duncan

[Skifledanabit]

Sorry guys, I\'m going to slightly hijack this thread because i\'m having the same problem, except my compression and engine is fine, had that checked over. It seems that if i leave the car for say, two hours, she wont start up again and i have to get her bump started, anytime less than that, say about an hours cooling or 3 or more hours and she starts up fine... i\'ve renewed the spark plugs, I\'ve cleaned the dizzy terminals... argh, someone please help me out here!

[TiddlesRX7]

Perhaps its got a leaky injector?