I'm currently at my local mazda dealer (going on 8 hours now). Got a compression test this morning. Car was running fabulous before the test. Get the car back, and it backfires under load and acceleration. Plugs, plug wires, O2, and fuel filter were changed 1 week ago by me and car was running perfectly. Compression check came back fine. We've changed out 2 plug wires (with AC delco....only ones available), because the tech ruined one of the OEM wires (pulled the wire out of the clamp where it connects to the coil).



Anyone have ANY ideas for us to try? I'm supposed to sell the car tomorrow, which is why I was getting this compression check done, and now the tech here has somehow made my car not run right. Anything we could try would be helpful.



One of the techs is thinking it might be a coil pack problem. While I think it's possible, i think it would be kinda weird this happening RIGHT when the tech did the compression test.

Jesus. Did he damage the coil(or the clamp for that matter)? That's kind of what it sounds like.

Are you absolutely sure all the plug wires went back on the right plugs?

did they **** with timing at all?

[quote name='TYSON' date='Apr 22 2005, 02:35 PM']Are you absolutely sure all the plug wires went back on the right plugs?


[/quote]



That's an interesting thought. Although when I did that to mine, my gauge told me I was making crazy boost, but I wasn't going anywhere under full throttle.

At first he thought he might have crossed the two leading wires. So he swapped them back, and the same "bucking" and backfiring was happening.



Is it possible for him to have shorted out the coil?

The two leading fire together anyway. He didn't touch the trailing?



He should be able to check for spark on all the plugs pretty easily to see if the coil is firing.



The map sensor is still connected?

[quote name='TYSON' date='Apr 22 2005, 12:22 PM']The two leading fire together anyway. He didn't touch the trailing?



He should be able to check for spark on all the plugs pretty easily to see if the coil is firing.



The map sensor is still connected?


[/quote]

The coils are testing fine non-under load. It's only underload that they're acting up (or at least there's only a problem under load.....can't really test the coils under load, at least to my knowledge).



Map sensor is still connected.

i'd check the coils.. he can test them..



your first mistake was taking it to a mazda dealer.



also your plugs could be bad. just a thought.

[quote name='twinturborx7pete' date='Apr 22 2005, 09:16 PM']i'd check the coils.. he can test them..



your first mistake was taking it to a mazda dealer.



also your plugs could be bad. just a thought.


[/quote]

I agree taking it there was stupid. Usually NO ONE but me works on the car, but all I was getting was a compression test, and now all this **** is fucked up. Wish I could do a compression test myself, cause then I would have all these problems. Fucked up thing is I was selling the car this weekend (today), and the compression test (which came back fine) was just to ease the mind of the guy buying the car. He has since postponed his trip down here to pick up the car.



I replaced the coil this morning, to no avail. Still the same bucking. Others said it was in limp mode. We used a jumper in the diagnosis relay place and came back with TPS sensor, MAP sensor. Is it possible that the TPS sensor just needs to be adjusted, or like Mazda is saying that it needs to be replaced?



I'm gonna try adjusting the TPS today (if I can get back to the dealer before they close) with things outlined here. http://www.scuderiaciriani.com/rx7/TPS_adjustment.html



If anyone has any other ideas, I'm all ears. Thanks for the help.

I wouldn't take my car to the dealer for an oil change-





Did you go into the service bay and see for yourself exactly what the tech did? If so, check everything he touched.



Good Luck-

[quote name='qwester007' date='Apr 26 2005, 01:38 PM']I wouldn't take my car to the dealer for an oil change-

Did you go into the service bay and see for yourself exactly what the tech did? If so, check everything he touched.



Good Luck-


[/quote]

Well, the only reason I had it there was for the compression test (I don't have the equipment to do it myself). Typically NO ONE touches my car except me. The problem has since been solved though, and I feel downright stupid ( https://www.nopistons.com/forums/pub...1047683664.gif ) for not thinking about this. The tech who did the test, seemed to kinda slowly disappear while me, the service manager, and another tech (who happens to be my friend) worked on things. Well, he never mentioned that he somehow (how I have NO idea) unpluged the hose to the MAP sensor (maybe while reaching in to disconnect the plug wires) before doing the test.......he didn't mention it until after we got it running. Anyway, he cranked the car for the test with that hose off, and I guess the ECU stored the information in there, and put the car in limp mode (he noticed the hose off the map sensor while putting the wires back on, so we never knew it was off). Anyway, all we had to do was reset the ECU (which we probably should have done anyway.........hindsight is 20/20), and she was good to go. I feel idiotic for it being something sooooo easy and stupid......but it's let me learn in that regard also. I'm also glad it wasn't some $700 part, because they weren't too helpful in fixing the car, OR wanting to pay for parts as they say it could have been something that was on it's way out anyway (too coincidental in my eyes). Anyway, all is good now, and I appreciate ALL input on this. Thanks guys. https://www.nopistons.com/forums/pub...IR#>/bigok.gif

I'm glad you figured it out. What a pain in the ass though.

WOO HOO! good job dude.





How did the compression check turn out?