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Car won't rev past 5k

1K views 17 replies 8 participants last post by  mikeyboy 
#1 ·
Car won\'t rev past 5k

The last two weeks have been great fun with this car.
2000 ZX3 5-Speed with about 97k on it. I tried to start it the Saturday before last and it cranked but nothing. After a day of towing and diagnosis from the dealer I was tracking down parts to change out the timing belt. That took about a week. Last weekend I dove in and changed out the timing belt (Ford OEM), idler, tensioner, cam gears (for a set of used Kent gears), crank pulley for a used FS UDP and new Goodyear belt) and an Esslinger intake cam. Long story short, the clearance on the Esslinger cam was about .20-.25 mm to wide even when using their shims so the stocker went back in this weekend. The gears are at 0/0 right now. They're within a fraction of a degree of dead on (the tool was a fraction of a mm away from sliding back when when checking after rotating the engine twice). I buttoned up the motor and crossed my fingers.

The car runs decently. Problem is that it absolutely will not rev over about 5k. I know the engine is non-interference so there shouldn't be any damage from the belt going or the mis-configured Esslinger cam). What I did notice is that I've got a nice little dent on the cat pipe (after the cat, before the flex pipe connection). I don't recall it being there, but maybe it was. I'm guessing it came from the tow truck. If not, then it was there when my car was running right.

Can anyone think of anything that could be "choking" my motor and not letting it rev over 5k? Prior to the timing belt going it'd rev over 7k just fine. I think I know where I can get a used cat locally to swap out. If that doesn't do it then I'm not sure where to start. I do have a SCT XCal2 so I can log if anyone has any suggestions on things to check into.

Thanks for any suggestions!
 
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#2 ·
Re: Car won\'t rev past 5k

If it helps you out any my stock cat had a pretty mean couple of dents in it and it still revved fine. Either way I don't see how a dent...even a pretty bad one would keep you from revving that high.
 
#5 ·
Re: Car won\'t rev past 5k

I'll grab the laptop and stuff after work and give it a shot. I haven't really had a chance to do any logging, but I have had it successfully hooked up and communicating with the car (while trying to diagnose the timing belt mess initially).
 
#6 ·
Re: Car won\'t rev past 5k

The last two weeks have been great fun with this car.
2000 ZX3 5-Speed with about 97k on it. I tried to start it the Saturday before last and it cranked but nothing. After a day of towing and diagnosis from the dealer I was tracking down parts to change out the timing belt. That took about a week. Last weekend I dove in and changed out the timing belt (Ford OEM), idler, tensioner, cam gears (for a set of used Kent gears), crank pulley for a used FS UDP and new Goodyear belt) and an Esslinger intake cam. Long story short, the clearance on the Esslinger cam was about .20-.25 mm to wide even when using their shims so the stocker went back in this weekend. The gears are at 0/0 right now. They're within a fraction of a degree of dead on (the tool was a fraction of a mm away from sliding back when when checking after rotating the engine twice). I buttoned up the motor and crossed my fingers.

The car runs decently. Problem is that it absolutely will not rev over about 5k. I know the engine is non-interference so there shouldn't be any damage from the belt going or the mis-configured Esslinger cam). What I did notice is that I've got a nice little dent on the cat pipe (after the cat, before the flex pipe connection). I don't recall it being there, but maybe it was. I'm guessing it came from the tow truck. If not, then it was there when my car was running right.

Can anyone think of anything that could be "choking" my motor and not letting it rev over 5k? Prior to the timing belt going it'd rev over 7k just fine. I think I know where I can get a used cat locally to swap out. If that doesn't do it then I'm not sure where to start. I do have a SCT XCal2 so I can log if anyone has any suggestions on things to check into.

Thanks for any suggestions!
Clogged cat?
Or your fuel pump is f7cked
 
#7 ·
Re: Car won\'t rev past 5k

Everything seemed fine a couple weeks ago, then the timing belt went... I'm borrowing a low-miles OEM cat tonight and will hopefully get it on in a few days and see if that fixes things up. There is what I suspect to be new damage on it...

As for the fuel pump, the car doesn't sound like it's starving for fuel or anything, it just has no more power to accelerate.
 
#9 ·
Re: Car won\'t rev past 5k

My money says you've got a clogged cat. If the cat takes a nasty hit, the ceramic core can fracture and cause a blockage.

Or your timing is way off. How did you verify TDC? I know the AEM tool I used was too long, so my cams were both retarded about 11 degrees when I thought they were at TDC.
 
#11 ·
Re: Car won\'t rev past 5k

I posted earlier this year in Zetec tuning, IIRC. And Terry Haines (KogboxKing) started a thread entitled "Ineffective Crank Angle" a day or two later. That thread became a pissing match between the guys who like to do it right vs. the guys who are content with "close enough", but Terry's method is the best way. For repeatability, I'm happy with the timing pin method, but you need the proper length pin. I'm not sure off-hand, but I'm thinking it's 53.4 mm. Edit: nope, it's 63.4 mm.

I cut my AEM pin shorter and then ground it to the exact length. So whenever I need to replace my timing belt, I can be sure to put things back exactly where they were in the first place.


Edit: here's a link to Terry's method:

http://www.focaljet.com/ubbthreads/showf...#Post2416561657

And here's a link to my post in the first timing pin thread:

http://www.focaljet.com/ubbthreads/showf...#Post2416561077

I'm too lazy to make the links pretty.


And I still think the timing pin length issue should be a sticky somewhere, if it isn't already.
 
#12 ·
Re: Car won\'t rev past 5k

I finally found my digital calipers (resolution of .1mm/.001"). My AEM tool is 76.1mm (plus the little "handle" on the end that doesn't thread in). Sounds like I need to cut/file it down? Think I'm OK doing it with a hacksaw and then finishing off with a fine file or should I be taking this to a machine shop?
I know that's probably overkill but I've been fighting with this for over 2 weeks (admidtedly the first week was waiting for parts
) and am ready for it to be completely together correctly so I can go back to fixing "fun" stuff.
 
#13 ·
Re: Car won\'t rev past 5k

I think I used a hacksaw and a hand file for mine - the length is all that matters.

And be sure to verify TDC at the piston itself. The timing pin will give you completely repeatable results, so it's a nice compromise between the inaccuracy of the "screwdriver" method and the PITA of the super-accurate degree wheel/dial indicator method.
 
#14 ·
Re: Car won\'t rev past 5k

I had this problem and so did a friend of mine. When you put your cams back in you probably put them on wrong. You probably had the lobes sitting in the wrong direction when you put the gears on and the belt and did timing that way. So your problem might lie in the cams. Remove the valve cover and the #1 spark and place a long screwdriver in there and manually turn the crank over from the crank pulley until the piston is up on top and see where the cam lobes are with the piston up and I assume you have a chilton or something and you can compare how they are supposed to sit. If not let me know and I'll pull mine and verify exactly how they go for you.
 
#15 ·
Re: Car won\'t rev past 5k

The slots in the end of the cams are cut off-center. You can only insert the bar cam tool one way if the cams are in the head. Im' pretty sure I've got a combination of a damaged cat and timing 11 or 12 degrees off.
 
#16 ·
Re: Car won\'t rev past 5k

I've done this too many times. Under 45 minutes to get the car up in the air, valve cover off, cam gears loose, etc. and ready to be re-timed. And that's after driving 1/2 an hour so everything is hot, hot, hot! Now to trim down that wonderful little AEM pin tool.
Hopefully that'll do it for the cams. If so, then I'll swap cats tomorrow (when things are cooler).
 
#17 ·
Re: Car won\'t rev past 5k

Car runs better and I suspect I'll get a bit of improvement when I change the cat. I verified that with the AEM tool I was a ways off from TDC. I rigged up a dial guage. Not the prettiest setup but it worked. After cutting the tool down to 63.4mm cylinder 1 was at TDC.
The car runs a lot better now too.
 
#18 ·
Re: Car won\'t rev past 5k

Car runs better and I suspect I'll get a bit of improvement when I change the cat...
rocking charles! keep us posted.

so, if you were unavailable to help out with this if i get some used cams someday (maybe i can find a way to bribe you into helping me
) what essential tools might one want to have on hand?

dial gauge? micrometer? calipers? feeler gauges? slide rule? abacus?

 
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