Wont rev past 2500 HELP!!

[CRFDAD]

First let me say I wish I had titled my first thread like this. I hope the moderator will let this thread stay because I am desperately seeking a solution.
I think I might get more feedback like this than another timing belt thread.

Anyway.

This PTC will not rev past 2500 rpm in or out of gear. Its a 5 speed. Its had cam sensor replaced, even a new computer put in with no luck. The dealer has no clue. Wires have been checked. It still will throw up a cam sensor error.

A couple of long time techs at a local Midas muffler shop have zeroed in that its probably the timing belt because there diagnostic equipment shows crank and cam sensor out of phase.

I know everything seems to be a guess at this time but I am looking for someone that has possibly been down this road and found the proper cure.

Any input would be greatly appreciated.

[CREWZIN]

I'll let it stay but it sure seems like you have your answer in the timing belt. Your long time mechanics and the mechanic on this forum both have said that it pinpoints to the timing belt and you are at the limit for changing it. Your going to have to put out the money anyhow to change it weather that's the rev limit problem or not so, JUST DO IT (as NIKE would say) and see if that clears up your problem.

[BLUEH20]

Hi, its me from your previous post.

We, all of us, are in agreement that you have a timeing belt at failure milage. When you do tht is up to you and the belt--only the belt knows whenit will fail. If the timing belt has stretched enough for it to jump cog on a gear I believe that the vehlce would run sloppy at al RPM--that said--one tooth might not too far out at low rpm and misrable at high rpm.

Now, lets put some more stuff in he game.

For all the mechanics on this forum--what if--

The catalyic convert is failed in that at a given exhaust pressure and temp the core will shift to the rear and choke off the exhaust creating high back pressure--high back pressure on the valve train may affect the cam sensor timing throwing off the angular relationship between it and the crank sensor.

When the cat is cool and/or the exhaust pressure is low enogh the core is stable and allows normal function.

This is a SWAG--but I have seen it before--it was on a 4 cycliner Dodge Dakota with manual transmissio.

Just a little more to make the soup soupier. Let's think this one outside the box.

The BCS game is really great--In honor to our moderator--GO SCHOONERS!
Back to the teley and chips and dip and soda pop!

[CREWZIN]

I came up with that on another post where an owner couldn't get past a certain point and I also had it happen to my Vette. The CAT broke up into hundreds of smaller pieces, went out the back of the converter box and jammed at the "Y" section of the exhaust. It would run OK and normal city speeds but couldn't get up to the higher rev limits at all.

[Hooligan]

[QUOTEThe BCS game is really great--In honor to our moderator--GO SCHOONERS!Back to the teley and chips and dip and soda pop![/QUOTE]

Final: 24 -14 Gators & Tebow!!!! Sorry Frank and BLUEH20.

[BLUEH20]

No regrets--Up here we have the Mariners, Seahawks and Huskies--losing is nothing new--Now winning--that is unusual.

Back to rev's issue--any new ideas out there?

[CRFDAD]

I understand what your saying about the cat. but at 2500 the computer shuts it off. It just jerks like the ignition or fuel is controlled by an on/off switch and somebody is turning off and on as fast as they can. Anything below 2500 is great. Every now and then it will clear up and run just fine as long as you keep the revs above 2500. But once you let it drop below 2500 it goes back into shut off mode again.

Its def. not a restriction in the exhaust. Its electronic and if the timing belt can can stretch enough to make the crank and cam sensor not geehaww well thats just the way it is. With a cam jumping a tooth it would not run as good as it does except for the 2500 rpm Bermuda Triangle.

I find it hard to believe that even a dealer cannot pinpoint an exact code for what is wrong.

And I also know of three other vehicles right now (various makes) that are having problems with engine management controls and dealers cannot find out the problems.

Amazing.....I think i'll blame it on ethanol. Whataya think?

[CREWZIN]

Originally Posted by CRFDAD

Amazing.....I think i'll blame it on ethanol. Whataya think?

I have an Ethanol FREE service station about 9 miles from my house and whenever possible I stop there and fill all three cars up, even go out of my way some times to go there. The price is the same as the other stations in the area.

[BLUEH20]

Let's play in the ethonol park.

Does the engine temp have any correlation to the cut off. Here is little money maker I had with vehiles coming across the mountains from Seattle.

Seattle, the good little green community, mandated the use of ethonol based fuel for clean air. The vollitality of ethonol bsed fuel is at a temp point than petrol only fuel. Some fuels have a higher percentage than others--they just had to meet the min. required by Seattle.

As the caravans, I do mean the dodge caravans and all its siblings, would climb hard up Stevens Pass ( of recent snow fall fame) the engine would heat a bit above normal for down town Seattle. This in turn heated the returning fuel to tank with a bit more areation (remember the volibility point earlier).

The return line dumped the areated fuel right next to the fuel pump pickup point. As the fuel continued to cycle through the system more areation was introduced to the fuel pickup point.

This starved the fuel system, engine ran rough, no power, stuttering and jerky and could not maintain rpm or speed.

Let it cool a bit and/or reduce the areation and the vehicle ran fine.

It the driver continued to drive during the areation phase the cooling effect of the fuel was lost and so was the cooling/lubrication for the fuel pump. Net effect--new fuel pump.

If any of this fits your driving condtions let us know and we will work from there.

[CRFDAD]

Tell if this makes sense. Th PT will start up and run fine for 8 to 10 miles. When it comes up to proper temp, it starts limiting RPM to 2500.