jgleano

I am frustrated...i just noticed that my car's power/gas shuts off at 5,000rpm in 3rd gear when I accelerate to get on an on-ramp. The same thing occurs when i am in 4th and 5th. I dont know what it could be. My car does seem to run smooth regardless of this problem though.....so i dont know. fuel governor/limiter ???

car: '89 944 n/a 2.7l

what i've done: changed the spark plugs, changed DME relay

any suggestions on what may be the cause for this?>??

PLEASE HELP!!!

J Silverman

I dont know if this will help, but recently my car had a similar problem. It ran fine up until about 5k and then just ran out of power. Turned out that part of the cat had broken off and clogged up the system.

User 41221

This might sound crazy, but you might look for a broken valve spring. What you have sounds like the classic symptom of it.

Regards,

Perry 951

I think we need a little more info. By shutting off, do you mean OFF, or misfire? What happens if you stay on the gas?

If it happened right after changing your plugs, go back and make sure they are torqued properly and the boots are nice and tight.

jgleano

yeah. well it does not misfire...it simply loses power at 5k....even when my foot is all the way down on the gas. .....it seems like i hit as rev limiter at 5k...it just simply stops accelerating.

User 41221

Like I said, classic symptom of a broken valve spring...

Regards,

Rock

Broken valve springs maybe yeah I second that, nine-44 had something similar like this when his valve springs were worn.

Doesnt the 2.7L N/a have a knock sensor as well? This kind of sounds like hitting the load protection, or overboost in a 951.

I may be totally wrong here, but if the 2.7 has a knock sensor, then its possible the car is knocking and the DME is shutting off the fuel.

jgleano

crap.....this sounds bad ill have to open up my valve cover on saturday. What is the knock sensor? and what does it do?

Rock

The knock sensor is on S2's and 951s that if it senses the engine knocking, it will retard the timing or something to prevent it from damaging itself.

I dont know if the 2.7 had one or not.

When you get to 5k, does it feel like youre hitting a wall almost. Does it do it in any other of the lower gears (2nd, or 1st?)

EDIT- Im almost sure the 2.7 had a knock sensor, and if it does it sounds like its knocking and its being stopped.

Rock

I dunno though, from what it sounds, it sounds identical to the overboost of a 951.

When my car hit the overboost, it would not do it in 1st or 2nd. It would only do it in 3rd or above, as those gears were long enough to hold enough boost to give it time to run lean and detonate (causing it to knock).

When the knock sensor picked up on that, the car would stop accelerating and it would feel like I slammed on the brakes almost.

jgleano

yea Rock it doesnt do it in 1st or 2nd, it only feels like its hitting a wall in 3, 4, and 5. It topped out at 110mph in 5th gear at 5k.

Rock

I dont think the valve springs are the problems then.

I think the car is knocking in the higher RPMS, and the DME is shutting it off.

Either youre running lean in the uppers, or something else is the problem. This sounds like the overload protection for sure.


Is the car stock? Any aftermarket parts or chips?

jgleano

ohh... ok. Would i have to adjust the air flow meter so that it runs richer? Or could it be the fuel pressure regulator or damper is going bad?

jgleano

"Is the car stock? Any aftermarket parts or chips?"

Its totally stock. no aftermarket parts besides k&n filter.

Rock

Dont mess with the AFM. Probally more likely the regulator going bad, but I wouldnt jump to conclusions yet.

Is your car originally a California car? If it isnt, then there is a place on the DME where you can adjust the fuel mixture a bit. Someone (maybe a PO) might have adjusted it to run too lean.

You can take a golf tee and scrape it down a bit, then insert the pointy in into the little hole on the DME, then turn it all the way counter-clockwise. That should adjust the switch to the stock position. If that doesnt work there are different positions that can make it run a little richer...


What grade fuel are you putting in it? If youre running 87- step it up a bit and see what happens.