Looses power at about 3500 RPM

[jfcroni]

My 91 NSX just came out of winter storage. I did start it several times during storage and did take it out for a ride once during the winter with no problem. Now however, it stalls at 3500RPM or so. Today it died but I was able to start it right back up. It seems as long as I kept the RPM’s low, it would be OK. If I punch it, I immediately looses power, and have to turn the ignition on and off to loose the power loss symptom.

Today I replaced the main relay, 39400-SLO-003 with no effect. I removed the air filter and cleaned the throttle body too, with no effect. I tuned the TCS off but that made no difference. I ordered a fuel filter but Acura sent me the wrong part. The FF is the next thing on my list to replace. I can hear the fuel pump when I start the car, and the car idles perfectly.

I looked for vacuum leaks, but found none. Any ideas?

Jim

 

[Brocz]

I had a similar problem. One issue I had was poor/loose fitting battery terminal cables. I actually pulled and replaced the battery. To no avail, I was still having bogging and lack of power.

I week ago I pulled the air filter and the whole box, cleaned everything, including the throttle body, etc.

The last and only time I have driven it since then it was back to normal. Don't know if this helps, but its what I have been through and thought it could be useful.

 

[jfcroni]

Today I tried driving the car again. I checked the battery cables again, but they are clean and tight. The car still dies out above 3000 of so RPM. When I got back to my garage, it smelled a little like an old car. That is, that smell of poorly burned gas or poor combustion. Kind of like the smell of an old car with its choke on during warm up. Any more ideas would be appreciated. Will probably take it to the dealer next week if I can't get this resolved.

Jim

 

[NSX-Racer]

Did you get a check engine light when it happened? And, if so, did you read an error code?

 

[jfcroni]

No engine check light. When it stalls, it sounds like it's running on 3 or 4 cylinders. It can barely get itsefl out of the way. Then I sit and or restart and I can drive away at low rpm.

 

[NSX-Racer]

Mmh - I would check first the spark plugs (oiled?), maybe clean or replace them. If that doesn't help I'd let the ignition coil be checked.

 

[Briank]

If your car is going very rich I would look a the fuel presure regulator system.
At around 4000 rpm the fuel pump goes to full speed and if the regulator can't control the presure because it's bad or the return line is restricted then you will get too much fuel.

 

[mystican]

Did you check for Mice????????????????????

Any updates????

 

[hlweyl]

Very strange he would get stalling and power loss without getting any check engine lights. Does sound fuel related, maybe even o2 sensors.

 

[jfcroni]

I"m back. I did check for mice, and there are no signs of them.

1. Car starts from cold without a problem
2. Car idles perfectly
3. If I pop open the engine compartment and goose the throttle, there no indications of a problem
4.I go for a ride and goose it and at about 3000rpm it feels like I'm running out of gas
5.If I stop the car when this happens, it seems to pass and I can low speed home
6. When this happens theres a funny sound with it kind of mechanical whine
7. Belts seem OK and not slipping
8. No indicator lights
9. No other symptoms
10. Still waiting for Acura ordered fuel filter

 

[Larry Bastanza]

Check lights for these conditions for ODBI cars are far and few between.

Brian may be on to something, but at this point replacing items in hope of a fix should stop, JMO. You need to get a fuel pressure gauge on the car to see what is happening when things go south. Brian's comment about the fuel pressure is a true possiblility, and a pressure gauge will tell the story. I also would have the map sensor checked if the fuel pressure looks good. The list of "possibilities" can be pretty long.

Have a qaulified tech look at it.

HTH,
LarryB

 

[Zennsx]

Whining from the fuel pump maybey?

 

[jfcroni]

Well....the fuel filter didn't fix anything. The "funny noise" is hard to describe. It sounds like a whine with a slight click. I don't know what a failing fuel pump sounds like, and I don't have a fuel pressure gauge. But the car still looses power at or around 3300 RPM. I guess it's time to have an expert take a look. JC

 

[matteni]

IMO you are haveing problems with one or more of your coil packs. Follow the service manual proceedure and check each of your 6 coils. When they go it feels like "hesitation" when you go to full gas.

 

[jfcroni]

OK, will check coil packs. Thing is, It is more than a hesitation. It's a complete loss of power, and will hardly run unless I pull over and let it sit a few seconds. Then I can drive off at low speed. If I give it gas it immediately looses power and chugs. No warning lights, but then it may even die. But it will start right back up and sound fine. It never backfires. JC

 

[matteni]

OK, will check coil packs. Thing is, It is more than a hesitation. It's a complete loss of power, and will hardly run unless I pull over and let it sit a few seconds. Then I can drive off at low speed. If I give it gas it immediately looses power and chugs. No warning lights, but then it may even die. But it will start right back up and sound fine. It never backfires. JC

Actually - it is sounding more and more like your coil packs have/are dying!

Then again - just another opportunity for me to be wrong too.

:wink:

Please report back with what you find. I have a bet running with one of the voices in my head that swears it is a clogged fuel filter (my second guess). Even replacing a fuel filter will sometime dislodge crap in your lines or allow crap that got into your system a new filter to clog up.

 

[jfcroni]

I checked all the coil pacs today. They are all comining in at about the same resistance 1.12 to 1.18 Ohms

 

[jfcroni]

It looks like the muffler for the right side is clogged. First I thought is was mouse fur I saw blowing out of the pipe. I took the assembly apart and found fiber glass packing and a loose inner baffle. These were very good stainless muffler and pipes. I'm surprised. jc

 

[jfcroni]

The problem was a loose baffle in the muffler. Now I'll be looking for a replacement for the Supertrapp that has died. Is there a direct replacement, or do I need to go cat back with a new system?

 

[Larry Bastanza]

Great find. I would have scratched my head on that one!!!

Glad you nabbed it.

I am not familar with teh Supertrapp, so I cannot advise you.

Good Luck,
LarryB